Injectable Hydrogel of Thiol Mediated Photopolymer Grafted Polyurethane as Controlled Drug Delivery Vehicle for Melanoma Treatment

Abstract

Ultraviolet (UV) photocurable bisphenol A-glycerolate dimethacrylate (bis-GMA) and pentaerythritol tetrakis(3-mercaptopropionate) (PETMP)-based copolymers have been synthesized usingthiol-ene chemistry with tailorable size. This copolymer was further grafted with polyurethane (PU) through in-situ polymerization using its diisocyanate chain ends to balance its hydrophobicity for controlled drug delivery. Characterization by various spectroscopic techniques confirmed the structure, shape, and size of the synthesized polymer; thermal analysis revealed higher glass transition temperatures, and enhanced thermal stability. Rheological analysis showed improved strength and favourable flow behaviour. UV–Vis and FTIR demonstrated strong polymer–drug interactions, correlating with the sustained drug release observed, in contrast to pure PU and copolymer. Drug-loaded graft copolymer was incorporated into 3D-printed scaffolds, supporting in vitro cell growth for 7 days, confirming biocompatibility. An in vivo melanoma mouse model study showed considerable tumor reduction without any side effects, unlike traditional chemotherapy, owing to localized hydrogel injection beneath the tumor for sustained release. Overall, this injectable hydrogel, derived from the synthesized graft copolymer, offers a thermally stable, mechanically robust, biocompatible, and a viable drug delivery system for cancer therapy, with reduced toxicity and high therapeutic potential.