Towards Robust Electroactive Biomaterials

Shah, Sayed and Firlak, Melike and Halcovitch, Nathan and Mort, Richard and Robinson, Benjamin and Hardy, John (2016) Towards Robust Electroactive Biomaterials. In: UNSPECIFIED.

Abstract

Bioelectronics: Introduction Electrical fields affect a variety of tissues (e.g. bone, cardiac, muscle, nerve and skin) and play important roles in a multitude of biological processes (e.g. angiogenesis, cell division, cell signalling, nerve sprouting, prenatal development and wound healing), which has inspired the development of electroactive biomaterials, some of which (e.g. non-biodegradable cardiac pacemakers, cochlear implants, electrodes for deep brain stimulation) have been clinically translated. Bioelectronics: Conductive/Electroactive Polymers The tuneable properties of conductive/electroactive polymers (CPs or EAPs, respectively) such as derivatives of polyaniline, polypyrrole or polythiophene (e.g. PEDOT) make them attractive components of electroactive biomaterials for drug delivery devices, electrodes or tissue scaffolds. The highly conjugated backbone of EAPs is responsible for their high conductivity, yet it also renders them non-biodegradable. Clearly, non-biodegradable EAPs are best suited for devices that will be implanted for long periods such as electrode-based biointerfaces, whereas, biodegradable EAPs are ideal for devices implanted for comparatively short durations such as drug delivery devices or tissue scaffolds. Electropolymerisation: problems and progress Electropolymerised films of polyaniline, polypyrrole or polythiophene (e.g. PEDOT) tend to have poor mechanical properties (particularly evident brittleness and cracking). We are developing simple scalable methods of preparing robust EAP-based materials. Examples presented here include negatively charged polysaccharides as dopants for positively charged polypyrrole. Characterisation We have begun to characterize the electrical, mechanical and biological properties of the films to identify problems and assess their prospects for biomedical applications in collaboration with physicists and biologists. Conclusion With a view towards the generation of robust electroactive biomaterials we have developed EAP-based materials with markedly improved mechanical properties (i.e. not as brittle and not cracked). Such materials may be capable of electrically stimulating the cells that reside thereon/therein and delivery of clinically used drugs. We will investigate their prospects for clinical translation in collaboration with our industrial partners.