Cellulose Mats Research Articles

Functionalizing the Electrical Properties of Kombucha Zoogleal Mats for Biosensing Applications.

Kombucha is a type of tea that is fermented using yeast and bacteria. During this process, a film made of cellulose is produced. This film has unique properties such as biodegradability, flexibility, shape conformability, and ability to self-grow as well as be produced across customized scales. In our previous studies, we demonstrated that Kombucha mats exhibit electrical activity represented by spikes of the electrical potential. We propose using microbial fermentation as a method for in situ functionalization to modulate the electroactive nature of Kombucha cellulose mats, where graphene and zeolite were used for the functionalization. We subjected the pure and functionalized Kombucha mats to mechanical stimulation by applying different weights and geometries. Our experiments demonstrated that Kombucha mats functionalized with graphene and zeolite exhibit memfractive properties and respond to load by producing distinctive spiking patterns. Our findings present incredible opportunities for the in situ development of functionalized hybrid materials with sensing, computing, and memory capabilities. These materials can self-assemble and self-grow after they fuse their living and synthetic components. This study contributes to an emergent area of research on bioelectronic sensing and hybrid living materials, opening up exciting opportunities for use in smart wearables, diagnostics, health monitoring, and energy harvesting applications.

Electroactive composite biofilms integrating Kombucha, Chlorella and synthetic proteinoid Proto-Brains.

In this study, we present electroactive biofilms made from a combination of Kombucha zoogleal mats and thermal proteinoids. These biofilms have potential applications in unconventional computing and robotic skin. Proteinoids are synthesized by thermally polymerizing amino acids, resulting in the formation of synthetic protocells that display electrical signalling similar to neurons. By incorporating proteinoids into Kombucha zoogleal cellulose mats, hydrogel biofilms can be created that have the ability to efficiently transfer charges, perform sensory transduction and undergo processing. We conducted a study on the memfractance and memristance behaviours of composite biofilms, showcasing their capacity to carry out unconventional computing operations. The porous nanostructure and electroactivity of the biofilm create a biocompatible interface that can be used to record and stimulate neuronal networks. In addition to in vitro neuronal interfaces, these soft electroactive biofilms show potential as components for bioinspired robotics, smart wearables, unconventional computing devices and adaptive biorobotic systems. Kombucha-proteinoids composite films are a highly customizable material that can be synthesized to suit specific needs. These films belong to a unique category of 'living' materials, as they have the ability to support cellular systems and improve bioelectronic functionality. This makes them an exciting prospect in various applications. Ongoing efforts are currently being directed towards enhancing the compositional tuning of conductivity, signal processing and integration within hybrid bioelectronic circuits.

Improving carbon yield of bacterial cellulose derived carbon by phosphorus/nitrogen doping

In this study, porous bacterial cellulose (BC) mat was prepared by freeze-thawing of BC hydrogel obtained from the kombucha fermentation process. Then, the porous BC was dyed with a nitrogen containing carbonyl dye (C.I. Vat Olive B) followed by phosphorus doping and employed as a precursor for preparation of carbon nanofilament. The P/N doped BC mat precursor was stabilized at 330 ºC for 2 h and carbonized at 800 ºC for 2 h. SEM images confirmed that BC based carbon exhibited the entangled filament structure. To follow the conversion of BC mat to carbon nanofilament, FTIR analysis and Raman spectroscopy were carried out. FTIR spectra of stabilized mats showed that the cellulose carbon-carbon double band centered at 1600 cm -1 appeared strongly. In contrast, the intensity of this band markedly decreased at carbonization stage, resulting from the conversion of cellulose carbon-carbon double bond into carbon aromatic ring which exhibited weak intensity. The graphitic structure was confirmed by the presence of sp 3 disorder hybridization and sp 2 hybridization (D and G bands, respectively) shown in Raman spectra). In addition, XRD diffractograms further confirmed the existence of amorphous carbon peak found at 26º, indicating that the P/N dopants played a role in inducing the graphitic structure as well as improving carbon yield. Finally, the electrochemical performance as a carbon electrode were revealed.

Comparison of microstructure and tensile behavior of hydroxyapatite-coated PEEK meshes and cellulose-based fabrics and mats

Polymeric biomaterials, such as polyether ether ketone (PEEK) and cellulose, have been explored as scaffolds for bone tissue engineering in the past decade. In this study, microstructure and mechanical behavior of uncoated and hydroxyapatite (HA)-coated polymeric meshes, fabrics, and mats were investigated. Commercially available monofilament PEEK meshes, and cellulose fabrics and mats were selected, then coated with a customized low temperature sol–gel method (≤ 150°C). Adhesive HA coating consisting of HA, β-TCP, and CaO with nanorod structure was derived. After HA coating, porosity of substrates (except filter-paper cellulose mats) decreased by up to 43%, indicating effective coating. Both uncoated and HA-coated substrates’ degradation rate in phosphate-buffered saline decreased after day 3. This is a result of ion precipitation or calcium compounds formation, indicating potential stability in biofluids for an extended period of time. Regarding tensile test results, highest tensile strength and elongation at break were obtained for PEEK meshes (approximately 80 MPa and 35%, respectively), as a result of the bulk material properties. HA coating did not significantly affect the tensile properties of the specimens, except for cellulose mats with an initial porosity of 77% (tensile modulus increased by 270% and strength by 210%). The increase in tensile properties could be attributed to increased rigidity, resulting from the adhesion between HA coating and cellulose fibers. Overall, HA-coated cellulose mats and PEEK meshes show promise as customizable, flexible scaffolds for implant applications and bone regeneration for future work.

Ionic Conductive Cellulose Mats by Solution Blow Spinning as Substrate and a Dielectric Interstrate Layer for Flexible Electronics.

Renewable cellulose substrates with submicron- and nanoscale structures have revived interest in paper electronics. However, the processes behind their production are still complex and time- and energy-consuming. Besides, the weak electrolytic properties of cellulose with submicron- and nanoscale structures have hindered its application in transistors and integrated circuits with low-voltage operation. Here, we report a simple, low-cost approach to produce flexible ionic conductive cellulose mats using solution blow spinning, which are used both as dielectric interstrate and substrate in low-voltage devices. The electrochemical properties of the cellulose mats are tuned through infiltration with alkali hydroxides (LiOH, NaOH, or KOH), enabling their application as dielectric and substrate in flexible, low-voltage, oxide-based field-effect transistors and pencil-drawn resistor-loaded inverters. The transistors exhibit good transistor performances under operation voltage below 2.5 V, and their electrical performance is strictly related to the type of alkali ionic specie incorporated. Devices fabricated on K+-infiltrated cellulose mats present the best characteristics, indicating pure capacitive charging of the semiconductor. The pencil-drawn load resistor inverter presents good dynamic performance. These findings may pave the way for a new generation of low-power, wearable electronics, enabling concepts such as the "Internet of Things".

Nanocellulose from Unbleached Hemp Fibers as a Filler for Biobased Photocured Composites with Epoxidized Cardanol

Biobased composites were successfully prepared using raw materials derived from biomass waste, i.e., an epoxy resin obtained from cardanol and nanocellulose from unbleached hemp fibers. The composites were prepared by solvent exchange and an impregnation of the cellulosic mat with the resin, followed by photocuring. Quantitative conversion was obtained, despite the high amount of fibers (30 wt%) and their absorbance in the UV region of the light spectrum. X-ray diffraction confirmed that the crystalline structure of cellulose did not change during the impregnation and curing process. The cured composites were flexible, hydrophobic, water resistant, transparent with a yellow/brown color, and in the rubbery state at room temperature.

Coloration of cellulose nanofibres with pigments

AbstractElectrospun nanofibrous mats are popular for their wide technological applications as medical, filtration, sensing and high performance textiles. The potential for coloration of electrospun nanofibrous mats for aesthetic purposes has also been explored recently, and the pigment coloration of cellulose electrospun nanofibrous mats is reported for the first time in this paper. Cellulose acetate electrospun nanofibrous mats were fabricated using electrospinning followed by treatment with sodium hydroxide to synthesise regenerated cellulose electrospun nanofibrous mats. Then the cellulose mats were coloured with commercially available pigments by a pad‐dry‐bake method. Excellent K/S and colour fastness to both washing and light were produced with the application of three commercial pigments. The pH and total dissolved solids content of the coloration wastewater, as well as the mechanical properties of the electrospun nanofibrous mats, were also tested. Attenuated total reflection‐Fourier Transform infrared spectroscopy and scanning electron microscopy analysis were used for characterisation.

Chitosan/tannic acid bilayers layer-by-layer deposited cellulose nanofibrous mats for antibacterial application

The research and development of environmentally friendly and nontoxic biomass products has become an important topic of worldwide concern. In this study, natural materials were used for producing a kind of antibacterial mats. Cellulose acetate (CA) mats prepared by electrospinning technology were converted to cellulose mats via alkali hydrolysis. Chitosan (CS) and tannic acid (TA) were used to fabricate the composite mats by using layer-by-layer (LBL) self-assembly technology. The cellulose mats exhibited good fibrous structure, three-dimensional network and small average fiber diameter ranging from 300 to 400 nm. Besides, the results of mechanical properties testing and water contact angle measurements of these LBL-structured mats demonstrated that the LBL technology was able to improve their surface characteristics, hydrophilicity and mechanical properties. The analysis of antibacterial activity of the mats revealed over 86% antibacterial activity against Escherichia coli and up to 99% antibacterial activity against Staphylococcus aureus. Hence, the LBL-structured cellulose mats have excellent antibacterial activity and mechanical properties. Therefore, these nano-cellulose mats can be expected to have considerable development prospects for food packaging or wound dressing.

Preparation and characterization of nanocellulose–polyvinyl alcohol multilayer film by layer-by-layer method

Nanofibrillated cellulose (NFC) and polyvinyl alcohol (PVA) were alternately deposited on a NFC/polyethylene terephthalate (PET) substrate by the use of layer-by-layer (LBL) self-assembly technique. The results reveal that by adding a single PVA layer on the NFC/PET substrate, the surface exhibited more hydrophilic properties showing reduced contact area and excellent surface wettability. Furthermore, the common FT-IR band for a carboxylic group was observed at 1535 cm−1, which indicates that NFC treated by TEMPO oxidation was attached to the surface layer of cellulose mats. Moreover, the 10 layer LBL assembly of the NFC and PVA were spread out into a reticulate structure during the drying process, resulting in a much rougher surface than that of 1 LBL assemble on the NFC/PET film. Finally, the thermal stability of the multilayer films had been significantly improved.

Switchable Liquid Crystal Composite Windows Using Bacterial Cellulose (BC) Mat Substrates

Performance properties were investigated for transparency switching devices fabricated with nematic LC filled bacterial cellulose (BC) mats as electro-optical components. Biobased BC is a nanoporous bicontinuous network of cellulose fibers produced by bacteria and cultured to form mats of desired thickness. Devices made from BC mats with thicknesses of 6, 20, and 40 μm were compared. Furthermore, the electro-optical response of the devices provides insight into the ordering of the nematic LC within the bicontinuous BC matrix.

Cellulose and/or lignin in fiber-aligned electrospun PET mats: the influence on materials end-properties

Cellulose, combined with lignin in some instances, was used to prepare mats made of fibers preferentially oriented in one direction. The aim of this study was evaluating the influence of this polysaccharide on the end properties of the mats when a thermoplastic polymer (in this case recycled polyethylene terephthalate; PET) is used as the primary component of solutions subjected to electrospinning. All of the prepared mats were composed mostly of ultrathin fibers. The mechanical properties were evaluated in the preferred and perpendicular directions of the alignment of the fibers. The storage and elastic moduli, as well as the tensile strength, were higher in the preferred direction. Cellulose led to mats with higher Tg PET values, indicating interactions at the molecular level between the chain segments of both polymers. One of the cellulose mats, (PETC-2), showed a superior alignment index (AI = 0.72 ± 0.03) and a higher average preferred orientation (APO = 88 ± 1°), which, in turn, led to higher mechanical properties, storage modulus, tensile strength, and elastic modulus when evaluated in the preferred direction of fiber alignment (PETC-2 dir), compared to the others. The results reveal that cellulose can be used to tune various properties of mats based on thermoplastics, thereby significantly increasing the range of applications of these materials.

Grown Ultrathin Bacterial Cellulose Mats for Optical Applications.

A facile and effective method is described for the biosynthesis of ultrathin bacterial cellulose (BC) mats, which are green, inexpensive, lightweight, and flexible. Physical properties studied include thickness, morphology, reflectance, transmittance, and crystallinity index. BC mat thickness was varied by controlling the depth of the culture broth so that films with predictable thickness, between 113 and 1114 nm, were produced. These BC films have similar fiber morphology to corresponding mm thick BC films prepared under static culture conditions. To increase BC film hydrophobicity, surface trihexylsilylated BC (THSBC) mats with DSavg 0.015 were prepared. Both native and THSBC mats were investigated as antireflection coatings for silicon substrates. The 328 ± 42 nm thick BC mat demonstrated broadband, interference type antireflection over a spectral range of 500-1800 nm. Different reflection properties obtained as a function of BC film orientation reveals that engineered density gradients can be used to manipulate BC optical properties. Thus, optical quality and environmental friendly ultrathin BC films are promising biomaterials for next-generation optoelectronic devices.

Microbial communities responsible for the degradation of poly(lactic acid)/poly(3-hydroxybutyrate) blend mulches in soil burial respirometric tests.

The microbial communities responsible for the degradation of poly(lactic acid)/poly(3-hydroxybutyrate) (PLA/PHB) blend foils were investigated in 1year long laboratory soil burial experiments. Different PLA/PHB foils were tested: (a) PLA/PHB original transparent foil, (b) PLA/PHB carbon black filled foil and (c) PLA/PHB black foil previously exposed for 90days to sun light. The microbiome diversity of these three types of foil was compared with that identified from soil/perlite sample at the beginning of experiment and that developed on a cellulose mat. Culture-dependent and culture-independent (DGGE-cloning) approaches together with PLA, PHB and PLA/PHB degradation plate assays were employed. The cultivation strategy combined with degradation tests permitted the isolation and evaluation of several PLA/PHB blend degrading microorganisms such as members of the genera Bacillus, Paenibacillus, Streptomyces, Rhodococcus, Saccharothrix, Arthrobacter, Aureobasidium, Mortierella, Absidia, Actinomucor, Bjerkandera, Fusarium, Trichoderma and Penicillium. The DGGE-cloning investigation increased the information about the microbial communities occurring during bioplastic degradation detecting several bacterial and fungal taxa and some of them (members of the orders Anaerolineales, Selenomonadales, Thelephorales and of the genera Pseudogymnoascus and Pseudeurotium) were revealed here for the first time. This survey showed the microbiome colonizing PLA/PHB blend foils and permitted the isolation of several microorganisms able to degrade the tested polymeric blends.

Natural cellulose fiber‐reinforced polyamide 6 thermoplastic composites prepared via in situ anionic ring‐opening polymerization

Thermoplastic polyamide 6 composites reinforced with flax fiber fabric and kraft pulp cellulose mat were prepared by anionic in situ ring‐opening polymerization (ROP) using a special vacuum‐assisted resin infusion process. The effects of the polymerization initiator, fiber alkali pre‐treatment, fiber type, polymerization temperature, and surface modification of fibers with organosilane coupling agents on the ROP reaction, polymer conversion and the physical and mechanical properties of the composites were investigated. The results showed that a combination of alkali pre‐treatment and the use of relatively less reactive magnesium bromide based anionic initiator gave a successful ROP reaction and high polymer conversion. Analysis of the physical and mechanical properties of the composite panels showed that optimal mechanical properties could be achieved by using a polymerization temperature of 150°C while polymerization at higher temperatures lowered both the flexural and tensile properties due to generation of more internal microvoids, as well as, decreased crystallinity of the matrix. In addition, it was found that optimal mechanical properties of the composites could be obtained using 2 wt% aminopropyltriethoxysilane (APS) coupling agent while higher APS concentrations negatively impacted the interfacial adhesion, resulting in lower mechanical properties. POLYM. COMPOS., 40:1104–1116, 2019. © 2018 Society of Plastics Engineers

Removal of hexavalent chromium from potable drinking using a polyaniline-coated bacterial cellulose mat

Polyaniline-based composites serve as adsorbent materials for the removal of hazardous heavy metal impurities such as Cr(vi) from wastewater.

In Situ Self-Assembled Nanocomposites from Bacterial Cellulose Reinforced with Eletrospun Poly(lactic acid)/Lipids Nanofibers.

The goal of this study is to explore a new strategy to improve the mechanical and hydrophobic properties of bacterial cellulose (BC) mats. The present work is the first to report the preparation of in situ self-assembled BC nanocomposites using electrospun hydrophobic poly(lactic acid) (PLA) or PLA/lipids (PLA/Lip) nanofiber mats as foundation for BC nanofiber growth. Adding electrospun PLA mats to the BC culture media led to a two-fold increase in toughness with a 52% increase in elongation of the nanocomposites with regard to BC. The incorporation of electrospun PLA and PLA/Lip nanofiber mats lowered the moisture regain and water vapor transmission of BC nanocomposites relative to pure BC mats. The interfacial bonding between the individual components of a nanocomposite is a key factor for the improvement of composite strength, stiffness, and barrier properties; thus additional strategies to improve interaction between hydrophilic BC and hydrophobic PLA fibers need to be explored.

Phosphoprotein/chitosan electrospun nanofibrous scaffold for biomineralization

In this study, negatively charged phosvitin (PV) and positively charged chitosan (CS) were alternately deposited on negatively charged cellulose mats via layer-by-layer (LBL) self-assembly technique. Morphologies of the LBL films coating mats were observed by scanning electron microscope (SEM). Afterwards, in vitro biomimetic mineralization was carried out through incubation of the fibrous mats in a simulated body fluid (SBF) solution for different time. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were used to characterize the morphology and structure of the deposited mineral phase on the scaffolds. In addition, the cell culture experiment demonstrated that the scaffolds with the LBL structured films were of good cell compatibility for MC3T3-E1 cells. Moreover, the cell proliferation was affected by the number of deposition layers and the composition of outer-most layer. Confocal laser scanning microscopy (CLSM) and SEM imaging revealed a good performance of cell adhesion and spreading of MC3T3-E1 cells on the surface of biocomposite scaffold. So CS/PV nanofibrous mats were satisfactory for the composite to be used in bioapplications.

Hydrogel and bacterial cellulose mats behavior with calcium phosphate deposition.

Event Abstract Back to Event Hydrogel and bacterial cellulose mats behavior with calcium phosphate deposition. Paula Braga Daltro1, Gildásio De Cerqueira Daltro2, Gabriel Molina De Olyveira1, Pierre Basmaji3 and Antônio Carlos Guastaldi1 1 IQ-UNESP/Brazil, Department of Physical Chemistry, Brazil 2 UFBA, College Hospital Complex Prof. Edgard Santos (COM-HUPES), Brazil 3 Innovatec's - Biotechnology Research and Development, Biotechnology Research and Development, Brazil Bacterial cellulose (BC) has become established as a remarkably versatile biomaterial and can be used in a wide variety of applied scientific applications, especially for medical devices . Although it’s hydrogel form is it’s natural form, the dehydrated membrane has been focus in research worldwide. This work aims to compare the differences in both bacterial cellulose conditions related of calcium phosphate deposition. Kokubo’s methodology based on a simulated body fluid(SBF) to mimic the calcium phosphate in the blood was used for incorporation of calcium phosphate in Bacterial cellulose. Thermal Analysis, Scanning Electron microscopy, and X-ray diffraction were used to better note the differences between the previously water stateted BC and the dry up state.Thermal analysis show considerable discrepancies when exposed to a heating increase of 10°C/min. A difference is also noted in DSC with the amount of heat injected to the samples. SEM shows a different fiber organization where the hydrogel has closer fibers than the dry membrane. X-ray diffraction shows higher differences in crystallinity, bacterial cellulose mats clearly is amorphous while hydrogel show much clearer peaks and better calcium phosphate phase definition. UNESP-IQ-Chemistry Institute; Innovatec´s-Biotechnology Research and Development.

Nanoderm Extracellular Matrix for Reconstructive Surgery Applications

Introduction: Bacterial cellulose (BC) can be used in wide area of applied scientific, especially for tissue regeneration and regenerative medicine, lately, bacterial cellulose mats are used in the treatment of skin conditions such as burns and ulcers, because of the morphology of fibrous biopolymers serving as a support for cell proliferation, its pores allow gas exchange between the organism and the environment.

Properties of Cellulose Microfibers Extracted from Pineapple Leaves by Steam Explosion

The aim of this work is to compare properties of cellulose mats from pineapple leaf fibers with and without using the steam explosion method. Pineapple leaf fibers were divided into two groups. The first group was chemically treated with sodium hydroxide for 24 h, and directly used to prepare cellulose mats. The other group was pre-treated by steam explosion before treating with sodium hydroxide. Cellulose mats of microfibers were then prepared. The structure of pineapple leaf fibers was found to be changed due to the steam explosion observed by scanning electron microscopy. The effect of the steam explosion treatment was studied from chemical composition of steam-exploded fibers and unsteam-exploded fibers. Mechanical properties of mats of steam-exploded fibers were also investigated, compared to those of unsteam-exploded fiber mats. Mechanical properties of the mats of steam-exploded fibers were higher than those of the mats of unsteam-exploded fibers. This is due to the fact that the smaller-size fibrils can be found in the steam-exploded fibril mats.