Sustained-release, antibacterial, adhesive gelatin composite hydrogel with AgNPs double-capped with curdlan derivatives

In this work, carboxymethylated curdlan (CMCD) was utilized as a capping and stabilizing agent for the green synthesis of silver nanoparticles. Subsequently, quaternized curdlan (QCD) was introduced as the second capping layer through electrostatic attraction, leading to the preparation of double-capped silver nanoparticles (AgNPs@CQ). The successful synthesis of silver nanoparticles was characterized using UV–vis, FTIR, XRD, TEM, and DLS. AgNPs@CQ were incorporated into gelatin and a AgNPs@CQ/Gel composite hydrogel was obtained. The incorporation of AgNPs@CQ imparts excellent antibacterial properties to the composite hydrogel, thereby enhancing its antimicrobial efficacy. The presence of double-capping layers significantly retards the release rate of silver, contributing to prolonged antimicrobial activity. The MTT and live/dead fluorescence staining results demonstrate that the gelatin hydrogel incorporating double-capped AgNPs exhibits enhanced cell viability compared to the one incorporating single-capped AgNPs. Additionally, the composite hydrogel exhibits remarkable mechanical strength and adhesive performance. The AgNPs@CQ/Gel composite hydrogel demonstrates a cost-effective and facile preparation, showing significant potential in the field of dressings.