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

Abstract

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/SP@AgNs). CA/SP@AgNs showed good biocompatibility. The growth and reproduction of Staphylococcus aureus and Pseudomonas aeruginosa were completely inhibited at a CA/SP@AgNs 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/SP@AgNs 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.