Effect of purification methods on the physicochemical and biological properties of Nata de fique: A sustainable material for biomedical applications

Bacterial nanocellulose (BNC) is a sustainable biopolymer valued for its high purity, biocompatibility, and mechanical performance. Previous studies have demonstrated that fique juice provides a cost-effective substrate for BNC production; however, efficient purification is required to remove medium residues and bacterial debris that may compromise safety. This study produced BNC membranes from Nata de fique and compared ozone-, NaOH-, and KOH-based purification methods to assess their effects on physicochemical and biological properties. Conventional alkaline treatments effectively removed impurities while preserving fiber morphology, crystallinity, and thermal stability, but generate alkaline waste. In contrast, ozone-based purification—explored here for the first time for Nata de fique—offered an environmentally friendly alternative with comparable efficiency. Ozone exposures of 6 and 15 h maintained crystallinity but did not completely eliminate chromophores derived from chlorophylls and phenolics. A 24 h ozone treatment (BNC-O24) successfully removed pigments and bacterial debris, causing only a slight decrease in crystallinity due to limited hydrogen-bond disruption. All membranes exhibited high cell viability, while KOH and BNC-O24 showed the lowest endotoxin levels. In vivo assays demonstrated that BNC-O24 induced only a mild and transient inflammatory response, with neutrophil infiltration decreasing from score 3 (week 1) to 2 (week 4), comparable to the negative control. Fibrosis remained low (score 2), and giant cells were absent after 4 weeks. Overall, ozone treatment represents an efficient and environmentally friendly purification approach. BNC-O24 stands out as a safe, biocompatible material with suitable physicochemical properties for biomedical applications.