Preparation of a novel injectable in situ -gelling nanoparticle with applications in controlled protein release and cancer cell entrapment.

Temperature sensitive injectable hydrogels have been used as drug/protein carriers for a variety of pharmaceutical applications. Oligo(ethylene glycol) methacrylate (OEGMA) monomers with varying ethylene oxide chain lengths have been used for the synthesis of in situ forming hydrogel. In this study, a new series of thermally induced gelling hydrogel nanoparticles (PMOA hydrogel nanoparticles) was developed by copolymerization with di(ethylene glycol) methyl ether methacrylate (MEO 2 MA), poly(ethylene glycol) methyl ether methacrylate (300 g mol -1 , OEGMA 300 ), and acrylic acid (AAc). The effects of acrylic acid content on the physical, chemical, and biological properties of the nanoparticle-based hydrogels were investigated. Due to its high electrostatic properties, addition of AAc increases LCST as well as gelation temperature. Further, using Cy5-labelled bovine serum albumin and erythropoietin (Epo) as model drugs, studies have shown that the thermogelling hydrogels have the ability to tune the release rate of these proteins in vitro . Finally, the ability of Epo releasing hydrogels to recruit prostate cancer cells was assessed in vivo . Overall, our results support that this new series of thermally induced gelling systems can be used as protein control releasing vehicles and cancer cell traps.