Co-cultivation of Komagataeibacter sp. and Lacticaseibacillus sp. strains to produce bacterial nanocellulose-hyaluronic acid nanocomposite membranes for skin wound healing applications.

Inspired by natural microbial cooperation, a co-culture approach was used to synthesize bacterial nanocellulose (BNC)-based nanocomposites for potential wound healing applications. By co-culturing either Komagataeibacter xylinus (K1G4) or the never tested strain K. rhaeticus (K2G46) with the hyaluronic acid (HA)-producer Lacticaseibacillus casei UMCC 2535, two BNC-HA nanocomposites were obtained (C1-K1 and C2-K2). The membranes showed a HA content of 0.49 ± 0.05 mg (C1-K1) and 1.40 ± 0.07 mg (C2-K2), and both revealing a nearly complete release of HA after 1 h in PBS. Compared to pure BNC membranes, the nanocomposites showed enhanced properties, including higher crystallinity (K1G4 = 84.6 %; K2G46 = 76.5 %; C1-K1 = 89.1 %; C2-K2 = 88.1 %), and Young's modulus (K1G4 = 3.38 ± 0.56 GPa; K2G46 = 2.22 ± 0.65 GPa; C1-K1 = 10.00 ± 1.32 GPa; C2-K2 = 7.90 ± 1.54 GPa). Additionally, both BNC-HA membranes exhibited increased moisture uptake (K1G4 = 9.06 ± 0.47 %; K2G46 = 9.27 ± 1.33 %; C1-K1 = 13.65 ± 0.53 %; C2-K2 = 16.26 ± 1.05 %) and water absorption (K1G4 = 82.18 ± 5.25 %; K2G46 = 86.54 ± 7.86 %; C1-K1 = 160.04 ± 9.33 %; C2-K2 = 144.42 ± 13.86 %) capacity. Moreover, they were non-cytotoxic towards human keratinocyte (HaCaT) cells, with >90 % cell viability for up to 72 h. The in vitro scratch assays showed a complete wound closure within 48 h for cells exposed to BNC-HA membranes. These findings underscore the potential of co-culturing system to develop BNC-HA nanocomposites for wound healing applications.