Bacterial Nanocellulose Membrane Research Articles

Chitosan particles embedded bacterial nanocellulose flat membrane for hemodialysis

The development of bio-based hemodialysis membranes continues to be a challenge. Bacterial nanocellulose (BNC) membranes show potential in hemodialysis but can hardly retain beneficial proteins. Here, chitosan particles/bacterial nanocellulose (CSP/BNC) membranes were designed to efficiently remove uremic toxins and retain beneficial proteins. First, CSPs were synthesized in situ within a BNC membrane by ionic gelation following negative pressure impregnation. Subsequently, these membranes were thoroughly characterized. Compared with the BNC membrane, the pore volume and pore size of the 3 % CSP/BNC membrane decreased by 42.2 % and 32.1 %, respectively. The increased 22.2 times of Young's modulus and 88.9 % of tensile strength in the 3 % CSP/BNC membrane confirmed enhanced mechanical property. The sieving coefficient of bovine serum albumin decreased to 0.05 ± 0.03 in the 3 % CSP/BNC membrane. Moreover, the CSP/BNC membrane exhibited good hemocompatibility and cytocompatibility. The simulated dialysis results showed that the 3 % CSP/BNC membrane exhibited high clearance of urea (16.37 %/cm2) and lysozyme (3.54 %/cm2), while efficiently retaining bovine serum albumin (98.04 %/cm2). This is the first demonstration of the construction of a BNC-based hemodialysis membrane with in situ CSP formation to effectively regulate the pore properties of the membrane, making the CSP/BNC membrane a promising candidate for hemodialysis applications.

Purification and Characterization of Bacterial Nanocellulose Produced by Gluconobacter 5AC Isolate from Apple Vinegar

Specific microorganisms can produce bacterial nanocellulose (BNC), with acetic acid bacteria (AAB) being the most active producer. The family Acetobacteraceae includes the obligate aerobic, motile acetic acid bacteria. The BNC has attracted a lot of interest across a wide range of industries, including pharmaceuticals, due to its flexible characteristics, properties, and advantages. The present study was conducted to purify and characterize BNC produced from AAB isolated from apple vinegar. Bacterial nanocellulose was synthesized using a natural date palm liquid medium at pH 6 at 30°C for 8–10 days. The bacterial cellulose produced was then purified using a technique involving 0.1 M sodium hydroxide. To ascertain the surface morphology, size, and form of the BNC membrane, three techniques were used for characterization: X-ray diffraction (XRD), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The results of the XRD analysis confirmed that the BNC particle size ranged between approximately 17.10 and 70.33 nm, while the AFM analysis revealed that the mean diameter of these nanofibers was 26.58 nm. The TEM images clearly showed that the diameters of the BNC fibers ranged between approximately 26-66 nm. The findings of this study reveal that the characterization of the purified BNC using the XRD, AFM, and TEM analyses showed the presence of fibers with varying nanoscale diameters.

A Humidity Sensor Based on Bacterial Nanocellulose Membrane (BNC)

This article presents the development of a humidity sensor based on bacterial nanocellulose membrane (BNC) produced from Komagataeibacter xylinus. BNC has a porous surface that absorbs water and therefore it changes the mechanical and electrical properties of the membrane. As the amount of water inside the membrane increases the capacitance of the membrane also increases. The capacitance of the BNC was measured in different values of temperature (from 30° to 100°) and relative humidity (from 30% to 100%). Chronoamperometry was used as a reproducibility test and the result was a linear and more precise variation for RH over 50% and a temperature of 30°. The measurements showed a combined sensitivity of −4.13 nF/°C in relation to the temperature, and +492 nF/(%RH) and +66.8 nA/(%RH) in relation to the relative humidity.

Bacterial nanocellulose membrane as novel substrate for biomimetic structural color materials: Application to lysozyme sensing

The development of optical biosensors based on structural colors generated by short-range ordered colloidal particles is attracting growing interest due to their non-iridescent and non-fading features. In this study, a biomimetic approach using biopolymers for the various steps of sensor construction is presented. Bacterial nanocellulose (BNC) has many foreseen applications in biomedical engineering because of its biocompatibility, good mechanical strength, and large modifiable surface area. Herein, a novel approach is taken by using functionalized BNC as a substrate to build a molecularly imprinted photonic sensing layer. BNC was modified with polydopamine (PDA), which improved the adhesion and mechanical properties of the BNC substrate while providing simultaneously a black background for color saturation. A molecularly imprinted polymer (MIP) also made of PDA was used to create the recognition sites for the biomarker lysozyme. A monodisperse colloidal suspension of silica particles was first synthesized and used as core of the MIP shell, and then the photonic structure was assembled on the PDA-BNC membrane. The biosensor showed a detection limit of about 0.8 nmol L−1 of lysozyme in spiked human serum and demonstrated to be selective against cystatin C. These properties, combined with biocompatible, eco-friendly, and low-cost materials, offer a sustainable sensing platform with great potential for healthcare applications.

Preparation and Evaluation of Bacterial Nanocellulose/Hyaluronic Acid Composite Artificial Cornea for Application of Corneal Transplantation.

The treatment for corneal damage requires donor corneal transplantation, but there is a serious scarcity of donor corneas worldwide. In this study, we aimed to design a new artificial cornea with good cytocompatibility, excellent optical properties and suture resistance, and great moisturizing properties. A new bacterial nanocellulose (BNC) membrane with anisotropic mechanical properties and high light transmission was produced in a horizontal rotary drum reactor. However, as a potential material for artificial keratoplasty, the transparency and mechanical properties of the new BNC membrane were not satisfactory. Thus, hyaluronic acid (HA) was introduced in the BNC to synthesize the BNC/HA composite membrane by using 1,4-butanediol diglycidyl ether (BDDE) as the chemical cross-linking agent. The micro-morphology, light transmittance, mechanical properties, water content, moisture retention ability, and cytocompatibility of the composite membranes were further evaluated. HA was fixed in the BNC network by the ether bond, and the composite membrane was found to have excellent light transmittance (up to 95.96%). The composite membrane showed excellent mechanical properties, for instance, its tensile strength exceeded the human normal intraocular pressure (IOP) (1.33-2.80 kPa), the maximum burst pressure was about 130 kPa, 46-97 times that of the normal IOP, and its suture force was close to that of the human amniotic membrane (0.1 N). Based on the three-dimensional network scaffold of BNC and the high water absorption characteristics of HA, the artificial cornea had high water content and high moisture retention ability. The rabbit corneal stromal cells cultured in vitro showed that the artificial cornea substitute had excellent cytocompatibility. BDDE is the most frequently used cross-linker in most HA products in the current cosmetic medicine industry owing to its long-term safety records for over 15 years. Therefore, the BNC/HA composite hydrogel cross-linked with BDDE has great potential in artificial keratoplasty or ocular surface repair.

Lignin-incorporated bacterial nanocellulose for proton exchange membranes in microbial fuel cells

Microbial fuel cells (MFCs) are based on organic waste and microbes to produce electricity. Bacterial nanocellulose (BNC) can be used to produce PEMs. Incorporating Lignin (LIG) into the BNC provides more proton transport pathways and improves thermal stability. In this work, a membrane of BNC and LIG, crosslinked by citric acid (CA), was developed. Scanning electron microscopy (SEM) showed that LIG was entrapped in BNC nanofibers. Fourier transform infrared spectroscopy (FTIR) spectra of BNC/LIG membrane showed typical structural patterns of cellulose, lignin, and sulfonic groups. Thermogravimetric analysis (TGA) showed that BNC/LIG membranes are thermally more stable than those of pure BNC. BNC membrane reaching ∼90% of weight loss to temperatures higher than 380 °C and after crosslinking LIG on BNC reaching ∼64% of weight loss to temperatures higher than 480 °C. The titration tests indicated good ion exchange capacity (IEC) of the BNC/LIG membrane, presenting values of 0.78 mmol g−1 compared with Nafion® (polytetrafluoroethylene) membrane appeared in the literature a range from 0.8 to 1.0 mmol g−1. The BNC/LIG membrane as PEM in an MFC presented a maximum power density of 18.5 mW m−2 after 54 h of operation. Thus, BNC/LIG membranes are promising alternative PEMs in microbial fuel cells.

Effect of Titanium Dioxide Nanoparticle on Properties of Nanocomposite Membrane Made of Bacterial Cellulose

ABSTRACT The purpose of this study was to see the effect of adding TiO2 nanoparticles had on the characteristics of bacterial nanocellulose (BNC)-based membranes. Pellicles were created from the pineapple peel waste extract, and to obtain BNC, pellicle was disintegrated in six cycles using high-pressure homogenizer at 150 bar. The concentrations of TiO2 nanoparticles in the membrane reinforcement solution were 0.5, 1.0, 1.5, 2.0, and 2.5 wt.%. They were sonicated and dried in an oven at 60°C for 8 h. X-ray diffraction, Fourier transform infrared spectroscopy, roughness test, mechanical properties, and scanning electron microscopy were investigated to explore its claims. The results revealed that diffraction pattern of BNC/TiO2 membrane has a new peak at 25.05° that ensures the presence of TiO2 nanoparticles as well as diffraction peak occurred at 22.49°, which indicates the presence of cellulose Iβ. Moreover, the addition of TiO2 nanoparticles until 1.5 wt.%, the crystallinity index is relatively same and the optimum strength of 99.5 MPa was attained. Further, improvement in addition of TiO2 nanoparticle at 2 wt.% showed a decline in crystallinity index as 80.16% to 74.72% at 2.5 wt.%. The morphology of the membrane surface revealed that TiO2 nanoparticles were still agglomerated and not equally distributed across the BNC membrane, leading to increase in surface roughness.

Evaluation of wet nanocellulose membranes produced by different bacterial strains for healing full-thickness skin defects

Bacterial nanocellulose (BNC) is an excellent candidate biomaterial for wound dressing applications, although its preparation should consider the differences in wound healing resulting from BNC biosynthesized by different bacterial strains. This study design aimed to characterize the BNC produced by three different bacterial strains and compare their effectiveness for wound healing applications. The results demonstrated that the upper surfaces of the BNC membranes were clearly denser and more compact than the lower surfaces, while all varieties were capable of serving as a physical barrier to the invasion of bacteria. The growth of fibroblasts demonstrated that the lower surfaces of BNC membranes exhibited biocompatibility superior to that of the upper surfaces. In vivo analysis indicated that, of all samples, wounds treated with the BNC membrane synthesized by DHU-WX-1 displayed the greatest wound repair efficacy. The results indicate that BNC biosynthesized by different strains displayed different wound healing effectiveness. Placing the lower surface of BNC membranes in contact with wounds, with the denser upper surface outward, satisfied the clinical requirements of a wound repair biomaterial.

Functionalization of Aminoalkylsilane-Grafted Bacterial Nanocellulose with ZnO-NPs-Doped Pullulan Electrospun Nanofibers for Multifunctional Wound Dressing.

High moisture permeability, excellent mechanical properties in a wet state, high water-holding capability, and high exudate absorption make bacterial nanocellulose (BNC) a favorable candidate for biomedical device production, especially wound dressings. The lack of antibacterial activity and healing-promoting ability are the main drawbacks that limit its wide application. Pullulan (Pul) is a nontoxic polymer that can promote wound healing. Zinc oxide nanoparticles (ZnO-NPs) are well-known as a safe antibacterial agent. In this study, aminoalkylsilane was chemically grafted on a BNC membrane (A-g-BNC) and used as a bridge to combine BNC with Pul-ZnO-NPs hybrid electrospun nanofibers. FTIR results confirmed the successful production of A-g-BNC/Pul-ZnO. The obtained dressing demonstrated blood clotting performance better than that of BNC. The dressing showed an ability to release ZnO, and its antibacterial activity was up to 5 log values higher than that of BNC. The cytotoxicity of the dressing toward L929 fibroblast cells clearly showed safety due to the proliferation of fibroblast cells. The animal test in a rat model indicated faster healing and re-epithelialization, small blood vessel formation, and collagen synthesis in the wounds covered by A-g-BNC/Pul-ZnO. The new functional dressing, fabricated with a cost-effective and easy method, not only showed excellent antibacterial activity but could also accelerate wound healing.

Optimization and characterization of eco-friendly antimicrobial nanocellulose sheet prepared using carbon dots of white mulberry (Morus alba L.).

Carbon dots (C-dots) with antimicrobial activity were synthesized from the white mulberry extract with the aim of fabricating anti-listeria nanopaper using bacterial nanocellulose (BNC). Highly dispersed synthesized C-dots with a size smaller than 10 nm (approximately 4.9 nm) were impregnated into BNC by an ex situ coating method and then mechanical, morphological, UV-protectant and antibacterial activity were assessed. Randomized response surface methodology using a central composite design was applied to investigate the optimized concentration of C-dots in the BNC membrane. An optimized nanopaper including C-dots at a concentration of 530 g L-1 and an impregnation time of 14 h at 30 °C with significant antimicrobial activity on Listeria monocytogenes was designed. The addition of C-dots into BNC significantly increased ultimate tensile strength and decreased strain with respect to breaking BNC. A BNC sheet with high-efficient UV-blocking property was prepared using C-dots. Based on the results, the designed nanopaper shows a substantial capacity with respect to the fabrication of antimicrobial/UV-blocking sheets for food active packaging. © 2020 Society of Chemical Industry.

Bacterial nanocellulose membrane as bolus in radiotherapy: "proof of concept"

Boluses characterize materials with an electromagnetic radiation attenuation coefficient similar to biological tissue and used to restrict the penetration of high energy photons and electrons used in radiotherapy for the treatment of superficial tumors. The development of new materials, mainly from sustainable biotechnological routes, will contribute to increase efficiency and expand the use of these technologies. The objective of this research was to develop the “proof of concept” regarding the use of the bacterial nanocellulose membrane (BNCm) as a bolus. For this purpose, BNCm were produced, purified and subjected to the physical–chemical characterization. The radiological density (RD) and radiation attenuation potential (RAP) of the BNCm were established and compared to a commercial bolus (CB). The moldability of BNCm was established and compared to the virtual bolus of dosimetric planning. The physical–chemical analysis demonstrated the constitution of a pure, highly hydrated, homogeneous and nanostructured network of cellulose fibers. BNCm showed superiority in relation to RD and similar RAP values when compared to CB. Moldability analysis showed a profile identical to a virtual bolus. The results validate the concept of using BNCm as a highly efficient biotechnological device, aligned with the idea of sustainability, as a bolus for use in radiotherapy.

A Novel Approach Using Conventional Methodologies to Scale up BNC Production Using Komagataeibacter medellinensis and Rotten Banana Waste as Alternative

Currently, cellulose nanostructures are among the most promising structures, and extensive work in materials and biotechnology industries is aimed at identifying an efficient process of production. Even when production at the laboratory scale is successful, crucial aspects of increased commercial applications for cellulose nanostructures are linked to large-scale production. Large-scale production requires a balance between the cost of the culture medium and product value. Therefore, in this work, for the optimization and scaling up of bacterial nanocellulose, a culture medium consisting of rotten banana unsuitable for human consumption was used for the first time as an inexpensive feedstock. Initially, the bacterial nanocellulose (BNC) culture medium conditions were optimized, and it was established that a glucose concentration of 26.4 g/L and a V/A ratio of 2.2 cm were the optimal conditions for production reaching a BNC yield of 5 g/L, which was 42.4% higher than the best result initially obtained. Finally, the scale-up process was performed, implementing a regime analysis methodology by comparing the characteristic times of the critical mechanisms involved in BNC production, namely, microbial growth, glucose consumption, BNC production, and glucose diffusion into the BNC membrane, as the first approach for this type of BNC production process. The mechanism underlying the BNC production process is glucose diffusion into the BNC membrane (characteristic time, 675.47 h). Thus, the V/A ratio was selected as the scale-up criterion most suitable for producing BNC under static culture conditions, allowing the production of 16 g of BNC after 12 d of fermentation in a plastic bioreactor, which was 3378% higher than that produced in glass vessels. The results obtained in this study may initiate further improvements in BNC commercial production by exploiting different feedstocks.

Bacterial Nanocellulose Membrane As Bolus in Radiotherapy: “Proof of Concept”

Bolus characterize materials with an electromagnetic radiation attenuation coefficient similar to biological tissue and which are positioned on the skin of patients during radiotherapy treatment. Such devices are responsible for the superficialization of the maximum dose of high energy photons and electrons, restricting its penetration and improving the coverage of the treatment isodose. The development of new materials, mainly from sustainable biotechnological routes, will contribute to increasing efficiency and expanding the use of these technologies. The objective of this research was to develop the “proof of concept” regarding the use of the bacterial nanocellulose membrane (BNCm) as a bolus for radiotherapy procedures. For this purpose, 1.4 cm thick BNCm were produced from static cultivation of the K. rhaeticus, purified and subjected to the physical‐chemical characterization process by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT‐IR). The samples were then subjected to the determination of the radiological density (RD), by computed tomography, and the radiation attenuation potential (%), after being irradiated with 6MV photons in a linear accelerator using ionization and phantom chamber at doses of 100 and 50 UM. The results were compared with data from the analyzes in a commercial bolus (CB) with same thickness. The physical‐chemical analysis demonstrated the constitution of a pure, highly hydrated, homogeneous and nanostructured network of cellulose fibers. The mean RD of BNCm was 1.1 and 5 Hounsfield units respectively, demonstrating high water (0HU) equivalence from BNCm. The values corresponding to the radiation attenuation at the dose of 100 MU were 5.1 ± 0.1% and 4.6 ± 0.2%, for CB and BNCm respectively. The values for the dose of 50 MU were 3.8 ± 0.1% and 3.0 ± 0.2%. In both doses, the attenuation of BNCm was similar to the CB. It stands out the superiority of the BNCm moldability and the possibility to change its composition to improve the radiation attenuation. The results support the concept of use the BNCm as an effective biotechnological device, align to the sustainability idea, as a bolus for radiotherapy treatment.Support or Funding InformationI.P.F.B. Indústria de Produtos Farm. e Biotecnológicos Ltda.

Topical Drug Delivery Systems Based on Bacterial Nanocellulose: Accelerated Stability Testing.

Bacterial nanocellulose (BNC) membranes have enormous potential as systems for topical drug delivery due to their intrinsic biocompatibility and three-dimensional nanoporous structure, which can house all kinds of active pharmaceutical ingredients (APIs). Thus, the present study investigated the long-term storage stability of BNC membranes loaded with both hydrophilic and lipophilic APIs, namely, caffeine, lidocaine, ibuprofen and diclofenac. The storage stability was evaluated under accelerated testing conditions at different temperatures and relative humidity (RH), i.e., 75% RH/40 °C, 60% RH/25 °C and 0% RH/40 °C. All systems were quite stable under these storage conditions with no significant structural and morphological changes or variations in the drug release profile. The only difference observed was in the moisture-uptake, which increased with RH due to the hydrophilic nature of BNC. Furthermore, the caffeine-loaded BNC membrane was selected for in vivo cutaneous compatibility studies, where patches were applied in the volar forearm of twenty volunteers for 24 h. The cutaneous responses were assessed by non-invasive measurements and the tests revealed good compatibility for caffeine-loaded BNC membranes. These results highlight the good storage stability of the API-loaded BNC membranes and their cutaneous compatibility, which confirms the real potential of these dermal delivery systems.

Modification of bacterial nanocellulose properties through mutation of motility related genes in Komagataeibacter hansenii ATCC 53582

Bacterial nanocellulose (BNC) produced by Komagataeibacter hansenii has received significant attention due to its unique supernetwork structure and properties. It is nevertheless necessary to modify bacterial nanocellulose to achieve materials with desired properties and thus with broader areas of application. The aim here was to influence the 3D structure of BNC by genetic modification of the cellulose producing K. hansenii strain ATCC 53582. Two genes encoding proteins with homology to the MotA and MotB proteins, which participate in motility and energy transfer, were selected for our studies. A disruption mutant of one or both genes and their respective complementation mutants were created. The phenotype analysis of the disruption mutants showed a reduction in motility, which resulted in higher compaction of nanocellulose fibers and improvement in their mechanical properties. The data strongly suggest that these genes play an important role in the formation of BNC membrane by Komagataeibacter species.

Nanocellulose biosynthesis by Komagataeibacter hansenii in a defined minimal culture medium

This study evaluates the capability of Komagataeibacter hansenii ATCC 23769 to synthesize bacterial nanocellulose (BNC) under strict limitation of nutrients with different carbon and nitrogen sources in a defined minimal culture medium in static culture. Five carbon sources were prepared based on the C-molar basis concentration: glycerol, glucose, fructose, mannitol and saccharose, combined with three different nitrogen sources: NH4Cl, NH4NO3 and (NH4)2SO4. BNC production yields were determined based on the dry weight of the produced BNC-Minimal membranes and the carbon consumption for each condition. The combination of 25 mM of glucose and 10 mM of NH4Cl showed the best concentration of C and N sources regarding BNC yield and membrane stability. This is a new proposal of defined minimal culture medium that supports growth of BNC membranes production, without the addition of complex elements such as yeast extract and peptone. BNC membranes produced under these conditions exhibited great optical transparency compared to the membranes produced in complex media (Mannitol and Hestrin–Schramm), therefore increasing a wide range of technological applications.

Bacterial nanocellulose membranes combined with nisin: a strategy to prevent microbial growth

Consumer concerns about synthetic additives is increasing and it can be interesting to apply natural antioxidants with antimicrobial properties. Developing a packing material composed by a natural polymer, such as bacterial nanocellulose membrane (BNCm) loaded with nisin may be applied as a method to keep food quality and to inhibit growth of microbial contaminants. For this reason, the aim of this study was to evaluate antimicrobial activity of BNCm loaded with nisin. Antimicrobial activity of nisin, utilizing or not EDTA solution,was assessed by minimal inhibitory concentration and agar diffusion assay, utilizing Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Antioxidant activity and physico-chemical properties were also evaluated. For the MIC evaluation, the combination of nisin solution with EDTA showed a synergistic effect. Concerning E. coli nisin with EDTA 20–40 mM, MIC was 31.25 μg/mL. Concerning P. aeruginosa nisin with EDTA 10–20 mM, MIC was 125 μg/mL. Concerning S. aureus nisin with EDTA 10 mM, MIC was 15.63 μg/mL, two times lower than without EDTA. The BNCm antimicrobial activity for E. coli, by agar diffusion assay, was observed when nisin was loaded at 250 or 500 μg/mL with EDTA 10 or 20 mM. However, for S. aureus, the antimicrobial activity was observed for BNCm loaded with nisin 15 μg/mL with 10 mM EDTA. For P. aeruginosa, antimicrobial activity was not observed. Nisin exhibited significant antimicrobial and antioxidant activity. The results provide evidence that BNCm loaded with nisin is a promising control strategy to prevent microorganism contamination.