Dual Release of Antibiotics with Additive Effect from Cleavable Hydrogels Based on Amino/Thiol–Yne Click Chemistry

Abstract

Dual-antibiotic loaded poly(ethylene glycol) (PEG)-based hydrogels were developed as antimicrobial wound dressings combining covalent and physical antibiotic incorporation. Hydrogels were prepared through amino-yne click conjugation of gentamicin sulfate (Gs) and thiol-yne cross-linking, followed by ciprofloxacin (CPX) loading via swelling-diffusion. The materials exhibited tunable gelation time, swelling capacity, and drug release profiles depending on thiol content. A dual-release mechanism was achieved, consisting of an initial burst release of CPX followed by a sustained, pH-responsive release of conjugated Gs through acid cleavage of β-aminoacrylate linkages. The hydrogels showed effective wide spectrum antibacterial activity against methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa, while cytotoxicity studies confirmed cytocompatibility at bactericidal concentrations. The results support the potential of these hydrogels as safe and effective dual-antibiotic wound dressings, allowing for the immediate elimination of invading bacteria after wounding (burst release), while maintaining long-term antibiotic release to minimize reinfection risk.