Polymer Scaffolds

Polymer Scaffolds

At present in medicine, the question is about creation of artificial tissue reproducing the functions and structure of living tissue for a limited period. Therefore, the development of bulk (3-D) scaffolds based on biodegradable polymers is an important area of bioengineering.

Biodegradable polymers are specific materials that are capable of degradation caused by microbiological and chemical processes. The development of biomaterials from biodegradable polymers will allow us to form the bone implants for the treatment of a broad spectrum of fractures that not only will support and serve as a damaged bone, but also to stimulate its growth and recovery. Biodegradable implants have all the advantages of conventional implants (from metal). Additional advantage is gradually breakdown in a patient organism to result in non-toxic products. After that, the decomposition products are extracted from the body during metabolism. It is therefore possible to remove the implants from a patient's body without repeated surgery. All these factors determined the great interest in search of technology, focused on a construction of materials and implants based on biodegradable polymeric materials.

The purpose of this research is the formation of a new hybrid composite material based on biodegradable polymers for regenerative medicine. New material should have gradient porosity to make imitation of bone structure. It should have mechanical properties similar with properties of damaged part of bone and repeat chemical composition of hard tissue, which contains 90% of calcium phosphate. In addition, implant surface should provide a good cell adherence to stimulate ingrowth of tissue into the matrix material.

Work is carried out with the collaboration of Technology Centre of Institute of Physics and Technology National Research Tomsk Polytechnic University, Fraunhofer Institute for Interfacial Engineering and Biotechnology, the University of Duisburg-Essen and Karlsruhe Institute of Technology KIT in Germany.

At present, synthesis and formation of 3-D bulk scaffolds are performed based on Technology Centre by using method of electrospinning. Materials are produced from next biodegradable polymers: polycaprolactone, poly-3- hydroxybutyrate and copolymer poly (3-hydroxybutyrate-co- 3-hydroxyvalerate). The method of electrospinning allows to synthesize 3-D bulk materials with fibrous structure and to control pore size and mechanical properties.

In Fraunhofer Institute for Interfacial Engineering and Biotechnology the polymeric films and 3-D scaffolds were modified by using radio-frequency (RF) reactive plasma. Studies have shown that surface of untreated polymer was hydrophobic, poor wettability, had low surface energy, that leads to bad cell adherence on the material surface. After plasma treatment the polymer's wettability improved significantly and surface energy increased. The advantage of plasma treatment is that it enables to form functional groups on the surface, which then allows an attachment of macromolecular compounds to the polymer. The results of performed researches
are presented in follow articles [Materials Letters 163 (2016) 277–280, Materials Science and Engineering: C, 62 (2016) 450–457].