Novel Bacterial Cellulose Composite Material Prepared by the Synergistic Deposition of Collagen and Tannin

Bacterial cellulose (BC) is a sustainable biopolymer whose composite fabrication is challenged by structural disruption during processing and potential cytotoxicity from cross-linkers. In this study, we developed a BC/collagen/tannin composite using a simple deposition method. The entire preparation process of this composite was free of toxic chemicals and was accomplished through a simple impregnation technique that preserved the structural integrity of the BC network. First, BC was pretreated in NaOH/urea solution to increase the proportion of amorphous regions within the membrane, which promoted the adsorption of collagen. Second, inspired by interactions between tannin and proteins during the leather tanning process, tannin was used to immobilize adsorbed collagen within the pores of BC to form a dense and stable cross-linked network. The BC composite exhibited a maximum tensile strength of 53.42 MPa and an elongation at break of 21.30%. The BC composite also showed an air permeability of 2.76 kg/(h·m²) and biocompatibility, with cell viability exceeding 85%. This composite can potentially be used to develop skin repair dressings and biobased leather materials. This paper presents an efficient and environmentally friendly strategy for preparing BC/collagen biocomposites.