Low-Extrusion-Force Injectable Chitosan Gel Microparticles for Effective Wound Dressing in Endoscopic Sinus Surgery

Chitosan hydrogels are effective wound dressings that promote healing through the synergy of chitosan’s inherent biological properties and the moist environment they maintain. We previously developed hydrogel microparticles using a highly biocompatible chitosan derivative with superior therapeutic effects. This study aimed to enhance their clinical translation for Endoscopic Sinus Surgery (ESS) by optimizing preparation conditions to achieve an extrusion force of <20 N, facilitating ergonomic, single-handed administration by surgeons. While reducing the particle size alone was insufficient to lower the extrusion force significantly, the introduction of a mechanical “kneading” process to de-agglomerate microparticle aggregates resulted in a substantial reduction in the required force from 213 ± 80 N to approximately 47 N. By further optimizing the polymer concentration to 5.0% (w/v), we successfully reduced the maximum extrusion force to below 20 N (17 ± 1 N). These results demonstrate that the optimized injectable chitosan gel microparticles achieve the practical usability required for precise surgical maneuvers during ESS.