Bacterial Cellulose Matrix Research Articles

Bacterial Cellulose–Silk Hydrogel Biosynthesized by Using Coconut Skim Milk as Culture Medium for Biomedical Applications

In this study, hydrogel films of biocomposite comprising bacterial cellulose (BC) and silk (S) were successfully fabricated through a simple, facile, and cost-effective method via biosynthesis by Acetobacter xylinum in a culture medium of coconut skim milk/mature coconut water supplemented with the powders of thin-shell silk cocoon (SC). Coconut skim milk/mature coconut water and SC are the main byproducts of coconut oil and silk textile industries, respectively. The S/BC films contain protein, carbohydrate, fat, and minerals and possess a number of properties beneficial to wound healing and tissue engineering, including nontoxicity, biocompatibility, appropriate mechanical properties, flexibility, and high water absorption capacity. It was demonstrated that silk could fill into a porous structure and cover fibers of the BC matrix with very good integration. In addition, components (fat, protein, etc.) in coconut skim milk could be well incorporated into the hydrogel, resulting in a more elastic structure and higher tensile strength of films. The tensile strength and the elongation at break of BC film from coconut skim milk (BCM) were 212.4 MPa and 2.54%, respectively, which were significantly higher than BC film from mature coconut water (BCW). A more elastic structure and relatively higher tensile strength of S/BCM compared with S/BCW were observed. The films of S/BCM and S/BCW showed very high water uptake ability in the range of 400–500%. The presence of silk in the films also significantly enhanced the adhesion, proliferation, and cell-to-cell interaction of Vero and HaCat cells. According to multiple improved properties, S/BC hydrogel films are high-potential candidates for application as biomaterials for wound dressing and tissue engineering.

Anti-pathogenic and probiotic-friendly effect of benzyloxy pyridine derivative impregnated into bacterial cellulose matrix

Bacterial cellulose (BC) has emerged as a promising biomaterial for biomedical applications due to its unique properties. In this study, firstly, the potential of BC as a carrier material for the originally synthesized benzyloxy pyridine derivative (BeOxP), and also an antimicrobial and probiotic bacteria-friendly (on Lactiplantibacillus plantarum 299v (LP299V®) (DSM 9843)) effect of BC- BeOxP was investigated. The BC- BeOxP composite material was developed using a simple and efficient method, ensuring the uniform dispersion of BeOxP within the BC matrix. Characterization of BeOxP has been carried out with High-Resolution Mass Spectroscopy (HRMS) and Nuclear Magnetic Resonance (NMR). Additionally, BC- BeOxP was characterized by Thermogravimetric analysis (TGA), Differential thermal analysis (DTA), Scanning Electron Microscopy (SEM), Texture analysis, and Fourier-transform infrared spectroscopy (FTIR), confirming the successful integration of BeOxP without compromising the structural integrity of BC. The mechanical properties of the BC- BeOxP composites were also evaluated to ensure their suitability for drug-carrying or food-packaging applications. Antimicrobial activity of the BC- BeOxP was analyzed against Staphylococcus aureus ATCC 29213 and Escherichia coli ATCC 25922 while the probiotic-friendly effect was tested on Lactiplantibacillus plantarum 299v (LP299V®) (DSM 9843). The findings open avenues for further research of BC-based drug carriers or packaging materials for advanced biomedical applications.

Profile of a Composite Based on Bacterial Cellulose and Polyvinyl Alcohol as a Drug Release Matrix for Tetracycline Hydrochloride

Bacterial cellulose (BC) is a natural polymer with good mechanical properties and hydrophilicity. Polyvinyl alcohol (PVA) is a synthetic polymer widely used in medicine. Both have been researched for their potential in drug release and acceptance. This study aims to determine the role of BC and PVA as drug release matrices for tetracycline hydrochloride (TCH), with additional fillers such as graphite (G) and TiO2. The results showed that the composites with BC matrix had lower mechanical properties than those with PVA matrix, with tensile strength values of 6.4075 and 17.446 MPa, respectively. However, the BC matrix was superior in porosity and swelling ability. The drug release testing of TCH from the composites showed that the appropriate model to describe drug release in BC matrix composites was in zero order, while the PVA matrix was in first order. The antibacterial activity of the composites on both matrices was tested against Staphylococcus aureus. The results indicate that both composites have potential applications in promising biomedical fields.

Fabrication and properties of conductive films based on bacterial cellulose and poly-N-isopropylacrylamide-modified graphene oxide

A conductive film (PNIPAM-rGO/BC) was fabricated combining bacterial cellulose (BC) with poly-N-isopropylacrylamide-modified graphene oxide (PNIPAM-GO) through vacuum filtration and steam reduction techniques. The conductivity and performance of PNIPAM-GO composite and the resulting conductive film were studied. The key findings revealed that PNIPAM-GO composite exhibited a reversible temperature-sensitive behavior. Specifically, the lower critical solution temperature (LCST) increased upon the introduction of graphene oxide (GO). Detailed analyses confirmed uniform dispersion of GO nanosheets within the BC matrix. The incorporation of 10.0 % PNIPAM-GO (containing 7.0 % GO) led to a remarkable 19.6 % increase in tensile strength and approximately 37.0 % enhancement in elongation at break for the conductive film (PNIPAM-rGO/BC) compared to BC. After steam reduction, the electrical conductivity of PNIPAM-rGO/BC exhibited significant improvement over BC. Furthermore, the conductive film demonstrated temperature-dependent conductivity, with a resistivity value approximately 5.2 ± 0.2 KΩ at 25 °C. As the test temperature above the LCST of PNIPAM-GO composite, the resistance decreased. These intriguing temperature-sensitive conductive properties position PNIPAM-rGO/BC as a promising material for smart switches.

Antimicrobial Activity against Cronobacter of Plant Extracts and Essential Oils in a Matrix of Bacterial Cellulose.

Bacterial cellulose (BC) is a biodegradable polymer resembling paper after being dried. It finds a growing number of applications in many branches of industry and in medicine. In the present study, BC was produced after Gluconacetobacter hansenii ATCC 23769 strain culture and used as a matrix for plant extracts (tulsi, brahmi, lemon, blackberry, nettle root, and nettle leave) and essential oils (cinnamon, sage, clove, mint, thyme, lemongrass, rosemary, lemon, anise, tea tree, lime, grapefruit, and tangerine), and the antimicrobial properties of these biomaterials was determined. The growth-inhibiting effects of plant extracts and essential oils combined with BC were analyzed against five Cronobacter species isolated from food matrix and two reference strains from the ATCC (513229 and 29544). Additional analyses were conducted for BC water activity and for its capability to absorb biologically active plant compounds. The cellulose matrix with a 50% extract from brahmi was found to effectively inhibit the growth of the selected Cronobacter strains. The other plant water extracts did not show any antimicrobial activity against the tested strains. It was demonstrated that BC soaked with thyme essential oil was characterized with the strongest antimicrobial activity in comparison to the other tested EOs. These study results indicate the feasibility of deploying BC impregnated with natural plant components as an active and environmentally-friendly packaging material.

Halochromic Bacterial Cellulose/Anthocyanins Hybrid Polymer Film with Wound-Healing Potential.

Polymer-based dressings deriving from natural biomaterials have advantages such as nontoxicity, biocompatibility, and mechanical stability, which are essential for efficient wound healing and microbial infection diagnostics. Here, we designed a prototype of an intelligent hydrogel dressing on the base of bacterial cellulose (BC) for monitoring wound microbial infection due to the uploaded natural pH dye-sensor, anthocyanins (ANC) of elderberry fruit (Sambucus nigra L.). The highest sensor responses to bacterial metabolites for ANC immobilized to BC were observed at pH 5.0 and 6.0. The detection limit of the sensor signals was 3.45 A.U., as it was evaluated with a smartphone-installed application. The FTIR spectral analysis of the hybrid BC/ANC hydrogel films has proved the presence of anthocyanins within the BC matrix. Hybrid films differed from the control ones by thicker microfibrils and larger pores, as detected with scanning electron microscopy. Halochromic BC/ANC films exhibited antimicrobial activities mainly against gram-positive bacteria and yeast. They showed no cytotoxicity for the in vitro human cell lines and mouse fibroblasts within a selected range of anthocyanin concentrations released from the BC/ANC film/dressing prototype. Compared to the control, the in vitro healing test showed overgrowth of primary mouse fibroblasts after applying 0.024-2.4 µg/mL ANC.

Towards Sustainable Packaging Using Microbial Cellulose and Sugarcane (Saccharum officinarum L.) Bagasse.

The high consumption of packaging has led to a massive production of waste, especially in the form of nonbiodegradable polymers that are difficult to recycle. Microbial cellulose is considered a biodegradable, low-cost, useful, ecologically correct polymer that may be joined with other biomaterials to obtain novel characteristics and can, therefore, be used as a raw material to produce packaging. Bagasse, a waste rich in plant cellulose, can be reprocessed and used to produce and reinforce other materials. Based on these concepts, the aim of the current research was to design sustainable packaging material composed of bacterial cellulose (BC) and sugarcane bagasse (SCB), employing an innovative shredding and reconstitution method able to avoid biomass waste. This method enabled creating a uniform structure with a 0.10-cm constant thickness, classified as having high grammage. The developed materials, particularly the 0.7 BC/0.3 SCB [70% (w/w) BC plus 30% (w/w) SCB] composite, had considerable tensile strength (up to 46.22 MPa), which was nearly thrice that of SCB alone (17.43 MPa). Additionally, the sorption index of the 0.7 BC/0.3 SCB composite (235.85 ± 31.29 s) was approximately 300-times higher than that of SCB (0.78 ± 0.09 s). The packaging material was also submitted to other analytical tests to determine its physical and chemical characteristics, which indicated that it has excellent flexibility and can be folded 100 times without tearing. Its surface was explored via scanning electron microscopy, which revealed the presence of fibers measuring 83.18 nm in diameter (BC). Greater adherence after the reconstitution process and even a uniform distribution of SCB fibers in the BC matrix were observed, resulting in greater tear resistance than SCB in its pure form. The results demonstrated that the composite formed by BC and SCB is promising as a raw material for sustainable packaging, due to its resistance and uniformity.

Biomimetic design of platelet-rich plasma controlled release bacterial cellulose/hydroxyapatite composite hydrogel for bone tissue engineering

Bacterial cellulose (BC) hydrogel is renowned in the field of tissue engineering for its high biocompatibility, excellent mechanical strength, and eco-friendliness. Herein, we present a biomimetic mineralization method for preparing BC/hydroxyapatite (HAP) composite hydrogel scaffolds with different mineralization time and ion concentration of the mineralized solution. Spherical HAP reinforcement enhanced bone mineralization, thereby imparting increased bioactivity to BC matrix materials. Subsequently, platelet-rich plasma (PRP) was introduced into the scaffold. The PRP-loaded hydrogel enhanced the release of growth factors, which promoted cell adhesion, growth, and bone healing. After 3 weeks of MC3T3-E1 cell-induced osteogenesis, PRP positively affected cell differentiation in BC/HAP@PRP scaffolds. Overall, these scaffolds exhibited excellent biocompatibility, mineralized nodule formation, and controlled release in vitro, demonstrating great potential for application in bone tissue repair.

Highly Thermally Conductive Flexible Biomimetic APTES-BNNS/BC Nanocomposite Paper by Sol-Gel-Film Technology.

Owing to the evolution of 5G technology, new energy vehicles, flexible electronics, miniaturization and integration of microelectronic devices, high-frequency and high-power devices, and thermal management of materials must consider additional limitations such as electrical insulation, excellent transverse heat transfer, flexibility, and weight. Boron nitride nanosheets (BNNSs) are ideal insulating materials with high thermal conductivity. However, the problem of the 3D thermal conductivity pathway and toughness strength of nanocomposite paper loaded with inorganic thermal conductivity fillers remains a huge challenge. In this study, we propose a new method for preparing ultrathin, large, and uniformly thick BNNS for quantitative production. Bulk hexagonal boron nitride (hBN) layers were exfoliated using a simple and low-cost hydrothermal reaction, and large-scale fewer-layered BNNSs were efficiently prepared by ball milling with a high yield (up to 80%). Based on the aforementioned step, a flexible insulating composite film with high thermal conductivity and a natural "brick-mud" shell structure was constructed via the sol-gel-film conversion method. After prestretching and hot-pressing treatment, the hydrogels became denser, and the modified BNNS formed a three-dimensional (3D) network structure with an ordered orientation and interconnections in the bacterial cellulose (BC) matrix. After 100 folding cycles, the tensile strength of the nanofiber composite film reached 53 MPa, and the strength retention rate exceeded 42%. By optimizing the modified BNNS content, the thermal conductivity reached 24 W/(m·K). This simple approach has wide application potential in the next-generation electronic devices, providing options for designing thermal interface materials with excellent electrical insulation, high thermal stability, and flexibility.

The production of bacterial cellulose from coconut water and its application as a green photocatalyst composite membrane

AbstractIn this research work, bacterial cellulose was produced from the fermentation of coconut water and incubated for 4, 5, and 6 days. The bacterial cellulose membrane was utilized as immobilized silver nanoparticles (AgNPs). A green photocatalyst membrane was prepared by reducing silver ions in the bacterial cellulose matrix structure using local fruit extracts, tomatoes, Citrus hystrix fruit, and mangosteen peel as a reducing agent. The composite was dried in the oven to obtain a more durable fixed structure. The properties of produced bacterial cellulose were determined by measuring the thickness, water retention capacity (WRC), cellulose content, and swelling. The functional group and crystallinity index of bacterial cellulose were observed by FTIR and XRD instrument analysis. The SEM EDX analysis confirms that the silver ions were successfully reduced in the BC matrix, and the UV–Vis spectrum showed that the composite membrane has the ability to degrade the methylene blue solution under sunlight irradiation. The maximum degradation efficiency of the composite membrane against 5 ppm methylene blue solution was achieved by the composite membrane reduced by tomatoes, with a value of 93%. This result proved that the composite membrane produced in this research has excellent capabilities as a green photocatalyst for degrading wastewater containing dye pollutants.

Bacterial cellulose-turmeric powder composites as potential therapeutic wound dressings

Bacterial cellulose (BC) has emerged as a promising biomaterial for rapid wound healing and tissue regeneration due to its excellent liquid absorbing and biocompatible properties. However, its lack of therapeutic properties restricts its applicability as a wound dressing. The current study was undertaken to develop bacterial cellulose-turmeric powder (BC-TP) composite films as wound dressing materials that combine the therapeutic properties of turmeric powder (TP) with the unique structural, physicochemical, and biological properties of BC. FTIR and SEM showed that TP was successfully impregnated into BC films using an ex-situ approach. Swelling and water release rate studies revealed that the composite films produced had high-water uptake and retention capacities. Antibacterial investigations using gram-positive and -negative species demonstrated the significant antibacterial potential of TP when incorporated into a BC matrix. Toxicity testing confirmed the non-cytotoxic nature of BC-TP composite films, while biocompatibility investigations demonstrated that fibroblast cells attached and proliferated effectively on BC films treated with TP. Furthermore, BC-TP composites promoted tissue regeneration, hair growth, and wound healing. BC composites exhibited over 90% wound closure by the 7th day, whereas untreated wounds demonstrated only approximately 24% closure during the same period. The study shows that the manufactured BC-TP composite films offer starting points for the development of alternative standard wound dressing systems.

Bacterial cellulose matrix and acellular dermal matrix seeded with fibroblasts grown in platelet-rich plasma supplemented medium, compared to free gingival grafts: a randomized animal study.

Mucogingival defects (MGDs), such as dental root recessions, decreased vestibular depth, and absence of keratinized tissues, are commonly seen in dental clinics. MGDs may result in functional, aesthetic, and hygienic concerns. In these situations, autogenous soft tissue grafts are considered the gold-standard treatment. This study compares the healing process of free gingival grafts (FGGs) to bacterial cellulose matrix (BCM) and human acellular dermal matrix (ADM) seeded with fibroblasts from culture supplemented with platelet-rich plasma in a rat model. Surgical defects were made in rats, which received the following treatments in a randomized manner: group I, negative control (defect creation only); group II, positive control (FGG); group III, BCM; group IV, BCM + fibroblasts; group V, ADM; and group VI, ADM + fibroblasts. Clinical, histological, and immunological analyses were performed 15 days after grafting. Clinical examinations recorded epithelium regularity and the presence of ulcers, erythema, and/or edema. The histological analysis revealed the degree of reepithelization, width, regularity, and presence of keratin. The Fisher exact statistical test was applied to the results (P<0.05). No groups showed ulcers except for group I. All groups had regular epithelium without erythema and without edema. Histologically, all groups exhibited regular epithelium with keratinization, and myofibroblasts were present in the connective tissue. The groups that received engineered grafts showed similar clinical and histological results to the FGG group. Within the limitations of this study, it was concluded that BCM and ADM can be used as cell scaffolds, with ADM yielding the best results. This study supports the use of this technical protocol in humans.

A lignin-derived carbon dot-upgraded bacterial cellulose membrane as an all-in-one interfacial evaporator for solar-driven water purification.

Solar-driven interfacial evaporation has emerged as an efficient approach for wastewater treatment and seawater desalination. New trends demand adaptive technology to develop photothermal membranes with multifunctional features. Herein, we report a robust multi-purpose near-infrared (NIR)-active hydrogel composite (c-BC@N-LCD) from broad-spectrum active nitrogen-doped lignin-derived carbon dots (N-LCDs) covalently cross-linked with a bacterial cellulose (BC) matrix. BC provides adequate porosity and hydrophilicity required for easy water transport while managing heat loss. A commendable evaporation rate (ER) of 2.2 kg m-2 h-1 under one sun (1 kW m-2) is achieved by c-BC@N-LCD. The developed hydrogel system is also found to be efficient for desalination (∼2.1 kg m-2 h-1) and for remediating various pollutants (heavy metal ions, dyes, and pharmaceuticals) from feed water. The efficacy of the membrane remains unaltered by different grades of water, and hence can be adoptable for economically stressed communities living in water-polluted regions as well as those residing in coastal areas.

Biodegradable Dual-Network Cellulosic Composite Bioplastic Metafilm for Plastic Substitute.

With the escalating environmental and health concerns over petroleum-based plastics, sustainable and biodegradable cellulosic materials are a promising alternative to plastics, yet remain unsatisfied properties such as fragility, inflammability and water sensitivity for practical usage. Herein, we present a novel dual-network design strategy to address these limitations and fabricate a high-performance cellulosic composite bioplastic metafilm with the exceptional mechanical toughness (23.5 MJ m-3 ), flame retardance, and solvent resistance by in situ growth of cyclotriphosphazene-bridged organosilica network within bacterial cellulose matrix. The phosphorus, nitrogen-containing organosilica network, verified by the experimental and theoretical results, plays a triple action on significantly enhancing tensile strength, toughness, flame retardance and water resistance of composite bioplastic metafilm. Furthermore, cellulosic bioplastic composite metafilm demonstrates a higher maximum usage temperature (245 °C), lower thermal expansion coefficient (15.19 ppm °C-1 ), and better solvent resistance than traditional plastics, good biocompatibility and natural biodegradation. Moreover, the composite bioplastic metafilm have a good transparency of average 74 % and a high haze over 80 %, which can serve as an outstanding substrate substitute for commercial polyethylene terephthalate film to address the demand of flexible ITO films. This work paves a creative way to design and manufacture the competitive bioplastic composite to replace daily-used plastics.

Biodegradable Dual‐Network Cellulosic Composite Bioplastic Metafilm for Plastic Substitute

AbstractWith the escalating environmental and health concerns over petroleum‐based plastics, sustainable and biodegradable cellulosic materials are a promising alternative to plastics, yet remain unsatisfied properties such as fragility, inflammability and water sensitivity for practical usage. Herein, we present a novel dual‐network design strategy to address these limitations and fabricate a high‐performance cellulosic composite bioplastic metafilm with the exceptional mechanical toughness (23.5 MJ m−3), flame retardance, and solvent resistance by in situ growth of cyclotriphosphazene‐bridged organosilica network within bacterial cellulose matrix. The phosphorus, nitrogen‐containing organosilica network, verified by the experimental and theoretical results, plays a triple action on significantly enhancing tensile strength, toughness, flame retardance and water resistance of composite bioplastic metafilm. Furthermore, cellulosic bioplastic composite metafilm demonstrates a higher maximum usage temperature (245 °C), lower thermal expansion coefficient (15.19 ppm °C−1), and better solvent resistance than traditional plastics, good biocompatibility and natural biodegradation. Moreover, the composite bioplastic metafilm have a good transparency of average 74 % and a high haze over 80 %, which can serve as an outstanding substrate substitute for commercial polyethylene terephthalate film to address the demand of flexible ITO films. This work paves a creative way to design and manufacture the competitive bioplastic composite to replace daily‐used plastics.

Bacterial cellulose based TiO2-CdS nanocomposite gel with enhanced photocatalytic activity for adsorptive degradation of cationic dye

Dye released by industrial is one of the main known pollutants in wastewater, which is harmfully affected to the human health. Adsorptive method by absorbents and photocatalytic degradation technique are advanced technologies to remove dyes from wastewater. However, the single technique mentioned above has imperfections limiting its application. Herein, in order to integrate the two techniques and take both advantages, bacterial cellulose (BC) based titanium dioxide (TiO2)‑cadmium sulfide (CdS) nanocomposite gel was prepared by microwave-assisted solvothermal synthesis. The BC@TiO2-CdS nanocomposite gel was characterized by SEM, EDS, XRD, XPS, Raman spectral and TG, its photocatalytic mechanism was proved by PL. The results showed the TiO2-CdS nanophotocatalyst exhibited binary hierarchical structure and followed the Z-scheme type photocatalytic system. The Z-scheme heterojunction is advantageous for photo-generated charge separation and migration. The photocatalytic performance of BC@TiO2-CdS nanocomposite gel was evaluated by MB degradation under visible light irradiation. Due to synergistic effect of BC matrix and TiO2-CdS, the as-prepared BC@TiO2-CdS nanocomposite gel possesses enhanced photocatalytic activity with 94.47 % removal of methylene blue (MB) after 180 min visible light irradiation. Therefore, this work provides a facile route to fabricate bio-mass based efficient nanophotocatalytic material for pretreating the water pollution.

Bacterial cellulose as a reinforcement material of alginate beads improves effectiveness and recycling potential of immobilized photosynthetic bacteria for cooking oil waste removal

The rapid degradation of alginate beads limits the lifespan of immobilized cells. In this study, bacterial cellulose (BC) incorporated in alginate was used to improve the mechanical properties, swelling ratio, and recycling time of the immobilized photosynthetic bacterium Rhodopseudomonas faecalis PA2 for the removal of cooking oil residues. Beads reinforced with 25 and 50% BC showed a higher Young's modulus and compressive strength and a lower swelling ratio than the control treatment (0% BC). The incorporation of 50% BC increased biomass production and oil removal. Field-emission scanning electron microscopy revealed several bacteria-infested internal pores in the reinforced beads, indicating bacterial growth in the presence of BC. Bacterial viability was verified by BC immersion in the bacterial culture broth and by injecting bacteria into the BC matrix. Without BC reinforcement, beads collapsed after reuse in two batches, whereas reinforced beads could be reused for five batches, resulting in an oil removal rate of up to 76.3 %. Our results show that BC can be used as an alginate reinforcing material to improve bead stability and prolong the effective recycling period of immobilized bacteria without negatively affecting bacterial growth or waste oil removal.

Silver phosphate–bacterial cellulose nanocomposites as visible light photocatalyst for wastewater purification

Silver phosphate (Ag3PO4) nanoparticles were deposited on bacterial cellulose (BC) nanofibrils as an eco-friendly, efficient, and reusable visible light active photocatalyst. BC–Ag3PO4 nanocomposites (BCAgP) with different BC/Ag3PO4 weight ratios were prepared by solution-precipitation method. The nanocomposites were characterized by UV-Visible diffuse reflection spectroscopy, XRD, FTIR, BET, and FESEM. Highly crystalline Ag3PO4 nanoparticles were well entrapped inside nano fibrillated BC matrix and eventually deposited along the fibers. Photocatalytic activity of the BCAgP nanocomposites were investigated by dye degradation experiments under solar light. The composite with BC: Ag3PO4 weight ratio of 1:4 (BCAgP14) showed the highest photocatalytic efficiency compared to other weight ratios and pure Ag3PO4. The sample also shows good photocatalytic activity even after 4 runs indicating its photostability. Higher photocatalytic efficiency of BCAgP14 nanocomposite was explained due to optimum Ag3PO4 loading and higher visible light absorption capacity. Bacterial cellulose is supposed to improve the photocatalytic activity of silver phosphate by promoting the adsorption of dyes and extending the charge recombination time under visible light of Ag3PO4 photocatalyst.

Platelet-Rich Plasma Composite Organohydrogel with Water-Locking and Anti-Freezing to Accelerate Wound Healing.

Hydrogels have gained impressive attention in biological medicine due to their excellent biosafety, softness, and varied functional components. However, conventional hydrogels have inherent defects, such as low tensile strength, weak water-locking, and poor anti-freezing. In tissue engineering, once the hydrogel loses water or freezes, it will harden the interaction interfaces and destroy the nascent granulation tissue. Herein, based on the design concept of "hard frame-soft penetration", a composite adhesive organohydrogel is fabricated by introducing bacterial cellulose and platelet-rich plasma (PRP) into a poly-N-(tris[hydroxymethyl]methyl)acrylamide (THMA)/N-acryloyl aspartic acid (AASP) hybrid gel network infiltrated with glycerol/water binary solvent. The resultant organohydrogels exhibit excellent antifreeze properties at low temperatures (-80 °C) and demonstrate stable long-term water retention (91%) in the open environment within 12days and can adhere firmly to the tissues by the action of "hydrogen bond clusters". Additionally, the introduction of bacterial cellulose matrix endows the organohydrogel with high tensile strength similar to that of skin. In vivo, the PRP-loaded organohydrogel can release a variety of growth factors to accelerate the wound healing process through collagen deposition and angiogenesis. Altogether, this strategy will extend the life of the hydrogel in some harsh medical environments.

Use of bacterial cellulose obtained from kombucha fermentation in spent coffee grounds for active composites based on PLA and maleinized linseed oil

Spent coffee grounds have been successfully used as an alternative infusion for kombucha fermentation (spent coffee kombucha, SCK). The obtained by-product of this fermentation consists of a kombucha bacterial cellulose (KBC) matrix. The bacterial cellulose was also fermented in pristine coffee grounds infusion for comparison (coffee kombucha, CK). The bacterial cellulose obtained from both infusion fermentations (SCK and CK) was used as filler in PLA matrix plasticized with a 5 wt% of maleinized linseed oil (MLO). Two different content of SCK and CK (3 and 5 wt%) were introduced in the PLA-MLO matrix to produce a film using a conical twin-screw microextruder to simulate the industrial processing conditions. The resultant bio-based films were studied in tern of morphological, tensile, and thermal properties, UV–visible absorption, water vapor permeability, and wettability. The antioxidant activity of the obtained materials was tested in contact with a fatty food simulant demonstrating antioxidant activity. In addition, disintegrability tests under composting conditions confirmed the compostable character of all films. The obtained results suggest the potential applicability of these bio-based materials obtained by the revaluation of HoReCa waste in antioxidant materials with interest as food packaging or for agricultural uses.