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China, a big paper-making country, produced hundreds of millions of tons of waste paper which contain a lot of fiber every year. Cellulose nanocrystals were extracted from recycled waste paper which can be a high value utilization of secondary fiber. In this paper, cellulose nanocrystals were successfully extracted from waste paper fibers via two different systems, sulfuric acid hydrolysis (SCNCs) and one-step ammonium persulfate (APS) oxidation (OCNCs). This not only broadened the methods of extracting CNCs from waste paper, but also improved the dispersion and reactivity of CNCs. The CNCs products were investigated by FT-IR spectroscopy for functional group structure, X-ray diffraction for crystal structure, TG-DTG for thermal stability and scanning electron microscope, transmission electron microscope for morphology. The results showed that both OCNCs and SCNCs were a rod-like structure. The crystallinity of OCNCs and SCNCs increased to 72.45 and 77.56, but with a low yield of 22.42% and 41.22%, respectively. The result also suggested H 2 O 2 formed by decomposition of APS, selectively oxidized the hydroxyl on the C 6 in cellulose to carboxyl, introduced 0.57 mmol/g carboxyl. Successful preparation of CNCs extracted from waste paper can effectively utilize the fiber resources in waste paper, thus transforming into higher economic benefits., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Assemblies of carbohydrate polymers are important in a number of applications and improved methods for their fabrication are increasingly sought after. Herein, we report that an aqueous two-phase system of alginate (Alg) and hydroxypropyl cellulose with poly(methacrylic acid) graft chains (HPC-PMA) facilitated the assembly of Alg/HPC-PMA in both phases. Dynamically formed filamentous domains in a flow field were gelled by rapid complexation with cationic polyethyleneimine (PEI). The fabricated HPC-PMA gel filament morphologies can be switched between the bundled and dissociated gel filaments using a co-flow microfluidic device in response to the amount of supplied PEI crosslinker. Excess complexation of PEI contributes to the fabrication of cationic gel filaments; this contribution results in a dissociated structure due to electrostatic repulsion. In contrast, an appropriate amount of PEI resulted in a bundle structure. The proposed spinning method avoids the risk of nozzle clogging, and enables the one-step spinning of multiple gel filaments., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Cellulose from cotton fibers was functionalized through a dissolution-regeneration process with phosphonate-based ionic liquids (ILs): 1,3-dimethylimidazolium methylphosphonate [DIMIM][(MeO)(H)PO 2 ] and 1-ethyl-3-methylimidazolium methylphoshonate [EMIM][(MeO)(H)PO 2 ]. The chemical modification of cellulose occurred through a transesterification reaction between the methyl phosphonate function of ILs and the primary alcohol functions of cellulose. The resulting cellulose structure and the amount of grafted phosphorus were then investigated by X-ray diffraction, ICP-AES, and ¹³C and ³¹P NMR spectroscopy. Depending on the IL type and initial cotton / IL ratio in the solution, regenerated cellulose contained up to 4.5% of phosphorus. The rheological behavior of cotton cellulose/ILs solutions and the microscale fire performances of modified cellulose were studied in order to ultimately prepare flame retardant cellulosic materials. Significant improvement in the flame retardancy of regenerated cellulose was obtained with a reduction of THR values down to about 5-6 kJ/g and an increase of char up to about 35 wt%.

Cellulose nanocrystals (CNC) were prepared using acid hydrolysis of cellulose fiber. The CNC modified topo-chemically by grafting of bulky cholesterol moieties which changed subsequent morphology, thermal behavior, lyotropic crystalline properties, and host-guest release behavior. Bond formation between the cellulose nanocrystals surfaces and cholesterol was confirmed by FT-IR and solid-state NMR. The product indicated strong hydrophobic characteristics with an ordered chiral nematic self-assembly. This novel biomaterials were exploited through uptake of folic acid as part of a preliminary host-guest system. The guest molecule released as a function of physiologically relevant pHs was examined., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The remedy for infected chronic wounds such as diabetic foot ulcers is more complicated particularly in the case of patients with an inefficient immune system. Also, fighting against microbial infections in the wound site by available antibiotics may not be effective because of emerging antibiotic resistance properties among pathogenic bacteria and fungi. Recently, applications of micro- and nanoformulations of biomaterials have demonstrated improved therapeutic abilities for wound dressings. In this way, carboxymethyl, dialdehyde, and 2,2,6,6-tetramethylpiperidine-1-oxyl-oxidized celluloses are common biomaterials having outstanding physicochemical and therapeutic properties compared to unmodified cellulose. Therefore, in this review, recent progress in the field of wound healing and antimicrobial activities of these derivatives are presented and discussed., (© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Organo-hydrogels are widely used in various fields, due to functional organic ingredients immobilized by the gel network or stored and protected by the gels. Herein, cellulose acetoacetate (CAA) served as reactive natural polymer emulsifier to stabilize thyme oil-in-water (O/W) emulsions. Hydroxypropyl chitosan (HPCS) was added to the continuous phase in emulsions to achieve the organo-hydrogel via the enamine bonds under mild conditions. The thyme@CAA emulsion with different loadings of the inner phase (up to 50%) displayed uniform droplets distribution (3-5 μm) and favorable stability. The organo-hydrogel was systematically analyzed by Fourier transform infrared spectroscopy, optical microscope, rheology analyses. The emulsion droplets evenly dispersed in the three-dimensional network. The modulus of organo-hydrogels depended on the viscosity of precursor emulsions and the crosslinking density. The resulting organo-hydrogel displayed favorable antibacterial activity against E. coli and S. aureus. CAA, as the reactive emulsifier and crosslinking agent, was a promising alternative candidate to fabricate a series of organo-hydrogel., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Creating a configurable and controllable surface for structure-integrated multifunctionality of ultralight aerogels is of significance but remains a huge challenge because of the critical limitations of mechanical vulnerability and structural processability. Herein, inspired by Salvinia minima , the facile and one-step coassembly approach is developed to allow the structured aerogels to spontaneously replicate Salvinia -like textures for function-adaptable surfaces morphologically. The in situ superimposed construction of bioinspired topography and intrinsic topology is for the first time performed for programmable binary architectures with multifunctionality without engendering structural vulnerability and functional disruption. By introducing the binding groups for hydrophobicity tailoring, functionalized nanocellulose (f-NC) is prepared via mechanochemistry as a structural, functional, and topographical modifier for a multitasking role. The self-generated bioinspired surface with f-NC greatly maintains the structural unity and mechanical robustness, which enable self-adaptability and self-supporting of surface configurations. With fine-tuning of nucleation-driving, the binary microstructures can be controllably diversified for structure-adaptable multifunctionalities. The resulting ultralight S. minima -inspired aerogels (e.g., 0.054 g cm -3 ) presented outstanding temperature-endured elasticity (e.g., 90.7% high-temperature compress-recovery after multiple cycles), durable superhydrophobicity, anti-icing properties, oil absorbency efficiency (e.g., 60.2 g g -1 ), and thermal insulating (e.g., 0.075 W mK -1 ), which are superior to these reported on the overall performance. This coassembly strategy offers the opportunities for the design of ultralight materials with topography- and function-tailorable features to meet the increasing demands in many fields such as smart surfaces and self-cleaning coatings.

Removal of non-cellulosic polymers from vegetable pulp to obtain cellulose nanofibers (CNF) is normally achieved by chemical pre-treatments which requires several washing steps. In the present study, it is demonstrated how incubation of sugar beet pulp at pH 9, followed by treatment with polysaccharide-degrading enzymes and subsequent bleaching can be done in a one-pot procedure to make CNF. The new method consumes 67% less water and removes non-cellulosic polysaccharides with similar efficiency as a chemical method. In addition, CNF produced by the new method contained slightly more pectin and formed gels with 2.7 times higher storage modulus. Nanopapers cast from chemically- and enzymatically produced CNF showed similar mechanical properties. However, without the pH 9 incubation step, the enzymes accessibility to cell-wall polymers was limited resulting in lower gel and paper strengths. In conclusion, the new method offers a sustainable route for producing high quality CNF from sugar beet waste., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Hydrogels of TEMPO-oxidized nanocellulose were stabilized for dry-jet wet spinning using a shell of cellulose dissolved in 1,5-diazabicyclo[4.3.0]non-5-enium propionate ([DBNH][CO 2 Et]), a protic ionic liquid (PIL). Coagulation in an acidic water bath resulted in continuous core-shell filaments (CSFs) that were tough and flexible with an average dry (and wet) toughness of ∼11 (2) MJ·m -3 and elongation of ∼9 (14) %. The CSF morphology, chemical composition, thermal stability, crystallinity, and bacterial activity were assessed using scanning electron microscopy with energy-dispersive X-ray spectroscopy, liquid-state nuclear magnetic resonance, Fourier transform infrared spectroscopy, thermogravimetric analysis, pyrolysis gas chromatography-mass spectrometry, wide-angle X-ray scattering, and bacterial cell culturing, respectively. The coaxial wet spinning yields PIL-free systems carrying on the surface the cellulose II polymorph, which not only enhances the toughness of the filaments but facilities their functionalization.

Bacterial cellulose (BC) is a biosynthesized carbohydrate polymer with excellent biocompatibility and water holding capability. However, it lacks an inherent antibacterial activity that has limited its in-depth biomedical applications. This study investigated a novel strategy of adopting a simultaneous process to chemically anchor a quaternary ammonium salt (R-N(CH 3 ) + ) with a special vinyl group (2-methacryloyloxyethyl trimethylammonium chloride, METAC) onto the BC, and meanwhile, enhance the density of (R-N(CH 3 ) + ) via free radical vinyl polymerization. The results have confirmed the transition of BC surface from a negatively-charged surface to a polycationic surface via such a simultaneous reaction. As compared to chitin film (a representative of R-NH 3 + ), the resulting METAC-grafted BC (a representative of high-density R- N(CH 3 ) + ) acquired excellent water absorbability (40 times of dry weight of the BC), 99% antibacterial activity against Escherichia coli and Staphylococcus aureus, a satisfactory in-vitro biocompatibility, and a better in-vivo wound healing outcome with an excellent in-vivo antibacterial efficacy. This study has exhibited potential in utilizing a facile method to prepare a bio-safe, adaptive antibacterial surface for various biomedical applications., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Novel, portable, probe-free, liquid cellulose biosensor was explored via a facile one-pot process for Cu 2+ ions detection by naked eyes. The as-prepared biosensor displayed specific recognition towards Cu 2+ ions in aqueous solution, even in complex urine and serum samples within 10 s, showing fast response characteristic. There is barely any interference on the Cu 2+ ions detection by other metal ions or other complex substances in urine and serum, and the corresponding detection limit is as low as 1.185, 1.9309 and 1.9154 ppm, respectively. Moreover, the cellulose biosensor could act as an excellent candidate to sense Cu 2+ ions in biological samples including urine and serum from SD rats with satisfying accuracies and biocompatibility. This study exploits a potential application of cellulose in biosensing and monitoring related to Cu 2+ ions., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The potential of electrospun cellulose acetate/chitosan/single walled carbon nanotubes/ferrite/titanium dioxide (CA/chitosan/SWCNT/Fe 3 O 4 /TiO 2 ) nanofibers was investigated for the removal of Cr(VI), As(V), Methylene blue and Congo red from aqueous solutions via the adsorption and photocatalytic reduction processes. The properties of synthesized SWCNT/Fe 3 O 4 /TiO 2 and fibers were characterized using TEM, SEM, FTIR, XRD, TGA and BET analysis. In adsorption process, the influence of adsorbent type including SWCNT to Fe 3 O 4 ratio, TiO 2 to SWCNT/Fe 3 O 4 ratio and SWCNT/Fe 3 O 4 /TiO 2 concentration as well as the adsorption parameters including pH, contact time, and initial concentration of adsorbates on the Cr(VI), As(V), Methylene blue and Congo red adsorption in a batch mode was investigated. The reusability of nanofibers was also investigated for five adsorption-desorption cycles. The photocatalytic reduction of Cr(VI), As(V), Methylene blue and Congo red was also investigated using various nanofibrous catalysts. The obtained results indicated that the removal of Cr(VI) and As(V) using CA/chitosan/SWCNT/Fe 3 O 4 /TiO 2 nanofibrous adsorbent via adsorption process could be preferred for the lower concentrations of metal ions. The photocatalytic reduction was an effective method for the Cr(VI), As(V) removal at higher concentrations and degradation of Methylene blue and Congo red under both lower and higher concentrations of azo dyes., (Copyright © 2019 Elsevier B.V. All rights reserved.)

There has been extensive utilization of poloxamer 407 (PM) for the delivery of various ophthalmic drugs aimed at efficient ophthalmic drug delivery approach for longer precorneal residence time along with acceptable bioavailability of drugs. We have studied the effect of nanocellulose grafted collagen (CGC) on the performance of in situ gels based on PM for the controlled in vitro release of Ketorolac Tromethamine (KT). CGC has shown great influence evident by the reduction in PM critical gelation concentration, increased gel strength, and prolonged the release of loaded drugs compared with the virgin PM gel. The engineered nanocomposite formulations established an anomalous diffusion mechanism along with a Fickian diffusion controlled drug release for 1.5 & 1.75 w/v% CGC reinforced PM. Hence, the synthesized in situ nanocomposites are potential candidates for ophthalmic drug delivery system., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Cardanol is a natural alkylphenolic compound derived from Cashew NutShell Liquid (CNSL), a non-food annually renewable raw material extracted from cashew nutshells. In the quest for sustainable materials, the curing of biobased monomers and prepolymers with environmentally friendly processes attracts increasing interest. Photopolymerization is considered to be a green technology owing to low energy requirements, room temperature operation with high reaction rates, and absence of solvents. In this work, we study the photocuring of a commercially available epoxidized cardanol, and explore its use in combination with microfibrillated cellulose (MFC) for the fabrication of fully biobased composites. Wet MFC mats were prepared by filtration, and then impregnated with the resin. The impregnated mats were then irradiated with ultraviolet (UV) light. Fourier Transform InfraRed (FT-IR) spectroscopy was used to investigate the photocuring of the epoxidized cardanol, and of the composites. The thermomechanical properties of the composites were assessed by thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. We confirmed that fully cured composites could be obtained, although a high photoinitiator concentration was needed, possibly due to a side reaction of the photoinitiator with MFC.

Bile salts tend to form micelles in aqueous media and can thereby contribute to drug solubilization; they also exhibit crystallization inhibition properties that can stabilize supersaturated drug solutions. Herein, we explore conjugation of bile salts with polysaccharides to create new, amphiphilic polysaccharide derivatives with intriguing properties, portending broad utility in various applications. We introduce efficient conjugation of cholesterol (as a model steroid), lithocholic acid, and deoxycholic acid by mild, modular olefin cross-metathesis reactions. These small molecules were first modified with an acrylate group from the A-ring hydroxyl, then reacted with cellulose derivatives bearing olefin-terminated metathesis "handles". Successful conjugation of bile acids has demonstrated chemoselective cross-metathesis with complex, polyfunctional structures, and large multi-ring systems. It also enabled an efficient, general pathway for polysaccharide-bile salt conjugates, which promise synergy for applications such as amorphous solid dispersion (ASD)., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Despite the advantages of bacterial cellulose (BC) over traditional cellulose, its low yield and little bioactivity makes a limitation to be used in an industrial scale. This paper was mainly dual aimed to increase the BC yield using a nanobioactive glass (NBG), and in situ synthesize BC/NBG bioactive nanocomposites by a novel and simple green method. Accordingly, the composites were prepared via in situ fermentation approach by incorporation of NBG particles into BC producing culture medium. The effect of NBG addition on the production process of cellulose, biocompatibility, bioactivity and antimicrobial activity were investigated. The results showed that NBG was enhanced and increased the BC yield and this has been achieved by maintaining these NBG on the pH value of the culture medium during the fermentation period. Moreover, it was effectively improved biocompatibility and antimicrobial properties of BC. This study evidenced that BC/NBG composite can be expected to be widely applied in biomedical industries such as bone regeneration and wound healing with the unique of being not harmful to humans., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Cellulose oligomers with a terminal alkyl group at the reducing end formed mechanically robust crystalline monolayers via self-assembly against water surfaces from aqueous solutions. The unique properties of the monolayers resulted in anisotropic deformation or manipulation of the aqueous solution droplets.

A new 3,5-dichlorophenylcarbamated cellulose-bonded silica gel stationary phase (CELCSP) was prepared by a "thiol-ene" addition reaction. The alkenyl group was first introduced onto the cellulose, and then the cellulose was completely isocyanated with 3,5-dichlorophenyl isocyanate. Finally, the alkenyl group was reacted with the 3-mercaptopropyl silica gel to obtain the cellulose-bonded stationary phase. The structures of the ligand and the stationary phase were characterized by infrared spectroscopy, nuclear magnetic resonance spectroscopy and elemental analysis. The newly prepared cellulose-bonded phase was successfully used for the enantio-resolution of six common chiral fungicides including triticonazole, hexaconazole, tebuconazole, triadimefon, metalaxyl and benalaxyl under reversed-phase mode, respectively. The resolution (Rs) and selectivity factor (α) of the above fungicide enantiomers on CELCSP could reach 3.46 and 1.27, respectiviely, by using the common 0.1% formic acid-acetonitrile as the mobile phase. Base on the CELCSP column, a new LC-MS/MS method for the quantitative determinations of all six chiral fungicide enantiomers in ten kinds of fruits and vegetables such as cucumber, grape, etc. was established within 30 min. After the sample pretreatment with Fe 3 O 4 magnetic particles, the enantiomers were separated by LC and determined in positive ion multi-reaction monitoring (MRM) by mass spectrometry. The good linear relationship between the response and the concentration of the enantiomers were observed in a range from 0.10 μg/L to 100 μg/L with the relative standard deviation (RSDs, correlation coefficient (0.9965-0.9982)). The averaged recoveries from fruits and vegetables were between 65% and 110% (n = 3). The detection limit (LODs) and limit of quantitation (LOQs) for the enantiomers were 0.05-0.61 μg/kg and 0.18-2.01 μg/kg, respectively. The RSDs of the repeated determination in the samples were 1.2%-6.0% (intra-day, n = 5) and 2.5%-13.0% (inter-day, n = 10), respectively. The mild condition of the thiol-ene addition reaction was beneficial to maintain the order stereostructure of cellulose, while its high yield of the oriented synthesis could also provide sufficient binding amount of chiral ligand, which made the new stationary phase have good chiral chromatographic performance. The newly prepared stationary phase has strong solvent resistance, which is a guarantee for establishing a reliable food safety analysis method for monitoring pesticide enantiomer residues by LC-MS/MS., (Copyright © 2019. Published by Elsevier B.V.)

A strategy is devised to synthesize zwitterionic acetylated cellulose nanofibrils (CNF). The strategy included acetylation, periodate oxidation, Schiff base reaction, borohydride reduction, and a quaternary ammonium reaction. Acetylation was performed in glacial acetic acid with a short reaction time of 90 min, yielding, on average, mono-acetylated CNF with hydroxyl groups available for further modification. The products from each step were characterized by FTIR spectroscopy, ζ-potential, SEM-EDS, AFM, and titration to track and verify the structural changes along the sequential modification route.

In this work, a novel poly(ionic liquid) with 1-vinyl-3-aminopropyl imidazolium cations was designed and used to modify cellulose aerogels via Schiff base reaction. The poly(ionic liquid) modified cellulose aerogels (PIL-CA) exhibited a well-interconnected porous structure and a high porosity of 86.2%. A zeta potential study showed the PIL-CA had a strong positive potential of more than 65 mV when its pH was below 6. Furthermore, after 350 min of adsorption experiments, the PIL-CA showed a superior adsorption capacity of 918 ± 8 mg g -1 towards bovine serum albumin (BSA) at pH 6 when its concentration was 1.5 mg m L -1 . Finally, the PIL-CA was employed for the selective separation of target protein from a real serum sample, obtaining the BSA with high purity of over 98%., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Facile strategy to construct a cellulose nanocomposite hydrogel with self-healing and biocompatible properties is reported by crosslinking dialdehyde cellulose nanocrystals with acylhydrazine-terminated polyethylene glycol via dynamic reversible acylhydrazone for the first time. The effects of process variables on gelation time, mechanical strength and self-healing efficiency of hydrogels were investigated. It was found that gelation time shortened from hours to seconds by adjusting gelator and catalyst concentration. Tensile and compressive strength of hydrogel could reach 141 K Pa and 580 K Pa at 20.1% gelator concentration, respectively. Interestingly, the as-prepared hydrogel presented excellent self-healing ability without additional stimuli whose healing efficiency was higher than 90% even at higher gelator concentration. Furthermore, Cytotoxicity test showed that cell viability almost reached 100% after culturing with hydrogel, which revealed the hydrogel was biocompatible., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The process employed for the pulping and bleaching of sorghum straw was optimized prior to the synthesis of cellulose acetate. A 2 2 factorial central composite design was carried out. The variables considered were cooking time (1.5 to 2.5 h) and dilute alkali concentration (0.75 to 1.25%) for the pulping and bleaching time (30 to 35 min) and bleach volume (20 to 25 mL) for the bleaching. The sorghum straw was comprised of 49.43% α-cellulose, 19.18% hemicellulose and 30.42% lignin. The optimum conditions that maximize these processes were 2.5 h and 1.25% (dilute alkali concentration) at 90 °C, and 35 min and 25 mL (bleach volume) at 80 °C, respectively, providing pulps with a low Kappa number (<3) and lignin content, and cellulose with a high degree of crystallinity. The 1 H NMR, XRD, FTIR spectroscopy, SEM and thermal analysis demonstrated that it is possible to synthetize cellulose acetate (with 2.62 degrees of substitution) by acetylating bleached pulp for 16 h at 25 °C., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Biodegradable, antimicrobial, and semiconducting cellulosic composite was synthesized by in-situ polymerization of polyaniline in the presence of cellulose. The cobalt ferrite nanoparticles (CFO-NPs) were added during the polymerization process to acquire this composite magnetic property. The CFO-NPs were prepared by sol-gel method with average particles size less than 50 nm. The nanocomposites were characterized by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). In addition, their magnetic, dielectric constant, dielectric loss, and conductivity behaviors were studied. The magnetization (M s ) and conductivity increased up to 3.7 emu/g and 3.5 × 10 -3  S/cm, respectively, with increasing CFO-NPs content. The prepared electromagnetic nanocomposite exhibits highly efficient biodegradability and antimicrobial activity against Escherichia coli, Bacillus subtilis, and Candida albicans. The antimicrobial activity increased with increasing CFO-NPs while the biodegradability decreased., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

A controllable drug delivery system demonstrates a promising tool for diverse biomedical applications. In this work, a group of amphiphilic macromolecules was designed and prepared via Schiff base reactions between 2,3-dialdehyde cellulose (DAC) with oleylamine and amino-containing compounds. Benefiting from the self-assemble process of these amphiphilic macromolecules in the poor solvent, a group of novel pH-responsive nanoparticles (NPs) were facilely fabricated by using nanoprecipitation dropping technique. The high amount of aldehyde groups on DAC chains enabled immobilization of tunable amounts of amine compounds (up to 1.67 mmol/g) in the NPs. Furthermore, the Schiff base bonds in NPs allowed the efficient release of the drug in acidic tumor microenvironment by cleaving the Schiff base linkages. This study demonstrates the formation of a group of novel pH-sensitive and drug-loadable NPs, which provide a simple and efficient drug delivery system for the potential application for cancer treatment., (Copyright © 2019. Published by Elsevier Ltd.)

In order to improve the antibacterial efficiency and spectrum of cellulose acetate reverse osmosis membrane (CA-RO), both quaternary ammonium and bromoacetyl groups were introduced into cellulose diacetate under mild conditions forming CA-RO with bi-antibacterial groups for seawater desalination. Bromoacetyl bromide and a series of tertiary amine were chosen as the modification agents respectively. The characterization results showed that both two antibacterial groups were successfully introduced with a certain density. The obtaining membrane had a less hydrophilic but more electronegative surface as well as improved mechanical property. The flux values increased firstly and decreased subsequently after twice modifications while the salt rejection rose. The membrane modified with N,N-dimethyloctylamine (DMOA) had the optimal comprehensive performance of flux and salt rejection. The antibacterial testing results indicated that the resulting RO membranes showed high antibacterial efficiency and broad-spectrum. Their bactericidal rates against gram-negative Escherichia coli (E. coli) and gram-positive Staphylococcus aureus (S. aureus) were more than 99.9%., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

This work reports on a simple and environmentally benign route to prepare freestanding magnetic films based on cellulose derivatives through the combination of cobalt ferrite (CoFe 2 O 4 ) nanoparticles with methyl cellulose (MC), hydroxypropyl cellulose (HPC), and sodium carboxymethyl cellulose (NaCMC). Nanoparticles are able to "shield" hydrogen bonding interactions between polysaccharide chains and lower the viscosity of water-dissolved MC, HPC, and NaCMC, allowing an easy film fabrication. Crack-free films with homogeneously dispersed nanoparticles having concentrations up to 50 wt % are fabricated by mechanical agitation followed by doctor blade casting. All of the nanocomposite films keep a substantial level of flexibility with elongation at break exceeding 5%. Halpin-Tsai equations serve to provide further insights on the character of matrix-CoFe 2 O 4 interfaces. Magnetization saturation increases almost linearly with cobalt ferrite concentration up to a maximum value of ∼24-27 emu g -1 for nanocomposites containing 50 wt % of nanoparticles. The dielectric response of the films demonstrates a strong dependence on both the functional groups attached to the main cellulose chain and the ferrite nanoparticle content. The renewable character of the hosting matrices, together with the fabrication methods that solely uses water as a solvent, the decrease of the viscosity with the inclusion of fillers, particularly suitable for printable materials, and the resulting magnetic performance provide novel avenues for the replacement of traditional magnetoactive composites based on petroleum-derived polymers and avoiding the use of toxic solvents.

Nanocellulose has been demonstrated as a suitable material for cell culturing, given its similarity to extracellular matrices. Taking advantage of the shear thinning behavior, nanocellulose suits three-dimensional (3D) printing into scaffolds that support cell attachment and proliferation. Here, we propose aqueous suspensions of acetylated nanocellulose of a low degree of substitution for direct ink writing (DIW). This benefits from the heterogeneous acetylation of precursor cellulosic fibers, which eases their deconstruction and confers the characteristics required for extrusion in DIW. Accordingly, the morphology of related 3D-printed architectures and their performance during drying and rewetting as well as interactions with living cells are compared with those produced from typical unmodified and TEMPO-oxidized nanocelluloses. We find that a significantly lower concentration of acetylated nanofibrils is needed to obtain bioinks of similar performance, affording more porous structures. Together with their high surface charge and axial aspect, acetylated nanocellulose produces dimensionally stable monolithic scaffolds that support drying and rewetting, required for packaging and sterilization. Considering their potential uses in cardiac devices, we discuss the interactions of the scaffolds with cardiac myoblast cells. Attachment, proliferation, and viability for 21 days are demonstrated. Overall, the performance of acetylated nanocellulose bioinks opens the possibility for reliable and scale-up fabrication of scaffolds appropriate for studies on cellular processes and for tissue engineering.

Nowadays the using of eco-systems to synthesize new materials is the promising issue. In this work, new eco-synthesis method was developed to prepare antimicrobial cellulosic-amino acid base ligand and complexes with copper. The complex was characterized via different instrumental analysis (Fourier transform infrared spectroscopy (FTIR), UV-vis, differential scanning calorimetry (DSC), dynamic light scattering (DLS), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX)) as well as two antimicrobial screening tools (minimal inhibition concentration (MIC) and time required for killing). The UV-vis spectroscopic data indicates the metal to-ligand charge transfer transitions which is consistent with square planar geometry. DLS and SEM approved that the complex particles are in nano-size. Prepared complex appeared highly antimicrobial activity against all tested microbial organisms which can be described as broad spectrum antimicrobial agent. Rapid killing kinetics was beneficial in helping to resolve an infection more rapidly., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In this study, zinc-sulfate-calcium-phosphate (ZSCAP) ceramics was prepared by calcination in the presence of microwave irradiation using precursors ZnSO 4 :ZnO:CaO:P 2 O 5 in a ratio of 15:30:30:25 (by weight). The calcined ZSCAP ceramics was mixed with microcrystalline cellulose and it was further heated by microwave radiation for the preparation of cellulose/ZSCAP nanocomposites. It was found that microwave heating time played an important role in the crystalline phase of synthesized nanocomposites of cellulose/ZSCAP. Well-crystalline phases of calcium phosphate, zinc oxide and zinc sulfate were observed in the nanocomposites at 20 min of microwave heating time. Fourier transformed infrared spectroscopy (FTIR) and Raman spectroscopy confirmed that the obtained products were of cellulose/ZSCAP nanocomposites. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images indicated that reinforced ZSCAP nanostructures were embedded into cellulose matrix. Energy dispersive X-ray spectroscopy (EDS) further supported the presence of Zn, S, Ca and P in cellulose/ZSCAP nanocomposites. The thermal behavior of the products was studied using thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The prepared nanocomposites showed antibacterial activity against Staphylococcus aureus and Escherichia coli. In vitro cytotoxicity assay revealed that the prepared nanocomposites had no influence on proliferation of MG-63 cells. This rapid microwave-assisted method is simple, fast and suitable for the production of cellulose/ZSCAP nanocomposites, which finds its biomedical applications in tissue engineering and bone repair., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Arabinoxylans (AX) are potential agricultural co-products for material applications. Sorghum has seen increased production as a bioenergy crop for biofuel and co-product generation. AX from three sorghum fractions (bran, bagasse, and biomass) were isolated to study film formation. All three AX fractions exhibited high moisture sensitivity. Sorghum biomass AX produced low water vapor permeability compared to sorghum bran or sorghum bagasse AX films. Glycerol addition to sorghum bran AX films reduced tensile strength from 34.8 to 16.0 MPa at 0% and 10% (w/w) glycerol, respectively; reduced the storage and loss moduli during dynamic mechanical analyses at 50% relative humidity (RH) and decreased the rubber-to-plastic material transition temperature at 50% RH, from 78.1 °C to 38.4 °C at 0 and 10% (w/w) glycerol, respectively. Sorghum bran AX, while sensitive to water absorption at high RH, produced favorable strength performance compared to AX from other cereal grains indicating potential utilization as a renewable material., (Published by Elsevier Ltd.)

Cellulose synthase is the enzyme that produces cellulose in the living organisms like plant, and has two functions: polymerizing glucose residues (polymerization) and assembling these polymerized molecules into a crystalline microfibril with a "cellulose I" crystallographic structure (crystallization). Many studies, however, have shown that an in vitro reaction of cellulose synthase produces aggregates of a non-native crystallographic structure "cellulose II", despite the remaining polymerizing activity. This is partial denaturation or loss of crystallization function in cellulose synthase, which needs to be resolved to reconstitute its native activity. To this end, we aimed to clarify the process of cellulose II formation by bacterial cellulose synthase in vitro, using in situ small angle X-ray scattering (SAXS). An increase in scattering specific to synthesis was observed around two distinct regions of q (0.2-0.4 nm -1 and <0.1 nm -1 ) by time-resolved SAXS measurement. The scattering at higher q-region appears prior to lower-q scattering at beginning of the reaction, indicating the existence of smaller primitive aggregations at the initiation stage. This study demonstrates the use of in situ SAXS measurement to decipher the dynamics of biosynthesized cellulose chains, which is a remarkable example of polymer assembly in ambient conditions., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Amphiphilic cellulose derivatives were synthesized from allyl cellulose (AC) and cystein (Cys)/n-dodecyl mercaptan (NDM) via the thiol-ene click reactions. The derivatives were self-assembled into micelles in distilled water, and the micelles sizes increased with an increase of the DS NDM . The amphiphilic cellulose micelles were served as the soft templates for the controllable synthesis of Ag nanoparticles (NPs) through the photo-reduction. Ag NPs were embedded and stabilized by the amphiphilic cellulose micelles, and their sizes increased from 3.1 to 14.4 nm with an increase of the original template sizes. The catalytic properties of the Ag-loaded micelles were evaluated by the reduction of p-nitropheonl to p-aminophenol. The results demonstrated that the Ag-loaded micelles exhibited excellent catalytic activity. The reduction followed the first-order rate law, and the reaction constant decreased with increasing size of Ag NPs. Moreover, the Ag-loaded micelles displayed good antimicrobial activities to both S. aureus and E. coli. Therefore, the Ag-loaded cellulose-based micelles have potential applications in various fields., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Straw is a green and promising material in nature. However, as is the case for all other biopolymers, straw have to face the challenge of underutilization thereby resulting in environmental and economic issues. To overcome these drawbacks, the urgent exploitation of straw is needed for its comprehensive utilization. In this paper, we chose cellulose as the straw model to prepare two amine ligands functionalized environmentally-friendly cellulose supported catalyst. The ethylenediamine functionalized cellulose catalyst (ADC) was effective in the reaction of aromatic aldehydes with nitromethane to synthesize nitroalkenes and 1,3‑dinitroalkanes. Based on ADC, the diethylenetriamine functionalized cellulose (CL-DETA-Cl) could capture Pd firmly by virtue of the covalent bonding between diethylenetriamine functionalized cellulose and palladium nanoparticles. The synthesized catalyst (CL-DETA-Pd) was then illuminated by using FT-IR, TGA, XRD, TEM, ICP-OES and XPS. The multifunctional complex could catalyze the Suzuki-Miyaura reactions efficiently and prevented the metal leaching through the multiple capturing sites (hydroxyl and amine groups) with palladium. Also, the catalyst could be completely regenerated in a few cycles with simple centrifugation. This study will provide reliable foundation and extensive application way to further utilization of straw., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The regeneration of cartilage is a challenging problem for lack of innate abilities to mount a sufficient healing response. Kartogenin (KGN), an emerging chondroinductive non-protein small molecule, bound to the surface of the ultrasmall super-paramagnetic iron-oxide (USPIO) by innovational one-step technology, followed by being incorporated into the cross-linking collagen/cellulose nanocrystals (Col/CNC) bioactive scaffolds to stimulate an appropriate microenvironment for the growth and differentiation of bone marrow-derived mesenchymal stem cells (BMSCs), thus facilitating the formation of chondrocyte. Herein, USPIO not only served as a carrier for small molecule drugs, but also as MRI contrast agents, which can non-invasively monitor the degradation of the scaffolds and the self-repair capacity of cartilage. In vitro studies showed that the KGN could release from the composite scaffolds in a sustained and stable manner and promote the chondrogenic differentiation of BMSCs based on UV spectrophotometry test, and specific markers analysis. Of note, USPIO labeled composite scaffolds retained their stability without loss of relaxation rate the composite scaffolds can be a promising biomaterials for cartilage repair, with the function of noninvasive visualization and semiquantitative analysis of scaffolds degradation and neocartilage., (Copyright © 2019. Published by Elsevier B.V.)

Cellulose, as one of the most abundant natural biopolymers, has been widely used in textile industry. However, owing to its drawbacks of flammability and ignitability, the large-scale commercial application of neat cellulose is limited. This study investigated some TEMPO-oxidized cellulose (TOC) which was prepared by selective TEMPO-mediated oxidation and ion exchange. The prepared TOC was characterized by Fourier transform infrared (FT-IR) spectroscopy and solid-state 13 C-nuclear magnetic resonance ( 13 C-NMR) spectroscopy. The thermal stability and combustion performance of TOC were investigated by thermogravimetry analysis (TG), microscale combustion calorimetry (MCC) and limiting oxygen index (LOI). The results demonstrated that the thermal stability of TOC was less than that of the pristine material cellulose, but the peak of heat release rate (pHHR) and the total heat release (THR) of all TOC were significantly reduced. Additionally, the LOI values of all TOC products were much higher 25%. In summary, the above results indicated that the modified cellulose with carboxyl groups and metal ions by selective oxidation and ion exchange endows efficient flame retardancy.

Developing biomaterials based on the natural biomacromolecule silk sericin from Bombyx mori cocoon is of great interest for biomedical application. Dialdehyde carboxymethyl cellulose (DCMC) is derived from periodate oxidation of carboxy- methyl cellulose. Here, we developed a novel strategy of cross-linking of sericin with DCMC via the Schiff's base reaction. Fourier transform infrared spectroscopy and scanning electron microscopy indicated the formation of Schiff's base via the blending of sericin and DCMC. The mechanical properties tests suggested the covalent cross-linking effectively enhanced the tensile strength of sericin. The swelling test and water contact angle indicated the DCMC/SS film had excellent hydrophilicity, swellability. Additionally, we demonstrated the DCMC/SS film had excellent blood compatibility, cytocompatibility and promoting cell proliferation activity by the hemolysis ratio analysis, cell adhesion, cells viability and proliferation assays. The prepared DCMC/SS film has shown great promise in biomedical applications such as wound dressing, artificial skin and tissue engineering., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Waterborne polyurethane (PU) is a green, high performance elastomer but the viscosity of the dispersion is generally too low for direct three-dimensional (3D) printing. Composite brings additional properties while reinforcing the substrate. In the study, printable PU composites were successfully prepared by introducing cellulose nanofibrils (CNFs) and the viscosity was effectively regulated by the amount of neutralizing agent during in-situ synthesis. Rheological measurements supported the good printability. TEM images revealed that CNFs linked multiple PU nanoparticles to form a 'skewer' structure. PU/CNF scaffolds were 3D-printed with excellent pattern fidelity and structure stability. Meanwhile, the compression modulus was much higher than the scaffolds printed with a water-soluble viscosity enhancer (PEO). Fibroblasts kept proliferating in the scaffolds for two weeks. The interaction between CNF and PU may offer a novel and unique way to tune the viscosity of waterborne PU for direct 3D printing and enhance the properties of the green elastomers., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Synthetic polymers are easy to process and have excellent mechanical properties but low wettability and poor cell compatibility limit their applications in tissue scaffolding. In this study, a facile procedure was established to regenerate cellulose and calcium lactate (CaL) into a polycaprolactone (PCL) nanofibrous scaffold for tissue engineering applications. Briefly, varying amounts of lactic acid (LA) was mixed with the blend of PCL and cellulose acetate (CA) solutions and electrospun to fabricate an optimal composite PCL/CA/LA fibrous membrane. Later on, as-prepared membranes were treated with calcium hydroxide solution. This process simultaneously converted CA and LA contents into Cellulose and CaL, respectively. In situ regeneration of Cellulose and CaL into the composite fiber remarkably enhanced the biological and physicochemical properties of the composite fiber. This work provides a novel dual-channel strategy for simultaneous regeneration of biopolymer and bioactive molecule into the PCL nanofiber for regenerative medicine and tissue engineering applications., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

An all-water-based procedure for "controlled" polymer grafting from cellulose nanofibrils is reported. Polymers and copolymers of poly(ethylene glycol) methyl ether methacrylate (POEGMA) and poly(methyl methacrylate) (PMMA) were synthesized by surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (SI-ARGET ATRP) from the cellulose nanofibril (CNF) surface in water. A macroinitiator was electrostatically immobilized to the CNF surface, and its amphiphilic nature enabled polymerizations of both hydrophobic and hydrophilic monomers in water. The electrostatic interactions between the macroinitiator and the CNF surface were studied by quartz crystal microbalance with dissipation energy (QCM-D) and showed the formation of a rigid adsorbed layer, which did not desorb upon washing, corroborating the anticipated electrostatic interactions. Polymerizations were conducted from dispersed modified CNFs as well as from preformed modified CNF aerogels soaked in water. The polymerizations yielded matrix-free composite materials with a CNF content of approximately 1-2 and 3-6 wt % for dispersion-initiated and aerogel-initiated CNFs, respectively.

Here, a method to synthesize cellulose nanofiber biotemplated palladium composite aerogels is presented. Noble metal aerogel synthesis methods often result in fragile aerogels with poor shape control. The use of carboxymethylated cellulose nanofibers (CNFs) to form a covalently bonded hydrogel allows for the reduction of metal ions such as palladium on the CNFs with control over both nanostructure and macroscopic aerogel monolith shape after supercritical drying. Crosslinking the carboxymethylated cellulose nanofibers is achieved using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) in the presence of ethylenediamine. The CNF hydrogels maintain their shape throughout synthesis steps including covalent crosslinking, equilibration with precursor ions, metal reduction with high concentration reducing agent, rinsing in water, ethanol solvent exchange, and CO2 supercritical drying. Varying the precursor palladium ion concentration allows for control over the metal content in the final aerogel composite through a direct ion chemical reduction rather than relying on the relatively slow coalescence of pre-formed nanoparticles used in other sol-gel techniques. With diffusion as the basis to introduce and remove chemical species into and out of the hydrogel, this method is suitable for smaller bulk geometries and thin films. Characterization of the cellulose nanofiber-palladium composite aerogels with scanning electron microscopy, X-ray diffractometry, thermal gravimetric analysis, nitrogen gas adsorption, electrochemical impedance spectroscopy, and cyclic voltammetry indicates a high surface area, metallized palladium porous structure.

The recycled paper and board industry needs to improve the quality of their products to meet customer demands. The refining process and strength additives are commonly used to increase mechanical properties. Interfiber bonding can also be improved using cellulose nanofibers (CNF). A circular economy approach in the industrial implementation of CNF can be addressed through the in situ production of CNF using side cellulose streams of the process as raw material, avoiding transportation costs and reducing industrial wastes. Furthermore, CNF fit for use can be produced for specific industrial applications.This study evaluates the feasibility of using two types of recycled fibers, simulating the broke streams of two paper machines producing newsprint and liner for cartonboard, to produce in situ CNF for direct application on the original pulps, old newsprint (ONP), and old corrugated container (OCC), and to reinforce the final products. The CNF were obtained by 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO)-mediated oxidation and homogenization at 600 bar. Handsheets were prepared with disintegrated recycled pulp and different amounts of CNF using a conventional three-component retention system. Results show that 3 wt.% of CNF produced with 10 mmol of NaClO per gram of dry pulp improve tensile index of ONP ~30%. For OCC, the same treatment and CNF dose increase tensile index above 60%. In both cases, CNF cause a deterioration of drainage, but this effect is effectively counteracted by optimising the retention system., Competing Interests: The authors declare no conflicts of interest.

Lethal bleeding due to street accidents, natural calamities, orthopedic/dental surgeries, organ transplantation and household injuries, is the leading cause of morbidity and mortality. In the current study, zinc oxide (ZnO) was incorporated in TEMPO-oxidized cellulose nanofiber (TOCN) and polyethylene glycol (PEG) polymer system for hemorrhage control by freeze drying method. SEM and XRD data showed the presence of ZnO in the porous structure. FT-IR analysis showed that, successful conjugation occurs among the TOCN and PEG. The results revealed that, the incorporation of ZnO and higher concentrations of PEG increased the degradability but decreased swelling of the scaffolds. The increase in PEG content and ZnO incorporation significantly decreased the bleeding time in rabbit ear arterial bleeding model. Further, the incorporation of ZnO enhanced the antibacterial property of TOCN-PEG. The results suggested that excellent hemostatic and mechanical properties of the TOCN-5% PEG-ZnO might contribute in controlling bleeding and reducing post traumatic dermal bacterial infection., (Copyright © 2018. Published by Elsevier B.V.)

Tissue adhesion is one of the most common complications after surgery (especially after abdominal surgery), causing notable influences after the damaged tissue has healed. A physical barrier placed between the wound site and the adjacent tissues is a convenient and highly effective technique to minimize or prevent abdominal adhesions. In this work, the N, O-carboxymethyl chitosan/oxidized regenerated cellulose (N, O-CS/ORC) composite gauze was prepared. The N, O-CS/ORC composite gauze is degradable; in addition, the gauze exhibits excellent antimicrobial functionality against S. aureus and E. coli bacteria. Moreover, the notable hemostatic efficacy of the N, O-CS/ORC composite gauze was confirmed in rabbit livers/ears as models. The results showed that the N, O-CS/ORC composite gauze is nontoxic toward normal cells and can restrain the adhesion of fibroblast cells, thereby indicating its potential use in preventing tissue adhesion. In addition, the rat models for abdominal defect-cecum abrasion were used to evaluate the efficacy of N, O-CS/ORC composite gauze in preventing tissue adhesions after surgery. The results indicated that the N, O-CS/ORC composite gauze can significantly prevent postsurgical peritoneal adhesions. Finally, the potential anti-adhesion mechanism of the N, O-CS/ORC composite gauze, which may attribute to the combination of barrier function and instinct activity of N, O-CS and ORC, was investigated., (Copyright © 2018. Published by Elsevier Ltd.)

Graphene oxide(GO), as an amphiphilic and biocompatible material, is often used to prepare Pickering emulsion. However, the preparation of stable Pickering emulsion by a low concentration of GO is very challenging. In this research, we prepared the hydrophobic modified hydroxyethyl cellulose (mHEC) which contained quaternary ammonium group and GO which the water contact angle was 84°-86°. A stable, low cost, and biocompatible Pickering emulsion was fabricated by a low concentration of GO and different contents of mHEC. The effects of mHEC concentration, electrolyte concentration, pH, and oil/water ratio on the stability of Pickering emulsion were investigated. What's more, we prepared the biomedical macroporous polyacrylamide hydrogel by the GO/mHEC composite stabilized emulsion template for drug controlled-release. The composite hydrogel by Pickering emulsion template is a potential drug controlled-release delivery platforms. Furthermore, our strategy is extremely versatile, as Pickering particles, polymer and the monomer of hydrogel can all be varied., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

This study describes the valorization of rice and oat husks by obtaining cellulose nanocrystals for the production of aerogels for food packaging applications. Commercial cellulose was used as a control sample. Nanocrystals from cellulose were obtained by enzymatic hydrolysis and mechanical treatment at high pressure. The morphology, particle size, functional groups, crystallinity, and thermal properties of the cellulose nanocrystals were analyzed. The morphology, functional groups, crystallinity, water absorption capability, and zeta potential of aerogels were also analyzed. Cellulose nanocrystals show different structural properties and crystallinity depending on the source of the cellulose. The average diameter of the nanocrystals varied from 16.0 to 28.8 nm. The aerogels prepared with cellulose nanocrystals showed a porous and uniform structure with a water absorption capacity between 264.2% and 402.8% at 25 °C. The aerogel of oat cellulose nanocrystals showed a larger pore size than that of eucalyptus cellulose nanocrystals, and this may have influenced the lowest water absorption capacity of the aerogels of eucalyptus cellulose nanocrystals. These results show that agroindustrial residues have promising applications in various industrial fields and could be used as aerogel absorbers of water in food packaging., (Copyright © 2018. Published by Elsevier B.V.)

A new approach for the preparation of poly (vinyl alcohol) (PVA) - cellulose based composite hydrogels by freezing/thawing method was conceived. We synthesized firstly the tricarboxy cellulose (OxC) (bearing three carboxyl groups in one anhydroglucose unit) using a one shot oxidation procedure and subsequently, the aqueous solutions of OxC were mixed with PVA solutions in different ratios, in the absence of any supplementary cross-linking agent. The spectral methods, FTIR, 1 H, 13 C NMR, as well as rheology measurements were used to assess the degree of interaction between the two components. The morphology studies of the resulted hydrogels, performed by SEM shows an excellent distribution of the tricarboxy cellulose inside the PVA matrix, the addition of tricarboxy cellulose contributing to an increase of the pore size. The rheological investigation reveals the synergistic network when an optimum amount of tricarboxy cellulose was introduced. In addition, the self-healing behavior reveals by the viscoelastic behavior, strongly recommend these hydrogels as potential candidates in tissue engineering applications., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Bacterial cellulose (BC) is a promising biopolymer with wound healing and tissue regenerative properties but lack of antimicrobial property limits its biomedical applications. Therefore, current study was proposed to combine wound healing property of BC with antimicrobial activity of montmorillonite (MMT) and modified montmorillonites (Cu-MMT, Na-MMT and Ca-MMT) to design novel artificial substitute for burns. Designed nanocomposites were characterized through Fe-SEM, FTIR and XRD. The antimicrobial activities of composites were tested against Escherichia coli, Salmonella typhimurium, Citrobacter fruendii, Pseudomonas aeruginosa, Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus. Tissue regeneration and wound healing activities of the composites were assessed in burn mice model. Physico-chemical characterization confirmed the loading of MMT onto surface and BC matrix. Modified MMTs-BC nanocomposites showed clear inhibitory zone against the tested pathogens. Animals treated with modified MMTs-BC nanocomposites exhibited enhanced wound healing activity with tissue regeneration, reepithelialization, healthy granulation and vascularization. These findings demonstrated that modified MMTs-BC nanocomposites could be used as a novel artificial skin substitute for burn patients and scaffold for skin tissue engineering., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Camptothecin (CPT), a potent anticancer drug with known antiviral activity, is halted of clinical use. Few drug delivery systems of CPT are approved for therapy. Hereby, we propose the encapsulation of hydrophobic CPT in the inner core of cellulose nanoaggregates for sustained release with retaining of antiproliferative activity. Cellulose conjugates were synthesized by esterification of methyl cellulose, hydroxyethyl cellulose and (hydroxypropyl)methyl cellulose with testosterone, ergocalciferol and dl-α-tocopherol hemisuccinates. The degree of substitution attained ranged from 0.004 to 0.025 and no depolymerization was observed by size exclusion chromatography. ATR-FTIR and NMR spectroscopies confirmed grafting of testosterone and vitamins to celluloses. According to dynamic light scattering, it resulted in their self-assembly in aqueous medium as stable and slightly negatively charged nanoaggregates of 213 to 731 nm. Nanoaggregates formation was also assessed using transmission electron and atomic force microscopies. CPT was encapsulated in the cellulose nanoaggregates, achieving a content of 1.7-13.0 wt %. Sustained release of camptothecin over 150 h was observed in simulated physiological conditions. CPT-loaded cellulose nanoparticles appeared to be possible candidates for chemotherapy, according to observed cytotoxicity against MCF-7 cancer cells., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Bacterial nanocellulose/hydroxyapatite/cellulose nanocrystal (BHC) composites were synthesized via in-situ synthesis using cellulose nanocrystals (CNCs) to improve colloidal stability and the dispersion of hydroxyapatite (HA) during the bacterial nanocellulose (BNC) cultivation period. Transmission electron microscopy images and energy dispersive spectroscopy (EDS) results confirmed the dispersion of HA on the CNC particles with a Ca/P ratio of 1.66 corresponding to that of the stoichiometric HA. The SEM images and EDS results showed that the integration of the HA and BNC network without CNC assistance (BHA (0.25 and 0.5 wt.%) composites) was less than that for BHC at both concentrations. Fourier-transform infrared analysis, XRD and thermal degradation revealed the effect of HA on the BHC composites with a decreased CrI% and improved thermal property. Cytotoxicity proved the potential for using BHC composites for bone tissue engineering scaffold with cell viability up to 83.4 ± 3.6% compared to the negative control (99.2 ± 0.08%)., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Medical cotton gauzes were modified by grafting poly(methacrylic acid) (PMAA) via free radical polymerization to obtain wound dressings with antimicrobial and drug delivery properties. The effect of several reaction parameters including monomer and initiator concentrations, reaction time, and temperature was studied. The grafting was confirmed by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), swelling studies, and scanning electron microscopy (SEM). The grafted cotton gauzes (gauze-g-PMAA) samples were loaded with ZnO nanoparticles to endow with antibacterial properties. Also, they were tested as drug eluting systems using nalidixic acid as antimicrobial agent. The antibacterial activity of the ZnO-loaded gauze-g-PMAA samples was evaluated against Escherichia coli (E. coli) and Staphylococcus epidermidis (S. epidermidis). The PMAA-grafted gauzes showed antibacterial activity and inhibited the growth of both microorganisms. These results suggest that the PMAA-grafted cotton gauzes could be used in the biomedical area particularly as antimicrobial and drug-eluting wound dressings., (Copyright © 2018 Elsevier Ltd. All rights reserved.)