Synthesis and Characterization of pH-Responsive Hydrogel Nanocomposites for Controlled Antibiotic Release

Abstract

The development of smart, stimuli-responsive hydrogel systems represents an advanced approach for achieving localized and sustained drug delivery. In this study, a pH-responsive hydrogel nanocomposite based on polyacrylamide–chitosan blends reinforced with zinc oxide (ZnO) nanoparticles was synthesized to control the release of the antibiotic ciprofloxacin. The incorporation of ZnO nanoparticles enhanced both mechanical stability and antimicrobial activity of the hydrogel matrix. The prepared hydrogel demonstrated a remarkable swelling ratio of 580% at pH 7.4, compared to 110% at pH 2.0, confirming its pH sensitivity and suitability for targeted drug release in physiological environments. Scanning Electron Microscopy (SEM) revealed a porous morphology with uniformly dispersed nanoparticles, while X-ray Diffraction (XRD) confirmed the crystalline nature of ZnO within the polymer network. The drug loading efficiency reached 91%, and the release profile followed non-Fickian diffusion kinetics, sustaining antibiotic release for up to 96 hours. Antibacterial assays exhibited significant inhibition zones against Escherichia coli and Staphylococcus aureus, demonstrating the synergistic antimicrobial effect of ciprofloxacin and ZnO nanoparticles. Cytocompatibility evaluation further confirmed the biocompatible and non-toxic nature of the nanocomposite. Overall, this multifunctional pH-sensitive hydrogel nanocomposite provides a promising platform for controlled antibiotic release, infection control, and wound healing applications.