Bacterial Cellulose Fibers Research Articles

Evolution of morphology of bacterial cellulose scaffolds during early culture

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.

The Effect of Bacterial Cellulose (BC) Fiber Content on the Properties of BC Fiber Reinforced Nanocomposites

Optically transparent nanocomposites were prepared by epoxy resin reinforced with bacterial cellulose nanofibers in volume fraction from 2.6 to 32.7wt%. The transparence, surface smoothness, thermal expansion and mechanic properties of the nanocomposites with different BC fiber content were characterized. It was found that the nanocomposites display high visible light transparence (84% at 600nm) even at high fiber content (32.7 wt%). The coefficient of planar thermal expansion (CTE) was reduced from 83.8 ppm/K (Epoxy resin) to 40.6 ppm/K at low fiber content (2.6 wt%). The high transparence was insensitive to the change of temperature from room temperature to 90 oC.

Structure and Properties of Bacterial Cellulose Produced Using a Trickling Bed Reactor

Structure and properties of bacterial cellulose (BC) produced by trickling fermentation were studied. The following indexes, such as extrinsic shapes, microstructure, chemical structure, purity, water holding capacity, porosity, and thermogravimetric characteristics, are recommended for assessing the structure and properties of bacterial cellulose. With the comparison to bacterial cellulose produced by static fermentation and shaking fermentation, the results showed that for different BC cultivation methods, the extrinsic shapes, synthetic mode, and microstructure were different. The basic consistency of the infrared spectrogram from three kinds of bacterial cellulose reflected that the chemical structures were very similar. But the -OH associating degree of trickling fermentation BC was higher, and the polymerization degree, purity, water holding capacity, porosity, and thermal stability of trickling fermentation BC were also higher than those of static fermentation BC and shaking fermentation BC. But the crystallinity and crystal grain size of trickling fermentation BC were less than those of static fermentation BC and greater than those of shaking fermentation BC and plant fiber. These above structure and properties of trickling fermentation BC could reference bacterial cellulose's application in food and material field.

Self-supported bacterial cellulose polyaniline conducting membrane as electromagnetic interference shielding material: effect of the oxidizing agent

Conducting bacterial cellulose (BC) membranes coated with a high proportion of polyaniline (PAni) were prepared through in situ oxidative polymerization of aniline on the surface of the BC in the presence of acetic acid as the protonating agent. The effect of two different oxidizing agents, ammonium persulfate (APS) or iron(III) chloride (FeCl3), on the mechanical performance, electrical conductivity, crystallinity, morphology and ability to absorb the electromagnetic radiation was investigated. BC/PAni membranes prepared with FeCl3 displayed higher conductivity and better mechanical performance than those observed for pure BC or the BC/PAni membranes prepared with APS. Experiments related to the electromagnetic absorbing properties revealed that BC/PAni membranes prepared with FeCl3 also present improved absorbing properties in the frequency range of 8–12 GHz. The morphology of the membranes, observed by field emission gun-scanning electron microscopy, is strongly affected by the oxidizing agent. Whereas the BC/PAni membranes prepared with APS present PAni nanoparticles attached on the fiber surface as agglomerates in the form of flakes, those prepared with FeCl3 display a uniform and smooth coating of PAni on the BC fibers as hierarchical mode.

Effects of Surface Treatments on Nata de Cassava on the Tensile Strength and Morphology of Bacterial Cellulose Sheet

Cellulose is natural fiber source that available abundant in the world. Besides lignin, hemi cellulose and wax, cellulose is the most component of plant. Cellulose can be produced from secretion of bacteria. Kind of bacteria that can produce cellulose are pseudomonas, Achromobacter, Alkaligene and Acetobacter, but bacteria strain that usually used to produce cellulose called bacterial cellulose is Acetobacter xylinum. Culture medium of Acetobacter xylinum are medium that contain of carbon and nitrogen. One of the medium that contain carbon and nitrogen is tapioka waste water. The gel that produce from tapioka water called nata de cassava. Cellulose fiber that produce from nata de cassava more pure than that from plant. Mechanical properties of single bacterial cellulose fiber as young’s modulus is 114 GPa and tensile strength is 78 GPa. Nata de cassava is produced with 1% sugar consentration and fermentation time is 14 days. pH of tapioka water medium is adjusting by acetic acid glacial. Nata de cassava gel washed for 2 days on running water than soaked in NaOH and NaOCl solution. Than washed on running water than dried on light pressure (0,2 MPa) and oven for an hour on 80°C. this bacterial cellulose film is ready to used as spesiment of tensile test and SEM observation. The aim of this research is to find the effect of surface treatments (Merserizing and Bleaching) on nata de cassava gel on mechanical properties and morfology of bacterial cellulose sheet. From the research find that NaOH treatment give the highest tensile strength of bacterial cellulose sheet compared to NaOCl treatment of nata de cassava.

Double network bacterial cellulose hydrogel to build a biology–device interface

Establishing a biology-device interface might enable the interaction between microelectronics and biotechnology. In this study, electroactive hydrogels have been produced using bacterial cellulose (BC) and conducting polymer (CP) deposited on the BC hydrogel surface to cover the BC fibers. The structures of these composites thus have double networks, one of which is a layer of electroactive hydrogels combined with BC and CP. The electroconductivity provides the composites with capabilities for voltage and current response, and the BC hydrogel layer provides good biocompatibility, biodegradability, bioadhesion and mass transport properties. Such a system might allow selective biological functions such as molecular recognition and specific catalysis and also for probing the detailed genetic and molecular mechanisms of life. A BC-CP composite hydrogel could then lead to a biology-device interface. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) are used here to study the composite hydrogels' electroactive property. BC-PAni and BC-PPy respond to voltage changes. This provides a mechanism to amplify electrochemical signals for analysis or detection. BC hydrogels were found to be able to support the growth, spreading and migration of human normal skin fibroblasts without causing any cytotoxic effect on the cells in the cell culture. These double network BC-CP hydrogels are biphasic Janus hydrogels which integrate electroactivity with biocompatibility, and might provide a biology-device interface to produce implantable devices for personalized and regenerative medicine.

Bacterial Cellulose as a Template for Preparation of Hydrotalcite-Like Compounds

Bacterial cellulose (BC) was used as a template for preparation of Hydrotalcite-type compounds or layered double hydroxides (LDHs) by co-precipitation method, and submitted to three aging times. Isolated composites containing LDH supported on BC (BC-LDH) were calcined to remove the organic matrix. Mixed metal oxides formed after thermal decomposition underwent reconstruction reaction in Na2CO3 solution producing again hydrotalcite-like materials (RBC-LDH). To evaluate the influence of BC on the LDH formation, it was also analyzed LDH fractions not attached to the BC fibers and LDH synthesized in absence of the polymeric membrane. XRD pattern of BC-LDH composites show broadened peaks related to the organic semi-crystalline matrix, indicating a deep level of interaction between organic and inorganic phases. Interaction is also evidenced by changes in the composites thermal decomposition profiles compared to pristine polymer. SEM images revealed formation of submicrometrical round-shaped LDH particles after removal of membrane (RBC-LDH), differently from the plate-habit exhibited by pristine LDH. Aging plays a key role in growth of all LDHs samples, leading to the formation of larger inorganic particles as time is increased. RBC-LDH aging for three days shows significant improvement in the surface area (more than three times) if contrasted to LDH prepared in BC absence.

Stimuli-responsive bacterial cellulose-g-poly(acrylic acid-co-acrylamide) hydrogels for oral controlled release drug delivery

This study evaluated the potential of stimuli-responsive bacterial cellulose-g-poly(acrylic acid-co-acrylamide) hydrogels as oral controlled-release drug delivery carriers. Hydrogels were synthesized by graft copolymerization of the monomers onto bacterial cellulose (BC) fibers by using a microwave irradiation technique. The hydrogels were characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). FT-IR spectroscopy confirmed the grafting. XRD showed that the crystallinity of BC was reduced by grafting, whereas an increase in the thermal stability profile was observed in TGA. SEM showed that the hydrogels exhibited a highly porous morphology, which is suitable for drug loading. The hydrogels demonstrated a pH-responsive swelling behavior, with decreased swelling in acidic media, which increased with increase in pH of the media, reaching maximum swelling at pH 7. The release profile of the hydrogels was investigated in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). The hydrogels showed lesser release in SGF than in SIF, suggesting that hydrogels may be suitable drug carriers for oral controlled release of drug delivery in the lower gastrointestinal tract.

Accelerated Preparation of Novel Bacterial Cellulose/Acrylamide-Based Hydrogel by Microwave Irradiation

The fabrication of novel bacterial cellulose/polyacrylamide-based hydrogels by accelerated radiation by microwave was investigated. This study was designed and optimized using the Taguchi method by taking irradiation time and power as the main parameters. The results revealed the dependence of percentage gel fraction and swelling index on the synthesis parameters using a microwave. The gel fraction was proportionally increased with power and time. The bacterial cellulose fibers crosslinked with polyacrylamide polymer chain as the thermal energy in the monomer mixture quickly rose, leading to a higher degree of polymerization. A highly time-efficient processing with interchangeable parameters allows various hydrogel properties to be developed.

Overview of bio nanofabric from bacterial cellulose

Nanofibers and bio-nonwoven fabrics of pure cellulose can be made from some bacteria such as Acetobacter xylinum. Bacterial cellulose fibers are very pure, 10 nm in diameter and about 0.5 micron long. The molecular formula of bacterial cellulose is similar to that of plant cellulose. Its fibers are very stiff and it has high tensile strength, high porosity, and nanofibrillar structure. They can potentially be produced in industrial quantities at greatly lowered cost and water content, and with triple the yield by a new process. This article presents a critical review of the available information on bacterial cellulose as a biological nonwoven fabric with special emphasis on its fermentative production and applications. Characteristics of bacterial cellulose biofabric with respect to its structure and physicochemical properties are discussed. Current and potential applications of bacterial cellulose in textile, nonwoven cloth, paper, films, synthetic fiber coating, food, pharmaceutical, and other industries are also presented.

Cellulose/iron oxide hybrids as multifunctional pigments in thermoplastic starch based materials

Cellulose/iron oxide hybrids were prepared by the controlled hydrolysis of FeC2O4 in the presence of vegetable and bacterial cellulose fibres as substrates. By varying the relative amount of FeC2O4 and NaOH, either hematite or magnetic iron oxides were grown at the cellulose fibres surfaces. This chemical strategy was used for the production of a number of materials, whose coloristic properties associated to their reinforcement role allowed their use as new hybrid pigments for thermoplastic starch (TPS) based products. The TPS reinforced materials were characterized by several techniques in order to evaluate: the morphology and the compatibility between the matrix and the fillers; the mechanical reinforcement effect of the cellulose/iron oxide pigments on TPS and the coloristic properties of the composites. All materials showed good dispersion and strong adhesion for the cellulose/iron oxide nanocomposites in the TPS matrix thus resulting in improved mechanical properties.

Nano-cellulose 3D-networks as controlled-release drug carriers.

Bacterial cellulose (BC) membranes are used as the carrier for berberine hydrochloride and berberine sulphate to produce a new controlled release system. Release studies and transdermal experiments were carried out in vitro. Carrier BC can significantly extend the drug release time, in contrast to existing commercial carriers. Freeze-dried BC membranes 10 mm thick were optimized for drug delivery. The lowest release rate was in simulated gastric fluid (SGF) or in H2SO4 solution, the highest in simulated intestinal fluid (SIF) and an intermediate rate was found in alkaline conditions. The release curves closely followed the Ritger-Peppas model with free diffusion the most prominent mechanism. Scanning electron microscopy (SEM) analysis demonstrated that BC fibers were swollen in acid and base conditions. 1H high-resolution magic angle spinning nuclear magnetic resonance (1H HRMAS NMR) diffusion-ordered spectroscopy (DOSY) analysis showed that there was an interaction between the drugs and BC. The structure of BC, the media and the solubility of the drug all influenced the sustained-release behavior. The results from the release studies, the electron micrographs, and the transdermal experiments were in good agreement.

Produção e degradação in vitro de estruturas tubulares de celulose bacteriana

The need of new techniques in cardiology has driven Tissue Engineering towards the development of artificial blood vessels that fulfill the requirements of the organism. In this work bacterial cellulose (BC) tubular structures were produced and their degradation in vitro was evaluated. No significant changes in microstructure and BC fiber morphology were observed by scanning electron microscopy after degradation tests. Degradation tests in physiological solutions (PBS and saline) revealed a very low degradation after 20 weeks. A low degradation rate of artificial vessels is important, since the process of new blood vessel formation (angiogenesis) demands time.

Polyol mediated synthesis of ZnO nanoparticles templated by bacterial cellulose

Zinc oxide nanoparticles have been successfully synthesized through a facile polyol method using bacterial cellulose (BC) as a template. BC membrane was used as a host matrix to introduce quantitatively Zn2+ ions and then as nanoreactors to fabricate ZnO nanoparticles by hydrolysis of zinc acetate in a polyol medium. The influence of the concentration of zinc acetate and hydrolytic time on the morphologies and size of ZnO nanoparticles were investigated. The results indicated that the uniform spherical ZnO nanoparticles were incorporated into BC fibers. The resulting nanocomposites show good mechanical properties and high photocatalytic activity in the degradation of methyl orange.

Growth and Chemical Stability of Copper Nanostructures on Cellulosic Fibers

AbstractThe design of paper products based on copper nanoparticles (NPs) is a challenge because of the intrinsic propensity of Cu to oxidize in contact with air. Here, a comparative study on the growth and chemical stability of Cu NPs in vegetable and bacterial cellulose is described for the first time. Furthermore, comparative studies were performed by using inorganic fillers of distinct dimensionality, Cu NPs and Cu nanowires (NWs), in both types of cellulose. Cu NWs were found to be more resistant to oxidation caused by prolonged air exposure than the Cu NPs. Notably, the cellulosic matrices behave differently for the growth or adsorption of the Cu nanofillers; bacterial cellulose fibers are the most efficient substrate to delay surface oxidation. The data support a role for bacterial cellulose in limiting the oxidation of Cu nanostructures that have been grown or blended in this type of matrix, hence opening up new perspectives for the development of electronic paper technologies that incorporate copper nanophases.

Badania nad zastosowaniem celulozy bakteryjnej w konserwacji i restauracji dzieł sztuki

Badania nad zastosowaniem celulozy bakteryjnej w konserwacji i restauracji dzieł sztuki

Development of Nanocomposites from Bacterial Cellulose and Poly(vinyl Alcohol) using Casting-drying Method

Nanocomposites of bacterial cellulose (BC) and poly(vinyl alcohol) (PVA) were prepared by cast-drying method as an easy way in producing nanocomposite films and to expand the use of BC. The contribution of PVA in nanocomposites was evaluated by measurement of cross-sectional surface, moisture uptake and mechanical properties. Morphological analysis shows that PVA covered a number of cellulosic fibres and formed denser material as a function of PVA addition. Based on the tensile test, the addition of PVA causes a very slight reduction compared with bacterial cellulose itself. The BC/PVA nanocomposites still have similar stiffness to BC with elongation at break less than 5%, while PVA film shows ductile properties with elongation at break more than 80%. On the other hand, the presence of BC fibres in the PVA matrix enhanced the tensile strength and the elastic modulus of pure PVA about two to three times, but it decreased the toughness of pure PVA. The highest tensile strength and elastic modulus of the nanocomposites are 164MPa and 7.4GPa, respectively at BC concentration of 64%. Increasing BC concentration is proportional to reducing moisture uptake of BC/PVA nanocomposites indicating that the existence of BC fibres inhibits moisture absorption.

Bacterial Nanocellulose for Medicine Regenerative

Bacterial cellulose (BC) has established to be a remarkably versatile biomaterial and can be used in a wide variety of applied scientific endeavours, especially for medical devices. Nanocellulose, such as that produced by the bacteria Gluconacetobacter xylinus (bacterial cellulose, BC), is an emerging biomaterial with great potential in flexible radar absorbing materials, in scaffold for tissue regeneration, water treatment, and medical applications. Bacterial cellulose nanofibril bundles have excellent intrinsic properties due to their high crystallinity, which is higher than that generally recorded for macroscale natural fibers and is of the same order as the elastic modulus of glass fibers. Compared with cellulose from plants, BC also possesses higher water holding capacity, higher degree of polymerization (up to 8000), and a finer weblike network. In addition, BC is produced as a highly hydrated and relatively pure cellulose membrane, and therefore no chemical treatments are needed to remove lignin and hemicelluloses, as is the case for plant cellulose. Because of these characteristics, biomedical devices recently have gained a significant amount of attention because of an increased interest in tissue-engineered products for both wound care and the regeneration of damaged or diseased organs. Hydrophilic bacterial cellulose fibers of an average diameter of 50 nm are produced by the bacterium Acetobacter xylinum, using a fermentation process. The architecture of BC materials can be engineered over length scales ranging from nano to macro by controlling the biofabrication process. Moreover, the nanostructure and morphological similarities with collagen make BC attractive for cell immobilization and cell support. This review describes the fundamentals, purification, and morphological investigation of bacterial cellulose. Besides, microbial cellulose modification and how to increase the compatibility between cellulosic surfaces and a variety of plastic materials have been reported. Furthermore, provides deep knowledge of current and future applications of bacterial cellulose and their nanocomposites especially in the medical field.

Bacterial cellulose production from a single sugar α-linked glucuronic acid-based oligosaccharide

A single sugar α-linked glucuronic acid-based oligosaccharide (SSGO), which is a by-product produced during bacterial cellulose (BC) synthesis by Gluconacetobacter hansenii, was evaluated as an additive to synthetic medium during BC production. We assessed the ability of the SSGO to serve as an alternative carbon source to glucose for BC production. To improve the BC yield from glucose by G. hansenii PJK, SSGO was added to a chemically defined medium (CDM). In the presence of 1% SSGO, the amount of BC produced was 10.5g/L after 10 days of cultivation, whereas in the absence of SSGO, only 7.4g/L of BC was produced. These results indicate that SSGO can be used as an alternative carbon source for BC production. Moreover, the addition of SSGO to the CDM increased the diameter of the BC fibers, which improved its tensile strength and water release properties.

Studies on the hemocompatibility of bacterial cellulose

Among the strategies to improve a material's hemocompatibility, pre-coating with the tripeptide Arg-Gly-Asp (RGD) is used to favor endothelialization thus lowering thrombogenicity. The blood compatibility of native and RGD-modified bacterial cellulose (BC) was studied in this work for the first time. The plasma recalcification time and whole blood clotting results demonstrate the hemocompatibility of BC. A significant amount of plasma protein adsorb to BC fibres, however, according to analysis by intrinsic tryptophan fluorescence techniques when albumin, γ-globulin, and fibrinogen from pure protein solutions adsorb to BC do not undergo detectable conformational modifications. Human microvascular endothelial cells cultured on RGD-modified BC readily form a confluent cell layer, inhibiting the adhesion of platelets. As a general conclusion, both native and RGD-modified BCs may be classified as hemocompatible materials.