Development of novel poly(glycidol) hydrogels for applications in regenerative medicine and drug delivery

Abstract

Regenerative medicine and drug delivery strategies require the use of advanced materials that can mimic the complex biological environment of native tissues. We present a series of advanced poly(glycidol) networks that are tunable based on the functionalization of the individual poly(glycidol) building blocks and the use of silica nanoparticles. Post-polymerization modification of branched poly(glycidol) furnished novel hydrophilic aminooxy and γ-keto-ester functionalized polymeric building blocks, which were then crosslinked via ketoxime formation to form highly sophisticated polymer networks without the need for any catalyst or external stimuli. The combination of the two branched components together with the variation in functionality showed a remarkable effect on its mechanical properties. Furthermore, the mechanical properties of these hydrogels could be further tuned through the use of supramolecular structures such as silica nanoparticles, which are capable of forming hydrogen bonds with the crosslinked polymer chains in the network. We demonstrated that the silica nanoparticles, in combination with linear poly(ethylene glycol) derivatives, increased the elasticity of the polyglycidol network, making it compressible up to 75% strain without failure. These findings demonstrate the advantages of branched poly(glycidol) in contrast to commonly used linear poly(ethylene glycol) and poly(vinyl alcohol), where network properties cannot be easily adjusted and high strength materials cannot be formed. Other properties which were investigated included water swelling ratios and biodegradability which were found to be easily tuned by varying the degree of functionality in each functional polymer. Furthermore, the cytotoxicity of the functionalized polyglycidols were investigated and found to have comparable biocompatibility to poly(ethylene glycol).