Bioresorbable surface-adhered enzymatic microreactors based on physical hydrogels of poly(vinyl alcohol)

Hydrogel biomaterials based on poly(vinyl alcohol), PVA, have an extensive history of biomedical applications, yet in their current form suffer from significant shortcomings, such as a lack of mechanism of biodegradation and poor opportunities in controlled drug release. We investigate physical hydrogels of PVA as surface-adhered materials and present biodegradable matrices equipped with innovative tools in substrate-mediated drug release. Toward the final goal, PVA chains with narrow polydispersities (1.1-1.2) and molecular weights of 5, 10, and 28 kDa are synthesized via controlled radical polymerization (RAFT). These molecular weights are shown to be suitably high to afford robust hydrogel matrices and at the same time suitably low to allow gradual erosion of the hydrogels with kinetics of degradation controlled via polymer macromolecular characteristics. For opportunities in controlled drug release, hydrogels are equipped with enzymatic cargo to achieve an in situ conversion of externally added prodrug into a final product, thus giving rise to surface-adhered enzymatic microreactors. Hydrogel-mediated enzymatic activity was investigated as a function of polymer molecular weight and concentration of solution taken for assembly of hydrogels. Taken together, we present, to the best of our knowledge, the first example of bioresorbable physical hydrogel based on PVA with engineered opportunities in substrate-mediated enzymatic activity and envisioned utility in surface-mediated drug delivery and tissue engineering.