(ORDO NEWS) — Chinese chemists have used lysine-rich structural proteins to create a superplastic bioplastic that has hemostatic properties and can store information in the form of a sequence of amino acids within its composition.
Bioplastic is a sustainable alternative to plastic, made from renewable biomass sources, as opposed to conventional plastic made from petrochemicals. The raw materials for bioplastics can be starch, vegetable fats or oils, polylactic acid and other compounds.
However, in most cases, bioplastics show insufficient durability, biocompatibility and/or biodegradability. In addition, they often require complex, energy-intensive processing methods and pesticides, so that their production ends up being no less toxic than the production of conventional plastic.
As an alternative, researchers from China have proposed a new method for producing bioplastics using two structural proteins rich in the amino acid lysine as raw materials.
One of them is 72 repeats of a polypeptide similar to the connective tissue protein elastin: it does not have a strictly defined spatial structure, which ensures strength and elasticity.
The second consists of five similar elastin polypeptides and a squid protein crystal segment with a β-sheet structure: this is necessary for the rigidity and mechanical strength of the bioplastic.
The researchers produced large quantities of proteins using microbial systems, then purified and chemically cross-linked with polyethylene glycol derivatives through the side groups of lysine. The result is a strong, transparent, solvent-resistant bioplastic whose stiffness can be adjusted by adding different amounts of polyethylene glycol.
This allows the production of bioplastics with high mechanical strength at room temperature in any desired shape, without the use of toxic chemicals or complex manufacturing steps. Their tensile strength exceeds that of many commercial plastics.
Conventional food dyes are suitable for staining the new bioplastic, and the elastase enzyme unravels it. In addition, protein bioplastic can be used to seal wounds because it has a hemostatic effect.
The researchers tested the biocompatibility and biodegradability in mice: the implants effectively healed wounds and completely degraded within a few weeks.
Another possibility of the created material is the recording of information in the form of a sequence of amino acids in the composition of its constituent proteins.
Moreover, the density of information storage in this form is greater than in similar DNA carriers, since there are more varieties of amino acids than nucleotides. Therefore, fewer bits are required to store the same amount of information.
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