Bioactivity of modified bacterial nanocellulose in non-surgical debridement and infection prevention in burn wound healing
Year: 2025
Type: article
Abstract: In the healing process of burns, removing eschar is essential to reduce infection risk and promote healthy granulation tissue formation and faster wound healing as eschar represents a source of local and systemic infections. Currently, the most common method for its removal is surgical debridement. However, this approach frequently leads to the unintended removal of viable tissue, thereby extending the duration of wound healing and increasing associated treatment costs. Additionally, there is a growing issue with multidrug resistance against conventional therapeutics agents. This study aims to address these challenges by incorporating natural proteolytic enzyme bromelain (Br) and antimicrobial peptide nisin (N) within bacterial nanocellulose (BnC) - material with high water-holding capacity, biocompatibility, ultra-high purity, non-toxicity and mechanical stability. BnC was modified in situ by adding varying concentrations of carboxymethyl cellulose (CMC) to growth medium and further ex-situ modified utilizing Br and N. Response surface methodology (RSM) was employed to determine the optimal combination of processing parameters to maximize proteolytic activity of immobilized Br. The co-immobilization of Br and N was investigated to impart BnC/BnC-CMC membranes with proteolytic and antimicrobial properties. The NBnC-CMC nanocrystals were synthesized from BnC-CMC membranes and subsequently utilized to investigate surface interactions with Br and N using QCM-D. The optimal membranes were characterized according to physical-chemical, morphological, mechanical and bioactive properties. The biological activity of the membranes was assessed through antimicrobial activity and various in vitro and ex vivo methods, including in vitro cell viability and morphology of NHDF and HaCaT cell line, in vitro wound healing, ex vivo bioadhesion testing and ex vivo toxicity testing on human skin explants. The in situ modification of BnC membranes yields BnC-CMC membranes characterized by the presence of carboxyl groups, a more densely distributed fibril structure and an enhanced rehydration ratio in comparison to the original BnC membrane. Identifying optimal immobilization conditions results in the hyperactivation of the Br, achieving a specific proteolytic activity of 2.3 U/mg and an immobilization efficiency of 39.1%. The immobilization of Br and/or N on the BnC-CMC membrane increased the average nanofiber diameter, rehydration ratio and water content and improved adhesion properties. Antimicrobial activity was observed against S. epidermidis, S. aureus and E. faecalis for BnC-N and BnC-CMC-N membranes. The BnC-CMC and BnC-CMC-N membranes were in vitro cytocompatible with NHDF and HaCaT cell lines (Fig 1b), promoting faster HaCaT cell proliferation and/or enhanced migration of NHDF cell lines compared to the commercial product Vivamel. The ex vivo human skin burn model indicated digestion of intercellular junctions in the epidermis for BnC-CMC-BrHC membrane and a moderate irritating effect for BnC-CMC-N membrane, while none of the membranes resulted in acute toxicity as determined by the LDH assay. The BnC-Br and BnC-CMC-Br can be applied topically on severe burn wounds to remove dead tissue through enzymatic debridement. Such mild enzymatic debridement, together with wound closure and maintenance of a moist environment, could result in a more patient-friendly outcome and, therefore, a preferable alternative to the currently predominant surgical debridement, which is often painful. On the other hand, BnC-N and BnC-CMC-N membranes are more suitable for debris-free burns with a high risk of infection due to the broad spectrum of antibacterial activity against numerous Gram-positive bacteria with a low bacterial resistance rate. Following the promising results regarding in vitro cytocompatibility and wound healing abilities of bioactive BnC-CMC membranes, as well as ex vivo evaluation, further in vivo biocompatibility studies in burn-induced rat models will be necessary to validate the long-term biocompatibility, wound healing properties and antibacterial efficacy of the membranes. Novel bioactive BnC membranes have been developed to facilitate effective, non-surgical debridement and infection prevention in the healing of burn wounds. The prepared BnC-CMC-Br and BnC-CMC-N membranes demonstrate significant potential for use in different stages of burn treatment.
Author: Jančič, Urška
Institution: University of Maribor
Language: English
Subfield: Biomaterials
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7083803126
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