The peripheral nervous system (PNS) is a complicated and extensive network of nerves that are controlled by the brain and spinal cord. The PNS is fragile and can be easily damaged by injuries or trauma. The current gold standard surgical treatment for defects greater than 8 mm is autologous nerve grafts; however only around 40% of the 1.8 million US PNS patients each year regain normal function. Scaffold-based strategies where a tubular nerve guidance channel (NGC) is used to bridge the nerve defect have been promoted as a potential alternative that could avoid the additional surgeries and associated donor site morbidity involved in the harvest of nerve grafts. Additionally, current NGCs lack patient-specific tunability and are only approved for small-gap (&lt; 3cm) injuries. This research seeks to create block copolymers with controlled thermodynamic and mechanical properties for use in additive manufacturing processes such as 3D printing. 3D printing has been increasingly used in research for computer-aided design of biomaterial-based scaffolds with complex architecture. The NGCs should contain an outer flexible shell that mimics the mechanical properties of the surrounding biological tissue and enables diffusion of nutrients to support encapsulated cells. The use of block copolymers with both hydrophilic and hydrophobic domains can provide a flexible, partially-hydrated, biocompatible and bioresorbable NGC shell. In this study, A-B-A type triblock copolymers of PLLA-Pluronic-PLLA were synthesized using varied ratios of Pluronic (F127 and P123) and PLLA. The resulting block copolymers were characterized with differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR) to determine polymer structure and thermal behavior. The synthesized block copolymers were shown to be a versatile material platform for biomedical applications through ease of melt-processing and tunable mechanical properties and degrees of swelling. These materials are particularly well suited for 3D-printing of biodegradable structures for in vivo implantation, such as nerve guidance channels.

Controlled thermodynamic properties of pluronic based copolymers as nerve guidance channels for peripheral nerve repair

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.