There is neither unanimity nor clarity around the use of nanotechnology and everything that it derives from: both security and privacy and the possible risks are not calculated. [6][7][8]​.

Nanotechnology includes the study, design, creation, synthesis, manipulation and application of materials, devices and functional systems through the control of matter at the nanoscale, and the exploitation of phenomena and properties of matter at the nanoscale.

When matter is manipulated on such a tiny scale, it presents totally new phenomena and properties. Therefore, scientists use nanotechnology to create novel and inexpensive materials, devices and systems with unique properties.

However, nanoscience is a discipline dedicated to the study of physical, chemical and biological phenomena that occur at the nanometer scale.

The winner of the 1965 Nobel Prize in Physics, Richard Feynman, was the first to refer to the possibilities of nanoscience and nanotechnology in a speech he gave at Caltech (California Institute of Technology) on December 29, 1959, entitled There's Plenty of Room at the Bottom")[9]​, in which he described the possibility of synthesis via the direct manipulation of atoms. The term "nanotechnology" was first used by Norio Taniguchi in 1974, although this is not widely known.

Inspired by Feynman's concepts, K. Eric Drexler independently used the term "nanotechnology" in his 1986 book Engines of Creation: The Coming Era of Nanotechnology, in which he proposed the idea of a nanoscale "assembler" that would be able to construct a copy of itself and other elements of arbitrary complexity with a level of atomic control. Also in 1986, Drexler co-founded The Foresight Institute, with which he is no longer affiliated, to help increase public awareness and understanding of the concepts of nanotechnology and its implications.

Thus, the emergence of nanotechnology as a field in the 1980s occurred through the convergence of the theoretical and public work of Drexler, who developed and popularized a conceptual framework for nanotechnology, and high-visibility experimental advances that brought additional broad-scale attention to the prospects for atomic control of matter.

For example, the invention of the scanning scanning microscope in 1981 provided unprecedented visualization of individual atoms and bonds, and was successfully used to manipulate individual atoms in 1989. Microscope developers Gerd Binnig and Heinrich Rohrer of the IBM Zurich Research Laboratory received a Nobel Prize in Physics in 1986.[10][11] Binnig, Quate") and Gerber also invented the analogous atomic force microscope that year.

Fullerenes were discovered in 1985 by Harry Kroto, Richard Smalley and Robert Curl, who together won the 1996 Nobel Prize in Chemistry.[12][13] Initially C was not described as nanotechnology; The term was used in connection with later work with graphene tubes (called carbon nanotubes) with potential applications for nanoscale electronics and devices.

In the early 2000s, the field garnered increased scientific, political, and commercial interest that led to both controversy and progress. Controversies arose over the definitions and potential implications of nanotechnologies, exemplified by the Royal Society report on nanotechnology.[14] Challenges arose from the feasibility of the applications envisioned by proponents of molecular nanotechnology, culminating in a public debate between Drexler and Smalley in 2001 and 2003.[15]

Meanwhile, commercialization of products based on advances in nanoscale technologies began to emerge. These products are limited to bulk applications of nanomaterials and do not involve atomic control of matter. Some examples include the Nano Silver platform, which uses silver nanoparticles as an antibacterial agent, transparent nanoparticle-based sunscreens, and carbon nanotubes for stain-resistant fabrics.[16]​[17]​.

Governments moved to promote and fund nanotechnology research, starting with the United States with its National Nanotechnology Initiative, which formalized the size-based definition of nanotechnology and created a funding pool for nanoscale research.

By the mid-2000s, serious new scientific attention began to flourish. Projects emerged to produce a roadmap for nanotechnology[18]​[19]​ that focused on the precise atomic manipulation of matter and discussed existing and projected capabilities, goals, and applications.

Other people in this area were Rosalind Franklin, James Dewey Watson and Francis Crick who proposed that DNA was the main molecule that played a key role in the regulation of all the processes of the organism, revealing the importance of molecules as determinants in life processes.

But this knowledge went further, since with this it was possible to modify the structure of the molecules, as is the case of the polymers or plastics that we find in our homes today. But it must be said that these types of molecules can be considered “large.”

Nowadays, medicine has more interest in research in the microscopic world, since the structural alterations that cause diseases are possibly found there, and it goes without saying that the branches of medicine that have benefited the most, such as microbiology, immunology, physiology; New sciences have also emerged, such as Genetic Engineering, which has generated controversy about the repercussions of processes such as cloning or eugenics.

The development of nanoscience and nanotechnology in Latin America is relatively recent, compared to what has happened globally. Countries such as Mexico, Costa Rica, Argentina, Venezuela, Colombia, Brazil and Chile contribute worldwide with research work in different areas of nanoscience and nanotechnology.[20] In addition, some of these countries also have educational programs at the bachelor's, master's, postgraduate and specialization levels in the area.

Contenido

La nanotecnología es la ingeniería de sistemas funcionales a escala molecular. Esto cubre tanto el actual trabajo como conceptos que son más avanzados. En su sentido original, la nanotecnología se refiere a la habilidad proyectada para construir elementos desde lo más pequeño a lo más grande, usando técnicas y herramientas, que actualmente están siendo desarrolladas, para construir productos completos de alto desempeño.

Un nanómetro (nm) es la mil millonésima parte, o 10, de un metro. Por comparación, los típicos largos de enlaces carbono-carbono, o el espacio entre estos átomos en una molécula, están alrededor de los y la doble hélice de un ADN tiene un diámetro de alrededor de 2 nm. Por otra parte, la forma de vida celular más pequeña, la bacteria del género Mycoplasma, tienen alrededor de 200 nm de largo. Por convención, la nanotecnología es medida en el rango de escala de entre de acuerdo a la definición usada por la Iniciativa Nanotecnológica Nacional en Estados Unidos. El límite inferior está dado por el tamaño de los átomos (el hidrógeno tiene los átomos más pequeños, que tienen un radio aproximado de un veinteavo de nm conocido como radio de Bohr) dado que la nanotecnología debe fabricar sus dispositivos a partir de átomos y moléculas. El límite superior es más o menos arbitrario, pero se encuentra alrededor del tamaño en que fenómenos que no pueden ser observados en estructuras más grandes comienzan a ser aparentes y pueden ser usados en el nanodispositivo.[21]​ Estos nuevos fenómenos hacen que la nanotecnología sea distinta de los dispositivos que son meramente versiones miniaturizadas de un dispositivo macroscópico equivalente; tales dispositivos se encuentran a una escala más grande y caen bajo la descripción de microtecnología.[22]​.

Para poner la escala en otro contexto, el tamaño comparativo de un nanómetro a un metro es lo mismo que el de una roca al tamaño de la Tierra.[23]​ Otra forma de ponerlo: un nanómetro es la cantidad en que la barba de un hombre promedio crece en el tiempo al que a este le toma levantar la afeitadora a su cara.[23]​.

Se usan dos aproximaciones a la nanotecnología. En la aproximación "del fondo hacia arriba", los materiales y dispositivos son construidos a partir de componentes moleculares que se ensamblan por sí mismos químicamente por los principios del reconocimiento molecular. En la aproximación "de arriba abajo", los nano-objetos son construidos a partir de entidades más grandes con un control a nivel atómico.[24]​.

Áreas de la física tales como la duvitación nanoelectrónica, la nanomecánica"), nanofotónica y la nanoiónica") han evolucionado durante estás últimas pocas décadas para proporcionar un fundamento científico básico a la nanotecnología.

From the largest to the smallest: a perspective from the materials

Several phenomena become pronounced as the system size decreases. These include statistical mechanical effects, as well as quantum mechanical effects, for example the “quantum size effect” where the electronic properties of solids are altered with large reductions in particle size. This effect is not brought into play when going from macro dimensions to micro dimensions. However, quantum effects can become significant when the nanometer size is reached, typically at distances of 100 nanometers or less, the so-called quantum domain. Additionally, a variety of physical properties (mechanical, electrical, optical, etc.) change when compared to macroscopic systems. An example is the increase in the ratio of surface area to volume altering the mechanical, thermal and catalytic properties of the materials. Diffusion and reactions at the level On the nanoscale, the materials of nanostructures and nanodevices with rapid ion transport are generally known as nanoionic. The mechanical properties of nanosystems are of interest in nanomechanics research. The catalytic activity of nanomaterials also opens up potential risks in their interaction with biomaterials.

Materials reduced to the nanoscale can exhibit different properties when compared to those they exhibit at the macroscale, allowing for unique applications. For example, opaque substances can become transparent (copper); stable materials can become fuel (aluminum); Insoluble materials can become soluble (gold). A material such as gold, which is chemically inert at normal scales, can serve as a powerful chemical catalyst at nanoscales. Most of the fascination with nanotechnology arises from these quantum and surface phenomena that matter exhibits at the nanoscale.[25]​.

From simple to complex: a molecular perspective

Modern synthetic chemistry has reached the point where it is possible to prepare small molecules for almost any structure. These methods are used today to manufacture a wide variety of useful chemicals such as pharmaceuticals or commercial polymers. This ability raises the question of extending this kind of control to the next larger level, seeking methods to assemble these single molecules into supramolecular structures or assemblies consisting of many molecules arranged in a well-defined shape.

These approaches use the concepts of molecular self-assembly or supramolecular chemistry to automatically arrange their own structures into some useful arrangement through a bottom-up approach. The concept of molecular recognition is especially important: molecules can be designed in such a way that a specific configuration or arrangement is favored due to non-covalent intermolecular forces. The Watson-Crick base pairing rules are a direct result of this, as is the specificity of an enzyme being targeted to a single substrate "Substrate (chemistry)") or the folding of the protein itself. Thus, two or more components can be designed for complementarity and mutual attraction in such a way that they build a more complex and useful whole.

Bottom-up approaches should be able to produce devices in parallel and be much cheaper than top-down methods, but could potentially be surpassed as the size and complexity of the desired assembly increases. The most successful structures require complex and thermodynamically unlikely arrangements of atoms. However, there are many examples of self-assembly based on molecular recognition in biology, one of the most notable being Watson-Crick base pairing and enzyme-substrate interactions. The challenge for nanotechnology is to discover if these principles can be used to achieve new constructions in addition to the existing natural ones.

Molecular nanotechnology: a long-term vision

Molecular nanotechnology, sometimes called molecular manufacturing, describes manufactured nanosystems (nanoscale machines) operating at the molecular scale. Molecular nanotechnology is especially associated with the molecular assembler, a machine that can produce a desired structure or device atom by atom using the principles of mechanosynthesis. "Manufacturing in the context of productive nanosystems is not related to, and should be clearly distinguished from, conventional technologies used for the manufacture of nanomaterials such as carbon nanotubes and nanoparticles.

When the term "nanotechnology" was independently coined and popularized by Eric Drexler (who at the time was unaware of an earlier use by Norio Taniguchi) to refer to a future manufacturing technology based on molecular machine systems. The premise was that molecular-scale biological analogies of traditional machine components demonstrated that molecular machines were possible: there are countless examples in biology, it is known that sophisticated stochastically optimized biological machines can be produced.

It is hoped that developments in nanotechnology will make it possible to construct them by some other means, perhaps using principles of biomimicry. However, Drexler and other researchers[26] have proposed that an advanced nanotechnology, although perhaps initially implemented by biomimetic means, could ultimately be based on the principles of mechanical engineering, that is, a manufacturing technology based on the mechanical functionality of these components (such as gears, bearings, motors, and structural members) that would allow programmable and positional assembly to an atomic specification.[27] The physics and engineering performance of example designs were discussed in the book. Drexler called Nanosystems.

In general it is very difficult to assemble devices at the atomic scale, since one has to position atoms on top of other atoms of comparable thickness and size. Another view, expressed by Carlo Montemagno"),[28]​ is that future nanosystems will be hybrids of silica technology and biological molecular machines. Richard Smalley argues that mechanosynthesis is impossible due to difficulties in the mechanical manipulation of individual molecules.

This led to an exchange of letters between the ACS publication Chemical & Engineering News in 2003.[29] Although biology clearly demonstrates that molecular machine systems are possible, nonbiological molecular machines are currently only in their infancy. The leaders in nonbiological molecular machine research are Alex Zettl and his colleagues working at Lawrence Berkeley National Laboratory and UC Berkeley. They have built at least three different molecular devices whose movements are controlled from the desktop by changing the voltage: a nanotube nanomotor, an actuator,[30]​ and a nanoelectromechanical relaxation oscillator.[31]​.

Nanomaterials

The field of nanomaterials includes subfields that develop or study materials that have unique properties arising from their nanoscale dimensions.[34]​.

Bottom-up approach

These seek to arrange the smallest components in more complex structures.

Top down approach

These seek to create smaller devices using larger ones to control their assembly.

Functional approaches

These seek to develop components of a desired functionality regardless of how they could be assembled.

Speculative

These subfields seek to anticipate what nanotechnological inventions could achieve or attempt to propose an agenda that mandates a path along which research can progress. These often take a large-scale view of nanotechnology, with more emphasis on its social implications than on the details of how such inventions might actually be created.

There are several important modern developments. The atomic force microscope (AFM) and the scanning tunneling microscope (STM) are early versions of the scanning probes that launched nanotechnology. There are other types of scanning probe microscope. Although conceptually similar to the scanning confocal microscopes developed by Marvin Minsky in 1961 and the Scanning Acoustic Microscope (SAM) developed by Calvin Quate and associated in the 1970s, newer scanning probe microscopes have much higher resolution, since they are not limited by the wavelength of sound or light.

The tip of a scanning probe can also be used to manipulate nanostructures (a process known as positional assembly). The feature-oriented scanning methodology "suggested by Rostislav Lapshin") seems to be a promising way to implement these nanomanipulations in an automatic mode.[48]​[49]​ However, this is still a slow process due to the low scanning speed of the microscope.

Various nanolithography techniques such as optical lithography, dip-pen nanolithography (X-ray lithography, electron beam lithography) or nanoimprint lithography) were also developed. Lithography is a top-down manufacturing technique where the raw material is reduced in size to a nanoscale pattern.

Another group of nanotechnological techniques includes those used for the fabrication of nanotubes and nanowires, those used in the fabrication of semiconductors such as deep ultraviolet lithography), electron beam lithography, focused ion beam machining, nanoimprint lithography, atomic layer deposition, and molecular vapor deposition, and also including molecular self-assembly techniques such as those employing di-block copolymers. The precursors of these techniques They predate the era of nanotechnology, and are extensions in the development of scientific advances rather than techniques that were devised solely for the purpose of creating nanotechnology and that were the result of nanotechnology research.

The top-down approach anticipates nanodevices that must be built piece by piece in stages, the same way other things are made. Scanning probe microscopy is an important technique for both the characterization and synthesis of nanomaterials. Atomic force microscopes and scanning tunneling microscopes can be used to examine surfaces and move atoms on them. By designing different tips for these microscopes, they can be used to carve structures into surfaces and to help guide self-assembled structures. By using, for example, the feature-oriented scanning approach, atoms or molecules can be moved on the surface with scanning probe microscopy techniques.[48]​[49]​ Currently, it is expensive and time-consuming to be used in mass production, but they are well suited for experimentation in a laboratory.

In contrast, bottom-up techniques build or grow larger structures atom by atom or molecule by molecule. These techniques include chemical synthesis, self-assembly, and positional assembly. Dual polarization interferometry is a suitable tool for the characterization of self-assembled thin films. Another variation of the bottom-up approach is molecular beam epitaxial growth (MBE). Bell Telephone Laboratories researchers such as John R. Arthur, Alfred Y. Cho, and Art C. Gossard developed and implemented the MBE as a research tool in the late 1960s and 1970s. Samples made by the MBE were key to the discovery of the fractional quantum Hall effect for which the 1998 Nobel Prize in Physics was awarded. MBE allows scientists to arrange atomically precise layers, and in the process, build complex structures. Important for semiconductor research, MBE is also widely used to make samples and devices for the recently emerging field of spintronics.

However, new therapeutic products, based on sensitive nanomaterials, such as the ultra-deformable and tension-sensitive vesicles Transfersome"), are in development and are approved for human use in some countries.

One of the key instruments in micro and nano science are scanning probe microscopes. They basically consist of a platform and a probe that sweeps or scans the sample.

The sweep can be done by moving either the probe or the platform, using high-precision actuators. Actuators are a key factor in this technology.

The probe can be raised or lowered, resulting in a system with three coordinate axes, on the one hand an x-y scanning plane and on the other hand a z height, with which the relief or topography of the microstructures can be studied.

Not only is the geometry of the sample measured, but depending on the type of probe used, chemical, thermal, electrical or mechanical properties can also be measured, which opens a very wide window of information that allows studying the properties of nanomaterials.

Some developing countries already allocate significant resources to nanotechnology research. Nanomedicine is one of the areas that can contribute the most to the sustainable advancement of the Third World, providing new methods for diagnosing and screening diseases, better systems for drug administration, and tools for monitoring some biological parameters.

Some giants of the computing world such as IBM, Hewlett-Packard (HP), NEC and Intel are investing millions of dollars a year in the subject. The governments of the so-called First World have also taken the issue very seriously, with the clear leadership of the US government, which dedicates hundreds of millions of dollars to its National Nanotechnology Initiative.

In Spain, scientists talk about “nanobudgets”. But interest is growing, since there have been some conferences on the subject: in Seville, at the San Telmo Foundation"), on investment opportunities, and in Madrid, with a meeting between heads of nanotechnology centers from France, Germany and the United Kingdom at the Autonomous University of Madrid.

Traditional industries will be able to benefit from nanotechnology to improve their competitiveness in common sectors, such as textiles, food, footwear, automotive, construction and health. The aim is for companies belonging to traditional sectors to incorporate and apply nanotechnology in their processes in order to contribute to the sustainability of employment. Currently the figure in everyday use is 0.2%.

The fundamental characteristic of nanotechnology is that it constitutes an interdisciplinary assembly of several fields of natural sciences that are highly specialized. Therefore, physicists play an important role not only in the construction of the microscope used to investigate such phenomena, but also in all the laws of quantum mechanics. Achieving the structure of the desired material and the configurations of certain atoms makes chemistry play an important role. In medicine, the specific development directed at nanoparticles promises to help the treatment of certain diseases. Here, science has reached a point where the boundaries that separate the different disciplines have begun to blur, and it is precisely for this reason that nanotechnology also refers to being a convergent technology.

A possible list of sciences involved would be the following:

Advanced nanotechnology, sometimes also called "molecular manufacturing", is a term given to the concept of nanosystem engineering (nanometric-scale machines) operating at a molecular scale. It is based on the fact that manufactured products are made from atoms. The properties of these products depend on how those atoms are arranged. For example, if we relocate the atoms of graphite (mainly composed of carbon) from the pencil lead we can make diamonds (pure crystallized carbon). If we relocate the atoms from sand (basically composed of silica) and we add some extra elements, they make the chips of a computer.

From the countless examples found in biology it is known that billions of years of evolved feedback can produce sophisticated and stochastically optimized biological machines. It is hoped that developments in nanotechnology will make it possible to construct some shorter meanings, perhaps using biomimetic principles. However, K. Eric Drexler and other researchers have proposed that advanced nanotechnology, although perhaps initially implemented through mimetic principles, could ultimately be based on mechanical engineering principles.

Determining a set of paths forward for the development of molecular nanotechnology is a goal for the Technology Mapping Project led by Battelle Memorial Institute (the head of several US national laboratories) and the Foresigth Institute. That map should be completed by the end of 2006.

According to a report by a group of researchers from the University of Toronto, in Canada, the fifteen most promising applications of nanotechnology are:[50]​.

Textil.

Desarrollo de tejidos inteligentes: capaces de repeler manchas, ser autolimpiables, anti olores o poseer nanochips para cambiar de color y temperatura.

Agricultura.

Diseño de productos para mejorar plaguicidas, herbicidas y fertilizantes. La principal finalidad es el mejoramiento de suelos. Además, podemos incluir en esta categoría los nano sensores para la detección de agua, nitrógeno, agroquímicos, etc.

Cosmética.

Desarrollo de cremas anti-arrugas o cremas solares con nanopartículas.

Ganadería.

Desarrollo de nanopartículas con el fin de administrar vacunas o fármacos para los animales, así como destinados a detectar microorganismos, enfermedades y sustancias tóxicas.

Alimentos.

Dispositivos (nanosensores y nanochips) que funcionen principalmente como nariz y lengua electrónica, es decir, para analizar aspectos relacionados con el olfato y el gusto. Son utilizados también para detectar la frescura y vida útil de un alimento, patógenos, aditivos, fármacos, metales pesados, toxinas, contaminantes… por otro lado, otro aspecto muy desarrollado es la creación de nanoenvases, como se explicará en el siguiente apartado. Estos poseen propiedades funcionales, nutritivas, saludables y organoeléctricas (descripciones de las características físicas que tiene la materia según las pueden percibir los sentidos, como sabor, textura, olor, color o temperatura).

Nanotechnology applied to food packaging

Food preservation is an idea that comes from the beginning of human history. Since the prehistoric age, the need to improve food preservation through different techniques has been a characteristic of human behavior. Fermentation, salinization, sun drying, roasting, curing, irradiation, carbonation, and the addition of chemical and physical preservatives have been developed since the beginning of humanity. All of these methods have the same central idea. Archaeological evidence supports the idea that preservation techniques were developed in the Greek, Roman and Egyptian civilizations. However, the various methods present the challenge of maintaining the original conditions for long periods of time.

Food packaging methods aim to ensure the quality of food so that its properties remain intact. The main packaging aims to provide physical protection with the purpose of preventing food contamination with other foods or with microorganisms. Packaging materials are preferably made of biodegradable materials, with the purpose of reducing environmental pollution. This idea has been carried out thanks to the introduction of nanotechnology.

One of the applications of nanotechnology in the field of food packaging is the application of additive materials with nanoclays, which improve the mechanical, thermal, and gas barrier properties, among others, of the packaging materials. In the case of improving the gas barrier, the nanoclays create a tortuous path for the diffusion of gas molecules, which allows achieving a similar barrier with lower thicknesses, thus reducing the costs associated with the materials.

The processes of incorporation of nanoparticles can be carried out by extrusion or by coating, and the parameters to control in the additive process of the materials are: the dispersion of nanoparticles, the interaction of the nanoparticles with the matrix, the aggregations that may take place between the nanoparticles and the amount of nanoparticles incorporated.

The nanosensors help detect any change in the color of the food and helps in the detection of gases within the product. These sensors are usually sensitive to gases such as hydrogen, hydrogen sulfide, nitrogen oxide, sulfur dioxide, and ammonium. Nanosensors are devices that process data capable of detecting changes at the level of light, heat, humidity, gases, and electrical and chemical signals.[51]​.

Nanoemulsions are used to produce foods for salad dressing, flavoring oils, sweeteners and others. They help in the release of different flavors with stimulation that are related to heat, pH, ultrasound waves, etc. Nanoemulsions can retain flavors efficiently and prevent oxidation and enzymatic reactions. Nanoemulsions are created primarily through high-energy engagement with high-pressure homogenization, ultrasound methods, high-speed liquid coaxial jets, and high-speed device methods. Similarly, low energy methods involve membrane emulsification, spontaneous emulsification, solvent displacement, emulsion inversion point and through phase inversion points. Nanoemulsions are created by dispersing the liquid phase in a continuous aqueous phase. The components that are used to create nanoemulsions are of the lipophilic type.[51]​.

Nanotechnology applied to drug administration

Within the possibilities of drug administration, the possibility of using nanotechnology as a release system for the active ingredient has emerged. In general, the vehicles used to administer a drug must be of low toxicity, with optimal properties for transport and release, and a long half-life. Examples of nanosystems are: micelles, liposomes, dentrimers, nanoparticles, nanotubes and bioconjugates.[52]​.

Nanoparticles are solid colloidal particles with a size of 1 nm to 1000 nm that are used as drug delivery agents. With this, an increase in the dissolution rate and the saturation limit of solubility is achieved.[53]​ There is also a special type called solid lipid nanoparticles (SLN). These nanoparticles protect the active ingredient against chemical degradation, in addition to generating greater flexibility in modulating drug release.[54]​.

Liposomes are amphiphilic molecules, such as phospholipids, that form bilayered membrane vesicles that can lead to vesicles. Liposomes are spherical structures formed by one or more layers that contain an aqueous phase inside. Liposomes have been used to improve the therapeutic effect of very powerful drugs. This delivery system is considered to reduce toxicity.[55]​.

bioconjugates or polymeric conjugates act as carriers and as biological components (peptides, proteins, nucleotides) that act as ligands for specific therapeutic effects or targets. An example of bioconjugates with the products obtained from the addition of polyethylene glycol (PEG) to drugs or therapeutic proteins.[56]​.

dendrons or dendrimers are nanomaterials that can incorporate synthetic polymer blocks or natural components. Its hierarchical factorial structure presents numerous conjugation sites for positions or target motives.[56]​.

Inorganic nanoparticles are nanoparticles constructed from inorganic materials. The most common materials are quantum dots along with gold, silver, iron oxide or mesoporous nanoparticles. The characteristic properties of each material are size, charge, surface chemistry and structure.[56]​.

One of the first drugs in nanomedicine that was shown to be safe by the FDA was obtained by encapsulating doxorubicin within liposomes. This nanoformulation improved the pharmacokinetic and distribution characteristics of doxorubicin, leading to the prolongation of the half-life and generating an accumulation process in the tumor tissue.[57]​.

In recent years, implantable drug delivery devices have been developed. The main function of this new technology is the controlled administration of drug over several weeks to months, according to the therapeutic needs of an individual patient. Long-term therapies can help improve patient compliance and adherence to pharmacological treatments. Implantable devices use an strategy for therapeutic agents and some technologies would help control the release remotely, using radiofrequency, ultrasound energy and magnetic fields, the administrations could be activated and controlled. Despite the large number of studies reported on self-regulating medical devices and technological efforts, the benefits of this type of technology have not been proven.

Nanotechnology applied to cancer therapy

One of the most challenging aspects of existing cancer therapies is the specificity of the treatments. This could lead to reducing the toxic effects that occur after administering anticancer therapies. In addition to this possibility, the solubility and bioavailability of drugs that are poorly soluble could be improved. Due to these needs, some research has emerged that uses nanocarriers (liposomes, polymeric micelles and polymeric nanoparticles) for the preparation of new formulations that improve the bioavailability of these treatments and improve the distribution of the anticancer drug at the tumor site. Among the factors that are considered physicochemical types are the Z potential, particle size, cationic charge on the surface and solubility.[58]​.

Nanotechnology applied to HIV/AIDS therapy

Drug delivery methods applied to systemic delivery of antiviral drugs could have similar advantages to successful examples in cancer therapy. Controlled release systems could increase the half-life of drugs, maintaining plasma concentrations at therapeutic levels for longer periods of time that ultimately have impacts on the efficacy of drug therapy. Additionally, a better safety profile could be obtained that leads to better patient adherence. Specifically, the targeted distribution of antiviral drugs against CD4+ cells and macrophages, as well as the distribution to difficult-to-access organs such as the brain, which could ensure the maintenance of concentrations through the generation of latent reserves. Together with the improvement of pharmacological therapy, the idea of ​​achieving gene therapy through nanotechnology was born. Gene therapy, in which a gene is inserted into a cell to interfere with infection or replication processes, appears to be promising. There is evidence indicating that gene silencing could be a potential tool to target genes of interest. It has also been described that it could be possible to generate vaccines that are effective and safe against HIV/AIDS. It is possible to use encapsulated antigens at their core from which antigen-presenting cells can process, present and cross-present antigens to CD4+ and CD8+ cells, respectively, or absorb antigens on their surface, allowing B cells to generate a humoral response. On the other hand, immunotherapy for HIV/AIDS based on viral agents and administration of autologous dendritic cells generated ex-vivo.[59]​.

Nanotechnology applied to Alzheimer's therapy

Nanotechnology treatment methods have produced interesting results in the therapy of Alzheimer's disease. The drugs usually available for the treatment of Alzheimer's disease include drugs that are inhibitors of the enzyme acetylcholinesterase, which have poor solubility and low bioavailability. Additionally, these drugs have an inability to cross the blood-brain barrier, so improving the distribution of these drugs at the site of action is challenging at a technological level. The nanotechnologies included are polymeric nanoparticles, solid-lipid nanoparticles, lipid nanostructure carriers, microemulsion, nanoemulsion and liquid crystals. The special physicochemical characteristics of the drugs available for the treatment of Alzheimer's lead to therapeutic failure in many cases. These limitations have been overcome, in part, due to the development of intranasal administration, which favors a non-invasive alternative for the distribution of the drug at the level of the central nervous system, through passage through the blood-brain barrier.

The applications of nanotechnology in cell biology have the deoxyribonucleic acid (DNA) molecule as a challenging focus. Structural elements have been developed with a certain molecular logic to carry out therapeutic actions in a certain cell type or tissue, leading to greater specificity and reducing the undesirable effects of conventional therapies. Furthermore, DNA nanostructures can be used as a programmable binding of drugs, target ligands and other modifications or systems such as lipid bilayers. On the other hand, imaging probes with good sensitivity and specificity have been developed, which are considered DNA-based amplification mechanisms and that can be programmed to specifically interact with ribonucleic acid (RNA) sequences at the intracellular level. Another application is the generation of DNA structures that provide precise control of intracellular spatial organization, providing a basis for developing quantification systems at the subcellular level.[60] DNA nanostructures as drug delivery vehicles have been significantly developed in recent years. To this end, CpG oligodeoxynucleotides (ODNs) can trigger an innate immune response by activating Toll-like receptors of the TLR9 type. These ODNs have become an interesting therapeutic cargo because they can be integrated directly into the DNA nanostructure through hybridization. Y-shaped DNA molecules with CpG motifs have been developed that can trigger an immune response by increasing macrophage recruitment efficiency. Other findings have led to the creation of synthetic vaccine complexes by assembly of tetrahedral DNA nanostructures (TDNs) that were modified with streptavidin and CpG ODNs. In that case, streptavidin serves as a model antigen that leads the construct to generate anti-streptavidin IgG antibodies.[60]​.

Argentina

According to the Argentine Foundation of Nanotechnology (FAN), "The properties of matter change when we go from a macroscopic scale to the nanoscopic scale... At the nanoscale the intensive properties (color, melting point, density, electrical and thermal conductivity, etc.) change surprisingly, they do not depend on the amount of matter. For example, silver, which on different scales acquires different colors."[61]​.

On the other hand, nanosciences according to the School of Nanosciences and Nanotechnologies[62]​ of Argentina, unlike nanotechnologies, address the study and explanation of the fundamental and technological aspects of the physical, chemical and/or biological properties and processes that emerge in systems and materials at the nanoscale; In addition to the different techniques, calculations and tools for the manufacture and control of nanosystems.

Since the beginning of the 2000s, this technology has experienced strong growth throughout the world, based on the manufacture of a large number of products benefiting from its contributions. In this context, our country has developed an ecosystem of research groups, companies and other public and private actors that have worked and are working in that same direction.[63]​.

In March 2004, the first national workshop on nanosciences and nanotechnologies was held in the then Secretariat of Science, Technology and Productive Innovation (SECyT), and currently the Ministry of Science, Technology and Innovation.

It is in 2005 that the State announced the creation of the Argentine Nanotechnology Foundation (FAN), which is still active today and is a very important pillar in the development and production of Nanotechnology in Argentina.

Considered a general-purpose technology for its ability to offer innovations to very dissimilar industries such as medicine, food and electronics, nanotechnology has become a relevant field in the scientific and technological development of countries and Argentina is no exception. Currently, the country has 335 groups in 91 science and technology institutes that develop lines of research on the subject and, in turn, according to the survey carried out, there are 73 national companies that market products or processes with their contributions or are in the process of doing so.

The range of options is really very wide, in Argentina for example, there are companies that manufacture dental implants with bio nanomaterials, face masks with silver and copper nanoparticles, healthy foods enriched with biodegradable organic nanomaterials or sustainable inputs for agricultural production. To those actors that constitute part of the ecosystem, others join to enhance them; Among them are technological linkage units, incubators, universities and public organizations that also play a key role in its development.

Geographically, the distribution of institutions that participate in the development of nanotechnology in Argentina is concentrated in the central provinces and specifically in large cities such as Capital Federal, Córdoba "Córdoba (Argentina)"), Río Cuarto "Río Cuarto (city)"), Santa Fe "Santa Fe (Argentina)"), Rosario "Rosario (Argentina)"), Mendoza "Mendoza (Argentina)"), La Plata, Mar del Plata and White Bay. Although these are the main places, there are also institutes with their research groups and in some cases companies in the northern and southern provinces of the country, mainly in Bariloche and San Miguel de Tucumán, among other cities.[63]​.

Conventional optical microscopes, such as those we can find in the laboratories of primary and secondary educational institutions, are obsolete. Currently, there are very useful tools, high-resolution microscopes, such as the scanning electron microscope (SEM) of the University of Buenos Aires (UBA), which allows us to visualize nanometric systems, such as Cu20 (copper dioxide) nanoparticles used in the agronomist sector as a fungicide.

Argentina currently has an increase in instruments and applications of nanotechnology, where 60% of R&D is carried out by research groups in institutes and centers that are found in science and technology organizations or in universities, mostly public and some private.[64]​.

Already in 2011, the Laboratory of Electron Microscopy and Analysis by X-rays (LAMARX)&action=edit&redlink=1 "Laboratory of Electron Microscopy and Analysis by Astronomy, Physics and Computing (National University of Córdoba)"), belonging to the National University of Córdoba (UNC).[65]​.

Currently, there is also, among others, the Nanofab,[66]​ a laboratory for advice, incubation and public equipment services that has the participation of more than 25 institutions.

The applications of nanotechnology and nanomaterials cover all types of industrial sectors. In Argentina some of these are:

Environment: According to the FAN "Nanotek S.A.[67]​ proposes the use of zero-valent iron nanoparticles in underground layers for the absorption of arsenic, a substance that affects a large part of the national territory (16 provinces, 435,000 km and 2.5 million inhabitants) and involves an outlay of 14 million dollars for the budget of the public health area."

Biomedicine: The pandemic generated by Covid-19 (SARS-CoV-2) led to the creation and improvements of face masks, again using technologies developed by Nanotek S.A. which indicate that these masks: “They have silver nanoparticles that release positive ions, capable of altering the biological processes of microorganisms.”[68]​.

Energy: There are 22 groups in Argentina aimed at producing new materials with greater efficiency for use in the energy sector, for example in the components of wind mills (improve their resistance and reduce their weight) and solar panels (semiconductors capable of capturing more solar energy).[69]​.

For its part, in the legislative field the European Commission provides a possible definition of nanomaterials based on their size[70][71]​(without taking into account the risk they may pose). However, it is really difficult to draw the line for their identification once incorporated into the final products. On the other hand, the production and import of this type of materials depend on the chemical compounds that form them, since all of them must be included in REACH. In addition, rigorous labeling and packaging techniques are required for these nanomaterials (especially if they contain hazardous substances, in which case the CLP must be notified); as well as the provision of an action protocol to guarantee their safe use. Despite everything, the legislative implications are tremendously broad as it is a discipline that covers so many scientific fields, and issues such as[72]​health law, market regulation or data protection remain pending.

As for ethical considerations, these have been discussed since 2003, at the meeting held in December by COMEST (an administrative body of UNESCO) in Rio de Janeiro. Three years later, at the meeting held in Dakar, a more detailed document was prepared in this regard, which are the well-known “COMEST Recommendations on Nanotechnology and Ethics Policies”.[73]​ This document talks, among other things, about:

However, despite all the debate and the apparent fragility of the legislative and ethical mechanisms, today there are hundreds of products that incorporate this type of technology on the market, especially medicines and cosmetics. This situation is wonderfully reflected in the article “Ethics and the development of Nanotechnology”,[74]​ in which Hugh Lacey alludes to the fact that the context of the development of nanotechnology is really similar to that of transgenic products at the time, that is, guided mainly by economic benefit (and the more immediate, the better). On the other hand, the ethical debate on issues such as the risks that these technologies could entail or the potential beneficiaries remains in the background, because it would imply delaying scientific progress and the possibility of falling behind technologically.

There is neither unanimity nor clarity around the use of nanotechnology and everything that it derives from: both security and privacy and the possible risks are not calculated. [6][7][8]​.

Nanotechnology includes the study, design, creation, synthesis, manipulation and application of materials, devices and functional systems through the control of matter at the nanoscale, and the exploitation of phenomena and properties of matter at the nanoscale.

When matter is manipulated on such a tiny scale, it presents totally new phenomena and properties. Therefore, scientists use nanotechnology to create novel and inexpensive materials, devices and systems with unique properties.

However, nanoscience is a discipline dedicated to the study of physical, chemical and biological phenomena that occur at the nanometer scale.

The winner of the 1965 Nobel Prize in Physics, Richard Feynman, was the first to refer to the possibilities of nanoscience and nanotechnology in a speech he gave at Caltech (California Institute of Technology) on December 29, 1959, entitled There's Plenty of Room at the Bottom")[9]​, in which he described the possibility of synthesis via the direct manipulation of atoms. The term "nanotechnology" was first used by Norio Taniguchi in 1974, although this is not widely known.

Inspired by Feynman's concepts, K. Eric Drexler independently used the term "nanotechnology" in his 1986 book Engines of Creation: The Coming Era of Nanotechnology, in which he proposed the idea of a nanoscale "assembler" that would be able to construct a copy of itself and other elements of arbitrary complexity with a level of atomic control. Also in 1986, Drexler co-founded The Foresight Institute, with which he is no longer affiliated, to help increase public awareness and understanding of the concepts of nanotechnology and its implications.

Thus, the emergence of nanotechnology as a field in the 1980s occurred through the convergence of the theoretical and public work of Drexler, who developed and popularized a conceptual framework for nanotechnology, and high-visibility experimental advances that brought additional broad-scale attention to the prospects for atomic control of matter.

For example, the invention of the scanning scanning microscope in 1981 provided unprecedented visualization of individual atoms and bonds, and was successfully used to manipulate individual atoms in 1989. Microscope developers Gerd Binnig and Heinrich Rohrer of the IBM Zurich Research Laboratory received a Nobel Prize in Physics in 1986.[10][11] Binnig, Quate") and Gerber also invented the analogous atomic force microscope that year.

Fullerenes were discovered in 1985 by Harry Kroto, Richard Smalley and Robert Curl, who together won the 1996 Nobel Prize in Chemistry.[12][13] Initially C was not described as nanotechnology; The term was used in connection with later work with graphene tubes (called carbon nanotubes) with potential applications for nanoscale electronics and devices.

In the early 2000s, the field garnered increased scientific, political, and commercial interest that led to both controversy and progress. Controversies arose over the definitions and potential implications of nanotechnologies, exemplified by the Royal Society report on nanotechnology.[14] Challenges arose from the feasibility of the applications envisioned by proponents of molecular nanotechnology, culminating in a public debate between Drexler and Smalley in 2001 and 2003.[15]

Meanwhile, commercialization of products based on advances in nanoscale technologies began to emerge. These products are limited to bulk applications of nanomaterials and do not involve atomic control of matter. Some examples include the Nano Silver platform, which uses silver nanoparticles as an antibacterial agent, transparent nanoparticle-based sunscreens, and carbon nanotubes for stain-resistant fabrics.[16]​[17]​.

Governments moved to promote and fund nanotechnology research, starting with the United States with its National Nanotechnology Initiative, which formalized the size-based definition of nanotechnology and created a funding pool for nanoscale research.

By the mid-2000s, serious new scientific attention began to flourish. Projects emerged to produce a roadmap for nanotechnology[18]​[19]​ that focused on the precise atomic manipulation of matter and discussed existing and projected capabilities, goals, and applications.

Other people in this area were Rosalind Franklin, James Dewey Watson and Francis Crick who proposed that DNA was the main molecule that played a key role in the regulation of all the processes of the organism, revealing the importance of molecules as determinants in life processes.

But this knowledge went further, since with this it was possible to modify the structure of the molecules, as is the case of the polymers or plastics that we find in our homes today. But it must be said that these types of molecules can be considered “large.”

Nowadays, medicine has more interest in research in the microscopic world, since the structural alterations that cause diseases are possibly found there, and it goes without saying that the branches of medicine that have benefited the most, such as microbiology, immunology, physiology; New sciences have also emerged, such as Genetic Engineering, which has generated controversy about the repercussions of processes such as cloning or eugenics.

The development of nanoscience and nanotechnology in Latin America is relatively recent, compared to what has happened globally. Countries such as Mexico, Costa Rica, Argentina, Venezuela, Colombia, Brazil and Chile contribute worldwide with research work in different areas of nanoscience and nanotechnology.[20] In addition, some of these countries also have educational programs at the bachelor's, master's, postgraduate and specialization levels in the area.

Contenido

La nanotecnología es la ingeniería de sistemas funcionales a escala molecular. Esto cubre tanto el actual trabajo como conceptos que son más avanzados. En su sentido original, la nanotecnología se refiere a la habilidad proyectada para construir elementos desde lo más pequeño a lo más grande, usando técnicas y herramientas, que actualmente están siendo desarrolladas, para construir productos completos de alto desempeño.

Un nanómetro (nm) es la mil millonésima parte, o 10, de un metro. Por comparación, los típicos largos de enlaces carbono-carbono, o el espacio entre estos átomos en una molécula, están alrededor de los y la doble hélice de un ADN tiene un diámetro de alrededor de 2 nm. Por otra parte, la forma de vida celular más pequeña, la bacteria del género Mycoplasma, tienen alrededor de 200 nm de largo. Por convención, la nanotecnología es medida en el rango de escala de entre de acuerdo a la definición usada por la Iniciativa Nanotecnológica Nacional en Estados Unidos. El límite inferior está dado por el tamaño de los átomos (el hidrógeno tiene los átomos más pequeños, que tienen un radio aproximado de un veinteavo de nm conocido como radio de Bohr) dado que la nanotecnología debe fabricar sus dispositivos a partir de átomos y moléculas. El límite superior es más o menos arbitrario, pero se encuentra alrededor del tamaño en que fenómenos que no pueden ser observados en estructuras más grandes comienzan a ser aparentes y pueden ser usados en el nanodispositivo.[21]​ Estos nuevos fenómenos hacen que la nanotecnología sea distinta de los dispositivos que son meramente versiones miniaturizadas de un dispositivo macroscópico equivalente; tales dispositivos se encuentran a una escala más grande y caen bajo la descripción de microtecnología.[22]​.

Para poner la escala en otro contexto, el tamaño comparativo de un nanómetro a un metro es lo mismo que el de una roca al tamaño de la Tierra.[23]​ Otra forma de ponerlo: un nanómetro es la cantidad en que la barba de un hombre promedio crece en el tiempo al que a este le toma levantar la afeitadora a su cara.[23]​.

Se usan dos aproximaciones a la nanotecnología. En la aproximación "del fondo hacia arriba", los materiales y dispositivos son construidos a partir de componentes moleculares que se ensamblan por sí mismos químicamente por los principios del reconocimiento molecular. En la aproximación "de arriba abajo", los nano-objetos son construidos a partir de entidades más grandes con un control a nivel atómico.[24]​.

Áreas de la física tales como la duvitación nanoelectrónica, la nanomecánica"), nanofotónica y la nanoiónica") han evolucionado durante estás últimas pocas décadas para proporcionar un fundamento científico básico a la nanotecnología.

From the largest to the smallest: a perspective from the materials

Several phenomena become pronounced as the system size decreases. These include statistical mechanical effects, as well as quantum mechanical effects, for example the “quantum size effect” where the electronic properties of solids are altered with large reductions in particle size. This effect is not brought into play when going from macro dimensions to micro dimensions. However, quantum effects can become significant when the nanometer size is reached, typically at distances of 100 nanometers or less, the so-called quantum domain. Additionally, a variety of physical properties (mechanical, electrical, optical, etc.) change when compared to macroscopic systems. An example is the increase in the ratio of surface area to volume altering the mechanical, thermal and catalytic properties of the materials. Diffusion and reactions at the level On the nanoscale, the materials of nanostructures and nanodevices with rapid ion transport are generally known as nanoionic. The mechanical properties of nanosystems are of interest in nanomechanics research. The catalytic activity of nanomaterials also opens up potential risks in their interaction with biomaterials.

Materials reduced to the nanoscale can exhibit different properties when compared to those they exhibit at the macroscale, allowing for unique applications. For example, opaque substances can become transparent (copper); stable materials can become fuel (aluminum); Insoluble materials can become soluble (gold). A material such as gold, which is chemically inert at normal scales, can serve as a powerful chemical catalyst at nanoscales. Most of the fascination with nanotechnology arises from these quantum and surface phenomena that matter exhibits at the nanoscale.[25]​.

From simple to complex: a molecular perspective

Modern synthetic chemistry has reached the point where it is possible to prepare small molecules for almost any structure. These methods are used today to manufacture a wide variety of useful chemicals such as pharmaceuticals or commercial polymers. This ability raises the question of extending this kind of control to the next larger level, seeking methods to assemble these single molecules into supramolecular structures or assemblies consisting of many molecules arranged in a well-defined shape.

These approaches use the concepts of molecular self-assembly or supramolecular chemistry to automatically arrange their own structures into some useful arrangement through a bottom-up approach. The concept of molecular recognition is especially important: molecules can be designed in such a way that a specific configuration or arrangement is favored due to non-covalent intermolecular forces. The Watson-Crick base pairing rules are a direct result of this, as is the specificity of an enzyme being targeted to a single substrate "Substrate (chemistry)") or the folding of the protein itself. Thus, two or more components can be designed for complementarity and mutual attraction in such a way that they build a more complex and useful whole.

Bottom-up approaches should be able to produce devices in parallel and be much cheaper than top-down methods, but could potentially be surpassed as the size and complexity of the desired assembly increases. The most successful structures require complex and thermodynamically unlikely arrangements of atoms. However, there are many examples of self-assembly based on molecular recognition in biology, one of the most notable being Watson-Crick base pairing and enzyme-substrate interactions. The challenge for nanotechnology is to discover if these principles can be used to achieve new constructions in addition to the existing natural ones.

Molecular nanotechnology: a long-term vision

Molecular nanotechnology, sometimes called molecular manufacturing, describes manufactured nanosystems (nanoscale machines) operating at the molecular scale. Molecular nanotechnology is especially associated with the molecular assembler, a machine that can produce a desired structure or device atom by atom using the principles of mechanosynthesis. "Manufacturing in the context of productive nanosystems is not related to, and should be clearly distinguished from, conventional technologies used for the manufacture of nanomaterials such as carbon nanotubes and nanoparticles.

When the term "nanotechnology" was independently coined and popularized by Eric Drexler (who at the time was unaware of an earlier use by Norio Taniguchi) to refer to a future manufacturing technology based on molecular machine systems. The premise was that molecular-scale biological analogies of traditional machine components demonstrated that molecular machines were possible: there are countless examples in biology, it is known that sophisticated stochastically optimized biological machines can be produced.

It is hoped that developments in nanotechnology will make it possible to construct them by some other means, perhaps using principles of biomimicry. However, Drexler and other researchers[26] have proposed that an advanced nanotechnology, although perhaps initially implemented by biomimetic means, could ultimately be based on the principles of mechanical engineering, that is, a manufacturing technology based on the mechanical functionality of these components (such as gears, bearings, motors, and structural members) that would allow programmable and positional assembly to an atomic specification.[27] The physics and engineering performance of example designs were discussed in the book. Drexler called Nanosystems.

In general it is very difficult to assemble devices at the atomic scale, since one has to position atoms on top of other atoms of comparable thickness and size. Another view, expressed by Carlo Montemagno"),[28]​ is that future nanosystems will be hybrids of silica technology and biological molecular machines. Richard Smalley argues that mechanosynthesis is impossible due to difficulties in the mechanical manipulation of individual molecules.

This led to an exchange of letters between the ACS publication Chemical & Engineering News in 2003.[29] Although biology clearly demonstrates that molecular machine systems are possible, nonbiological molecular machines are currently only in their infancy. The leaders in nonbiological molecular machine research are Alex Zettl and his colleagues working at Lawrence Berkeley National Laboratory and UC Berkeley. They have built at least three different molecular devices whose movements are controlled from the desktop by changing the voltage: a nanotube nanomotor, an actuator,[30]​ and a nanoelectromechanical relaxation oscillator.[31]​.

Nanomaterials

The field of nanomaterials includes subfields that develop or study materials that have unique properties arising from their nanoscale dimensions.[34]​.

Bottom-up approach

These seek to arrange the smallest components in more complex structures.

Top down approach

These seek to create smaller devices using larger ones to control their assembly.

Functional approaches

These seek to develop components of a desired functionality regardless of how they could be assembled.

Speculative

These subfields seek to anticipate what nanotechnological inventions could achieve or attempt to propose an agenda that mandates a path along which research can progress. These often take a large-scale view of nanotechnology, with more emphasis on its social implications than on the details of how such inventions might actually be created.

There are several important modern developments. The atomic force microscope (AFM) and the scanning tunneling microscope (STM) are early versions of the scanning probes that launched nanotechnology. There are other types of scanning probe microscope. Although conceptually similar to the scanning confocal microscopes developed by Marvin Minsky in 1961 and the Scanning Acoustic Microscope (SAM) developed by Calvin Quate and associated in the 1970s, newer scanning probe microscopes have much higher resolution, since they are not limited by the wavelength of sound or light.

The tip of a scanning probe can also be used to manipulate nanostructures (a process known as positional assembly). The feature-oriented scanning methodology "suggested by Rostislav Lapshin") seems to be a promising way to implement these nanomanipulations in an automatic mode.[48]​[49]​ However, this is still a slow process due to the low scanning speed of the microscope.

Various nanolithography techniques such as optical lithography, dip-pen nanolithography (X-ray lithography, electron beam lithography) or nanoimprint lithography) were also developed. Lithography is a top-down manufacturing technique where the raw material is reduced in size to a nanoscale pattern.

Another group of nanotechnological techniques includes those used for the fabrication of nanotubes and nanowires, those used in the fabrication of semiconductors such as deep ultraviolet lithography), electron beam lithography, focused ion beam machining, nanoimprint lithography, atomic layer deposition, and molecular vapor deposition, and also including molecular self-assembly techniques such as those employing di-block copolymers. The precursors of these techniques They predate the era of nanotechnology, and are extensions in the development of scientific advances rather than techniques that were devised solely for the purpose of creating nanotechnology and that were the result of nanotechnology research.

The top-down approach anticipates nanodevices that must be built piece by piece in stages, the same way other things are made. Scanning probe microscopy is an important technique for both the characterization and synthesis of nanomaterials. Atomic force microscopes and scanning tunneling microscopes can be used to examine surfaces and move atoms on them. By designing different tips for these microscopes, they can be used to carve structures into surfaces and to help guide self-assembled structures. By using, for example, the feature-oriented scanning approach, atoms or molecules can be moved on the surface with scanning probe microscopy techniques.[48]​[49]​ Currently, it is expensive and time-consuming to be used in mass production, but they are well suited for experimentation in a laboratory.

In contrast, bottom-up techniques build or grow larger structures atom by atom or molecule by molecule. These techniques include chemical synthesis, self-assembly, and positional assembly. Dual polarization interferometry is a suitable tool for the characterization of self-assembled thin films. Another variation of the bottom-up approach is molecular beam epitaxial growth (MBE). Bell Telephone Laboratories researchers such as John R. Arthur, Alfred Y. Cho, and Art C. Gossard developed and implemented the MBE as a research tool in the late 1960s and 1970s. Samples made by the MBE were key to the discovery of the fractional quantum Hall effect for which the 1998 Nobel Prize in Physics was awarded. MBE allows scientists to arrange atomically precise layers, and in the process, build complex structures. Important for semiconductor research, MBE is also widely used to make samples and devices for the recently emerging field of spintronics.

However, new therapeutic products, based on sensitive nanomaterials, such as the ultra-deformable and tension-sensitive vesicles Transfersome"), are in development and are approved for human use in some countries.

One of the key instruments in micro and nano science are scanning probe microscopes. They basically consist of a platform and a probe that sweeps or scans the sample.

The sweep can be done by moving either the probe or the platform, using high-precision actuators. Actuators are a key factor in this technology.

The probe can be raised or lowered, resulting in a system with three coordinate axes, on the one hand an x-y scanning plane and on the other hand a z height, with which the relief or topography of the microstructures can be studied.

Not only is the geometry of the sample measured, but depending on the type of probe used, chemical, thermal, electrical or mechanical properties can also be measured, which opens a very wide window of information that allows studying the properties of nanomaterials.

Some developing countries already allocate significant resources to nanotechnology research. Nanomedicine is one of the areas that can contribute the most to the sustainable advancement of the Third World, providing new methods for diagnosing and screening diseases, better systems for drug administration, and tools for monitoring some biological parameters.

Some giants of the computing world such as IBM, Hewlett-Packard (HP), NEC and Intel are investing millions of dollars a year in the subject. The governments of the so-called First World have also taken the issue very seriously, with the clear leadership of the US government, which dedicates hundreds of millions of dollars to its National Nanotechnology Initiative.

In Spain, scientists talk about “nanobudgets”. But interest is growing, since there have been some conferences on the subject: in Seville, at the San Telmo Foundation"), on investment opportunities, and in Madrid, with a meeting between heads of nanotechnology centers from France, Germany and the United Kingdom at the Autonomous University of Madrid.

Traditional industries will be able to benefit from nanotechnology to improve their competitiveness in common sectors, such as textiles, food, footwear, automotive, construction and health. The aim is for companies belonging to traditional sectors to incorporate and apply nanotechnology in their processes in order to contribute to the sustainability of employment. Currently the figure in everyday use is 0.2%.

The fundamental characteristic of nanotechnology is that it constitutes an interdisciplinary assembly of several fields of natural sciences that are highly specialized. Therefore, physicists play an important role not only in the construction of the microscope used to investigate such phenomena, but also in all the laws of quantum mechanics. Achieving the structure of the desired material and the configurations of certain atoms makes chemistry play an important role. In medicine, the specific development directed at nanoparticles promises to help the treatment of certain diseases. Here, science has reached a point where the boundaries that separate the different disciplines have begun to blur, and it is precisely for this reason that nanotechnology also refers to being a convergent technology.

A possible list of sciences involved would be the following:

Advanced nanotechnology, sometimes also called "molecular manufacturing", is a term given to the concept of nanosystem engineering (nanometric-scale machines) operating at a molecular scale. It is based on the fact that manufactured products are made from atoms. The properties of these products depend on how those atoms are arranged. For example, if we relocate the atoms of graphite (mainly composed of carbon) from the pencil lead we can make diamonds (pure crystallized carbon). If we relocate the atoms from sand (basically composed of silica) and we add some extra elements, they make the chips of a computer.

From the countless examples found in biology it is known that billions of years of evolved feedback can produce sophisticated and stochastically optimized biological machines. It is hoped that developments in nanotechnology will make it possible to construct some shorter meanings, perhaps using biomimetic principles. However, K. Eric Drexler and other researchers have proposed that advanced nanotechnology, although perhaps initially implemented through mimetic principles, could ultimately be based on mechanical engineering principles.

Determining a set of paths forward for the development of molecular nanotechnology is a goal for the Technology Mapping Project led by Battelle Memorial Institute (the head of several US national laboratories) and the Foresigth Institute. That map should be completed by the end of 2006.

According to a report by a group of researchers from the University of Toronto, in Canada, the fifteen most promising applications of nanotechnology are:[50]​.

Textil.

Desarrollo de tejidos inteligentes: capaces de repeler manchas, ser autolimpiables, anti olores o poseer nanochips para cambiar de color y temperatura.

Agricultura.

Diseño de productos para mejorar plaguicidas, herbicidas y fertilizantes. La principal finalidad es el mejoramiento de suelos. Además, podemos incluir en esta categoría los nano sensores para la detección de agua, nitrógeno, agroquímicos, etc.

Cosmética.

Desarrollo de cremas anti-arrugas o cremas solares con nanopartículas.

Ganadería.

Desarrollo de nanopartículas con el fin de administrar vacunas o fármacos para los animales, así como destinados a detectar microorganismos, enfermedades y sustancias tóxicas.

Alimentos.

Dispositivos (nanosensores y nanochips) que funcionen principalmente como nariz y lengua electrónica, es decir, para analizar aspectos relacionados con el olfato y el gusto. Son utilizados también para detectar la frescura y vida útil de un alimento, patógenos, aditivos, fármacos, metales pesados, toxinas, contaminantes… por otro lado, otro aspecto muy desarrollado es la creación de nanoenvases, como se explicará en el siguiente apartado. Estos poseen propiedades funcionales, nutritivas, saludables y organoeléctricas (descripciones de las características físicas que tiene la materia según las pueden percibir los sentidos, como sabor, textura, olor, color o temperatura).

Nanotechnology applied to food packaging

Food preservation is an idea that comes from the beginning of human history. Since the prehistoric age, the need to improve food preservation through different techniques has been a characteristic of human behavior. Fermentation, salinization, sun drying, roasting, curing, irradiation, carbonation, and the addition of chemical and physical preservatives have been developed since the beginning of humanity. All of these methods have the same central idea. Archaeological evidence supports the idea that preservation techniques were developed in the Greek, Roman and Egyptian civilizations. However, the various methods present the challenge of maintaining the original conditions for long periods of time.

Food packaging methods aim to ensure the quality of food so that its properties remain intact. The main packaging aims to provide physical protection with the purpose of preventing food contamination with other foods or with microorganisms. Packaging materials are preferably made of biodegradable materials, with the purpose of reducing environmental pollution. This idea has been carried out thanks to the introduction of nanotechnology.

One of the applications of nanotechnology in the field of food packaging is the application of additive materials with nanoclays, which improve the mechanical, thermal, and gas barrier properties, among others, of the packaging materials. In the case of improving the gas barrier, the nanoclays create a tortuous path for the diffusion of gas molecules, which allows achieving a similar barrier with lower thicknesses, thus reducing the costs associated with the materials.

The processes of incorporation of nanoparticles can be carried out by extrusion or by coating, and the parameters to control in the additive process of the materials are: the dispersion of nanoparticles, the interaction of the nanoparticles with the matrix, the aggregations that may take place between the nanoparticles and the amount of nanoparticles incorporated.

The nanosensors help detect any change in the color of the food and helps in the detection of gases within the product. These sensors are usually sensitive to gases such as hydrogen, hydrogen sulfide, nitrogen oxide, sulfur dioxide, and ammonium. Nanosensors are devices that process data capable of detecting changes at the level of light, heat, humidity, gases, and electrical and chemical signals.[51]​.

Nanoemulsions are used to produce foods for salad dressing, flavoring oils, sweeteners and others. They help in the release of different flavors with stimulation that are related to heat, pH, ultrasound waves, etc. Nanoemulsions can retain flavors efficiently and prevent oxidation and enzymatic reactions. Nanoemulsions are created primarily through high-energy engagement with high-pressure homogenization, ultrasound methods, high-speed liquid coaxial jets, and high-speed device methods. Similarly, low energy methods involve membrane emulsification, spontaneous emulsification, solvent displacement, emulsion inversion point and through phase inversion points. Nanoemulsions are created by dispersing the liquid phase in a continuous aqueous phase. The components that are used to create nanoemulsions are of the lipophilic type.[51]​.

Nanotechnology applied to drug administration

Within the possibilities of drug administration, the possibility of using nanotechnology as a release system for the active ingredient has emerged. In general, the vehicles used to administer a drug must be of low toxicity, with optimal properties for transport and release, and a long half-life. Examples of nanosystems are: micelles, liposomes, dentrimers, nanoparticles, nanotubes and bioconjugates.[52]​.

Nanoparticles are solid colloidal particles with a size of 1 nm to 1000 nm that are used as drug delivery agents. With this, an increase in the dissolution rate and the saturation limit of solubility is achieved.[53]​ There is also a special type called solid lipid nanoparticles (SLN). These nanoparticles protect the active ingredient against chemical degradation, in addition to generating greater flexibility in modulating drug release.[54]​.

Liposomes are amphiphilic molecules, such as phospholipids, that form bilayered membrane vesicles that can lead to vesicles. Liposomes are spherical structures formed by one or more layers that contain an aqueous phase inside. Liposomes have been used to improve the therapeutic effect of very powerful drugs. This delivery system is considered to reduce toxicity.[55]​.

bioconjugates or polymeric conjugates act as carriers and as biological components (peptides, proteins, nucleotides) that act as ligands for specific therapeutic effects or targets. An example of bioconjugates with the products obtained from the addition of polyethylene glycol (PEG) to drugs or therapeutic proteins.[56]​.

dendrons or dendrimers are nanomaterials that can incorporate synthetic polymer blocks or natural components. Its hierarchical factorial structure presents numerous conjugation sites for positions or target motives.[56]​.

Inorganic nanoparticles are nanoparticles constructed from inorganic materials. The most common materials are quantum dots along with gold, silver, iron oxide or mesoporous nanoparticles. The characteristic properties of each material are size, charge, surface chemistry and structure.[56]​.

One of the first drugs in nanomedicine that was shown to be safe by the FDA was obtained by encapsulating doxorubicin within liposomes. This nanoformulation improved the pharmacokinetic and distribution characteristics of doxorubicin, leading to the prolongation of the half-life and generating an accumulation process in the tumor tissue.[57]​.

In recent years, implantable drug delivery devices have been developed. The main function of this new technology is the controlled administration of drug over several weeks to months, according to the therapeutic needs of an individual patient. Long-term therapies can help improve patient compliance and adherence to pharmacological treatments. Implantable devices use an strategy for therapeutic agents and some technologies would help control the release remotely, using radiofrequency, ultrasound energy and magnetic fields, the administrations could be activated and controlled. Despite the large number of studies reported on self-regulating medical devices and technological efforts, the benefits of this type of technology have not been proven.

Nanotechnology applied to cancer therapy

One of the most challenging aspects of existing cancer therapies is the specificity of the treatments. This could lead to reducing the toxic effects that occur after administering anticancer therapies. In addition to this possibility, the solubility and bioavailability of drugs that are poorly soluble could be improved. Due to these needs, some research has emerged that uses nanocarriers (liposomes, polymeric micelles and polymeric nanoparticles) for the preparation of new formulations that improve the bioavailability of these treatments and improve the distribution of the anticancer drug at the tumor site. Among the factors that are considered physicochemical types are the Z potential, particle size, cationic charge on the surface and solubility.[58]​.

Nanotechnology applied to HIV/AIDS therapy

Drug delivery methods applied to systemic delivery of antiviral drugs could have similar advantages to successful examples in cancer therapy. Controlled release systems could increase the half-life of drugs, maintaining plasma concentrations at therapeutic levels for longer periods of time that ultimately have impacts on the efficacy of drug therapy. Additionally, a better safety profile could be obtained that leads to better patient adherence. Specifically, the targeted distribution of antiviral drugs against CD4+ cells and macrophages, as well as the distribution to difficult-to-access organs such as the brain, which could ensure the maintenance of concentrations through the generation of latent reserves. Together with the improvement of pharmacological therapy, the idea of ​​achieving gene therapy through nanotechnology was born. Gene therapy, in which a gene is inserted into a cell to interfere with infection or replication processes, appears to be promising. There is evidence indicating that gene silencing could be a potential tool to target genes of interest. It has also been described that it could be possible to generate vaccines that are effective and safe against HIV/AIDS. It is possible to use encapsulated antigens at their core from which antigen-presenting cells can process, present and cross-present antigens to CD4+ and CD8+ cells, respectively, or absorb antigens on their surface, allowing B cells to generate a humoral response. On the other hand, immunotherapy for HIV/AIDS based on viral agents and administration of autologous dendritic cells generated ex-vivo.[59]​.

Nanotechnology applied to Alzheimer's therapy

Nanotechnology treatment methods have produced interesting results in the therapy of Alzheimer's disease. The drugs usually available for the treatment of Alzheimer's disease include drugs that are inhibitors of the enzyme acetylcholinesterase, which have poor solubility and low bioavailability. Additionally, these drugs have an inability to cross the blood-brain barrier, so improving the distribution of these drugs at the site of action is challenging at a technological level. The nanotechnologies included are polymeric nanoparticles, solid-lipid nanoparticles, lipid nanostructure carriers, microemulsion, nanoemulsion and liquid crystals. The special physicochemical characteristics of the drugs available for the treatment of Alzheimer's lead to therapeutic failure in many cases. These limitations have been overcome, in part, due to the development of intranasal administration, which favors a non-invasive alternative for the distribution of the drug at the level of the central nervous system, through passage through the blood-brain barrier.

The applications of nanotechnology in cell biology have the deoxyribonucleic acid (DNA) molecule as a challenging focus. Structural elements have been developed with a certain molecular logic to carry out therapeutic actions in a certain cell type or tissue, leading to greater specificity and reducing the undesirable effects of conventional therapies. Furthermore, DNA nanostructures can be used as a programmable binding of drugs, target ligands and other modifications or systems such as lipid bilayers. On the other hand, imaging probes with good sensitivity and specificity have been developed, which are considered DNA-based amplification mechanisms and that can be programmed to specifically interact with ribonucleic acid (RNA) sequences at the intracellular level. Another application is the generation of DNA structures that provide precise control of intracellular spatial organization, providing a basis for developing quantification systems at the subcellular level.[60] DNA nanostructures as drug delivery vehicles have been significantly developed in recent years. To this end, CpG oligodeoxynucleotides (ODNs) can trigger an innate immune response by activating Toll-like receptors of the TLR9 type. These ODNs have become an interesting therapeutic cargo because they can be integrated directly into the DNA nanostructure through hybridization. Y-shaped DNA molecules with CpG motifs have been developed that can trigger an immune response by increasing macrophage recruitment efficiency. Other findings have led to the creation of synthetic vaccine complexes by assembly of tetrahedral DNA nanostructures (TDNs) that were modified with streptavidin and CpG ODNs. In that case, streptavidin serves as a model antigen that leads the construct to generate anti-streptavidin IgG antibodies.[60]​.

Argentina

According to the Argentine Foundation of Nanotechnology (FAN), "The properties of matter change when we go from a macroscopic scale to the nanoscopic scale... At the nanoscale the intensive properties (color, melting point, density, electrical and thermal conductivity, etc.) change surprisingly, they do not depend on the amount of matter. For example, silver, which on different scales acquires different colors."[61]​.

On the other hand, nanosciences according to the School of Nanosciences and Nanotechnologies[62]​ of Argentina, unlike nanotechnologies, address the study and explanation of the fundamental and technological aspects of the physical, chemical and/or biological properties and processes that emerge in systems and materials at the nanoscale; In addition to the different techniques, calculations and tools for the manufacture and control of nanosystems.

Since the beginning of the 2000s, this technology has experienced strong growth throughout the world, based on the manufacture of a large number of products benefiting from its contributions. In this context, our country has developed an ecosystem of research groups, companies and other public and private actors that have worked and are working in that same direction.[63]​.

In March 2004, the first national workshop on nanosciences and nanotechnologies was held in the then Secretariat of Science, Technology and Productive Innovation (SECyT), and currently the Ministry of Science, Technology and Innovation.

It is in 2005 that the State announced the creation of the Argentine Nanotechnology Foundation (FAN), which is still active today and is a very important pillar in the development and production of Nanotechnology in Argentina.

Considered a general-purpose technology for its ability to offer innovations to very dissimilar industries such as medicine, food and electronics, nanotechnology has become a relevant field in the scientific and technological development of countries and Argentina is no exception. Currently, the country has 335 groups in 91 science and technology institutes that develop lines of research on the subject and, in turn, according to the survey carried out, there are 73 national companies that market products or processes with their contributions or are in the process of doing so.

The range of options is really very wide, in Argentina for example, there are companies that manufacture dental implants with bio nanomaterials, face masks with silver and copper nanoparticles, healthy foods enriched with biodegradable organic nanomaterials or sustainable inputs for agricultural production. To those actors that constitute part of the ecosystem, others join to enhance them; Among them are technological linkage units, incubators, universities and public organizations that also play a key role in its development.

Geographically, the distribution of institutions that participate in the development of nanotechnology in Argentina is concentrated in the central provinces and specifically in large cities such as Capital Federal, Córdoba "Córdoba (Argentina)"), Río Cuarto "Río Cuarto (city)"), Santa Fe "Santa Fe (Argentina)"), Rosario "Rosario (Argentina)"), Mendoza "Mendoza (Argentina)"), La Plata, Mar del Plata and White Bay. Although these are the main places, there are also institutes with their research groups and in some cases companies in the northern and southern provinces of the country, mainly in Bariloche and San Miguel de Tucumán, among other cities.[63]​.

Conventional optical microscopes, such as those we can find in the laboratories of primary and secondary educational institutions, are obsolete. Currently, there are very useful tools, high-resolution microscopes, such as the scanning electron microscope (SEM) of the University of Buenos Aires (UBA), which allows us to visualize nanometric systems, such as Cu20 (copper dioxide) nanoparticles used in the agronomist sector as a fungicide.

Argentina currently has an increase in instruments and applications of nanotechnology, where 60% of R&D is carried out by research groups in institutes and centers that are found in science and technology organizations or in universities, mostly public and some private.[64]​.

Already in 2011, the Laboratory of Electron Microscopy and Analysis by X-rays (LAMARX)&action=edit&redlink=1 "Laboratory of Electron Microscopy and Analysis by Astronomy, Physics and Computing (National University of Córdoba)"), belonging to the National University of Córdoba (UNC).[65]​.

Currently, there is also, among others, the Nanofab,[66]​ a laboratory for advice, incubation and public equipment services that has the participation of more than 25 institutions.

The applications of nanotechnology and nanomaterials cover all types of industrial sectors. In Argentina some of these are:

Environment: According to the FAN "Nanotek S.A.[67]​ proposes the use of zero-valent iron nanoparticles in underground layers for the absorption of arsenic, a substance that affects a large part of the national territory (16 provinces, 435,000 km and 2.5 million inhabitants) and involves an outlay of 14 million dollars for the budget of the public health area."

Biomedicine: The pandemic generated by Covid-19 (SARS-CoV-2) led to the creation and improvements of face masks, again using technologies developed by Nanotek S.A. which indicate that these masks: “They have silver nanoparticles that release positive ions, capable of altering the biological processes of microorganisms.”[68]​.

Energy: There are 22 groups in Argentina aimed at producing new materials with greater efficiency for use in the energy sector, for example in the components of wind mills (improve their resistance and reduce their weight) and solar panels (semiconductors capable of capturing more solar energy).[69]​.

For its part, in the legislative field the European Commission provides a possible definition of nanomaterials based on their size[70][71]​(without taking into account the risk they may pose). However, it is really difficult to draw the line for their identification once incorporated into the final products. On the other hand, the production and import of this type of materials depend on the chemical compounds that form them, since all of them must be included in REACH. In addition, rigorous labeling and packaging techniques are required for these nanomaterials (especially if they contain hazardous substances, in which case the CLP must be notified); as well as the provision of an action protocol to guarantee their safe use. Despite everything, the legislative implications are tremendously broad as it is a discipline that covers so many scientific fields, and issues such as[72]​health law, market regulation or data protection remain pending.

As for ethical considerations, these have been discussed since 2003, at the meeting held in December by COMEST (an administrative body of UNESCO) in Rio de Janeiro. Three years later, at the meeting held in Dakar, a more detailed document was prepared in this regard, which are the well-known “COMEST Recommendations on Nanotechnology and Ethics Policies”.[73]​ This document talks, among other things, about:

However, despite all the debate and the apparent fragility of the legislative and ethical mechanisms, today there are hundreds of products that incorporate this type of technology on the market, especially medicines and cosmetics. This situation is wonderfully reflected in the article “Ethics and the development of Nanotechnology”,[74]​ in which Hugh Lacey alludes to the fact that the context of the development of nanotechnology is really similar to that of transgenic products at the time, that is, guided mainly by economic benefit (and the more immediate, the better). On the other hand, the ethical debate on issues such as the risks that these technologies could entail or the potential beneficiaries remains in the background, because it would imply delaying scientific progress and the possibility of falling behind technologically.