An important difference between the definition of biopolymers and other existing polymers can be found in their structures. All polymers are made of repeating units called monomers. Biopolymers generally have a well-defined structure, although this is not a defining characteristic (example: ligno-cellulose.

The exact chemical composition and the sequence in which these units are arranged is called primary structure, in the case of proteins. Many biopolymers spontaneously fold into characteristic compact shapes, which determine their biological functions and depend on said primary structure. Structural biology is responsible for studying the structural properties of these biopolymers.

On the contrary, most synthetic polymers have much simpler and randomly organized structures. This fact leads to a molecular mass distribution that is not observed in biopolymers. In fact, since their synthesis is controlled by a directed process, in most "in vivo" systems, all biopolymers of a type (coming from a specific protein) are all the same. They all contain similar sequences and numbers of monomers and therefore all have the same mass. This phenomenon is called monodispersity in contrast to the polydispersity found in synthetic polymers. As a result, biopolymers have a polydispersity index of 1.[5]​

Among the synthetic biopolymers used in implants, the following stand out:

Derived biopolymers include biopolymers synthesized artificially but from natural substances. These materials are also called bioplastics, although this category would also include all biopolymers of natural origin. These materials include:

It should be mentioned that there is a new branch of study in which some materials derived from geological inorganic materials are considered as "geopolymers". These materials are of interest as substitutes for more traditional cements.[6]​.

Polypeptides

The convention for a polypeptide is to list its constituent amino acid residues as they run from the amino terminus to the terminus where the carboxylic acid is located. Amino acid residues are always linked by peptide bonds. Proteins can also be modified to include non-peptide components, such as saccharide chains and lipids.

The convention for a nucleic acid sequence is to number the nucleotides that occur from the end of the '5' chain, to the end of the '3' polymer chain, where '5' and '3' refer to the numbering of the carbons of the entire ribose ring that participate in the formation of phosphate diester bonds in the chain. Such a sequence is called the primary structure of the biopolymer.

Sugars

Sugar-based biopolymers are often complex, relative to established convention. These can be linear or branched and are usually linked through glycosidic bonds. The exact location of the bond can vary, and the orientation of the linking functional groups is also important, resulting in α- and β-glucosidic bonds with definitive numbering of the location of the carbons involved in the bond. Furthermore, many saccharide units can undergo different chemical modifications, such as amination, and can even form parts of other molecules, such as glycoproteins.

There are a number of biophysical techniques for determining sequence information. These methods are Edman degradation, in which the N-terminal residues are hydrolyzed from the chain, one by one, to be later identified.

The mass spectrometer technique can also be used, starting with gel electrophoresis and capillary electrophoresis.

Dual polarization interferometry can be employed to measure conformational changes or self-assembly of these materials when stimulated by pH, temperature, or ionic strength. Finally, the mechanical properties of these biopolymers can frequently be measured using optical tweezers or atomic force microscopy.

Biopolymers can be considered sustainable because carbon neutral is always renewable, and they are made from materials from plants that can be grown continuously. These plant materials come from non-food agricultural crops. Therefore, the use of biopolymers tends to create a sustainable industry, in contrast to raw materials from polymers derived from petrochemicals. Furthermore, biopolymers have the potential to reduce carbon emissions and decrease the amounts of CO in the atmosphere: this is because the carbon dioxide released when they degrade can be reabsorbed by crops.

Some biopolymers are biodegradable, breaking down into CO and water by microorganisms over a period of six months. Biopolymers that do this may be marked with a 'compostable' symbol, under the European standard EN 13432 (2000). The packaging of these products is marked with a symbol that allows recognition of the industrial composting process to which they were subjected.[7]​.

An important difference between the definition of biopolymers and other existing polymers can be found in their structures. All polymers are made of repeating units called monomers. Biopolymers generally have a well-defined structure, although this is not a defining characteristic (example: ligno-cellulose.

The exact chemical composition and the sequence in which these units are arranged is called primary structure, in the case of proteins. Many biopolymers spontaneously fold into characteristic compact shapes, which determine their biological functions and depend on said primary structure. Structural biology is responsible for studying the structural properties of these biopolymers.

On the contrary, most synthetic polymers have much simpler and randomly organized structures. This fact leads to a molecular mass distribution that is not observed in biopolymers. In fact, since their synthesis is controlled by a directed process, in most "in vivo" systems, all biopolymers of a type (coming from a specific protein) are all the same. They all contain similar sequences and numbers of monomers and therefore all have the same mass. This phenomenon is called monodispersity in contrast to the polydispersity found in synthetic polymers. As a result, biopolymers have a polydispersity index of 1.[5]​

Among the synthetic biopolymers used in implants, the following stand out:

Derived biopolymers include biopolymers synthesized artificially but from natural substances. These materials are also called bioplastics, although this category would also include all biopolymers of natural origin. These materials include:

It should be mentioned that there is a new branch of study in which some materials derived from geological inorganic materials are considered as "geopolymers". These materials are of interest as substitutes for more traditional cements.[6]​.

Polypeptides

The convention for a polypeptide is to list its constituent amino acid residues as they run from the amino terminus to the terminus where the carboxylic acid is located. Amino acid residues are always linked by peptide bonds. Proteins can also be modified to include non-peptide components, such as saccharide chains and lipids.

The convention for a nucleic acid sequence is to number the nucleotides that occur from the end of the '5' chain, to the end of the '3' polymer chain, where '5' and '3' refer to the numbering of the carbons of the entire ribose ring that participate in the formation of phosphate diester bonds in the chain. Such a sequence is called the primary structure of the biopolymer.

Sugars

Sugar-based biopolymers are often complex, relative to established convention. These can be linear or branched and are usually linked through glycosidic bonds. The exact location of the bond can vary, and the orientation of the linking functional groups is also important, resulting in α- and β-glucosidic bonds with definitive numbering of the location of the carbons involved in the bond. Furthermore, many saccharide units can undergo different chemical modifications, such as amination, and can even form parts of other molecules, such as glycoproteins.

There are a number of biophysical techniques for determining sequence information. These methods are Edman degradation, in which the N-terminal residues are hydrolyzed from the chain, one by one, to be later identified.

The mass spectrometer technique can also be used, starting with gel electrophoresis and capillary electrophoresis.

Dual polarization interferometry can be employed to measure conformational changes or self-assembly of these materials when stimulated by pH, temperature, or ionic strength. Finally, the mechanical properties of these biopolymers can frequently be measured using optical tweezers or atomic force microscopy.

Biopolymers can be considered sustainable because carbon neutral is always renewable, and they are made from materials from plants that can be grown continuously. These plant materials come from non-food agricultural crops. Therefore, the use of biopolymers tends to create a sustainable industry, in contrast to raw materials from polymers derived from petrochemicals. Furthermore, biopolymers have the potential to reduce carbon emissions and decrease the amounts of CO in the atmosphere: this is because the carbon dioxide released when they degrade can be reabsorbed by crops.

Some biopolymers are biodegradable, breaking down into CO and water by microorganisms over a period of six months. Biopolymers that do this may be marked with a 'compostable' symbol, under the European standard EN 13432 (2000). The packaging of these products is marked with a symbol that allows recognition of the industrial composting process to which they were subjected.[7]​.