Konjac glucomannan/xanthan gum hydrogels loaded with metal-phenolic networks encapsulated probiotic to promote infected wound healing

Abstract

Probiotic hydrogel systems have been reported to promote healing of infected wounds by secreting functional bioactive secondary metabolites (BSM) of probiotics. Herein, Bacillus subtilis (B. subtilis), a probiotic, are encapsulated via a metal-phenolic networks (MPNs) and loaded into konjac glucomannan/xanthan gum-based hydrogels for wound repair. This MPNs were designed and composed of Bletilla striata polysaccharide, procyanidin, Ca²⁺, which can enhance the cross-linking through hydrogen bonding to form the KGXM-PCB@Bsubtilis hydrogel, protects the probiotic from antibiotics and prevents B. subtilis from escaping into the wound microenvironment, thereby avoiding exposure to a possible threat. Moreover, the KGXM-PCB@Bsubtilis hydrogel not only exhibits superior mechanical characteristics and biocompatibility, but also shows excellent antimicrobial, antioxidant and anti-inflammatory properties that can inhibit the growth of Staphylococcus aureus, remove the active oxygens, and promote cell migration. In vivo experiments showed that after treatment with the KGXM-PCB@Bsubtilis hydrogel, the wound healing rate reached 98.31 % on day 14, and collagen deposition was highly expressed (81.11 ± 2.20 %), which promoted wound healing and regeneration of new tissue. This study provides new ideas for developing wound dressings based on living bacterial hydrogels.

Keywords: Bacillus subtilis; Encapsulation of probiotics; Hydrogel; Metal-phenolic networks; Polysaccharide; Wound healing.