Balanced biocompatibility in high-viscosity hydroxypropyl methylcellulose-based sponge containing nanoconfined silver citrate nanoparticles.

Balancing antibacterial efficacy, mechanical integrity, and biocompatibility remains a critical challenge in drug release systems for wound dressings. Many antimicrobial agents exhibit inherent cytotoxicity, compromising cell viability and tissue compatibility. To address this, an Absorbable Gelatine Sponge was synthetised based on high-viscosity hydroxypropyl methylcellulose (HPMC K100M) and loaded with silver citrate nanorods (AgCit), which confine silver nanoparticles to enable controlled ion release. This matrix slows dissolution and restricts diffusion, preventing burst effects and maintaining sustained antimicrobial action. Sponges were synthesised via lyophilisation with AgCit at 0, 1, 3, and 5 %, and characterised using SEM and FTIR/Raman spectroscopy. While thickness and water absorption improved with nanoparticle inclusion (>13 % sponge weight in 2 h), tensile strength decreased at 5 % AgCit (from 2.05 to 0.32 MPa). Cytotoxicity assays with L929, MC3T3-E1, and HaCaT cells confirmed excellent biocompatibility (~0.5 % haemolysis), and antimicrobial studies showed >93 % inhibition against Escherichia coli, Staphylococcus aureus, and Candida albicans within 12 h. Among concentrations, 3 % AgCit achieved the best performance balance. These findings highlight the potential of HPMC/AgCit sponges as sustainable, silver-based delivery platforms for wound healing, and suggest future evaluation of integrated systems in vivo.