Evaluation of Bacterial Nanocellulose Membranes Loaded or Not with Nisin as a Complementary Treatment in Surgical Dehorning Wounds in Bovines

Bacterial Cellulose Membrane Experimentally Implanted in the Peritoneum of Wistar Rats-Inflammatory Immunoreactivity and Oxidative Stress

Bacterial cellulose (BC) has been used for various applications; however, studies investigating the immunohistochemical characteristics of the inflammatory and scarring component in BC implanted in the peritoneum in vivo have not yet been fully described. This study aimed to evaluate the systemic and organic safety of BC through oxidative stress, blood, and serum biochemical markers, as well as the late inflammatory response in rats, using histopathology and immunohistochemistry. Forty-three rats (26 males; 17 females) received BC in the peritoneal cavity (implanted group-IG), while twenty-seven rats (12 males; 15 females) served as the control (sham group-SG). Sixty days after surgery, oxidative stress in tissues, blood biochemical markers, and histopathological and immunohistochemical analyses for lymphocytes, macrophages, collagen, and vascular response around the BC were assessed. Only one oxidative stress marker, glutathione peroxidase, was elevated in the liver of IG rats. Creatine kinase MB and lactate dehydrogenase levels were significantly lower in IG animals. Histopathological analysis showed granulomatous inflammation in 93% of IG rats, with 74% of mild intensity. Immunohistochemistry revealed a significant macrophage presence (F4/80), with CD3, CD20, and F4/80 markers indicating differences favoring macrophages. In conclusion, BC implantation in the peritoneum induces a foreign body granulomatous response with prominent macrophage presence (F4/80). Type I and III collagen were observed around the membrane, and vascularization was intense 60 days post-implantation. From a biochemical and oxidative stress perspective, BC seems to be a safe material to be used in the peritoneal cavity.

Opportunities for bacterial nanocellulose in biomedical applications: Review on biosynthesis, modification and challenges

Bacterial nanocellulose (BNC) is a natural polysaccharide produced as extracellular material by bacterial strains and has favorable intrinsic properties for primary use in biomedical applications. In this review, an update on state-of-the art and challenges in BNC production, surface modification and biomedical application is given. Recent insights in biosynthesis allowed for better understanding of governing parameters improving production efficiency. In particular, introduction of different carbon/nitrogen sources from alternative feedstock and industrial upscaling of various production methods is challenging. It is important to have control on the morphology, porosity and forms of BNC depending on biosynthesis conditions, depending on selection of bacterial strains, reactor design, additives and culture conditions. The BNC is intrinsically characterized by high water absorption capacity, good thermal and mechanical stability, biocompatibility and biodegradability to certain extent. However, additional chemical and/or physical surface modifications are required to improve cell compatibility, protein interaction and antimicrobial properties. The novel trends in synthesis include the in-situ culturing of hybrid BNC nanocomposites in combination with organic material, inorganic material or extracellular components. In parallel with toxicity studies, the applications of BNC in wound care, tissue engineering, medical implants, drug delivery systems or carriers for bioactive compounds, and platforms for biosensors are highlighted.

Bacterial Cellulose Membranes as Carriers for Nisin: Incorporation, Antimicrobial Activity, Cytotoxicity and Morphology

Based on the previous study, in which nisin and bacterial cellulose were utilized, this new experiment loads nisin into bacterial cellulose (N–BC) and evaluates the morphological characteristics, cytotoxicity, antimicrobial activity and stability of the developed system. The load efficiency of nisin in BC was evaluated by an agar diffusion assay, utilizing Lactobacillus sakei, and total proteins. After having found the ideal time and concentration for the loading process, the system stability was evaluated for 100 days at 4, 25 and 37 °C against Staphylococcus aureus and L. sakei. Thus, in this study, there is a system that proves to be efficient, once BC has enhanced the antimicrobial activity of nisin, acting as a selective barrier for other compounds present in the standard solution and protecting the peptide. After 4 h, with 45% of proteins, this activity was almost 2 log10 higher than that of the initial solution. Once the nisin solution was not pure, it is possible to suggest that the BC may have acted as a filter. This barrier enhanced the nisin activity and, as a consequence of the nisin loading, a stable N–BC system formed. The N–BC could create meaningful material for pharmaceutical and food applications.