Novel Biodegradable Electrically Conducting Polymers for Nerve Regeneration

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9702882 Schmidt The proposed research focuses on the synthesis of a novel biodegradable polymer that will be inherently electrically conductive. This research is motivated by past work which demonstrates that electric fields and electrical charges improve the healing of several tissues, including bone and nerve. There are drawbacks to the presently available approaches. External electromagnetic fields suffer from the inability to accurately localize the electrical effect to the desired tissue, and the use of non-biodegradable electrically-conducting or electrically - charged materials can pose long-term risks that are associated with any permanent material. Thus, there is ample motivation to develop a biodegradable polymer, which has desirable electrically conductive properties that can be localized to the tissue of choice, and which will not pose long-term health risks. Such a polymer does not currently exist. In addition to its possible utility for peripheral nerve regeneration, the polymer could also be applied to other areas of tissue engineering as well, such as spinal cord regeneration and muscle tissue. To synthesize a biodegradable electrically conducting polymer, electrically conducting pyrrole oligomers will be coupled to one another via hydrolyzable (degradable) urethane linkages. Pyrrole was selected based on extensive previous research by the PI showing that poly(pyrrole) is biocompatible and can be used to significantly s the extension of axons from nerve cells. Poly(pyrrole), in the form of guidance channels, has also been shown by the PI to guide peripheral nerve regeneration better than inert materials such as silicone. Unfortunately, poly(pyrrole) in its present form is not biodegradable and not easily processed into different shapes. Thus, pyrrole oligomers will be coupled with urethane linkages to render it biodegradable an d more easily processed. The urethane linkage was selected for many reasons, including urethane's prior use in clinical applications such as heart valves and the fact that urethane, in its uncrosslinked form, is biodegradable and pliable. Other cross linking chemistries (e.g., an ester linkage) will be utilized in the unlikely event that the polymer product proves to be deleterious to living tissue. In summary, the proposed studies will focus on the synthesis of a novel biodegradable electrically conducting polymer, based on previous work showing that electrical charges are beneficial to wound healing, and in particular, to nerve regeneration. Thus, the resultant polymer will be a useful material not only for devices to aid peripheral nerve regeneration (e.g., nerve guidance channels), but for other tissue engineering applications as well. ***