Controlling the Surface Reactivity of a Central Nervous System Repair Hydrogel

Abstract

Implants currently used in regenerating damaged central nervous system (CNS) neurons do not optimally support the microenvironment of the lesion site. The hydrogel oligo(polyethylene glycol) fumarate (OPF) exhibits attractive properties as a biomaterial for developing an addition to a class of decellularized conduit devices for a native extracellular matrix environment suitable for regenerating aligned neuronal regrowth. A self-assembled monolayer of phosphonates on titanium oxide (TIO({2}) / SAMP) modification can make the cell non-adhesive surface of OPF become cell-adhesive, but the conventional vapor deposition technique used to create the TIO({2}) interface is incompatible with a hydrated sample. The work in this thesis develops a solution deposition method to create the metal interface, on which a SAMP layer was grown. Using octadecylphosphonic acid (ODPA) as proof of concept, a TIO({2}) / ODPA bilayer was constructed on the surface of hydrated OPF and its properties and interfacial stability were characterized and studied through ATR-FTIR spectroscopy and contact angle goniometry. Optimizing conditions for manufacturing this TIO({2}) / ODPA modification gave rise to a hydrophobic and even water repellent hydrogel surface. The bilayer ensemble was found to be stable under typical (\textit{in vitro}) biological conditions. Switching from ODPA to 1,12-BPA changed the hydrophobic surface to become cell-adhesive.