Surface Of Bacterial Cellulose Nanofibers Research Articles

Calcium crosslinked macroporous bacterial cellulose scaffolds with enhanced in situ mineralization and osteoinductivity for cranial bone regeneration

The inherent biological inertness and lack of three-dimensional (3D) macroporous structures greatly hinder the use of pristine bacterial cellulose (BC) as a tissue engineering scaffold for bone regeneration. To address this issue, we developed a simple and effective strategy to fabricate a BC-based scaffold with excellent bioactivity and macroporous structure by crosslinking short-cut BC nanofibers using Ca2+. The Ca2+ crosslinked macroporous BC scaffold (MPBC@Ca) presents better structural stability due to the enhanced cellulose hydration. Importantly, the Ca2+ on the surface of BC nanofibers can serve as an active nucleation site to accelerate the deposition of hydroxyapatite (HAp), which is beneficial for the construction of biomimetic bone tissue extracellular matrix (ECM) microenvironment. The HAp-deposited MPBC@Ca scaffolds (HAp-MPBC@Ca) with biomimetic ECM microenvironment have excellent cytocompatibility and enhanced osteogenic differentiation of stem cells in vitro. Furthermore, the results of in vivo tests revealed that the HAp-MPBC@Ca scaffold has favorable osteoinductivity and accelerates cranial bone tissue regeneration. This study proposes a novel strategy to improve the bioactivity of BC and presents the great potential of biomimetic ECM microenvironment BC-based scaffold for repairing large cranial bone defects.

Biomass-derived photothermal carbon aerogel for efficient solar-driven seawater desalination

Solar-driven interface evaporation is an effective method to produce fresh water to alleviate the shortage of water resources. However, there are still challenges in preparing photothermal conversion materials with high evaporation rate, high photothermal conversion efficiency and low cost. Herein, a 3D carbon aerogel with excellent photothermal conversion performance was prepared by using environmental-friendly biomass materials as the matrix. The hydrophilic 3D photothermal carbon aerogel with low thermal conductivity was prepared by depositing polydopamine and loading Cu nanoparticles (CuNPs) on the surface of bacterial cellulose nanofibers. The deposition of PDA improved the mechanical properties and hydrophilicity of carbon aerogel, and the introduction of CuNPs further enhanced the photothermal conversion performance of carbon aerogel. Interestingly, the side temperature of 3D carbon aerogel was lower than the ambient temperature in the evaporation process, which could absorb energy from the environment and significantly improve the photothermal conversion efficiency, giving rise to the impressive water evaporation rate (2.07 kg·m−2·h−1) and photothermal conversion efficiency (115.36%) of 3D carbon aerogel under 1 sun. Moreover, the prepared 3D carbon aerogel had excellent purification effect on seawater, strong acid/alkali and dye solution, demonstrating its broad application prospect in the field of solar-driven seawater desalination.

Hydrophobically Modified Cellulose Nanofibers-Enveloped Solid Lipid Microparticles for Improved Antioxidant Cargo Retention.

This study introduces a cellulose nanofiber surfactant system, in which the surface is hydrophobically modified with different alkyl chain structures for the effective envelopment of solid lipid microparticles (SLMs). To endow bacterial cellulose nanofibers (BCNFs) with excellent ability to assemble at the lipid-water interface, alkyl chains with designated molecular structures, such as decane, didecane, and eicosane, are covalently grafted onto the BCNF surface. Interfacial tension and interfacial rheology measurements indicate that dialkyl chain-grafted BCNFs (diC10 BCNF) exhibit strong interfibrillar association at the interface. The formation of a dense and tough fibrillary membrane contributes significantly to the enveloping of the SLMs, regardless of the lipid type. Because the diC10 BCNF-enveloped SLMs exhibit a core molecular crystalline phase at the microscale, they can immobilize an oil-soluble antioxidant while maintaining its long-term storage stability. These findings show that the cellulose-surfactant-based SLM technology is applicable to the stabilization and formulation of readily denatured active ingredients.

Ultra-thin bacterial cellulose/poly(ethylenedioxythiophene) nanofibers paper electrodes for all-solid-state flexible supercapacitors

Ultra-thin, flexible supercapacitors for portable energy storage devices and intermittent electronic applications are closer to reality. This study developed a kind of thin flexible nanofibers paper electrodes (only about 12 μm in thickness) for all-solid-state supercapacitors, which combines the features of three-dimensional porous structure from bacterial cellulose (BC) and the advantages of highly ordered conductive polymer chains from polyethylenedioxythiophene (PEDOT). The capacity and conductivity of the conductive polymer PEDOT, which was coated evenly on the surface of BC nanofibers, were exploited sufficiently. And the flexible symmetric supercapacitors device assembled with the paper electrodes demonstrated an attractive electrochemical performance (a specific volumetric capacitance of 106.3 F cm-3 at a current density of 0.83 A cm−3) and an excellent cyclic stability. The electrical and mechanical properties of the devices still keep stable under various flexible conditions. So this material maybe a new choice for flexible energy-storage devices.

Flexible Metal–Organic Framework-Bacterial Cellulose Nanocomposite for Iodine Capture

A flexible nanocomposite pellicle consisting of bacterial cellulose (BC) and zeolitic imidazolate framework-8 (ZIF-8) nanoparticles was prepared by sequentially soaking the BC pellicle in zinc ion and 2-methylimidazole (2-MI) solutions. The quality and quantity of ZIF-8 in situ crystallized in the pellicle was significantly improved when polydopamine, oxidatively self-polymerized dopamine, coating was applied prior on the surface of BC nanofibers. The polydopamine coating not only insulates the cellulose structure from competitive complex interaction with zinc ions employed for ZIF-8 formation but also can provide a photothermal feature to the ZIF-BC composite. ZIF-8 was well embedded inside the BC pellicle with a uniform shape and size of about 127 nm. Approximately, 70% (w/w) of the as-prepared nanocomposite (BC@Dopa-ZIF) is ZIF-8, which demonstrated a high iodine uptake capacity from vapor (1.87 ± 0.18 g I2/g) and aqueous I2/KI solution (1.31 ± 0.02 g I2/g). The iodine captured by BC@Dopa-ZIF could be ...

Recognition of lysozyme using surface imprinted bacterial cellulose nanofibers

Here, we developed the lysozyme imprinted bacterial cellulose (Lyz-MIP/BC) nanofibers via the surface imprinting strategy that was designed to recognize lysozyme. This study includes the molecular imprinting method onto the surface of bacterial cellulose nanofibers in the presence of lysozyme by metal ion coordination, as well as further characterizations methods FTIR, SEM and contact angle measurements. The maximum lysozyme adsorption capacity of Lyz-MIP/BC nanofibers was found to be 71 mg/g. The Lyz-MIP/BC nanofibers showed high selectivity for lysozyme towards bovine serum albumin and cytochrome c. Overall, the Lyz-MIP/BC nanofibers hold great potential for lysozyme recognition due to the high binding capacity, significant selectivity and excellent reusability.

Immobilization of lecithin on bacterial cellulose nanofibers for improved biological functions

In an attempt to improve the biological behavior of pristine bacterial cellulose (BC), lecithin (LEC) has been immobilized on the surface of BC nanofibers by solution immersion and subsequent chemical crosslinking with proanthocyanidin (PA). The as-prepared LEC-immobilized BCs (denoted as BC/LECs) were characterized by SEM, FTIR, and XRD, and their dynamic mechanical properties, thermal stability, and hydrophilicity were assessed. The presence of LEC on BC surface was confirmed by SEM and FTIR analyses. It has been found that BC/LECs retain the three-dimensional (3D) porous network structure of pristine BC. The BC/LECs still demonstrate favorable mechanical properties, surface hydrophilicity, and thermal stability. More importantly, preliminary cell studies suggest that the BC/LECs show improved cell behavior over pristine BC.

In situ phosphorus K-edge X-ray absorption spectroscopy studies of calcium–phosphate formation and transformation on the surface of bacterial cellulose nanofibers

In this work, for the first time, in situ formation and transformation process of embryo calcium phosphate (Ca–P) minerals on three-dimensional bacterial cellulose nanofibers was investigated. Combined with XRD, X-ray absorption near-edge structure results revealed that the embryo precursor was amorphous calcium phosphate which was subsequently converted to β-tricalcium phosphate, octacalcium phosphate, and finally to the more thermodynamically stable form of hydroxyapatite. The methodology reported herein may be extended to the studies of Ca–P and other minerals on various substrates.

Silver nanoparticle/bacterial cellulose gel membranes for antibacterial wound dressing: investigation in vitro and in vivo

Bacterial cellulose (BC) has attracted increasing attention as a novel wound dressing material, but its antimicrobial activity, which is one of the critical skin-barrier functions in wound healing, is not sufficient for use in practical applications. To overcome such a deficiency, silver nanoparticles were generated and self-assembled on the surface of BC nanofibers, forming a stable and evenly distributed Ag nanoparticle coated BC nanofiber (AgNP-BC). The performance of AgNP-BC was systematically studied in terms of antibacterial activities, cytocompatibility and effects on wound healing. The results showed that AgNP-BC exhibited significant antibacterial activity against Staphylococcus aureus. Moreover, AgNP-BC allowed attachment, and growth of rat fibroblasts with low cytotoxicity emerged. Based on these advantages, AgNP-BC samples were applied in a second-degree rat wound model. Wound flora showed a significant reduction during the healing. The fresh epidermal and dermis thicknesses with AgNP-BC samples were 111 and 855 µm respectively, higher than 74 and 619 µm for BC groups and 57 and 473 µm for untreated control wounds. The results demonstrated that AgNP-BC could reduce inflammation and promote scald wound healing.

Antibacterial Properties of Novel Bacterial Cellulose Nanofiber Containing Silver Nanoparticles

In this work, we describe a novel facile method to prepare long one-dimensional hybrid nanofibers by using hydrated bacterial cellulose nanofibers (BCF) as a template. Silver (Ag) nanoparticles with an average diameter of 1.5 nm were well dispersed on BCF via a simple in situ chemical-reduction between AgNO3 and NaBH4 at a relatively low temperature. A growth mechanism is proposed that Ag nanoparticles are uniformly anchored onto BCF by coordination with BC-containing hydroxyl groups. The bare BCF and as-prepared Ag/BCF hybrid nanofibers were characterized by several techniques including transmission electron microscopy, X-ray diffraction, thermogravimetric analyses, and ultraviolet-visible (UV-Vis) absorption spectra. The antibacterial properties of Ag/BCF hybrid nanofibers against Escherichia coli (E. coli, Gram-negative) and Staphylococcu saureus (S. saureus, Gram-positive) bacteria were evaluated by using modified Kirby Bauer method and colony forming count method. The results show that Ag nanoparticles are well dispersed on BCF surface via in situ chemical-reduction. The Ag/BCF hybrid nanofiber presents strong antibacterial property and thus offers its candidature for use as functional antimicrobial agents.

In situ nano-assembly of bacterial cellulose–polyaniline composites

Bacterial cellulose (BC), produced by Gluconacetobacter xylinum, consists of ribbon-shaped nano-fibers in web-like structures. Polyaniline (PAni) is a conductive polymer, the conductivity of which is related to the synthesis and doping process. In this paper, we report on the in situ nano-assembly of BC nanofibers and PAni to enhance the electronic conductivity. PAni could be synthesized on the surface of BC nano-fibers and assembled into a novel 3D network. The reaction time of polymerization, the types and concentration of doping protonic acids play a major role on the electroconductivity properties of the composites. The electroconductivity of composite hydrogels was enhanced from 10−8 to 10−2 S cm−1, and can be further improved by doping with various protonic acids. The BC–PAni nanofiber composite is an electro-conductive hydrogel that combines the properties of hydrogels and conductive systems, and it may potentially be used for flexible displays, biosensors, and platform substrates to study the effect of electrical signals on cell activity, and to direct desirable cell function for tissue engineering applications.

Immobilization of gelatin on bacterial cellulose nanofibers surface via crosslinking technique

Bacterial cellulose is considered to be a potential material for tissue engineering. However, the absence of enough activity restricts its practical application as tissue engineering scaffold. This paper describes the synthesis of a novel bacterial cellulose/gelatin composite via crosslinking by procyanidin (PA). The morphology of the bacterial cellulose/gelatin composite was observed by field emission scanning electron microscopy (FE-SEM) and transmission electronic microscope (TEM). The composites were further characterized by fourier transformed infrared spectroscopy (FTIR) and X-ray diffraction (XRD). It was found that the 0.25wt.% Gel solution was the appropriate concentration for the BC/Gel composite. Furthermore, the proliferation, infiltration and adhesion of NIH3T3 cells on the BC/Gel-025 composite were evaluated. The results showed that the composite had better bioactivity than pure bacterial cellulose, and the composite supported cell growth.

Biotemplated preparation of CdS nanoparticles/bacterial cellulose hybrid nanofibers for photocatalysis application

In this work, we describe a novel facile and effective strategy to prepare micrometer-long hybrid nanofibers by deposition of CdS nanoparticles onto the substrate of hydrated bacterial cellulose nanofibers (BCF). Hexagonal phase CdS nanocrystals were achieved via a simple hydrothermal reaction between CdCl 2 and thiourea at relatively low temperature. The prepared pristine BCF and the CdS/BCF hybrid nanofibers were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), UV–vis absorption spectroscopy (UV–vis), and X-ray photoelectron spectroscopy (XPS). The results reveal that the CdS nanoparticles were homogeneously deposited on the BCF surface and stabilized via coordination effect. The CdS/BCF hybrid nanofibers demonstrated high-efficiency photocatalysis with 82% methyl orange (MO) degradation after 90 min irradiation and good recyclability. The results indicate that the CdS/BCF hybrid nanofibers are promising candidate as robust visible light responsive photocatalysts.

Preparation of Novel Ag/Bacterial Cellulose Hybrid Nanofibers for Antimicrobial Wound Dressing

In this work, we describe a novel facile method to prepare long one-dimensional hybrid nanofibers by using hydrated bacterial cellulose nanofibers (BCF) as template. Silver (Ag) nanoparticles with an average diameter of 1.5 nm were well dispersed on BC nanofibers via a simple in situ chemical-reduction between AgNO3 and NaBH4 at relatively low temperature. The bare BCF and as-prepared Ag/BCF hybrid nanofibers were characterized by a range of analytical techniques including transmission electron microscopy (TEM), X-ray diffraction (XRD), and UV–vis absorption spectra (UV–vis). The results reveal that Ag nanoparticles were homogeneously precipitated on the BCF surface. The results indicate that Ag/BCF hybrid nanofibers are promising candidate materials for functional antimicrobial agents.

バイオナノファイバーを鋳型とした金属ナノ粒子の創製

We have prepared silver nanoparticles on the surface of bacterial cellulose (BC) nanofibers. The synthesis of silver nanoparticles incorporates 2,2,6,6-tetramethylpiperidine-1-oxyradical (TEMPO)-mediated oxidation to introduce carboxylate groups on the surface of BC nanofibers. An ion exchange of the sodium to the silver salt was performed in AgNO3 solution, followed by thermal reduction. By using oxidized BC nanofibers as a reaction template, we have prepared stable silver nanoparticles with a narrow size distribution and high density through strong ion interactions between host carboxylate groups and guest silver cations, which have been investigated by scanning electron microscopy, UV-visible spectroscopy, and a small-angle X-ray scattering method.

Novel Pd-Cu/bacterial cellulose nanofibers: Preparation and excellent performance in catalytic denitrification

In this work, we describe a novel facile method to prepare long one-dimensional hybrid nanofibers by using hydrated bacterial cellulose nanofibers (BCF) as template. Palladium-copper nanoparticles were prepared in BCF by immersing BCF in a mixture solution of PdCl 2 and CuCl 2 in water and followed reduction of absorbed metallic ion inside of BCF to the metallic Pd-Cu nanoparticles using potassium borohydride. The bare BCF and the composites were characterized by a range of analytical techniques including scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results reveal that the Pd-Cu nanoparticles were homogeneously precipitated on the BCF surface. The Pd-Cu/BCF was used as a catalyst for water denitrification, which showed that it has high catalytic activity.

Synthesis of Silver Nanoparticles Templated by TEMPO-Mediated Oxidized Bacterial Cellulose Nanofibers

We have prepared silver nanoparticles on the surface of bacterial cellulose (BC) nanofibers. The synthesis of silver nanoparticles incorporates 2,2,6,6-tetramethylpiperidine-1-oxyradical (TEMPO)-mediated oxidation to introduce carboxylate groups on the surface of BC nanofibers. An ion exchange of the sodium to the silver salt was performed in AgNO(3) solution, followed by thermal reduction. By using oxidized BC nanofibers as a reaction template, we have prepared stable silver nanoparticles with a narrow size distribution and high density through strong ion interactions between host carboxylate groups and guest silver cations, which have been investigated by scanning electron microscopy, UV-visible spectroscopy, and a small-angle X-ray scattering method.