Smart Plastics For Medicine

Biopolymers obtained by Russian researchers with the help of hydrogen bacteria, are compatible with tissues of the organism and are autodestractive after a while. That makes such biopolymers indispensable for medical articles.

Polymers of microbe origin, or biopolymers, have recently drawn increasing attention of a great variety of specialists. These polymers have two important advantages. Firstly, they get destroyed in the environment and thus solve the contamination problem. Secondly, they are biocompatible, and consequently, they are not rejected by the organism when applied for medical purposes. The Krasnoyarsk and Moscow researchers from the Institute of Biophysics (Siberian Branch, Russian Academy of Sciences) and ??? “Biokhimmash” supported by the International Science and Technology Center are developing technology of biopolymer production and manufacturing of medical articles from them.

These are polymers of oxyderivative fatty acids, the so-called polyhydroxyalkanoates (PHAs). Some microorganism, for example hydrogen bacteria that get vital energy via oxidizing hydrogen, are able to synthesize PHAs. PHAs have a lot of advantages – their physicochemical characteristics, for example, thermoplasticity, is the same as that of polypropylene and polyethylene, and on top of that they possess antioxidant and optical properties and piezoelectric effect. Besides, like any biopolymers, they are compatible with tissues of organism and get destroyed in the environment. That is why they are promising for use in medicine (surgical and disposable materials), pharmacology (prolongation of drug action), food industry (packing and antioxidant materials), agriculture (seed obducers, destructible films).

The researchers tested the polymer production technology first in the laboratory and then in production environment. So far, the scientists can obtain three types of polymers: polyoxybutyrate and its copolymers with oxybutyrate and oxyvalerianate, but in the future the range of goods will increase. Within a week, 1 kilogram of polymer (or up to 50 kilograms per year) can be produced on the installation.

The researchers are mainly interested in PHA utilization for medical articles. They have already produced out of them wound healing films, suture material, covering for vessel prostheses (stents), matrix for bioartificial organs and implantates, membranes, microparticles, etc.

It is interesting to note that various articles need absolutely different rate of polymer biodegradation – suture threads and films should dissolve quickly, but stents and valve prostheses should serve for a long time. How do scientists solve this problem? “The degradation rate depends on the surface type, it can vary if different fillings are used, or it can be accelerated when needed through preliminary gamma irradiation”, explains Tatiana Volova.

Biopolymers underwent tests on animals at the Scientific Research Institute of Transplantology and Bioartificial Organs (Ministry of Health of the Russian Federation). Trade mark of biomaterial – ElastoPOBtm – has been registered. Clinical trials have been started. Specialists say that the current demand for polymers for medicine makes 400 thousand tons per year, therefore they consider industrial production of destructible bioplastics economically feasible. Based on the polymer’s sale price of 95 rubles per kilogram, they have already calculated polymer’s pay-back, return and profitability.