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Stimuli-responsive materials exhibiting exceptional room temperature phosphorescence (RTP) hold promise for emerging technologies. However, constructing such systems in a sustainable, scalable, and processable manner remains challenging. This work reports a bio-inspired strategy to develop RTP nanofiber materials using bacterial cellulose (BC) via bio-fermentation. The green fabrication process, high biocompatibility, non-toxicity, and abundant hydroxyl groups make BC an ideal biopolymer for constructing durable and stimuli-responsive RTP materials. Remarkable RTP performance is observed with long lifetimes of up to 1636.79 ms at room temperature. Moreover, moisture can repeatedly quench and activate phosphorescence in a dynamic and tunable fashion by disrupting cellulose rigidity and permeability. With capabilities for repeatable moisture-sensitive phosphorescence, these materials are highly suitable for applications such as anti-counterfeiting and information encryption. This pioneering bio-derived approach provides a reliable and sustainable blueprint for constructing dynamic, scalable, and processable RTP materials beyond synthetic polymers.

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The aim of this study was to develop novel konjac glucomannan (KGM)-based highly antibacterial active films, where five types of films were prepared and compared. The microstructure results showed that KGM-based films loaded with thyme essential oil (TEO) through bacterial cellulose nanofibers/Ag nanoparticles (BCNs/Ag nanoparticles) stabilized Pickering emulsions (Type V films) displayed the smoothest surface and the most evenly dispersed TEO droplets as compared with the other four types of films. Moreover, Type V films showed the highest contact angle value (86.28°), the best thermal stability and mechanical properties. Furthermore, Type V films presented the highest total phenol content (13.23 mg gallic acid equivalent/g film) and the best antioxidant activity (33.96 %) as well as the best sustained-release property, thus showing the best antibacterial activity, which was probably due to that BCNs/Ag nanoparticles and TEO displayed a synergistic effect to some extent. Consequently, Type V film-forming solutions were used as coatings for tangerines. The results showed that the tangerines treated with Type V coatings displayed excellent fresh-keeping properties. Therefore, the coatings, KGM-based film-forming solutions loaded with TEO through BCNs/Ag nanoparticles stabilized Pickering emulsions, have great potential for the preservation of fruits and vegetables.

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The aim of this study was to compare the characterization of bacterial cellulose nanofibers/Ag nanoparticles (BCNs/Ag nanoparticles) obtained by three different pretreatment methods of BCNs (no pretreatment, sodium hydroxide activation pretreatment and TEMPO-mediated oxidation pretreatment), which were recoded as N-BCNs/Ag nanoparticles, A-BCNs/Ag nanoparticles and O-BCNs/Ag nanoparticles, respectively. The results of scanning electron microscopy and transmission electron microscopy showed the prepared Ag nanoparticles by three different pretreatment methods were spherical and dispersed on the surface of BCNs, while the Ag nanoparticles in O-BCNs/Ag nanoparticles displayed the smallest diameter with a value of 20.25 nm and showed the most uniform dispersion on the surface of BCNs. The ICP-MS result showed O-BCNs/Ag nanoparticles had the highest content of Ag nanoparticles with a value of 2.98 wt%, followed by A-BCNs/Ag nanoparticles (1.53 wt%) and N-BCNs/Ag nanoparticles (0.84 wt%). The cytotoxicity assessment showed that the prepared BCNs/Ag nanoparticles were relatively safe. Furthermore, the O-BCNs/Ag nanoparticles had the best antioxidant and antibacterial activities as compared with the other two types of BCNs/Ag nanoparticles, where O-BCNs/Ag nanoparticles destroyed the structure of bacterial cell membranes to lead the leakage of intracellular components. This study showed that O-BCNs/Ag nanoparticles as antibacterial agents have great potential in food packaging.

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Cellulose composite nanopaper is extensively employed in flexible energy storage systems owing to their light weight, good flexibility and high specific surface area. Nevertheless, achieving flexible and ultrathin nanopaper supercapacitors with excellent electrochemical performance remains a challenge. Herein, surface cationization of bacterial cellulose (BC) nanofibers was conducted using 2,3-epoxypropyltrimethylammonium chloride (EPTMAC). Anion-doped polypyrrole (PPy) was incorporated onto the surface of the cationic bacterial cellulose (BCE) nanofibers by an interfacial electrostatic self-assembly process. The obtained PPy@BCE electrode exhibited excellent electrochemical performance, including an areal capacitance of 3988 mF cm-2 at 1.0 mA cm-2 and a capacitance retention of 97 % after 10,000 cycles. A laminated paper-forming strategy was adopted to design and fabricate all-in-one integrated flexible supercapacitors (IFSCs) using PPy@BCE nanopaper as electrodes and BC nanopaper as a separator. The IFSCs showed superior areal capacitance (3669 mF cm-2 at 1 mA cm-2), high energy density (193.7 µWh cm-2 at a power density of 827.3 µW cm-2), and outstanding mechanical flexibility (with no significant capacitance attenuation after repeatedly bending for 1000 times). The present strategy paves a way for the large-scale production of paper-based energy storage devices.

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The aim of this study was to develop highly pH-sensitive bacterial cellulose nanofibers/gelatin-based intelligent films, where the intelligent films were loaded with different ratios (10:0, 0:10 2:8, 5:5 and 8:2, w/w) of curcumin:anthocyanin (Cur/ATH), and the characterization of intelligent films was investigated. The results showed that the microstructures of intelligent films were much rougher as the proportion of curcumin increased. FTIR results showed that anthocyanin and curcumin were fixed in gelatin matrix by hydrogen bonds. Moreover, XRD results showed that curcumin had a significant effect on the crystal structure of the films. Interestingly, films loaded with a Cur/ATH ratio of 5:5 had the best mechanical and antioxidant properties and a high pH-sensitivity property. Consequently, the bacterial cellulose nanofibers/gelatin-based intelligent films loaded with a Cur/ATH ratio of 5:5 were used for the packaging of fresh pork, displaying good fresh-keeping and freshness detection effects. Therefore, this study suggested that bacterial cellulose nanofibers/gelatin-based intelligent films have great potential in the fresh-keeping and freshness detection of meat.

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In this study, bacterial cellulose nanofibers (BCNs) (0%, 1%, 2%, and 3%) were used as nanofillers to prepare gelatin-based edible films, and their physical properties and fresh-keeping performance were investigated. The microstructure observation showed that the BCNs were well dispersed in the gelatin-based edible films and the surface roughness of the films increased with the increase of BCNs content. X-ray diffraction and thermogravimetric analysis showed that the crystallinity and thermal stability of the film were significantly increased with the increase of BCNs. Fourier-transform infrared spectroscopy analysis suggested that hydrogen bond interactions occurred between BCNs and gelatin polymers, leading to improved mechanical properties with the increase of BCNs content. Furthermore, the barrier performance was also improved with the increase of BCNs content, where gelatin-based edible films with 2% BCNs showed the best mechanical property. Meanwhile, the gelatin-based film-forming solutions (FFSs) containing different BCNs were coated on the fresh-cut apples and the corresponding fresh-keeping performance was investigated. The results showed that the fresh-keeping parameters of fresh-cut apples coated with FFSs containing BCNs were better as compared with those of pure gelatin FFSs. Moreover, the fresh-keeping parameters were improved with the increase of BCNs, especially the FFSs containing 2% BCNs that showed the best fresh-keeping parameters. Therefore, BCNs, used as nanofillers, are an excellent enhancer to improve the fresh-keeping performance of the gelatin-based edible coating, showing a promising potential application in the food preservation field.

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The aim of this work was to study the influence of water as a co-solvent on the interaction between a polymerizable ionic liquid-choline acrylate (ChA)-and bacterial cellulose. Bacterial cellulose dispersed in ChA is a new type of UV-curable biopolymer-based ink that is a prospective material for the 3D printing of green composite ion-gels. Higher cellulose content in inks is beneficial for the ecological and mechanical properties of materials, and leads to increased viscosity and the yield stress of such systems and hampers printability. It was found that the addition of water results in (1) a decrease in the solvent viscosity and yield stress; and (2) a decrease in the stability of dispersion toward phase separation under stress. In this work, an optimal composition in the range of 30-40 wt% water content demonstrating 97-160 Pa of yield stress was found that ensures the printability and stability of inks. The rheological properties of inks and mechanical characteristics (0.7-0.8 MPa strength and 1.1-1.2 MPa Young's modulus) were obtained. The mechanism of influence of the ratio ChA/water on the properties of ink was revealed with atomic force microscopy, wide-angle X-ray diffraction studies of bacterial cellulose after regeneration from solvent, and computer simulation of ChA/water mixtures and their interaction with the cellulose surface.

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Porous carbons have been widely applied for capacitive energy storage, yet usually suffer from insufficient rate performance because of the sluggish ion transport kinetics in deep and multi-branched pores. Herein, we fabricated an interconnected microporous capacitive carbon (IMCC) by growing D (+)-glucosamine on bacterial cellulose (BC) nanofibers scaffold, followed by carbonization and activation. The BC nanofibers acted as a sacrificial template during pre-carbonization, facilitating the subsequent KOH permeation and homogeneous activation. By taking advantage of the interconnected microporous structure, the IMCC delivers a high capacitance of 302 F g-1 at 1 A g-1 and an excellent rate capability of 165 F g-1 at 100 A g-1 for aqueous supercapacitor, demonstrating its fast ion transport capability. Impressively, it also shows a superior gravimetric capacity of 177 mAh g-1 at 0.5 A g-1 and remains a high value of 72 mAh g-1 at 20 A g-1 as a cathode material for Zn-ion hybrid capacitor. This facile and cost-effective design strategy exhibits a great potential to construct carbohydrates-derived interconnected microporous carbon materials for high-rate energy storage.

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This research focuses on preparing a natural-based drug delivery system for α-arbutin (AR) as a skin lightening. Bacterial cellulose nanofibers (BC) pad was used for controlled-AR release through two approaches. First was the dip-drying method (P-BC), in which AR cross-linked to BC pads using citric acid (CA). The second was simultaneously entrapping of AR in Tragacanth gum (AR-TG) and stabilized on BC (BC-T) through the ultrasonic-assisted microemulsion method. UV-Vis spectra revealed better control of AR release in BC-T in the first hour. High cell viability (above 70 %) of the pads containing 1-3 % AR was reported using MTT assay. The in-vitro permeation study indicated the proper AR penetration in the treated pads. The Fickian diffusion model was determined as a fitted model for all pads in the drug release kinetics. FTIR, XRD, and TGA analyses further characterized the pads. FESEM images verified AR-TG and BC structures with average diameters of 410.7 ± 25.4 and 34.5 ± 7.51 nm, respectively. The hydrophilicity and mechanical properties of the pads were also investigated. Finally, the high biocompatibility, initial controlled release, and proper permeation suggested BC-T as a more promising delivery platform for AR.

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Two polymerizable ionic liquids (or monomeric ionic liquids, mILs) namely 1-butyl-3-methylimidazolium and choline acrylates ([C4mim]A and ChA, respectively) were synthesized using the modified Fukumoto method from corresponding chlorides. The chemical structure of the prepared mILs was confirmed with FTIR and NMR study. Investigation of the thermal properties with DSC demonstrates that both mILs have a Tg temperature of about 180 K and a melting point around 310 K. It was shown that the temperature dependence of FTIR confirm the Tg to be below 200. Both mILs exhibited non-Newtonian shear thinning rheological behavior at shear rates >4 s−1. It was shown that [C4mim]A is able to dissolve bacterial cellulose (BC) leading to a decrease in its degree of polymerization and recrystallisation upon regeneration with water; although in the ChA, the crystalline structure and nanofibrous morphology of BC was preserved. It was demonstrated that the thixotropic and rheological properties of cellulose dispersion in ChA at room temperature makes this system a prospective ink for 3D printing with subsequent UV-curing. The 3D printed filaments based on ChA, containing 2 wt% of BC, and 1% of N,N'-methylenebisacrylamide after radical polymerization induced with 1% 2-hydroxy-2-methylpropiophenone, demonstrated Young's modulus 7.1 ± 1.0 MPa with 1.2 ± 0.1 MPa and 40 ± 5% of strength and ultimate elongation, respectively.

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Soft-tissue replacements are challenging due to the stringent compliance requirements for the implanted materials in terms of biocompatibility, durability, high wear resistance, low friction, and water content. Acrylate hydrogels are worth considering as soft tissue implants as they can be photocurable and sustain customized shapes through 3D bioprinting. However, acrylate-based hydrogels present weak mechanical properties and significant dimensional changes when immersed in liquids. To address these obstacles, we fabricated double network (DN) hydrogels composed of polyacrylic acid (PAA) and bacterial cellulose nanofibers (BCNFs) by one fast UV photopolymerization step. BCNFs/PAA hydrogels with a 0.5 wt% BCNFs content present an increased stiffness and a lower, non-pH-dependent swelling than PAA hydrogels or PAA hydrogels with cellulose nanocrystals. Besides, BCNFs/PAA hydrogels are biocompatible and can be frozen/thawed. Those characteristics endorse these hybrid hydrogels as potential candidates for vascular and cartilage tissue implants.

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Herein, we propose a cellulose-reinforced hybrid hydrogel system that not only increases mechanical strength, but also allows on-demand drug release. This hybrid hydrogel is specialized by its semi-interpenetrating network structure in which bacterial cellulose nanofibers (BCNFs) penetrate through a polyacrylamide (PAM) mesh. We showed that the interpenetrating BCNFs with a higher aspect ratio of 240 increased the compression strength of PAM/BCNF composite hydrogels approximately 3-fold, compared with that prepared with PAM only, stemming from the reinforcing effect of the rigid natural nanofibers between PAM meshes. We also observed that the swelling kinetics depended on the mechanical properties determined by the BCNF aspect ratio. From further studies on drug release, we demonstrated that the tailored composition of BCNFs with PAM retarded drug release by a factor of two compared to PAM only while enabling on-demand drug release in response to the applied compressive stress. These results highlight that our BCNFs-reinforced hydrogel system can be applied as a mechanical stress-responsive smart drug delivery patch.

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The large osmotic energy between river water and seawater is an inexhaustible blue energy source; however, the complicated manufacturing methods used for ion-exchange devices hinder the development of reverse electrodialysis (RED). Here, we use a wet-spinning method to continuously spin meter-scale 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized bacterial cellulose (TOBC) nanofiber filaments, which are then used to construct nanochannels for osmotic energy conversion. These are then used to build a nacre-like structure by adding graphene oxide (GO), which provides narrow nanochannels in one-dimensional and two-dimensional nanofluid systems for rapid ion transport. With a 50-fold concentration gradient, the nanochannels in the fibers generate electricity of 0.35 W m-2, with an ionic mobility of 0.94 and an energy conversion efficiency of 38%. The assembly of GO and TOBC results in a high power density of 0.53 W m-2 using artificial seawater and river water. The RED device fabricated from TOBC/GO fibers maintains a stable power density for 15 days. This research proposes a simple method to reduce the size of nanochannels to improve the ionic conductivity, ionic selectivity, and power density of cellulose-based nanofibers to increase the possibility of their application for the conversion of osmotic energy to electrical energy.

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BACKGROUND: The objective of the present study was co-delivery of venlafaxin (VEN) and doxycycline (DOX), a matrix metalloproteinase inhibitor drug, for alleviating inflammation and neuropathy in diabetic foot ulcer (DFU). METHODS: Bacterial cellulose nanofiber sheets (BCNS) were loaded with DOX and VEN and categorized by their loading efficiency, release profiles and ex vivo permeation throughrat skin. The optimized nanofibers were used in patients with DFU to compare with the standard wound care regimen during a 12-week trial. Wound area was measured every 2 weeks. Biochemical parameters and microscopic studies of the skin were examined prior and at the end of the treatment. The Michigan Neuropathy Screening Instrument (MNSI) questionnaire was utilized to assess diabetic neuropathy. RESULTS: The optimum formulation showed loading efficiency of 37.8 ± 1.6% for DOX and 48 ± 1.9% for VEN. Rat skin permeation was 40% for DOX after 7-29 h and 83% for VEN during 105 h. Patients treated with BCNS showed no significant difference in their biochemical parameters before and after intervention. The ulcer size showed faster reduction after 12 weeks in the treatment group compared to the control group. The abnormal responses in the MNSI questionnaire decreased and pain-free walking distance increased significantly in the treatment group compared with the control group (p < 0.001). Microscopic studies of the skin after using nanofibers showed a large number of polymorphonuclear chronic inflammatory cells and formation of new capillary beds. CONCLUSIONS: The BCNS loaded with DOX and VEN may expedite healing and reduce neuropathy in the DFU of diabetic patients.

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Bacterial cellulose nanofibrils (BCNFs), possessing excellent biocompatibility as well as hygroscopicity, are receiving high interest as a biomaterial for biomedical and healthcare treatments, since they exert various interactions with tissues after surface modification with biochemicals such as peptides, proteins, and catechols. Herein, we report a BCNF-based skin adhesion system, wherein cell penetrating peptide (CPP)-conjugated BCNFs were employed to enhance the attraction to the skin under wet conditions. For this, we conjugated Bac7, a type of CPP, with the carboxylate of 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-oxidized BCNFs. We showed that Bac7-conjugated BCNFs exhibited both hydrophobic and electrostatic interactions with the cell membrane, which eventually led to the remarkable adhesion against the skin surface. Furthermore, we demonstrated that such tailored skin attraction played a key role in improving skin water retention.

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The aim of this work was to evaluate the expression profile of genes involved in signaling, intracellular and extracellular Ca+2 concentration and apoptosis pathways of osteoblasts in contact with a scaffold made of a composite of BCN/MWCNTs. Osteoblasts were cultivated on BCN, MWCNTs and their mixtures. Osteoblast RNA was extracted for sintering cDNA to amplify genes of interest by PCR; intra- and extracellular calcium (Ca2+) was also quantified. Regarding the genes that participate in the regulation paths (MAPK and NF-KB), it was found that only the expression of NF-KB was affected in all treatments. The expression of VEGFA increased, except in the treatment of high concentration of MWCNTs, where remained unchanged. The expression of genes Apaf-1 and Bcl-2/Bax and TP53 increased as compared to the control (except for TP53 in BC and C1/MWCNTs) indicating that cells are responding to the presence of BCN-MWCNTs composites scaffolds. The results suggest that osteoblast developed a modification in the expression profile of genes that actively participate in cellular processes such as proliferation, vasculogenesis and apoptosis, which may be modulated by the increase of intra- and extracellular Ca2+ concentration.

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Natural polymer hydrogels are expected to be promising biomaterial because of its excellent biocompatibility and biodegradability, but they are soft and easily broken. Herein, the poly (γ-glutamic acid) (γ-PGA)/bacterial cellulose (BC) composite hydrogels with excellent mechanical properties were constructed by introducing bacterial cellulose. The γ-PGA/BC composite hydrogels were obtained by the covalent cross-linking of γ-PGA in the BC nanofibers suspensions. The γ-PGA/BC composite hydrogels exhibited excellent strength and toughness due to the more effective energy dissipation of hydrogen bonds network among BC nanofibers and γ-PGA hydrogel matrix and BC also acts as an enhancer. The compressive fracture strength and toughness of the γ-PGA/BC composite hydrogels could reach up to 5.72 MPa and 0.42 MJ/m3 respectively. Additionally, the tensile strength of γ-PGA/BC composite hydrogels were improved 8.16 times compared with γ-PGA single network hydrogels. More significantly, BC could disperse evenly in the γ-PGA hydrogels because of the hydrophilic nature of γ-PGA and BC nanofillers, which led to good interface compatibility. The result of cytotoxicity tests indicated that γ-PGA/BC composite hydrogels present excellent cytocompatibility, which suggested that the γ-PGA/BC composite hydrogels could serve as promising materials for many biomaterial related applications.

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Defibrillation of bacterial cellulose by ultra-refining was efficient to release nanofibers (BCNF) which were spray dried with the matrices formers mannitol (MN), maltodextrin or hydroxypropylmethylcellulose. The best microsystem comprised the association of BCNF and MN, so the selected microparticles were loaded with diclofenac sodium or caffeine. Depending on the proportion of BCNF, the nanofibers collapse promoted by spray drying can occur onto surface or into microparticles core, leading to different release behaviors. Samples showed pH-dependent drug release, so the microsystem developed with the lowest BCNF concentration showed important trend to gastroresistance. Caffeine was spray dried as a free drug and for this reason it was devoid of any control over release rates. The set of results showed BCNF can be considered an interesting and potential pharmaceutical excipient for lipophilic drugs. Beyond that, BCNF association with MN can lead to novel enteric drug delivery systems based on natural polymers.

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Although dissolving microneedles have garnered considerable attention as transdermal delivery tools, insufficient drug loading remains a challenge owing to their small dimension. Herein, we report a one-step process of synthesizing semi-dissolving microneedle (SDMN) patches that enable effective transdermal drug delivery without loading drugs themselves by introducing TEMPO-oxidized bacterial cellulose nanofibers (TOBCNs), which are well dispersed, while retaining their unique properties in the aqueous phase. The SDMN patch fabricated by the micro-molding of a TOBCN/hydrophilic biopolymer mixture had a two-layer structure comprising a water-soluble needle layer and a TOBCN-containing insoluble backing layer. Moreover, the SDMN patch, which had a hole in the backing layer where TOBCNs are distributed uniformly, could offer novel advantages for the delivery of large quantities of active ingredients. In vitro permeation analysis confirmed that TOBCNs with high water absorption capacity could serve as drug reservoirs. Upon SDMN insertion and the application of drug aqueous solution through the drug inlet hole, the TOBCNs rapidly absorbed the solution and supplied it to the needle layer. Simultaneously, the needle layer dissolved in body fluids and the drug solution to form micro-channels, which enabled the delivery of larger quantities of drugs to the skin compared to that enabled by solution application alone.

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The present research aimed to study the nanofibers from bacterial cellulose (BC) by HCl hydrolysis and explore its new potential application in fresh-cut apples. Bacterial cellulose nanofibers (BCNs) showed low and more homogeneity particle size, as well as higher zeta potential and transparency in comparison with BC, which was confirmed by morphological analysis. Physical properties analysis showed that BCNs was more excellent semi-crystalline polymer with higher thermal stability as compared with BC. Rheological results displayed that BCNs suspensions presented a shear thinning behaviour with higher apparent viscosity, storage (G') and loss (G'') moduli at the same concentration in comparison with BC. Furthermore, BCNs suspensions were more stable than BC suspensions under storage condition of 4 °C. Additionally, 2% (wt%) of BCNs suspensions were coated on fresh-cut apples. Results showed that the samples coated with BCNs suspension displayed more excellent properties of keeping fresh-cut apples as compared with that coated with BC suspensions, including delaying weight loss, improving firmness and soluble solids content, reducing browning index and titratable acidity. Therefore, the low cost and high biocompatibility of BCNs can be used as new coatings for fresh-cut apples and have great potential to coat fresh-cut fruits and vegetables in food industry.

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