Cellulose Gel Research Articles

Simultaneously Suppressing Shuttle Effect and Dendrite Growth in Lithium-Sulfur Batteries via Building Dual-Functional Asymmetric-Cellulose Gel Electrolyte.

Polysulfides huttling and interfacial instability of Lithium-anode are the main technical issues hindering commercialization of high-energy-density lithium-sulfur batteries. Simply addressing the problem of polysulfide shuttling or lithium dendrite growth can result in safety hazards or short lifespan. To synchronously tackle the aforementioned issues,the authorshave designed an asymmetric cellulose gel electrolyte, a defective and ionized UiO66/black phosphorus heterostructure coating layer (Di-UiO66/BP) and a cationic cellulose gelelectrolyte (QACA). Defective and ionized engineered UiO66 particles significantly enhances performance of UiO66/BP layer in anchoring free polysulfides, promoting smooth and effective polysulfide conversion and expediting the redox kinetics of sulfur cathode, therefore suppressing polysulfide shuttling. QACA electrolyte with numerous cationic groups can interact with anions via electrostatic adsorption, thus enhancing lithium-ion transference number and contributing to formation of stable solid electrolyte interface to suppress lithium dendrite growth. Owing to the superior performance of QACA/Di-UiO66/BP, the final cells exhibit outstanding electrochemical performance, presenting high sulfur utilization (1420.1 mAh g-1 at 0.1 C), high-rate capacity (665.4 mAh g-1 at 4 C) and long cycle lifespan. This work proposes a strategy of designing asymmetric electrolytes to simultaneously address the challenges in both S-cathode and Li-anode, which contributes to advanced Li-S batteries and their practical application.

Extraction and Compositional Analysis of Anthocyanins and Polysaccharides from Aronia Melanocarpa Fruit

We have examined the basic composition of anthocyanins and polysaccharides, the active components in Aronia melanocarpa fruit. To this end, microwave-assisted ethanol extraction and cellulase enzymatic hydrolysis were employed to extract anthocyanins and crude polysaccharides, respectively. Aronia melanocarpa fruit polysaccharides were separated and purified by DEAE-52 cellulose and Sephadex G-100 glucan gel column chromatography, followed by high-performance liquid chromatography. The results demonstrated that the optimal extraction parameters of anthocyanin from Aronia melanocarpa fruit were a 60% ethanol volume fraction, a liquid-to-solid ratio of 30:1, a microwave time of 60 s, and a microwave power of 210 W. The extracted anthocyanins reached 200.47 mg/100 g, while the yield of polysaccharides was 3.82%. Anthocyanins in Aronia melanocarpa fruit were mainly composed of cyanidin, delphinidin, and mallow pigment, among which cyanidin was the main component, with a content as high as 90.79%. There were two distinct fractions of polysaccharides. The fraction-I polysaccharides were mainly composed of rhamnose, galacturonic acid, glucose, galactose, and arabinose, with a molar ratio of 8.80: 8.97: 2.38: 27.46: 47.94. In contrast, the fraction-II polysaccharides were primarily composed of rhamnose, glucuronic acid, galactose, xylose, and arabinose, with a molar ratio of 1.67: 9.22: 8.47: 70.69: 6.16. The results of this study can provide a reference for the in-depth development of Aronia melanocarpa resources

Self-adhesive, ionic-conductive, mechanically robust cellulose-based organogels with anti-freezing and rapid recovery properties for flexible sensors

Cellulose-based functional gels have received considerable attention because of their good mechanical properties, biocompatibility, and low cost. However, the preparation of cellulose gels with self-adhesion, mechanical robustness, ionic conductivity, anti-freezing ability, and environmental stability remains a challenge. Here, gallic acid esterified microcrystalline cellulose (MCC-GA) was obtained by grafting gallic acid (GA) onto the macromolecular chains of microcrystalline cellulose (MCC) through a one-step esterification method. Then the prepared MCC-GA was dissolved in Lithium chloride/dimethyl sulfoxide (LiCl/DMSO) system and polymerized with acrylic acid (AA) to prepare a multi-functional cellulose-based organogel. The prepared MCC-GA/polyacrylic acid (PAA) organogels exhibited enhanced interfacial adhesion through hydrogen bonding, π–π interactions, and electrostatic interactions. Additionally, the MCC–GA/PAA organogels could withstand 95 % of the compressive deformation and rapidly self-recover owing to chemical cross-linking and dynamic non-covalent interactions. The organogels also exhibited excellent anti-freezing properties (up to −80 °C), solvent retention, and ionic conductivity. Considering its excellent overall performance, the MCC–GA/PAA organogel was used as an effective flexible sensor for human motion detection and is expected to play an important role in the future development of flexible bioelectronics.

Amorphous Cellulose: Graphene Oxide Composite Bead

In this research, we developed an efficient method for the fabrication of amorphous cellulose-graphene oxide composite. Amorphous cellulose (AC) and amorphous cellulose-graphene oxide (ACGO) beads were fabricated via H2SO4 gelatinization using eucalyptus paper as a raw material. The cellulose gel was droplet-extruded into deionized (DI) water and transformed to a solid bead via the water-regeneration process. Small AC and ACGO quasi-sphere beads with diameter of 2 mm were obtained. The semicrystalline eucalyptus cellulose was transformed into amorphous cellulose after the regeneration process. The entrapment of graphene oxide (GO) by the amorphous cellulose was confirmed by scanning electron microscopy (SEM), fourier-transform infrared (FTIR) and raman spectroscopies (Raman). The gelatinization and regeneration processes offered a simple and efficient methodology for AC and ACGO bead fabrication. HIGHLIGHTS Amorphous cellulose (AC) and amorphous cellulose-graphene oxide (ACGO) beads were successfully fabricated via sulfuric acid gelatinization The average sizes of AC and ACGO beads were 2.11±13 and 2.14 ± 0.12 mm, respectively Structural characterization confirmed the transformation of cellulose I to cellulose II and graphene oxide was successfully embedded in ACGO beads The added graphene oxide interacted with the amorphous cellulose and made the surface of ACGO beads smooth GRAPHICAL ABSTRACT

Cellulose‐based Conductive Gels and Their Applications

AbstractCellulose‐based conductive gels are representative nanomaterials and have a good flexibility, biodegradability, and biocompatibility due to the cellulose. Therefore, they are considered as important candidates for the development of next generation nanoarchitectonics materials for electronics and green energy. To date, conductive cellulose gels have been widely investigated for various applications, including sensors, energy storage devices, energy generators, and actuators. A number of studies has shown that cellulose‐based conductive gels have a superior performance compared to gels prepared using petroleum‐derived chemicals. Therefore, in this review, we will introduce the general preparation method of cellulose‐based conductive gels in order to present the latest research results and to provide information for future nanoscience and research studies. Also, the main applications of cellulose‐based conductive gels and the progress of their research will be described.

DEVELOPMENT OF MUCOADHESIVE CELLULOSE DERIVATIVES BASED FILMS FOR THE TREATMENT OF VAGINAL CANDIDIASIS

"The development of easily administered targeted delivery for vaginal candidiasis is an area of active research. Challenges emerge from the specific conditions that may not permit enough time for the dosage form to reside on the infected area. Herein, we propose to develop films based on cellulose derivatives for the treatment of vaginal candidiasis. Gels of sodium carboxymethyl cellulose (Na-CMC) (F1), equal combination of Na-CMC and hydroxyethyl cellulose (HEC) (F2) and hydroxyethyl cellulose (HEC) (F3) were prepared and loaded with nystatin (NYS). The resultant gels were dried using solvent casting and characterized to detect glass transition temperature (Tg), mechanical properties, mucoadhesion, inhibition of candida growth toxicity on human embryonic kidney 293 cells (HEK) cells and drug release. Tg was affected by the polymer type and was found to be highest in F2, where equal ratios of HEC and Na-CMC were used. Mucoadhesion was highest in F1 (Na-CMC) films. The films showed moderate toxicity. The zone of inhibition was observed for the three formulations. Drug release was affected by the polymer type and was complete after 8 h in F2. The findings allowed concluding that the cellulose derivative based films were successfully prepared and were efficient in allowing the drug to elute and minimizing the growth of candida."

Cellulose Gel Mechanoreceptors – Principles, Applications and Prospects

AbstractIn order to effectively harness varieties of mechanical waves or vibrations for the purpose of monitoring and/or powering, developments in responsive materials and conversion technologies are taking place driven by the world's current and future demands. One of the most popular novelties of the last two decades is represented by hydrogel‐ or ionogel‐based flexible iontronics which constitute a wide family of innovative smart (self‐powered) mechanoreceptors relevant for various applications such as personal health care, identity and safety monitoring, intelligent human‐machine operation interfaces, underwater listening and communication, and so on. Cellulosic gels (CGs), as a promising green substitute for fossil fuel‐derived materials, are extensively studied due to the possibility to choose between different cellulose types and to formulate networks chemically or physically, according to the adaptability requirements for each target application. The aim of this review is to showcase the cellulose structural versatility and to provide a summary of the principles during the formulation of CGs used for mechanosensing and mechanical energy scavenging, as well as their practical applications. Such an outlook of current challenges and overall prospects will serve as a stimulus for research on CG‐based mechanoreceptors in the future.

Preparation and Optimization of Itraconazole Transferosomes-Loaded HPMC Hydrogel for Enhancing Its Antifungal Activity: 2^3 Full Factorial Design.

Itraconazole (ITZ) is a triazole antifungal agent characterized by broad-spectrum activity against fungal infections. The main drawback of ITZ, when applied topically, is the low skin permeability due to the stratum corneum, the outermost layer of the skin, which represents the main barrier for drug penetration. Therefore, this study aimed to prepare itraconazole as transferosomes (ITZ-TFS) to overcome the barrier function of the skin. ITZ-TFSs were prepared by thin lipid film hydration technique using different surfactants, sodium lauryl sulfate (SLS) and sodium deoxycholate (SDC). The prepared ITZ-TFS were evaluated for entrapment efficiency (EE) %, particle size, polydispersity index (PDI), zeta potential, and in vitro drug release to obtain an optimized formula. The surface morphology of the optimized formula of ITZ-TFS was determined by transmission electron microscope (TEM). The optimized formulation was prepared in the form of gel using hydroxyl propyl methyl cellulose (HPMC) gel base. The prepared ITZ-TFS gel was evaluated for homogeneity, drug content, spreadability, pH, and in vitro antifungal activity in comparison with the free ITZ gel. The prepared ITZ-TFS formulations exhibited high EE% ranging from 89.02 ± 1.65% to 98.17 ± 1.28% with particle size ranging from 132.6 ± 2.15 nm to 384.1 ± 3.46. The PDI for all ITZ-TFSs was less than 0.5 and had a negative zeta potential. The TEM image for the optimized formulation (ITZ-TFS4) showed spherical vesicles with a smooth surface. The prepared gels had good spreadability, pH, and acceptable drug content. ITZ-TFS gel showed higher antifungal activity than free ITZ gel as determined by zone of inhibition. ITZ was successfully prepared in form of TFSs with higher antifungal activity than the free drug.

The Effect of Local Melatonin Application Following the Removal of an Impacted Mandibular Third Molar

Pain, swelling, limitation of the mouth opening, development of intra-bony defects, and bone loss are common side effects of removing the impacted third molar. The purpose of this study was to measure the association of applying melatonin in the socket of an impacted mandibular third molar with osteogenic activity and the anti-inflammatory effects. This prospective, randomized, blinded trial comprised of patients who required removal of the impacted mandibular third molar. The patients were divided into two groups (n=19) as follows: melatonin group (3mg of melatonin into 2ml of 2% hydroxyethyl cellulose gel was packed into the socket) and placebo group (2ml of 2% hydroxyethyl cellulose gel was placed in the socket). The primary outcome was bone density, measured using Hounsfield unit immediately after surgery and 6months later. Secondary outcome variables included serum osteoprotegerin level (Ng/ml) that measured immediately, 4weeks and 6months postoperatively. Other clinical outcome measures were pain by visual analog scale, maximum mouth opening (MMO) (millimeter), and swelling (millimeter) that were evaluated immediately, 1, 3, and 7days postoperatively. The data were analyzed by independent t-test of Wilcoxon's rank-sum, analysis of variance, and generalized estimating equation (P≤.05). Thirty-eight patients (25 female and 13 males) with a median age of 27years were enrolled in the study. There was no statistical significance in bone density observed in both groups [melatonin group: 978.5(951.3-1015.8), control group: 965.8 (924.6-998.7), P=.1]. Alternatively, there were statistically significant improvements in osteoprotegerin levels (on week 4), MMO (on day1), and swelling (on day 3) in the melatonin group compared to those in the placebo group [1.9(1.4-2.4), 39.68±1.35, and 14.36±0.80 versus 1.5(1.2-1.4); 38.33±1.20, and 14.88±0.59; P=.02, .003, 0.031, respectively]. The pain values showed statistically significant improvement throughout the follow-up period in the melatonin group compared to the placebo group [5(3-8), 2(1-5), and 0(0-2) versus 7(6-8), 5(4-6), and 2(1-3); P<.001, respectively]. The results support the anti-inflammatory effect of melatonin in reducing the pain scale and swelling. Furthermore, it plays a role in the improvement of MMO. On the other hand, the osteogenic activity of melatonin could not be detected.

Bacterial Cellulose/Cellulose Imidazolium Bio-Hybrid Membranes for In Vitro and Antimicrobial Applications

In biomedical applications, bacterial cellulose (BC) is widely used because of its cytocompatibility, high mechanical properties, and ultrafine nanofibrillar structure. However, biomedical use of neat BC is often limited due to its lack of antimicrobial properties. In the current article, we proposed a novel technique for preparing cationic BC hydrogel through in situ incorporation of cationic water-soluble cellulose derivative, cellulose bearing imidazolium tosylate function group (Cell-IMD), in the media used for BC preparation. Different concentrations of cationic cellulose derivative (2, 4, and 6%) were embedded into a highly inter-twined BC nanofibrillar network through the in situ biosynthesis until forming cationic cellulose gels. Cationic functionalization was deeply examined by the Fourier transform infrared (FT-IR), NMR spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) methods. In vitro studies with L929 cells confirmed a good cytocompatibility of BC/cationic cellulose derivatives, and a significant increase in cell proliferation after 7 days, in the case of BC/Cell-IMD3 groups. Finally, antimicrobial assessment against Staphylococcus aureus, Streptococcus mutans, and Candida albicans was assessed, recording a good sensitivity in the case of the higher concentration of the cationic cellulose derivative. All the results suggest a promising use of cationic hybrid materials for biomedical and bio-sustainable applications (i.e., food packaging).

Development and evaluation of wafer loaded with sertaconazole solid dispersion for the treatment of oral candidiasis

Candidiasis is one of the most common fungal infections of oral cavity in humans, causing great oral discomfort, pain and aversion to food. To develop more effective antifungal systems for the treatment of oral candidiasis, an oral mucoadhesive wafer containing sertaconazole solid dispersion (STZ-SD) was developed in this study. Dispersion of STZ in Soluplus® as a solubility enhancement excipient was done by melting, solvent evaporation and freeze drying method at various STZ to Soluplus® ratios. The optimized STZ-SD was then incorporated in the sodium carboxymethyl cellulose (SCMC) gel, xanthan gum gel, or their combination to prepare the lyophilized wafers. The swelling capacity, porosity, and mechanical, release and mucoadhesive properties of the wafers, together with their antifungal activity, were then evaluated. The melting method sample with the ratio of 8:1 showed the best results in terms of saturation solubility and dissolution rate. The STZ-SD-composite wafer exhibited higher hardness and mucoadhesion, as compared to those made of the SCMC polymer. The STZ-SD-wafer also exhibited a greater antifungal effect when compared to the STZ-wafer. The present study, thus, suggested that the STZ-SD-wafer could serve as a novel effective delivery system for oral candidiasis treatment.

Cellulose Hydrogel and Its Impact on Mung Bean Growth

Cellulose hydrogels were prepared from commercial cellulose using NaOH/urea and LiCl/DMAc methods. For NaOH/urea method, alkali hydrates (OH-(H2O)x), urea hydrates (urea(H2O)y), and water were adsorbed into cellulose fiber to break hydrogen bonds between cellulose molecules yielding HG_Urea. For LiCl/DMAc method, the Lithium-DMAc complexes, [Li(DMAc)n]+Cl-, were seeped into cellulose fibers and the hydrogen bonds between the fibers were substituted by O-H…Cl-[Li(DMAc)n]+ bonds to produce transparent cellulose gel, HGL. Both freeze-dried hydrogels show the characteristics of cellulose vibrational modes and nano-sized fibrous SEM images. For water retention study, there was no significant difference when different amounts of HG_Urea were being used. Covering mung bean seeds directly helps improve the growth of roots, leaves and stems by 410, 28 and 27%, respectively. HGL and HGL in water were also tested on the germination of the mung bean seeds. As compared with HGL, the average lengths of roots, stems and leaves of mung bean on HGL-water were increased by 82, 32 and 14%, respectively

Cyclodextrin-based nanogel of flurbiprofen for dermal application: In vitro studies and in vivo skin irritation evaluation

The aim of this study was to develop and characterize flurbiprofen (FB)-loaded cyclodextrin (CD) based nanogel formulations for dermal application. Nanogels were produced via emulsification solvent evaporation and then incorporated into a hydroxypropyl methyl cellulose (HPMC) gel. The visual examination, pH, viscosity, dynamic rheological measurements and drug content analysis of nanogels were assessed. In vitro and ex vivo permeation, stability, and skin irritation were performed. pH of the FB-loaded nanogel and the nanogels in HPMC were 10.6 ± 0.1 and 7.5 ± 0.1 (neutral) respectively. The highest and lowest viscosities were observed in FB-loaded nanogels and in FB-free nanogels in HPMC, respectively. The tangent δ and storage modulus values of FB-loaded nanogel in HPMC were higher than those of FB-loaded nanogel. FB from nanogels in HPMC was 100% by 48 h. The final nanogel formulation was physically and chemically stable over 12 months. Skin irritation test showed no skin irritation or cellular infiltration on the histological level. In vitro and ex vivo permeation showed that the nanogels could be effective and stable formulations, especially in the dermal application of a hydrophobic molecule.

Cellulose gelation in NaOH(aq) by CO2 absorption: Effects of holding time and concentration on biomaterial development

We address the limited solubility and early onset of gelation of aqueous sodium hydroxide to position it as a preferred green solvent for cellulose. For this purpose, we expand the concentration window (up to 12 wt%) by using a CO2-depleted air and adjusting the time the dope remains in the given atmosphere, before further processing (holding time) and regeneration conditions. Cellulose solutions are extruded following characteristic (rheology and extrusion) parameters to yield aligned filaments reaching tenacities up to 2.3 cN·dtex−1, similar to that of viscose. Further material demonstrations are achieved by direct ink writing of auxetic biomedical meshes (Poisson's ratio of −0.2, tensile strength of 115 kPa) and transparent films, which achieved a tensile strength and toughness of 47 MPa and 590 kJ·m−3, respectively. The results suggest an excellent outlook for cellulose transformation into bioproducts. Key to this development is the control of the gelation ensuing solution flow and polymer alignment, which depend on CO2 absorption, cellulose concentration, and holding time.

Nanocellulose coated paper diagnostic to measure glucose concentration in human blood.

A new generation of rapid, easy to use and robust colorimetric point of care (POC) nanocellulose coated-paper sensors to measure glucose concentration in blood is presented in this study. The cellulose gel containing the enzyme with co-additive is coated and dried onto a paper substrate. Nanocellulose gel is used to store, immobilize and stabilize enzymes within its structure to prolong enzyme function and enhance its availability. Here, we immobilize glucose oxidase within the gel structure to produce a simple colorimetric blood glucose sensor. Increase in blood glucose concentration increases the concentration of reaction product which decreases the system pH detected by the pH indicative dye entrapped in the nanocellulose gel. The sensor produces a color change from red to orange as pH decreases due to the enzymatic reaction of glucose into gluconic acid and hydrogen peroxide. This sensor can measure glucose concentrations of 7-13mM (medical range for diabetes control) at temperatures of 4°C-40°C. Stability tests confirm that no denaturation of enzyme occurs by measuring enzyme activity after 4weeks. A prototype device is designed to instantly measure the glucose concentration from blood in a two steps process: 1) red blood cell separation and 2) quantification of glucose by color change. This study demonstrates nanocellulose sensor as an economical, robust, and sensitive diagnostic technology platform for a broad spectrum of diseases.

Local time-dependent microstructure of aging TEMPO nanofibrillated cellulose gel

The aging behavior of TEMPO-CNF suspensions is investigated using rheological measurements and experiments involving the free-falling solid sphere. The properties of CNF suspensions, which are formed of water and cellulose fibers with a large aspect ratio, are fundamentally different from those commonly known as model low-density gels. We characterize their aging utilizing SAOS rheometry following a period of shear rejuvenation, measuring the effect of aging time on the observed stress overshoot, and additionally measure the rheological hysteresis under continuous shear. In addition to such tests, which probe the sample at the bulk level, we study their local aging behavior via the Stokes’ experiment. During SAOS, the aging of the material results in a logarithmic growth of the elastic modulus over the first 50 minutes. In the Stokes’ experiment, depending on the sphere size, we find a systematic decrease in the sphere velocity with aging times up to 16 days and identify a range of intermittent particle motion. Based on our experimental evidence, we propose that the aging effect within the TEMPO-CNFs occurs due to the restructuring of fibrous elements by Brownian diffusion and that the aging of the system does not develop homogeneously across the whole sample as a consequence of the wide size distribution of CNFs. Finally, we note that this may be one of the primary reasons why the rheological data on even the same batch of CNFs show a large scatter.Graphical abstract

Laboratory and field trials reveal the potential of a gel formulation of entomopathogenic nematodes for the biological control of fall armyworm caterpillars (Spodoptera frugiperda)

The fall armyworm (FAW), Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) can cause tremendous yield losses in maize. Its invasion into Africa and Asia has dramatically increased the use of insecticides in maize agro-ecosystems. Safe, effective and readily available alternatives are urgently needed. Entomopathogenic nematodes (EPN) represent a promising and sustainable option to control fall armyworm caterpillars on maize. Commonly used against soil insect pests, EPN can also be applied to control above-ground pests if formulated appropriately. We explored the possibility to control FAW by incorporating the EPN species Steinernema carpocapsae into protective formulations that can be easily applied into the whorl of maize plants, where the caterpillars mostly feed. We tested this approach in laboratory cage experiments as well as in field trials. In the laboratory, treating maize plants with a low dose of S. carpocapsae (3000 infective juveniles per plant) formulated in a carboxymethyl cellulose (CMC) gel caused 100% mortality of FAW caterpillars and substantially reduced plant damage, whereas EPN applied in water or a surfactant-polymer-formulation (SPF) caused 72% and 94% mortality, respectively. Under field conditions, one-time treatments with S. carpocapsae applied in water, SPF or CMC decreased plant damage, but only the EPN-gel formulation significantly reduced FAW infestation. As compared to control, about 40% fewer caterpillars were found on plants treated with EPN formulated in the gel. Notably, the EPN-gel formulation was as effective as a standard dose of cypermethrin, a pyrethroid insecticide commonly used against FAW, in reducing FAW infestation. Repeated applications may be needed to reduce re-infestations by FAW across a whole cropping season depending on the local maize phenology and pest dynamics. These findings demonstrate that EPN, when properly formulated, are excellent candidates for the biological control of FAW, and can be a safe and sustainable alternative to synthetic insecticides.

Engineering a superwetting membrane with spider-web structured carboxymethyl cellulose gel layer for efficient oil-water separation based on biomimetic concept

Superhydrophilic and underwater superoleophobic membranes have recently attracted significant interest as materials for effective oil-water emulsion separation.In this work, a superwetting membrane with a spider web structured gel layer was designed for efficient oil-water separation. Biomaterial, carboxymethyl cellulose (CMC), was used as the raw material, a spider web structured gel layer was constructed on the PVDF membrane surface by heat-treatment and chemical cross-linking. The hydrophilic gel layer imparted excellent superhydrophilic and underwater superoleophobic properties to the membrane, while the special spider web structure improved the membrane mechanical stability. The fabricated membrane exhibited superhydrophilicity and underwater superoleophobicity. Among different CMC concentration-modified membranes, the M-0.5 membrane containing 0.5 wt% CMC exhibited a flux of 612 L·m−2 h−1 during dichloromethane oil-water emulsion separation, which was 4.2-fold higher than that of the pristine PVDF membrane, while the membrane showed efficient oil-water separation capacity. Additionally, the water flux recovery reached as high as 93.3 %, and oil rejection attained 99.1 %. Meanwhile, the spiderweb-structured gel layer on the membrane surface displayed good mechanical stability. In summary, this novel membrane-modification method, inspired by the spider web structure, was simple, cost effective and environmentally friendly, thereby making it promising for future preparation of highly efficient oil-water emulsion separation membranes.

High oxygen barrier materials from paper to regenerated cellulose films

AbstractA transparent, bendable, high oxygen barrier cellulose‐based film was prepared, which has far better oxygen barrier properties than conventional polyethylene, polypropylene and cellophane materials. A series of regenerated cellulose films (RCs) were prepared from filter paper lacking oxygen barrier properties under different cellulose concentrations and gelation times. It was shown that the cellulose concentration and gel time had a greater effect on the oxygen barrier properties of RCs. When the cellulose concentration was 4 wt% and the gel time was 3 h, the RCs obtained the lowest oxygen permeability coefficient (OPC) down to 2.21 × 10−17 cm3 cm cm−2 s−1 Pa−1. The films have a tensile strength of 109.5 MPa, an elongation at break of 27.3% and a light transmission rate of 89%. In further, molecular dynamics simulations showed that when the filter paper was converted to RCs, the increase in hydrogen bonding and the decrease in free volume between cellulose chains caused a decrease in the diffusion coefficient of oxygen. As a novel biobased high oxygen barrier material, the film has broad application prospect in packaging and chemical industry.

Extraction, characterization, antioxidant and anti-tumor activities of polysaccharides from Camellia fascicularis leaves

The ultrasonic-assisted extraction of polysaccharides from Camellia fascicularis (PCF) was optimized using response surface methodology. After separation and purification with DEAE-52 cellulose and Sephadex G-200 glucan gel columns, the purified polysaccharide components of PCFa-1 and PCFc-1 were analyzed for their structural characterization, antioxidant and anti-tumor activities in vitro. The results indicated that liquid to material ratio of 42 mL/g, ultrasonic time of 53 min, ultrasonic temperature of 73 °C, and ultrasonic power of 215 W were the optimum extraction conditions for PCF with maximum yields (4.05 %). PCFa-1 and PCFc-1 contained 5.88 % and 9.58 % uronic acid content, with 7.53 and 108.91 kDa of average molecular weights, respectively. The PCFa-1 was mainly constituted of galactose, arabinose, and glucose, while PCFc-1 was primarily composed of arabinose, glucose, galacturonic acid, and rhamnose. Fourier transform infrared spectra revealed that PCFa-1 and PCFc-1 contained typical polysaccharide bands. Scanning electron microscopy showed that the surface of PCFa-1 and PCFc-1 were irregular and clumpy structures. Nuclear magnetic resonance showed that PCFa-1 and PCFc-1 were mainly α-glycosidic bond conformation. Furthermore, the PCFc-1 showed better antioxidant capacities than PCFa-1 against hydroxyl, DPPH, and ABTS radicals and exhibited more potent toxicity on A549 and HepG2 cells. These research results suggested that PCF, especially PCFc-1, possesses great potential as natural antioxidants and anti-tumor drugs.