Modification Of Bacterial Cellulose Research Articles

Metal-Free, Bio-Triboelectric Nanogenerator Based on a Single Electrode of Bacterial Cellulose Modified with Carbon Black

Developing metal-free electrodes for prototypes of bio-based devices is an essential step in producing non-toxic components for implantable devices and wearables. In particular, the advancement in self-powered devices is a hot topic for several applications due to the possibility of creating free-battery devices and sensors. In this paper, the modification of bacterial cellulose by the progressive incorporation of carbon black (a conductive filler) was explored as a prototype for bio-based electrodes for triboelectric nanogenerators. This process was controlled by the percolation pathways’ activation through the contact of carbon black grains with the bacterial cellulose membrane, which represents a critical step in the overall process of optimization in the power output performance, reaching an open circuit voltage value of 102.3 V, short circuit current of 2 μA, and power density of 4.89 μW/cm2.

Properties and Applications of Modified Bacterial Cellulose-Based Materials

Background: Bacterial cellulose (BC) is the purest form of cellulose as it is free from pectin, lignin, hemicellulose and other active constituents associated with cellulose derived from plant sources. High biocompatibility and easy molding into the desired shape make BC an ideal candidate for applications in the biomedical fields, such as tissue engineering, wound healing and bone regeneration. In addition to this, BC has been widely studied for applications in the delivery of proteins and drugs in various forms via different routes. However, BC lacks therapeutic properties and resistance to the free movement of small molecules, i.e., gases and solvents. Therefore, modification of BC is required to meet the research ad market demand. Methods: We have searched the updated data relevant to as-synthesized and modified BC, properties and applications in various fields using Web of science, Science direct, Google and PubMed. Results: As-synthesized BC possesses properties such as high crystallinity, well organized fibrous network, higher degree of polymerization, and ability of being produced in swollen form. The large surface area with abundance of free accessible hydroxyl groups makes BC an ideal candidate for carrying out surface functionalization to enhance its features. The various reported surface modification techniques including, but not limited to, are amination, methylation and acetylation. Conclusion: In this review, we have highlighted various approaches made for BC surface modification. We have also reported enhancement in the properties of modified BC and potential applications in different fields ranging from biomedical science to drug delivery and paper-making to various electronic devices.

Синтез и изучение антибиотических свойств 6-(2-фталимидоэтансульфоната) бактериальной целлюлозы

Bacterial cellulose obtained by culturing Gluconacetobacter sucrofermentans in HS environment was converted to sulfonate derivatives using methane-, toluene- and 2-phthalimidoethanesulfonic acids in pyridine. When the ratio of the starting reagents is 1 : 1, the modification of bacterial cellulose according to the primary hydroxyl group of glucopyranose fragments is most likely. The formation of 6-substituted bacterial cellulose derivatives was observed in the reaction mixture. The IR spectra of the reaction products contain absorption bands, which are specific for (O–SO2) group in the region 1377-1338 cm−1 (as), 1178-1154 cm−1 (s), fragments of the corresponding sulfonic acids, as well as free hydroxyl groups of glucopyranose in the region 3495-3382 cm−1. Bacterial cellulose 2-phthalimidoethanesulfonate was dissolved in pyridine. After drying with a desiccant in a desiccator, it turned into a dense transparent film of brown color. The increased molecular film allows to explain the side reaction occurring between the oxo group and fragments of one of the chains of modified cellulose and the non-substituted hydroxymethyl group. The IR spectrum of bacterial cellulose 6-(2-phthalimidoethanesulfonate) contains absorption bands in the region 1711 cm−1, which are specific for (Ar–CO–O) group, and absorption bands in the region 1618 cm−1, which prove the presence of (CO–NH) group. In order to impart antibiotic properties to the bacterial cellulose 6-(2-phthalimido-ethanesulfonate) film, it was physically modified with clotrimazole. The obtained experimental data showed that the films subjected to treatment with a 1% solution of clotrimazole have antibacterial and antifungal effects and prevent the growth of pathogenic microbiota on the wound surface. The exit rates of clotrimazole from the bacterial cellulose 6-(2-phthalimidoethanesulfonate) film and from the pure bacterial cellulose film differed, but only slightly. 2-Phthalimidoethanesulfonate bacterial cellulose films can be used to form composites of effective wound covering, since in addition to the unique properties of bacterial cellulose itself (low allergenicity and adhesion to the wound surface, high hygroscopicity) they will have a regenerating effect.

Modification of Bacterial Cellulose with Quaternary Ammonium Compounds Based on Fatty Acids and Amino Acids and the Effect on Antimicrobial Activity

In the present work, bacterial cellulose (BC) membranes have been modified with bioactive compounds based on long chain dimer of C18 linoleic acid, referred to as the dilinoleic acid (DLA) and tyrosine (Tyr), a natural amino acid capable of forming noncovalent cation-π interactions with positively charged ethylene diamine (EDA). This new compound, [EDA][DLA-Tyr], has been synthesized by simple coupling reaction, and its chemical structure was characterized by 1H NMR and Fourier transform infrared spectroscopy. The antimicrobial activity of a new compound against S. aureus and S. epidermidis, two cocci associated with skin and wound infections, was assessed. The [EDA][DLA-Tyr] impregnated BC exhibited strong and long-term antimicrobial activity against both staphylococcal species. The results showed a 57-66% and 56-60% reduction in S. aureus and S. epidermidis viability, respectively, depending on [EDA][DLA-Tyr] concentration used. Importantly, [EDA][DLA-Tyr] molecules were released gradually from the BC pellicle, while a reference antibiotic, erythromycine (ER), did not show any antibacterial activity against S. aureus and S. epidermidis after 48 h of soaking in deionized water. Thus, a combination of [EDA][DLA-Tyr] and BC could be a promising new class of wound dressing displaying both biocompatibility and antimicrobial activity.

ENZYMATIC SYNTHESIS OF CELLULOSE PROPIONATE AND ITS POTENCY AS RAW MATERIAL FOR MEMBRANE

ABSTRACT Modification of bacterial cellulose through enzymatic esterification between cellulose and propionic acid has been carried out to produce cellulose propionate as raw material of dialysis membrane. The research aimed to characterize of cellulose propionate and assess its potency as raw material for membrane. The esterification was performed for 8 hours at 50 ⁰C with cellulose and propionic acid in mass ratio of 1:5. The physical chemical properties of resulted cellulose propionate were determined for functional group using FTIR, crystallinity index by XRD, swelling index by gravimetric method, specific gravity, maximum pore size diameter and membrane thickness. The cellulose propionate showed peak absorbance at wave number of 1743 cm -1 from C=O absorption and 1108 cm -1 and 1037 cm -1 from C-O absorption with degree of crystallinity of 61.56% and density of 1.39 g/cm 3 . Cellulose propionate membrane has maximum poressize of 2.25 ± 0.04 µm and thickness of 0.029 ±0.001mm, the swelling index of 153%. Diffusion equilibrium of uric acid was 3 hours at average diffusion rate of 1.48ppm/h. Keywords : Bacterial cellulose, cellulose propionate, characteristic, diffusion rate

Surface Modification of Bacterial Cellulose Film

Bacterial cellulose (BC) is the cellulose which is produced by specific bacteria such as Acetobacter xylinum, Agrobacterium, Gluconacetobacter, Rhizobium, Achromobacter, Alcaligenes, Aerobacter, Azotobacter, Salmonella, Esherichia, and Sarcina. Surface modification of bacterial cellulose (BC) by coating with synthetic biodegradable polyester on it was reported. BC films were coated with the polymer at different concentrations in order to improve the surface structure of BC. Tear and burst indices of the BC film were increased with such modification.

Modification of bacterial cellulose through exposure to the rotating magnetic field

The aim of the study was to assess the influence of rotating magnetic field (RMF) on production rate and quality parameters of bacterial cellulose synthetized by Glucanacetobacter xylinus. Bacterial cultures were exposed to RMF (frequency f=50Hz, magnetic induction B=34mT) for 72h at 28°C. The study revealed that cellulose obtained under RMF influence displayed higher water absorption, lower density and less interassociated microfibrils comparing to unexposed control. The application of RMF significantly increased the amount of obtained wet cellulose pellicles but decreased the weight and thickness of dry cellulose. Summarizing, the exposure of cellulose-synthesizing G. xylinus to RMF alters cellulose biogenesis and may offer a new biotechnological tool to control this process. As RMF-modified cellulose displays better absorbing properties comparing to non-modified cellulose, our finding, if developed, may find application in the production of dressings for highly exudative wounds.

Modification of Bacterial Cellulose with Organosilanes to Improve Attachment and Spreading of Human Fibroblasts.

Bacterial Cellulose (BC) synthesized by Acetobacter xylinum has been a promising candidate for medical applications. Modifying BC to possess the properties needed for specific applications has been reported. In this study, BCs functionalized by organosilanes were hypothesized to improve the attachment and spreading of Normal Human Dermal Fibroblast (NHDF). The BC gels obtained from biosynthesis were dried by either ambient-air drying or freeze drying. The surfaces of those dried BCs were chemically modified by grafting methyl terminated octadecyltrichlorosilane (OTS) or amine terminated 3-aminopropyltriethoxysilane (APTES) to expectedly increase hydrophobic or electrostatic interactions with NHDF cells, respectively. NHDF cells improved their attachment and spreading on the majority of APTES-modified BCs (∼70-80% of area coverage by cells) with more rapid growth (∼2.6-2.8× after incubations from 24 to 48h) than on tissue culture polystyrene (∼2×); while the inverse results (< 5% of area coverage and stationary growth) were observed on the OTS-modified BCs. For organosilane modified BCs, the drying method had no effect on in vitro cell attachment/spreading behaviors.

Adsorptive behavior of acrylic acid-grafted bacterial cellulose to remove cadmium for a membrane-adsorbent hybrid process

Abstract An adsorbent for Cd ions was prepared through the modification of bacterial cellulose (BC) with acrylic acid (AAc) using electron beam-induced grafting polymerization. The modification of BC was confirmed by FTIR/ATR and scanning electron microscope (SEM). Batch adsorption test was performed to investigate adsorptive behavior of the adsorbent in aqueous solution. Adsorption was analyzed using the Benaissa, Kurniawan, Langmuir, and Freundlich models. In the kinetic behavior, it was confirmed that it was pseudo-second-order rather than pseudo-first-order kinetic rate expression. Adsorption isotherm behavior followed the Langmuir model rather than Freundlich model, indicating that AAc-grafted BC was monolayer covered with Cd ions. The adsorption capacity (Q m) calculated from Langmuir isotherm was 68.97 mg g−1. AAc-g-BC shows potential as a useful Cd-adsorbent made of an environmentally friendly material.

Conductivity-Dependent Strain Response of Carbon Nanotube Treated Bacterial Nanocellulose

This paper reports the strain sensitivity of flexible, electrically conductive, and nanostructured cellulose which was prepared by modification of bacterial cellulose with double-walled carbon nanotubes (DWCNTs) and multiwalled carbon nanotubes (MWCNTs). The electrical conductivity depends on the modifying agent and its dispersion process. The conductivity of the samples obtained from bacterial cellulose (BNC) pellicles modified with DWCNT was in the range from 0.034 S·cm−1to 0.39 S·cm−1, and for BNC pellicles modified with MWCNTs it was from 0.12 S·cm−1to 1.6 S·cm−1. The strain-induced electromechanical response, resistance versus strain, was monitored during the application of tensile force in order to study the sensitivity of the modified nanocellulose. A maximum gauge factor of 252 was found from the highest conductive sample treated by MWCNT. It has been observed that the sensitivity of the sample depends on the conductivity of the modified cellulose.

Synthesis of PLA-co-PGMA Copolymer and its Application in the Surface Modification of Bacterial Cellulose

Nature fibers have been developed for the reinforcement of polymers. The main disadvantage of the natural fibers to be used as reinforcement is their hydrophilic nature. In this paper, a novel copolymer of polylactide and glycidyl methacrylate (PLA-co-PGMA) was prepared by free radical polymerization and used to modify the cellulose surface. The characterization of the PLA-co-PGMA copolymers was conducted by Fourier transform infrared (FTIR) and gel permeation chromatography. Modified bacterial cellulose (BC) with the copolymer was characterized by FTIR and contact angle measurements. Interfacial thermodynamic properties were studied. The results suggested that PLA-co-PGMA was efficient in modifying the BC nanofibril surface and in improving the compatibility of PLA/cellulose composites.

Synthesis and Characterization of MPS-g-PLA Copolymer and its Application in Surface Modification of Bacterial Cellulose

Polylactide-graft-γ-methacryloxypropyltrimethoxysilane (MPS-g-PLA) was prepared by grafting MPS onto PLA. MPS-g-PLA was characterized by Fourier transform-infrared spectroscopy (FT-IR), hydrogen nuclear magnetic resonance (1H-NMR), and gel permeation chromatography. Furthermore, MPS-g-PLA was used to modify bacterial cellulose (BC), and the changes of surface properties of BC resulting from the treatment were followed by FT-IR and contact angle measurements. The results revealed that the modified BC possessed a much more hydrophobic nature than virgin BC. The surface modification of BC with MPS-g-PLA offers a way to increase the compatibility between the components in biocomposites, and thereby to improve the properties of these composites.