Bacterial Nanocellulose Functionalized with Graphite and Niobium Pentoxide: Limited Antimicrobial Effects and Preserved Cytocompatibility

TL;DR

Researchers modified bacterial nanocellulose with graphite and niobium pentoxide to create antimicrobial wound dressings that remain biocompatible.

Contribution

The study introduces a novel approach to functionalizing bacterial nanocellulose with graphite and niobium pentoxide for antimicrobial wound dressings.

Findings

BNC/f-Gr showed moderate antimicrobial activity, especially against Staphylococcus aureus.

BNC/Nb2O5 did not significantly improve antimicrobial performance compared to unmodified BNC.

Cytocompatibility was preserved in all formulations, with only slight reductions in the combined group.

Abstract

Chronic wounds remain locked in persistent inflammation with high microbial burden, demanding dressings that suppress infection without sacrificing biocompatibility. Bacterial nanocellulose (BNC) is an attractive matrix due to its biocompatibility, nanofibrillar architecture, and moisture retention, but it lacks antimicrobial activity. Here, we engineer BNC membranes post-functionalized with functionalized graphite (f-Gr; predominantly graphitic with residual surface groups) and/or niobium pentoxide (Nb2O5), and evaluate four groups: BNC (matrix control), BNC/Nb2O5, BNC/f-Gr, and BNC/f-Gr/Nb2O5. Physicochemical analyses (Raman and Voigt fitting, FTIR-ATR, XRD, and SEM) confirm a graphitic carbon phase and physical incorporation of the modifiers into the BNC network, with a noticeable shift in the hydration/polarity profile—more evident in the presence of f-Gr. In standardized microbiological assays, BNC/f-Gr promoted a moderate, contact-dependent reduction in bacterial proliferation, particularly against Staphylococcus aureus, whereas BNC/Nb2O5 behaved similarly to pristine BNC under the tested conditions. The combined f-Gr/Nb2O5 formulation showed an intermediate antimicrobial response, with no clear synergy beyond f-Gr alone. Cytotoxicity assays indicated cytocompatibility for BNC, BNC/f-Gr, and BNC/Nb2O5; the combined group displayed a slight reduction that remained within acceptable limits. Overall, BNC/f-Gr emerges as the most promising antimicrobial dressing, while Nb2O5 did not significantly enhance antimicrobial performance under the tested conditions and warrants further optimization regarding loading and distribution.

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