The peripheral nervous system (PNS) is a complicated and extensive network of nerves that are controlled by brain and spinal cord. The PNS can be easily damaged by injuries or trauma. The 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 (< 3cm) injuries.
This research seeks to use additive manufacturing technologies to create block copolymers with controlled thermodynamic properties integrating with 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 the diffusion of nutrients to support encapsulated cells. The use of block copolymers with both hydrophilic and relative hydrophobic functions 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 polymer structure and thermal behavior.