Litchi-like silver nanoparticles immobilized in microspheres for effective bacteriostasis, rapid hemostasis, and wound healing

Metal nanoparticles, particularly silver nanoparticles (AgNs), exhibit excellent antibacterial properties. However, their high mobility and Ag+ release rate can damage normal tissues and cells. Therefore, their application in wound healing is limited. Reducing Ag+ to AgNs using tannic acid (TA) and Fe complexes (TA/Fe) could effectively prevent the migration of AgNs and slow the release of Ag+ to achieve effective inhibition of bacteria. Ag+ was reduced to AgNs using TA/Fe coating on the surface of calcium alginate and silk fibroin peptide microspheres (CA/SP) to prepare novel litchi-like microspheres (CA/[email protected]). CA/[email protected] showed good biocompatibility. The growth and reproduction of Staphylococcus aureus and Pseudomonas aeruginosa were completely inhibited at a CA/[email protected] concentration of 20 mg/mL. The redox reaction of Ag+ with TA/Fe resulted in the oxidation of Fe2+ to Fe3+. The hemostatic ability of CA/[email protected] was significantly enhanced owing to the good coagulation ability of TA/Fe3+ in the blood, which reduced the bleeding time and hemostatic volume of the femoral artery to 109 s and 0.115 g, respectively. Therefore, TA/Fe-modified microspheres are good carriers of AgNs that can be used for efficient bacteriostasis, rapid hemostasis, and wound healing.