In Situ Synthesis and Characterization of a Strontium Nitrate-Impregnated Starch-Collagen Hydrogel for Antimicrobial Applications

Abstract

Background: The development of effective antimicrobial biomaterials remains a critical challenge in healthcare applications, requiring materials that can provide sustained therapeutic action while maintaining biocompatibility.

Objective: To develop and characterize a novel hybrid hydrogel system incorporating strontium nitrate for antimicrobial drug delivery applications

Methods: A hybrid hydrogel was synthesized using natural polymers (starch, collagen, gelatin) and synthetic polymers (polyvinyl alcohol [PVA], polyethylene glycol [PEG]). Strontium nitrate (Sr(NO₃)₂) was incorporated and reduced in situ within the hydrogel matrix using glutaraldehyde crosslinking. The hydrogel was characterized using UV-visible spectroscopy, scanning electron microscopy (SEM), swelling studies in simulated tear fluid, antimicrobial assays against Staphylococcus aureus and Pseudomonas aeruginosa, and strontium ion release profiling over 24 hours.

Results: The hydrogel demonstrated a porous microstructure suitable for fluid absorption. The system exhibited high swelling capacity (>1200% of dry weight) in simulated tear fluid, reaching equilibrium within 6 hours. Antimicrobial testing showed significant activity with inhibition zones of 18 mm against S. aureus and 15 mm against P. aeruginosa. Strontium ion release exhibited an initial burst (30% within 4 hours) followed by sustained release, achieving 85% cumulative release over 24 hours.

Conclusions: The developed starch-collagen-strontium nitrate hybrid hydrogel demonstrates promising characteristics for antimicrobial applications, combining high fluid absorption, broad-spectrum antimicrobial activity, and controlled strontium ion release. These properties position it as a viable candidate for advanced therapeutic platforms in infection management.