Photo-Degradable Polycaprolactone Fumarate Block Copolymers: The First Example of Approaches to Nanoporous Biomaterials

Technology #2011-242

Nanoporous materials have numerous applications in nonmedical industries for uses such as membranes, surface patterning, and templates for inorganic materials. These applications have typically used block copolymer (one example is A-B block copolymer) self-assembly, the block copolymers assembly by phase separation of A and B blocks to form nanostructures. Although these types of nanomaterials are widely used in other industries, they have yet to find a robust approach for incorporation into the biomaterials field. Nanoporous biomaterials will be found to be useful in a multitude of applications within the biomedical field in the future, once a methodology is developed. The specific application that we initially pursued these nanoporous biomaterials for is the creation of nanoporous nerve conduits. Nerve conduits are used to repair segmental nerve defects, however defects larger than 3cm are challenging. It has become increasingly believed that porous nerve conduit walls enhance regeneration. However, techniques to creating porous structures have been limited to porogen leaching techniques which result in microporosity, typically 5 microns and larger. Not only are the pores larger than 5 microns, many times tens to hundreds of microns, the pores are also random, this allows fibrous tissue infiltration and uncontrolled diffusion of all molecules through the porous walls. Also, high porosity is required (>80% porosity) to reach interconnect porosity resulting in compromised mechanical properties.