From Structure to Function: Chitosan-ZIF-8@PDMS Sponges for Controlled Berberine Delivery

Abstract Berberine is a plant-derived alkaloid that combines chemical versatility, vigorous biological activity, and natural origin. In hybrid polymer or MOF systems, it serves as both a functional agent (enhancing activity) and a sustainable component consistent with modern green material design. This study aimed to incorporate Berberine into porous sponges (CS-ZIF-8@PDMS) to improve their antibacterial and antioxidant properties. The proposed novel composites are designed for controlled drug release. The porous sponge CS-ZIF-8@PDMS-BER was synthesized by integrating chitosan and ZIF-8 NPs (nanoparticles) into a PDMS sponge. Several characterization techniques were used to reveal the presence of chitosan and ZIF-8 NPs on PDMS sponges. The average particle size of ZIF-8 NPs, as determined by TEM, is 53 nm, which decreases to 47 nm after chitosan doping. The effects of chitosan and ZIF-8 were studied in terms of the hydrophilicity and porosity of the sponges. Moreover, the highest water absorption of 33.7 ± 1.68% was found for CS-ZIF-8@PDMS. The integration of chitosan and ZIF-8 improved the hydrophilicity, porosity, and mechanical properties of as-synthesized sponges. The composites revealed a two-stage berberine release profile, driven by chitosan’s hydrophilicity, resulting in rapid initial release. Antioxidant testing (ABTS assay) confirmed significantly enhanced radical-scavenging performance, with CS-ZIF-8@PDMS reaching 99.6% inhibition and further improvement upon berberine incorporation due to synergistic redox interactions. Antibacterial evaluation (ISO 20743) demonstrated strong biological activity, with CS-ZIF-8@PDMS-BER achieving complete inhibition of E. coli and S. aureus after 24 h. Furthermore, cytotoxicity studies validated the biocompatibility of the developed sponge, demonstrating high cell viability, while stability assessments indicated that the sponge maintained its structural integrity for a minimum of two weeks under physiological conditions. Overall, the materials show robust multifunctionality, underscoring their potential for biomedical and antimicrobial applications.