While silver nanoparticles are widely used to endow materials with antibacterial activity, silver nanowires (AgNWs) have not attracted much attention. Herein, the composites of bacterial cellulose ...(BC) and AgNWs were prepared through a novel step-by-step in situ biosynthesis which retains the three-dimensional network of BC. The results of water vapor permeability, water uptake rate, and water retention rate showed that the BC/AgNW wound dressings could absorb wound skin exudates and maintain moisture environments. Furthermore, the BC/AgNW dressings were robust and stretchable. More importantly, the BC/AgNW dressings exhibited sustained release of Ag+. The results from animal tests indicated that the BC/AgNW dressing with 38.4 wt% AgNWs exhibited higher expression levels of cytokeratin-10 and integrin-β4, greater proliferation of keratinocytes and formation of epithelial tissues and greatly improved skin regeneration over the bare BC. We propose that the integrated nanofibrous structure and the excellent and sustained antibacterial activity of AgNWs are responsible for the excellent in vivo wound healing ability and biocompatibility. These results suggest that the BC/AgNW composites have promising application as wound dressings.
Display omitted
•Silver nanowires (AgNWs) and bacterial cellulose (BC) were integrated to obtain an advanced wound dressing.•The BC/AgNW dressing exhibited sustained release of silver ions.•The BC/AgNW dressing is robust, stretchable, antibacterial, and biocompatible.•The BC/AgNW dressing showed improved in vivo skin regeneration over bare BC.
Display omitted
•A novel layer-by-layer in situ culture (LBLC) method was developed.•Bacterial cellulose/graphene/polyaniline nanocomposites were made by LBLC and polymerization.•The as-prepared ...nanocomposites are mechanically strong and highly flexible.•The as-prepared nanocomposites show excellent gravimetric capacitance and cycling stability.
Rational structure, mechanical robustness, high conductivity, and favorable flexibility are important requirements for superior electrodes, which should not only possess high capacitance but also have freestanding structure without collector to improve the overall performance of supercapacitors. Herein, we demonstrate the fabrication of three-dimensional (3D) porous graphene-containing nanocomposites with highly dispersed graphene (GE) nanosheets in a 3D matrix of bacterial cellulose (BC) by a novel layer-by-layer in situ culture (LBLC) method. The BC/GE nanocomposites are then deposited with polyaniline (PANI), leading to the formation of BC/GE/PANI nanocomposites. Mechanical tests demonstrate excellent robustness and flexibility of the as-prepared BC/GE/PANI nanocomposites, which are used as electrodes directly without any nickel foam or stainless steel wire. The BC/GE/PANI electrode with an optimal GE content has a specific capacitance of 645 F g−1 at a current density of 1 A g−1, which is 2.5 times higher than that of BC/PANI and superior to most previously reported PANI-based electrodes. In addition, the symmetric supercapacitor assembled with BC/GE/PANI demonstrates a high energy density of 14.2 Wh kg−1 at a power density of 200 W kg−1. The excellent electrochemical performance of this BC/GE/PANI electrode is due to its unique 3D porous structure with the uniform distribution of GE nanosheets in the BC matrix and even PANI on BC nanofibers and GE nanosheets, which makes it very promising for diverse flexible energy storage devices. The methodology presented in this work can be extended to the preparation of other BC-based nanocomposite electrodes.
A novel facile and scalable strategy is developed to prepare freestanding carbon nanofiber/graphene nanosheet composites using a scalable membrane–liquid interface culture method followed by ...carbonization. The carbon nanofibers (CNFs) and graphene nanosheets (GNs) are uniformly dispersed in a three‐dimensional (3D) conductive architecture. Robust mechanical properties are demonstrated with fine flexibility, good structure stability, and high specific surface area. As supercapacitor electrodes, the 3D nanocomposite delivers good electrochemical performance with a high capacitance of 215 F g−1 at 1 A g−1 and extraordinary cycling stability with no capacitance degradation after 5000 cycles, which are among the best carbon electrodes in supercapacitors. The energy density is as high as 20 Wh kg−1 at a power density of 900 W kg−1, superior to other CNF‐based electrode materials. The superb electrochemical performance of the 3D nanocomposite electrode is ascribed to the unique structure: 3D conductive network, uniform dispersion of carbon nanofibers and graphene nanosheets, robust mechanical property, and large specific surface area. The combination of facile fabrication method, good performance, and robust mechanical property makes the 3D nanocomposites very promising as a new type of superior supercapacitor electrodes.
Large‐area freestanding carbon nanofiber/graphene nanosheet composite electrodes are prepared using a facile and scalable membrane–liquid interface biological culture method and demonstrate a high reversible capacity and extraordinary cycling stability with no capacitance degradation after 5000 cycles. The energy density is as high as 20 Wh kg−1 at a power density of 900 W kg−1.
Graphene-based nanocarriers not only possess large specific surface area but also prevent drugs from premature release outside the target cells. However, agglomeration in aqueous solution is a ...critical challenge. In this work, graphene oxide (GO) was uniformly embedded into the three-dimensional (3D) porous network of bacterial cellulose (BC) to form a novel BC/GO nanocomposite drug nanocarrier. For the first time, ibuprofen (IBU) was loaded onto the BC/GO nanocomposites. Scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) reveal the successful drug loading onto BC/GO nanocomposites. In vitro drug release studies indicate that the drug release of IBU@BC/GO follows a non-Fickian diffusion mechanism. Another important feature of this BC/GO nanocarrier is its better cell viability in comparison to BC. It is believed that this new nanocarrier is a potential choice for drug delivery system.
Display omitted
•Graphene oxide (GO) was incorporated into 3D porous bacterial cellulose (BC).•Incorporation of GO into BC greatly increases the drug loading capacity of BC.•The BC/GO nanocarrier shows better cell viability than BC does.
In this work, biocompatibility of bacterial cellulose (BC) was assessed as the scaffold for corneal stroma replacement. Biocompatibility was evaluated by examining rabbit corneal epithelial and ...stromal cells cultured on the BC scaffold. The growth of primary cells was assessed by optical microscope, scanning electron microscope (SEM), and transmission electron microscope (TEM). Live/dead viability/cytotoxicity assay and CCK-8 assay were used to evaluate cell survival. BC was surgically implanted in vivo into a stromal pocket. During a 3-month follow-up, the biocompatibility of BC was assessed. We found that epithelial and stromal cells grew well on BC and showed a survival rate of nearly 100%. The SEM examination for both kinds of cell showed abundant leafy protrusions, spherical projections, filopodia, cytoskeletons, and cellular interconnections. The stromal cells cultured on BC arranged regularly. TEM observation revealed normal cellular microstructure and a tight adhesion to the BC membrane. In vivo observation confirmed the optical transparency of BC during 3-month follow-up. The results demonstrated that BC had good biocompatibility for the tissue engineering of corneal stroma.
Turning insulating silk fibroin materials into conductive ones turns out to be the essential step toward achieving active silk flexible electronics. This work aims to acquire electrically conductive ...biocompatible fibers of regenerated Bombyx mori silk fibroin (SF) materials based on carbon nanotubes (CNTs) templated nucleation reconstruction of silk fibroin networks. The electronical conductivity of the reconstructed mesoscopic functional fibers can be tuned by the density of the incorporated CNTs. It follows that the hybrid fibers experience an abrupt increase in conductivity when exceeding the percolation threshold of CNTs >35 wt%, which leads to the highest conductivity of 638.9 S m−1 among organic‐carbon‐based hybrid fibers, and 8 times higher than the best available materials of the similar types. In addition, the silk‐CNT mesoscopic hybrid materials achieve some new functionalities, i.e., humidity‐responsive conductivity, which is attributed to the coupling of the humidity inducing cyclic contraction of SFs and the conductivity of CNTs. The silk‐CNT materials, as a type of biocompatible electronic functional fibrous material for pressure and electric response humidity sensing, are further fabricated into a smart facial mask to implement respiration condition monitoring for remote diagnosis and medication.
A new conceptual silk meso‐fibrous material for biocompatible electronic applications is developed by carbon nanotubes meso reconstruction. It can be adopted to fabricate various fibrous sensors, i.e., electronic humidity sensors. In combination with internet of things (IoTs) and artificial intelligence technologies, a remote respiratory condition monitoring and diagnosis can be achieved.
Graphene oxide–bacterial cellulose (GO/BC) nanocomposite hydrogels with well‐dispersed GO in the network of BC are successfully developed using a facile one‐step in situ biosynthesis by adding GO ...suspension into the culture medium of BC. During the biosynthesis process, the crystallinity index of BC decreases and GO is partially reduced. The experimental results indicate that GO nanosheets are uniformly dispersed and well‐bound to the BC matrix and that the 3D porous structure of BC is sustained. This is responsible for efficient load transfer between the GO reinforcement and BC matrix. Compared with the pure BC, the tensile strength and Young's modulus of the GO/BC nanocomposite hydrogel containing 0.48 wt% GO are significantly improved by about 38 and 120%, respectively. The GO/BC nanocomposite hydrogels are promising as a new material for tissue engineering scaffolds.
Graphene oxide–bacterial cellulose (GO/BC) nanocomposite hydrogels with well‐dispersed GO in the network of BC have been successfully developed using a facile one‐step in situ biosynthesis by adding GO suspension into the culture medium of BC. The composites show a significant increase in tensile properties at relatively low GO loadings.
► Magnetic carbon fiber coated with Fe–Co alloy is prepared by electroplating, which is simple, time saving and without using any toxic reductant or solvent. ► The magnetic alloy coatings show ...sheet-like morphology, and temperature plays a key role in controlling the coating morphology. ► Fe–Co alloy coated carbon fiber by electroplating seems very attractive for a thin, light and easy for production EMA material with strong and wide absorption.
Magnetic carbon fiber coated with Fe–Co alloy was prepared by electroplating at 25
°C for 5
min. The obtained magnetic coatings show sheet-like morphology and the crystal structure of the uniform coating is Co
3Fe
7 with a thickness of about 0.5
μm. The saturation magnetization of the magnetic carbon fiber reaches 31.5
emu/g with a coercivity of 87.1
Oe. The complex permittivity and permeability of magnetic carbon fiber/paraffin (30
wt%) composite were measured in the 2–18
GHz frequency range. The reflection loss below −10
dB covers the whole frequency range while below −20
dB the absorption frequency bandwidth is 6.8
GHz, and the minimum value is −48.2
dB at a coating thickness of 1.7
mm. Magnetic carbon fiber exhibits excellent electromagnetic wave absorption properties.
Polyetheretherketone (PEEK) is a promising biomedical material for orthopedic and dental applications owing to its excellent mechanical properties, near absence of immune toxicity, and X-radiolucency ...but suffers from bioinertness and inferior osteo-conduction. Surface modification of PEEK can effectively overcome these problems, while retaining most of its advantageous properties. In this study, the dual growth factors IGF-1 and BMP-2 were immobilized onto the porous surface of PEEK materials using polydopamine (pDA) coating to construct a bioactive interface. The surface characteristics of modified PEEK were evaluated by scanning electron microscopy and X-ray photoelectron spectroscopy. The pore size, generally distributed between 0.24 and 0.74 µm, was evaluated using ImageJ software. Hydrophilicity and BSA protein adsorption capacity were significantly enhanced after pDA coating. IGF-1 and BMP-2 were successfully immobilized onto the porous surface via pDA coating, and the immobilization efficiency was determined by ELISA. In vitro, samples treated with 50 ng/ml IGF-1 and 50 ng/ml BMP-2 showed better cytocompatibility for cell proliferation. The in vitro studies revealed that PEEK immobilized with dual growth factors could significantly improve cell attachment, spreading, proliferation, extracellular matrix secretion, alkaline phosphatase activity, and mineralization of MC3T3-E1 cells.
•Evolution of morphology of bacterial cellulose during early culture was examined.•The starting culture time of bacterial cellulose was set as short as 0.5h.•Morphology of bacterial cellulose ...scaffolds was controlled by culture time.
Morphological characteristics of a fibrous tissue engineering (TE) scaffold are key parameters affecting cell behavior. However, no study regarding the evolution of morphology of bacterial cellulose (BC) scaffolds during the culture process has been reported to date. In this work, BC scaffolds cultured for different times starting from 0.5h were characterized. The results demonstrated that the formation of an integrated scaffold and its 3D network structure, porosity, fiber diameter, light transmittance, and the morphology of hydroxyapatite (HAp)-deposited BC scaffolds changed with culture time. However, the surface and crystal structure of BC fibers did not change with culture time and no difference was found in the crystal structure of HAp deposited on BC templates regardless of BC culture time. The findings presented herein suggest that proper selection of culture time can potentially enhance the biological function of BC TE scaffold by optimizing its morphological characteristics.
PDF
