Injectable multifunctional modified sodium alginate microparticles for rapid hemostasis and wound repair following endoscopic submucosal dissection

Designing a material that can serve as both a submucosal injectable material (SIM) and a wound treatment agent is highly desirable for achieving optimal outcomes in endoscopic submucosal dissection (ESD), yet it remains a significant challenge. In this study, a series of injectable multifunctional microparticles were developed as SIMs to achieve rapid hemostasis and wound repair after ESD. To enhance the biofunctional properties of these microparticles, sodium alginate (SA) was modified through serotonin and cysteine grafting. Following crosslinking with ferric ions, three types of microparticles (SA/cOSAFe, SA/OSASFe, and SA/cOSASFe) were synthesized. The particle size distribution, adhesion performance, and hemostatic and antibacterial properties were systematically evaluated. Results demonstrated that all these microparticles outperformed normal saline, achieving mucosal uplifting heights exceeding 10 mm and maintenance times over 20 min. Furthermore, the serotonin-containing SA/OSAS Fe and SA/cOSAS Fe microparticles exhibited superior photothermal antibacterial activity against S. aureus and E. coli , along with strong antioxidant activity against DPPH and ABTS radicals, reaching over 85 %, and better hemostatic performance compared with clinical gauze. Notably, SA/OSAS Fe under NIR irradiation significantly facilitated infected-wound regeneration by reducing inflammation, increasing blood vessel formation, and promoting denser collagen fiber deposition, highlighting their great potential for rapid hemostasis and wound repair following ESD.