Compositional Control of Stereocomplexed Hydrogel Microparticle Network Formation and Physical Properties

Granular hydrogel scaffolds composed of many discrete hydrogel microparticles (HMPs) have demonstrated significant advantages over bulk hydrogels, including injectability and the flexibility to incorporate diverse chemistries, physical properties, and bioactive payloads. Herein, we demonstrate the ability to tune HMP properties through varying the length of poly(ethylene glycol) (PEG) arms and stereocomplexed poly(lactic acid) (SC PLA) cross-links within PEG-based HMPs to further understand the networks' structure-property relationships and utility in a model prodrug delivery system. DSC and WAXS revealed that hydrogels with shorter PEG arms were able to form stereocomplex domains to a greater extent than longer PEG arms. Additionally, as the SC PLA length increased, the HMPs were more thermally and mechanically stable. HMPs were also loaded with model prodrug, doxorubicin, to characterize compositional variations' effects on release profiles. These studies suggest that variations in the cross-linker concentration influence the crystallinity of each HMP formulation, allowing for tunable drug loading and release.