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Bacterial cellulose (BC) is produced by several microorganisms as extracellular structures and can be modified by various physicochemical and biological strategies to produce different cellulosic formats. The main advantages of BC for biomedical applications can be summarized thus: easy moldability, purification, and scalability; high biocompatibility; and straightforward tailoring. The presence of a high amount of free hydroxyl residues, linked with water and nanoporous morphology, makes BC polymer an ideal candidate for wound healing. In this frame, acute and chronic wounds, associated with prevalent pathologies, were addressed to find adequate therapeutic strategies. Hence, the main characteristics of different BC structures—such as membranes and films, fibrous and spheroidal, nanocrystals and nanofibers, and different BC blends, as well as recent advances in BC composites with alginate, collagen, chitosan, silk sericin, and some miscellaneous blends—are reported in detail. Moreover, the development of novel antimicrobial BC and drug delivery systems are discussed.

In this paper, we present a novel, ecologically friendly technology for the synthesis and modification of kombucha-derived bacterial cellulose in order to produce textiles of desired physicochemical and mechanical properties. The procedure of manufacturing cellulose in the form of a stable hydrogel bacterial cellulose (HGBC) ensures the desired properties for the application of such a material, e.g., in the textile industry. Bacterial cellulose was obtained from a yeast/bacteria kombucha culture (a symbiotic consortium also known as “tea fungus” or SCOBY) that is easy and cheap to breed. The process of bacterial cellulose manufacturing and modification was optimized in order to obtain a maximum recovery of raw materials, minimal energy consumption and ensure the use of only natural and renewable resources. The obtained materials were characterized in terms of their wettability, mechanical properties, and flame resistance. Moreover, the morphology and composition of the materials were determined by using scanning electron microscopy and infrared spectroscopy, respectively. Additionally, it was proven that the HGBC materials might be used to manufacture various articles of clothing using commonly available sewing techniques, which are not adequate for non-modified cellulose-based materials. Finally, the synthesized fabrics were used as wristbands and parts of T-shirts and tested on volunteers to determine a skin-to-skin contact behaviour of the prepared fabrics. The reported results allow for confirming that the HGBC fabric may be used as a new textile and the proposed synthesis method is in accordance with the “green chemistry.”Graphic abstract

Bacterial cellulose (BC) is a unique microbial biopolymer with a huge number of significant applications in the biomedical field, including bone tissue engineering. The present study proposes to obtain and characterize BC hybrid composites with calcium phosphate as biocompatible and bioactive membranes for bone tissue engineering. BC precursor membranes were obtained in static culture fermentation, and after purification, were oxidized to obtain 2,3-dialdehyde bacterial cellulose (DABC). Calcium phosphate-BC oxidized membranes were produced by successive immersion in precursor solutions under ultrasonic irradiation. The samples were characterized for their physicochemical properties using scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy grazing incidence X-ray diffraction (GI-XRD), solid-state 13C nuclear magnetic resonance (CP/MAS 13C NMR), and complex thermal analysis. In vitro cell studies were also performed to evaluate the influence of modified morphological characteristics on cell adhesion and proliferation. The results showed an increase in porosity and biodegradability for DABC hybrid composites compared with BC. In vitro cell studies have revealed that both hybrid composites favor cell adhesion to the surface. The new BC and DABC hybrid composites with calcium phosphate could be considered promising materials for bone tissue regeneration.

Nata de coco has been used as a raw material for food preparation. In this study, the production of carboxymethyl cellulose (CMC) film from nata de coco and the effect of monochloroacetic acid on carboxymethyl bacterial cellulose (CMCn) and its film were investigated. Bacterial cellulose from nata de coco was modified into CMC form via carboxymethylation using various concentrations of monochloroacetic acid (MCA) at 6, 12, 18, and 24 g per 15 g of cellulose. The results showed that different concentrations of MCA affected the degree of substitution (DS), chemical structure, viscosity, color, crystallinity, and morphology of CMCn. The optimum treatment for carboxymethylation was found using 24 g of MCA per 15 g of cellulose, which provided the highest DS at 0.83. The morphology of CMCn was related to DS value; a higher DS value showed denser and smoother surface than nata de coco cellulose. The various MCA concentrations increased the mechanical properties (tensile strength and percentage of elongation at break) and water vapor permeability of CMCn, which were related to the DS value.

As a conventional medical dressing, medical gauze does not adequately protect complex and hard-to-heal diabetic wounds and is likely to permit bacterial entry and infections. Therefore, it is necessary to develop novel dressings to promote wound healing in diabetic patients. Komagataeibacter intermedius was used to produce unmodified bacterial cellulose, which is rarely applied directly to diabetic wounds. The produced cellulose was evaluated for wound recovery rate, level of inflammation, epidermal histopathology, and antimicrobial activities in treated wounds. Diabetic mices’ wounds treated with bacterial cellulose healed 1.63 times faster than those treated with gauze; the values for the skin indicators in bacterial cellulose treated wounds were more significant than those treated with gauze. Bacterial cellulose was more effective than gauze in promoting tissue proliferation with more complete epidermal layers and the formation of compact collagen in the histological examination. Moreover, wounds treated with bacterial cellulose alone had less water and glucose content than those treated with gauze; this led to an increase of 6.82 times in antimicrobial protection, lower levels of TNF-α and IL-6 (39.6% and 83.2%), and higher levels of IL-10 (2.07 times) than in mice wounds treated with gauze. The results show that bacterial cellulose produced using K. intermedius beneficially affects diabetic wound healing and creates a hygienic microenvironment by preventing inflammation. We suggest that bacterial cellulose can replace medical gauze as a wound dressing for diabetic patients.

A soft synthesis of nanoceria with non-stoichiometric composition (33% Ce3+/67% Ce4+) named CeO2 NPs in bacterial cellulose (BC) matrix in the form of aerogel and hydrogel with controlled CeO2 NPs content was proposed. The advantage of CeO2 NPs synthesis in BC is the use of systemic antacid API–trisamine as a precursor, which did not destruct cellulose at room temperature and enabled a reduction in the duration of synthesis and the number of washes. Moreover, this method resulted in the subsequent uniform distribution of CeO2 NPs in the BC matrix due to cerium (III) nitrate sorption in the BC matrix. CeO2 NPs (0.1–50.0%) in the BC matrix had a fluorite structure with a size of 3–5 nm; the specific surface area of the composites was 233.728 m2/g. CeO2 NPs in the BC-CeO2 NPs composite demonstrated SOD-like activity in the processes of oxidation and reduction of cytochrome c (cyt c3+/cyt c2+), as well as epinephrine to inhibit its auto-oxidation in aqueous solutions by 33–63% relative to the control. In vitro experiments on rat blood showed a decrease in the MDA level and an increase in the activity of antioxidant defense enzymes–SOD by 24% and G6PDH by 2.0–2.5 times. Therefore, BC-CeO2 NPs can be proposed for wound healing as antioxidant material.

The versatility, contribution to sustainability, and diversity of applications of bacterial cellulose require large-scale production processes and new alternatives in terms of biological systems that, under controlled conditions, favor the growth and production of this biomaterial. This review article describes the technologies developed and the advances achieved in regard to the production of bacterial cellulose on a small and large scale, according to the findings evidenced in the scientific literature in the last ten years. A review, based on the guidelines in the PRISMA® methodology, of a selection of articles was carried out, with a Cohen’s Kappa coefficient of 0.465; scientific databases, such as Web of Science, SCOPUS, PubMed, Taylor and Francis, and ProQuest, were considered. There is a wide variety of bacterial pulp production systems and the design of such a system is based on the type of cellulose-producing bacteria, oxygen requirements, mixing and agitation, temperature control, sterilization and cleaning requirements, and production scalability. The evolution in the development of bioreactors for bacterial cellulose has focused on improving the production process’s efficiency, productivity, and control, and adapting to the specific needs of bacterial strains and industrial applications.

New carriers for protein immobilization are objects of interest in various fields of biomedicine. Immobilization is a technique used to stabilize and provide physical support for biological micro- and macromolecules and whole cells. Special efforts have been made to develop new materials for protein immobilization that are non-toxic to both the body and the environment, inexpensive, readily available, and easy to modify. Currently, biodegradable and non-toxic polymers, including cellulose, are widely used for protein immobilization. Bacterial cellulose (BC) is a natural polymer with excellent biocompatibility, purity, high porosity, high water uptake capacity, non-immunogenicity, and ease of production and modification. BC is composed of glucose units and does not contain lignin or hemicellulose, which is an advantage allowing the avoidance of the chemical purification step before use. Recently, BC–protein composites have been developed as wound dressings, tissue engineering scaffolds, three-dimensional (3D) cell culture systems, drug delivery systems, and enzyme immobilization matrices. Proteins or peptides are often added to polymeric scaffolds to improve their biocompatibility and biological, physical–chemical, and mechanical properties. To broaden BC applications, various ex situ and in situ modifications of native BC are used to improve its properties for a specific application. In vivo studies showed that several BC–protein composites exhibited excellent biocompatibility, demonstrated prolonged treatment time, and increased the survival of animals. Today, there are several patents and commercial BC-based composites for wounds and vascular grafts. Therefore, further research on BC–protein composites has great prospects. This review focuses on the major advances in protein immobilization on BC for biomedical applications.

Bacterial cellulose (BC) is naturally degradable, highly biocompatible, hydrophilic, and essentially non-toxic, making it potentially useful as a base for creating more sophisticated bio-based materials. BC is similar to plant-derived cellulose in terms of chemical composition and structure but has a number of important differences in microstructure that could provide some unique opportunities for use as a scaffold for other functions. In this study, bacterial cellulose was alkylated and then esterified to produce a carboxymethyl bacterial cellulose (CMBC) that was then used to produce six different composite films with potential antibacterial properties. The films were assessed for antibacterial activity against Staphylococcus aureus and Escherichia coli, pyrolysis characteristics using thermogravimetric analysis (TGA), microstructure using scanning electron microscopy (SEM), and mechanical properties. The addition of nano-silver (nano-Ag) markedly improved the antimicrobial activity of the films while also enhancing the physical and mechanical properties. The results indicate that the three-dimensional reticulated structure of the bacterial cellulose provides an excellent substrate for scaffolding other bioactive materials. Thus, the nano-BC was added into the CMBC/nano-Ag composites furthermore, and then the antibacterial and mechanical properties were improved 44% for E. coli, 59% for S. aureus, and 20% for tensile strength, respectively.

This study investigated the nitration of nanostructured bacterial cellulose (NBC). The NBC, obtained using symbiotic Medusomyces gisevii Sa-12 as the microbial producer and then freeze-dried, was nitrated herein by two methods, the first using mixed sulphuric–nitric acids (MA) and the second using concentrated nitric acid in the presence of methylene chloride (NA+MC). The synthesized samples of NBC nitrates (NBCNs) exhibited 11.77–12.27% nitrogen content, a viscosity of 1086 mPa·s or higher, 0.7–14.5% solubility in an alcohol–ester mixture, and 0.002% ash. Scanning electron microscopy showed that the nitration compacted the NBC structure, with the original reticulate pattern of the structure being preserved in full. Infrared spectroscopy for the presence of functional nitro groups at 1658–1659, 1280, 838–840, 749–751 and 693–694 cm−1 confirmed the synthesis of cellulose nitrates in particular. Thermogravimetric and differential thermal analyses showed the resultant NBCNs to have a high purity and high specific heats of decomposition of 6.94–7.08 kJ/g. The NBCN samples differ conceptually from plant-based cellulose nitrates by having a viscosity above 1086 mPa·s and a unique 3D reticulate structure that is retained during the nitration. The findings suggest that the NBCNs can be considered for use in novel high-tech materials and science-driven fields distinct from the application fields of plant-based cellulose nitrates. The NBCN sample obtained with NA+MC has the ability to generate an organogel when it is dissolved in acetone. Because of the said property, this NBCN sample can find use as a classical adhesive scaffold and an energetic gel matrix for creating promising energetic polymers.