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Bio-based additives received significant attention in pulp and paper properties improvement. For this, the most cited biochemical Cellulose Nano Fibrils (CNFs) and Cationic Starch (CS) were experimentally compared with the most declared synthetic chemical, Cationic Polyacrylamide (CPAM). SEM images showed better paper surface filling by the utilization of the chemicals. The three studied polymers, in solely or combination mechanism, improved mainly bagasse pulp and paper properties compared to the blank sample, except for pulp drainage, which decreased by CNFs to lower volumes presumably due to its intrinsic characteristics. Cationic polymers (CP) compared to CP/CNFs approaches increased pulp retention and drainage but decreased paper density and strengths. The best pulp retention and drainage achieved by CS followed by CPAM, while paper air persistency, density, and strength properties evaluated highest by CP/CNFs followed by CNFs. Generally, CS revealed a more significant improvement in pulp and paper properties than CPAM either with or without CNFs.

Funding Information: The financial support of the Austrian Federal Ministry of Digital and Economic Affairs and the National Foundation for Research, Technology and Development , Austria, is gratefully acknowledged. We also thank the industrial partners Mondi, Canon Production Printing, Kelheim Fibres, and SIG Combibloc for their support. Publisher Copyright: © 2021 Copyright: Copyright 2021 Elsevier B.V., All rights reserved. Hydrophobization of cellulosic materials and particularly paper products is a commonly used procedure to render papers more resistant to water and moisture. Here, we explore the hydrophobization of unsized paper sheets via the gas phase. We employed three different compounds, namely palmitoyl chloride (PCl), trifluoroacetic anhydride/acetic anhydride (TFAA/Ac2O)) and hexamethyldisilazane (HMDS) which were vaporized and allowed to react with the paper sheets via the gas phase. All routes yielded hydrophobic papers with static water contact angles far above 90° and indicated the formation of covalent bonds. The PCl and TFAA approach negatively impacted the mechanical and optical properties of the paper leading to a decrease in tensile strength and yellowing of the sheets. The HMDS modified papers did not exhibit any differences regarding relevant paper technological parameters (mechanical properties, optical properties, porosity) compared to the non-modified sheets. XPS studies revealed that the HMDS modified samples have a rather low silicon content, pointing at the formation of submonolayers of trimethylsilyl groups on the fiber surfaces in the paper network. This was further investigated by penetration dynamic analysis using ultrasonication, which revealed that the whole fiber network has been homogeneously modified with the silyl groups and not only the very outer surface as for the PCl and the TFAA modified papers. This procedure yields a possibility to study the influence of hydrophobicity on paper sheets and their network properties without changing structural and mechanical paper parameters.

In this work, we prepared novel cellulosic paper by incorporating tannin into the kraft pulp for potential application in active food packaging. The kraft pulp fibers were firstly periodate oxidized to obtain the dialdehyde cellulosic fibers, and then reacted with varied dosages of tannin to incorporate them into the fibers by covalent bondings between aldehyde groups on cellulose and active hydrogen on tannin. Handsheets were prepared using the tannin incorporated fibers through papermaking process and the properties were characterized. The percentage of tannin in the paper increased with the increase of the tannin dosage. FT-IR spectra confirmed the successful incorporation of tannin into the cellulosic fibers. It was found that paper after incorporation of tannin turned to be surface hydrophobic with contact angles higher than 90°, which may probably due to the covalent bonds between tannin and cellulose. The handsheets show high antioxidative and UV-shielding properties, which both increased with the increase of the tannin percentage in the paper. Water vapor transmission rate (WVTR) decreased after the incorporation of tannin, and this could facilitate its application in food packaging. The breaking length of tannin incorporated paper decreased insignificantly, less than 10% with the tannin percentage as high as 45%.

Starch and derivatives thereof have proven their usefulness in paper coating processes. Among these derivatives, cationic starch has been widely used in the paper industry as a flocculation, dispersion and ink fixing agent. In another context, nanoscale cellulosic materials have been shown to improve the strength, retention of fillers, the barrier properties of packaging paper products, and printing qualities. This review summarizes the recent studies on the general components used in paper coating, describes the conventional and alternative synthetic processes of cationic starches and nanocellulose, and deals with their current and potential applications in papermaking, focusing primarily on surface treatments. Moreover, environmental applications have been considered to expand the understanding and usefulness of these materials. Further research on modified polysaccharides is encouraged to replace, in a feasible way, petro-based components of coating formulations, and to provide paper surfaces with new properties.

In this paper, nanochitin was used as an alternative natural nanomaterial to combine with cellulose fibers for fabricating high-strength paper. Two typical chitin nanowhiskers having contrasting sign of surface charge were compared to evaluate the enhancement performance on paper in details. The results show that nanochitin with positive charges on the surface has a significant effect on the strength properties of the prepared paper, especially on wet strength. When the dosage of chitin nanowhiskers was 2%, the wet strength index was increased to 2.48 N·m/g, which is important for paper-based analytical devices with the common use in liquid analysis. Typical colorimetric glucose assays were successfully performed, suggesting the improved analytical performance on these prepared paper.

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 H2O2 formed by decomposition of APS, selectively oxidized the hydroxyl on the C6 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.

Point-of-care (POC) detection is crucial in clinical diagnosis in order to provide timely and specific treatment. Combining polyamidoamine (PAMAM) dendrimer, p-phenylene diisothiocyanate (PDITC) and superparamagnetic beads, a novel method to activate the surface of filter paper to bind DNA molecules has been developed. The method is based on the primary amination of the filter paper surface with PAMAM dendrimer, followed by generation of isothiocyanate groups via PDITC, and subsequent repetition of these two steps. Different parameters of the process have been optimized, including probe printing, preparation of target DNAs and detection. The result shows that, due to the highly porous structure of filter paper, high amounts of printed probes, target DNAs and magnetic beads can provide high signal intensities in the detection area via probe/target duplex formation. This method is suitable for rapid, specific and cost-efficient DNA detection on cellulose filter paper. It can be used as a POC device, in particular for diagnosis and treatment management of infectious diseases and identification of antimicrobial drug resistance genes.

The production of cellulose nanofibers (CNF) usually consist of two different phases. First of all, lignocellulosic fibers need to be treated by means of either chemical, enzymatic or mechanical treatments. Then, in the second phase, the treated lignocellulosic fibers need to be submitted to mechanical fibrillation. This last treatment is usually critical in terms of energy consumption, as well as for providing the appropriate characteristics to the resulting CNF. In the present work, we have investigated the effect of fibrillating lignocellulosic nanofibers (LCNF) made from eucalyptus sawdust by means of high-pressure homogenization and grinding. The obtained results showed that, to achieve the same property level of LCNF, the grinder consumed 12.86 kWh/kg, while the homogenizer, 19.07 kWh/kg, bringing to the light the suitability of grinding for LCNF production. Overall, the present work shows the feasibility of using eucalyptus sawdust, which is a residue from the pulp and paper industry, as raw material for LCNF production, at the same time that brings to the light the relevance of the fibrillation equipment in terms of energy efficiency, approaching the production of LCNF to the industry.

The current work describes the development of a "nanopaper-based analytical device (NAD)", through the embedding of curcumin in transparent bacterial cellulose (BC) nanopaper, as a colorimetric assay kit for monitoring of iron and deferoxamine (DFO) as iron-chelating drug in biological fluids such as serum blood, urine and saliva. The iron sensing strategy using the developed assay kit is based on the decrease of the absorbance/color intensity of curcumin-embedded in BC nanopaper (CEBC) in the presence of Fe(III), due to the formation of Fe(III)-curcumin complex. On the other hand, releasing of Fe(III) from Fe(III)-CEBC upon addition of DFO as an iron-chelating drug, due to the high affinity of this drug to Fe(III) in competition with curcumin, which leads to recovery of the decreased absorption/color intensity of Fe(III)-CEBC, is utilized for selective colorimetric monitoring of this drug. The absorption/color changes of the fabricated assay kit as output signal can be monitored by smartphone camera or by using a spectrophotometer. The results of our developed sensor agreed well with the results from a clinical reference method for determination of Fe(III) concentration in human serum blood samples, which revealed the clinical applicability of our developed assay kit. Taken together, regarding the advantageous features of the developed sensor as an easy-to-use, non-toxic, disposable, cost-effective and portable assay kit, along with those of smartphone-based sensing, it is anticipated that this sensing bioplatform, which we name lab-on-nanopaper, will find utility for sensitive, selective and easy diagnosis of iron-related diseases (iron deficiency and iron overload) and therapeutic drug monitoring (TDM) of iron-chelating drugs in clinical analysis as well.

The present study delineates the preparation, characterization, and application of (3-Aminopropyl)triethoxysilane (APTES)/Caprine liver-derived extracellular matrix (CLECM) coated paper matrix for cell delivery. Here, we exploited positively charged surface of the paper matrix (as imparted by APTES derivatization) to improve the biological responses of the cells. Our results demonstrated that the functionalized paper matrixes favored the adhesion, growth, and proliferation of multiple cell types including normal, transformed, cancerous, and stem cells as compared to the pristine paper matrix. Upon implantation into the mice model, the developed paper matrix supported infiltration of the host cells and vasculature without showing any evidence of significant systemic toxicity. Moreover, the cells cultured on the paper matrix, when delivered to the CAM and mouse models, showed an enhanced vascular network around the substrate, thereby confirming its potential to deliver the cells in vivo. Together, the study confirms that the reported paper-based platform is easy to fabricate, cheap, portable and could efficiently be applied to cell delivery applications for either tissue repair or the development of humanized animal model.

Thermophilic methane fermentation was a valid approach for handling the stillage eluted from ethanol fermentation of waste paper and kitchen waste. The wide organic loading rate (OLR) range (2-14 g VTS/(L d)) for stable performance and relatively high energy recovery efficiency (79.0%) were achieved, and OLR of 8 g VTS/(L d) was optimum for achievement of highest biogas evolution and VTS removal efficiency. Microbial community analysis revealed that hydrolysis of cellulose was the critical step for methane production from the stillage.

This study reports on eco-friendly graft polymerization approach for the modification of a cellulosic material via combination between enzymatic catalysis and reversible addition-fragmentation chain transfer polymerization (RAFT). Polyacrylamide (PAM) was polymerized on a cellulosic filter paper via horseradish peroxidase (HRP)-initiated RAFT polymerization. The results of grafting ratio, conversion, and pseudo-first-order kinetics were proved that the PAM graft polymerization on the filter paper followed RAFT rules. The results of Attenuated total reflection (ATR-FTIR), elemental analysis, and X-ray photoelectron spectroscopy (XPS) confirmed the presence of PAM in PAM-grafted filter paper. The results of water contact angle and Thermogravimetric analysis (TG) evidenced the change in the wetting properties and thermal performance, respectively of the treated filter paper. This work provides a new environmentally approach to graft polymerization on cellulosic materials.

Gaseous acetic acid is formed under conditions of storage of historic paper objects. Its presence not only promotes hydrolytic cleavage of cellulose, but also causes acetylation of the cellulosic material to very small degree. The acetylation reaction proceeds under ambient conditions and without catalyst. Different analytical methods were used to prove the presence of organic acetates on cellulosic paper matrices. DESI-MS in combination with 2H-isotopic labeling showed the presence of sugar fragments with different acetylation patterns. A method based on Zemplen saponification was applied and worked also in the presence of a large excess of acetic acid and/or inorganic acetates. The acetylation effect was quantified for model papers and original, naturally aged paper samples. While cellulose acetylation was clearly proven to be another general pathway of paper aging, further studies of this acetylation phenomenon are needed with regard to conservational aspects and suitable paper storage conditions.

Solar-reflective thermal insulating coating (SRC) has received great attention because of its desired heat reflective properties and water repellency, which may impart high-value to cellulosic paper via industrially well-established surface coating process. However, the feasibility and possibility of surface application of SRC to cellulosic paper have not been explored. Herein, in the present work, SRC was designed/developed and subsequently used in the surface application to cellulosic paper. Effect of feeding level of titanium dioxide nanoparticles (nano-TiO2) on rheological behavior of the coating, as well as heat-reflective properties, water repellency and mechanical properties of the surface-coated paper was studied. Results showed that the as-obtained coating samples exhibited a notable shear-thinning behavior and displayed strong dependence of rheological behavior on nano-TiO2 amount. Furthermore, the increased nano-TiO2 amount appeared to induce the improved hemispherical emittance of coated paper. The coating weight was also found to exert a positive effect on the hemispherical emittance of coated paper. In addition, it was confirmed that the nano-TiO2 addition played an important role in improving the water repellency and mechanical properties of coated paper.

Filtration is a promising water treatment method to purify drinking water. To develop highly efficient drinking water filter paper, water-resistant cellulose foam paper with a high wet strength property was fabricated using diverse metal oxide (e.g., copper oxide (CuO), zinc oxide (ZnO), and silver oxide (Ag2O)) nanoparticles. These nanoparticles were synthesized using the hydrothermal reaction method. Their morphological structures were studied using a field emission scanning electron microscope (FESEM). The presence of coated nanoparticles on the cellulose foam filter was verified by energy dispersive X-ray spectroscopy (EDX) methods. The antibacterial performance of different types of modified cellulose foam filters was studied against E. coli, P. aeruginosa, B. subtilis, and B. cereus strains using the zone of inhibition test. The antibacterial profile of the cellulose foam filter impregnated with Ag2O nanoparticles, when tested against different types of bacteria, exhibited higher antibacterial activity than the cellulose foam filter impregnated with ZnO and CuO nanoparticles.

Cellulose fibers come in a wide range of shapes and sizes. The heterogeneity of the fiber length, width, wall thickness, curl and external fibrillation is detrimental to the mechanical performance of products such as paper and paperboard. Although micro-mechanical models of these materials sometimes incorporate features of this heterogeneity, so far there is no standardized method of fully incorporating this. We examine a large number of industrial mechanical fiber pulps to determine what information such a standardized method would have to have. We find that the method must allow for both non-Gaussian distributions and dependence between the variables. We present a method of characterizing mechanical pulp under these conditions that views the individual fiber as outcome of a sampling process from a multivariate distribution function. The method is generally applicable to any dataset, even a non-Gaussian one with dependencies. Using a micro-mechanical model of a paper sheet the proposed method is compared with previously presented methods to study whether incorporating both a varying fiber size and dependencies is necessary to match the response of a sheet modeled with measured characterization data. The results demonstrate that micro-mechanical models of paper and paperboard should not neglect the influence of the dependence between the characteristic shape features of the fibers if the model is meant to match physical experiments. © 2022 The Authors

In this study, we have attempted to extract cellulose fiber from newspaper waste for circular economy project. Cellulose was successfully extracted from newspaper waste with high purity. It was further developed as a composite with Fe3O4 powder. 10–30 wt% of Fe3O4 was synthesized from conventional synthetic route and it was uniformly distributed into cellulose suspension. The composite was prepared by freeze-dry technique in order to remove water and create the porosity. X-ray diffraction and thermogravimetric analysis were employed to characterize the structural and thermal properties of composite. Scanning electron microscope with energy dispersion analysis can be confirmed that uniformity of cellulose and the existence of Fe3O4 powder. Frequency dependence of dielectric properties was used to imply the polarity enhancement of composite. Preliminary adsorption of composite as adsorbent material for Congo red was investigated.

Driven by the environmental benefits that bio-bleaching could bring, the interest in xylanase has received enormous attention and hence, the search of xylanase with properties like no cellulase activity, function at elevated temperatures and pH continues. The present study reports the production of extracellular xylanase from Aspergillus nidulans using waste agro-residues as substrate. The optimum temperature (60 °C) and pH (9.0), classified the xylanase as thermo and alkali tolerant. The addition of salt of Mn2+ increased the xylanase activity to almost double; however, these ions were unable to protect the enzyme from thermal inactivation. The FTIR spectra of bamboo pulp treated with this xylanase, revealed reduction in lignin as evident from reduced peak intensity coupled with the reduction in kappa number. The SEM image of enzyme treated pulp, exhibited dissociation in fibers exposing the internal structure with slight roughness. Swelling was also observed there by increasing its thickness which eventually helped in improving its physical properties. The bleaching efficacy of indigenous xylanase as indicated in this study, has established its competence as a promising candidate for pre-treating the bamboo pulp.

Disassembly of cell wall polysaccharides accompanied with softening is very common in harvested fruits. To develop a facile postharvest approach, which can be used at ambient temperature, for suppressing softening and maintaining higher nutritive cell wall polysaccharides of Younai plums, influences of paper containing 1-methylcyclopropene (1-MCP) on firmness, activities of cell wall-degrading enzymes, and contents of cell wall polysaccharide in Younai plums during storage at 25 ± 1 °C were investigated. As compared to the control plums, 1.2 μL·L−1 1-MCP-treated plums exhibited higher firmness, lower activities of cell wall-degrading enzymes (pectinesterase, polygalacturonase, cellulase and β-galactosidase), higher contents of cell wall polysaccharides (sodium carbonate-soluble pectin, chelate-soluble pectin, cellulose, and hemicelluloses), and lower content of water-soluble pectin. The results suggested that paper containing 1-MCP, which was convenient to apply under ambient temperature, could significantly inhibit activities of cell wall degrading-enzymes and decrease disassembly of cell wall polysaccharides, and subsequently retard softening in Younai plums.

Hypotheses (1) The equilibrium size and characteristics of a radially wicked fluid on porous material such as paper is expected to be dependent on the fluid properties and therefore could serve as a diagnostic tool. (2) The change in wicked stain size between biological fluids is dependent on a change in solid-liquid surface interfacial energy due to protein adsorption. Experiments Sessile droplets of increasing volume of blood, its components, and model fluids were deposited onto paper and the equilibrium stain size after coming to a halt was recorded. The contact angle of fluid droplets on model cellulose surfaces was measured to quantify the effect that blood protein adsorption at the solid-liquid interface has on radially wicked equilibrium size. Finally the significance of droplet evaporation for the time scale of interest was analysed. Findings The final stain area of all fluids tested on paper scales remarkably linearly with droplet volume. Different fluids were compared and the gradient of this linear relation was measured. Model fluids varying in surface tension and viscosity all behave similarly and exhibit a constant gradient. Blood and its components produce smaller stains, demonstrated by lower gradients. The gradient is a function of protein concentration, thus the mechanism of this phenomenon was identified as protein adsorption at the cellulose-liquid interface. The slope of the area/volume relationship for droplets is an important quantitative mechanistic variable.

Development of a foam-formed cellulose filter paper with high wet strength was carried out for application as a drinking water filter. The wet strength and antimicrobial activity of cellulose foam paper against several bacteria species (Bacillus subtilis MTCC 441 (Gram +ve), B. cereus NCDC 240 (Gram +ve), Pseudomonas aeruginosa NCDC 105 (Gram -ve), Klebsiella pneumonia NCDC 138 (Gram -ve), and Escherichia coli MTCC 40 (Gram -ve)) were investigated. The morphology and structure of the cellulose foam paper were characterized using scanning electron microscopy (SEM). The results of our study confirmed that glutaraldehyde solution or 1,2,3,4-butanetetracarboxylic acid (BTCA) added to cellulose foam paper pretreated with cationic polyacrylamide (C-PAM) provided very high and stable wet strength performance together with excellent antimicrobial properties.

Waste paper, a major fraction of municipal solid waste, has a potential to serve as renewable feedstock for the biorefineries of fuels, chemicals and materials due to rich in cellulose and abundant at low cost. This study evaluates the possibility of waste office paper (WOP) to serve as a potential feedstock for the biorefinery production of poly (3-hydroxybutyrate). In this study, the WOP was pretreated, enzymatically saccharified and the hydrolysate was used for PHB production. The hydrolysate mainly consists of glucose (22.70 g/L) and xylose (1.78 g/L) and the corresponding sugar yield was about 816 mg/g. Ammonium sulphate and C/N ratio 20 were identified as most favorable for high yield of PHB. The batch fermentation of Cupriavidus necator using the pretreated WOP hydrolysate resulted in cell biomass, PHB production and PHB content of 7.74 g/L, 4.45 g/L and 57.52%, respectively. The volumetric productivity and yield achieved were 0.061 g/L/h and 0.210 g/g sugar, respectively. The results suggested that WOP could be a potential alternative feedstock for the biorefinery production of bioplastics.

A visual colorimetric microfluidic paper-based analytical device (μPAD) was constructed following the direct synthesis of enzyme-inorganic hybrid nanomaterials on the paper matrix. An inorganic solution of MnSO4 and KH2PO4 containing a diluted enzyme (glucose oxidase, GOx) was subsequently pipetted onto cellulose paper for the in situ growth of GOx@Mn3(PO4)2 hybrid functional materials. The characterization of the morphology and chemical composition validated the presence of hybrid materials roots in the paper fiber, while the Mn3(PO4)2 of the hybrid provided both a surface for enzyme anchoring and a higher peroxidase-like catalytic activity as compared to the Mn3(PO4)2 crystal that was synthesized without enzyme modulation. This new approach for the in situ growth of an enzyme-inorganic hybrid on a paper matrix eliminates centrifugation and the dry process by casting the solution on paper. The sensing material loading was highly reproducible because of the accuracy and stability of pipetting, which eventually contributed to the reliability of the μPAD. The self-assembled natural and artificial enzyme hybrid on the μPADs specifically detected glucose from a group of interferences, which shows great specificity using this method. Moreover, the colorimetric signal exhibited detection limitation for glucose is 0.01mM, which lies in the physiological range of glucose in biological samples.

Cellulose nanofibril (CNF) paper has various applications due to its unique advantages. Herein, we present the intrinsic mechanical properties of CNF papers, along with the preparation and properties of nanoparticle-reinforced CNF composite papers. The literature on CNF papers reveals a strong correlation between the intrafibrillar network structure and the resulting mechanical properties. This correlation is found to hold for all primary factors affecting mechanical properties, indicating that the performance of CNF materials depends directly on and can be tailored by controlling the intrafibrillar network of the system. The parameters that influence the mechanical properties of CNF papers were critically reviewed. Moreover, the effect on the mechanical properties by adding nanofillers to CNF papers to produce multifunctional composite products was discussed. We concluded this article with future perspectives and possible developments in CNFs and their bionanocomposite papers.

In the present work, lignocellulosic micro/nanofibers (LCMNF) were produced from pine sawdust. For that, pine sawdust was submitted to alkali treatment and subsequent bleaching stages, tailoring its chemical composition with the purpose of obtaining effective LCMNF. The obtained LCMNF were characterized and incorporated to recycled cardboard boxes with the purpose of producing recycled paper. The obtained results showed that it was possible to obtain LCMNF with the same reinforcing potential than those cellulose nanofibers (CNF) prepared by oxidative or other chemical methods In fact, the obtained papers increased the breaking length of recycled cardboard from 3338 m to 5347 m, being a value significantly higher than the requirements to produce paper bags. Overall, the studied strategies could allow a significant reduction of paper basis weight, with the consequent material saving and, thus, contribution to the environment.

Paper-based packaging generally has poor performances in the gas/oil barriers. This work reports a paper-based packaging material prepared via the modification of conventional papers with TEMPO-oxidized cellulose nanofibers (TOCN)/cationic guar gum (CGG) hydrogel film. Specifically, the hydrogel film modification was realized through a layer-by-layer deposition on paper. The hydrogel film modification significantly improved the mechanical and barrier properties of the paper. Specifically, the 4-layer hydrogel film modified paper showed a tensile strength of 34.03 MPa and a burst strength of 510 kPa, respectively. In contrast, the unmodified paper exhibited a tensile strength of 26.78 MPa and a bursting strength of 388 kPa. The packaging performance of this TOCN/CGG hydrogel film modified paper was demonstrated via the fresh mooncake packaging test. Such hydrogel film not only provided the oil resistance, but also maintained the mooncake's freshness. This material can serve as a green and sustainable food packaging.

Radiometric assays have widely been used for measuring protein kinase activity for decades. In addition, several non-radiometric kinase assay formats have been developed over the years, including luciferase-based and fluorescence-based assays. However, radiometric assays are still considered as the "gold standard" for protein kinase assays, because of their direct readout, high sensitivity, reproducibility, reliability, and very low background signals. These radiometric assays rely on P81 phosphocellulose paper to capture the phosphorylated substrate and wash out unreacted [γ-32P] ATP. However, recently the production of P81 was discontinued by the manufacturer, causing major concern within the protein kinase research community. The advantages of radiometric assays over other kinase assay methods call for an urgent alternative to the discontinued P81 paper. In this report, we demonstrate that the LSA-50 paper is a worthy alternative for radiometric protein kinase assays originally using P81 phosphocellulose paper. ispartof: ANALYTICAL BIOCHEMISTRY vol:630 ispartof: location:United States status: published

Cellulose is a naturally occurring organic polymer extracted mainly from lignocellulosic biomass of terrestrial origin. However, the increasing production of seaweeds for growing global market demands has developed the opportunity to use it as an additional cellulose source. This review aims to prepare comprehensive information to understand seaweed cellulose and its possible applications better. This is the first review that summarizes and discusses the cellulose from all three types (green, red, and brown) of seaweeds in various aspects such as contents, extraction strategies, and cellulose-based products. The seaweed cellulose applications and future perspectives are also discussed. Several seaweed species were found to have significant cellulose content (9-34% dry weight). The review highlights that the properties of seaweed cellulose-based products were comparable to products prepared from plant-based cellulose. Overall, this work demonstrates that cellulose could be economically extracted from phycocolloids industrial waste and selected cellulose-rich seaweed species for various commercial applications.

Electron beam irradiation (EBI) is an alternative treatment for intrinsic viscosity (IV) control in cellulose pulps, but has never been integrated in full bleaching sequences for comparison to conventional methods. Both eucalyptus kraft (EK) paper pulp and beech sulfite (BS) dissolving pulp were subjected to totally chlorine free (TCF) bleaching sequences comprising either EBI, ozone, or both for IV control. Additionally, effects of EBI on hexenuronic acid (HexA) and xylan were investigated. IV was adjusted to 450–500 mL g−1 and properties including carbonyl content, kappa, brightness, alkali-resistance and sugar composition were compared. Pulps produced with EBI had a higher alkali-resistance, uniformity and less cellulose oxidation. However, the degree of bleaching (DoB) was low without the use of ozone. HexA content in a birch pulp was halved by EBI. Isolated xylans were more resistant to irradiation than cellulose with little decrease of molar masses and moderate oxidation.

A direct production route of cellulose nanofibers (TOCN-D) from raw wood particles of paulownia using simultaneous bleaching and TEMPO oxidation process was specifically investigated and introduced. For comparison, we prepared cellulose nanofibers (TOCN-C) through a common route of TEMPO oxidation of cellulose fibers, and cellulose nanofibers with disk grinding (GCNF). FE-SEM analysis showed that the average diameter of TOCN-D (5 ± 3 nm) was similar to that of TOCN-C (6 ± 3 nm). XRD results confirmed that the crystal properties of TOCN-D and that of TOCN-C were almost the same. TOCN-D and TOCN-C showed similar chemical, thermal and optical properties in FTIR, TGA and transparency tests, respectively. The nanopaper made from TOCN-D showed high Young's modulus (13.8 GPa) and tensile strength (233 MPa), which were similar to those of TOCN-C nanopaper. Owing the aforementioned similarities, it is concluded that the TOCN-D produced through direct route is a technically, environmental-friendly and economically valuable product.

Luminescent quantum dot (QD) ink is currently a powerful tool for generating hidden information on paper substrates. Herein, we fabricated a nanohybrid ink of bacterial cellulose nanocrystal (BCNC) and UV-responsive ZnO QD via electrostatic self-assembly for improving solvent resistance and message encryption process. Under investigations on the printed areas, the nanohybrid can slightly infiltrate into the paper fibers and form a thin layer on the top of paper substrates, conferring an enhanced print permanence against wetting conditions while maintaining the daylight unobservability and its luminescent stability. The water resistance of the proposed nanohybrid ink enables developing a higher security level that the prints can be submerged in CuCl2 aqueous solutions to quench the luminescent message. The concealed message can eventually be revealed under UV light again after submerging in EDTA solution. Our ZnO QD/BCNC nanohybrid with eco-friendly nature therefore exhibits great potential as security marking ink for counterfeit protection with sustainable uses.

The aim of this study was to prepare cellulose nanowhiskers (CNWs) from wastepaper powder (WPP), as an environmentally friendly approach for obtaining the source material, which is a highly available and low-cost precursor for cellulose nanomaterial processing. Acid hydrolysis and calcification treatments were employed for extraction of CNWs and preparation of novel phospho-calcified cellulose nanowhiskers (PCCNWs). CNWs and PCCNWs were analyzed through optical microscopy (OM), scanning electron microscopy (SEM), Fourier-transformed infrared spectra (FTIR) and X-ray diffraction analysis (XRD). Cell behaviors in the presence of CNWs and PCCNWs were studied by MTT assay and live-dead staining. Finally, the effect of these particles on osteogenic differentiation of stem cells was evaluated based on alkaline phosphatase activity (ALP), calcium mineralization as well as von Kossa and alizarin red staining. Based on the results, PCCNWs had a positive effect on osteogenic differentiation of human mesenchymal stem cells (hMSCs) and can be used for developing new approaches for bone tissue engineering.

Hypothesis Due to their highly retentive properties, innovative recently developed, semi-interpenetrated hydrogels made up of poly(vinyl pyrrolidone) (PVP) chains embedded in a poly(2-hydroxyethyl methacrylate) (p(HEMA)) network should be efficiently used as cleaning material for fragile and degraded paper artworks. In restoration practice, indeed the wet cleaning of these artworks is usually performed by immersion of paper in water, a procedure which may lead to several drawbacks, including paper fibers swelling and dissolution of water-soluble original components. Experiments This class of gels were yet presented in literature, but their interactions with paper materials and ability to be spiked with active enzymes (as cleaning agents), have not been analyzed. To establish the suitability of these hydrogels as paper cleaning materials, first, a rheological and microstructural characterization of the gels was performed. Moreover, diffusion of macromolecules inside gels was studied using fluorescence microscopy, to check if these innovative hydrogels can be used as carriers for hydrolytic enzymes. Indeed, pastes and glues are usually found in old paper artworks, and their removal is a very delicate operation that requires a selective action, which is granted by specific hydrolytic enzymes. At the same time, spectroscopic analyses on paper samples under investigation before and after cleaning treatment has been performed, thus assessing the capabilty of these gels as cleaning materials. Findings With the aim of demonstrating the versatility of these hydrogels, several case studies, i.e., the removal of grime and water-soluble cellulose degradation byproducts, the removal of animal glue and the removal of starch paste from real samples, are presented. Results obtained with these gels have been compared to those obtained by using another gel used for paper artworks cleaning, i.e., Gellan gel.

The main goal of this work was to reinforce softwood pulp (SP) with bacterial cellulose (BC) to generate a sustainable biocomposite. BC is a nanocellulose, which was anticipated to increase interfacial adhesion between the cellulosic fibers and BC. The organism used was Gluconacetobacter xylinus, which was incubated in a static Hestrin-Schramm culture at 28°C for 14days. The specimens of BC, SP and the reinforced SP with BC were characterized using X-ray diffraction (XRD), FT-IR, FESEM, and physico-mechanical testing. The crystallinity index was found to be 83 and 54% for BC and SP, respectively. FT-IR spectra showed that the composition of BC was fully different from that of SP fibers. Based on FESEM images, one can conclude that BC and softwood fibers do form a good combination with a nonporous structure. BC fibers fill in among the softwood fibers in the sheet. The physical and mechanical properties showed that as the dosage of BC increased, the properties of tensile index, tear index, and burst index greatly improved, while the porosity and the elongation decreased. The reason for the improved mechanical properties can be attributed to the increase of interfibrillar bonding which reduced porosity. This would be due to the high aspect ratio of BC that is capable of connecting between the cellulosic fibers and BC nanofibers, enhancing a large contact surface and therefore producing excellent coherence. This study suggests that BC could be a promising material for reinforcing composites at low loading.

This study aims to understand the effect of micro- and nanofibrillated cellulose (MNFC) on the tensile index, softness, and water absorbency of tissue paper. MNFC was produced from four different fiber sources. The results show that MNFC acts as an effective strength enhancer at the expense of a reduced water absorbency and softness. The impact of the fiber source on MNFC manufacturing cost and the trade-off with performance was also investigated. MNFCs produced from southern bleached hardwood kraft, northern bleached softwood kraft, and deinked pulp exhibited similar performance trends with the MNFC from the deinked pulp having a significantly lower cost. This suggests that MNFCs with similar degrees of fibrillation may be used interchangeably regardless of the fiber source, revealing the possibility to minimize MNFC manufacturing costs based on fiber selection. MNFC produced from bleached Eucalyptus kraft showed the lowest degree of fibrillation and the lowest strength improvements among the MNFCs evaluated.

This paper presents the technical–economic and environmental assessment of four lignin extraction processes from two different raw materials (sugarcane bagasse and rice husks). The processes are divided into two categories, the first processes evaluates lignin extraction with prior acid hydrolysis step, while in the second case the extraction processes are evaluated standalone for a total analysis of 16 scenarios. Profitability indicators as the net present value (NPV) and environmental indicators as the potential environmental impact (PEI) are used through a process engineering approach to understand and select the best lignin extraction process. The results show that both economically and environmentally process with sulfites and soda from rice husk presents the best results; however the quality of lignin obtained with sulfites is not suitable for high value-added products. Then, the soda is an interesting option for the extraction of lignin if high quality lignin is required for high value-added products at low costs.

Cellulose oxidative and hydrolytical degradation is one of the greatest problems for the conservation of paper supports. To contrast these degradation processes, both deacidification and reduction of the oxidized functions are needed. Dealing with original documents, it is often impossible to perform the two mentioned treatments in aqueous solutions and in a distinct subsequent way, because of the fragility of the artifacts. After studying, in a separate way, an effective deacidifier (calcium propionate) soluble in ethyl alcohol and many reducers (boron complexes), able to act in different non-aqueous solvents, it was decided to test a simultaneous method of deacidification and reduction in ethanol. This paper presents the chemical-physical results obtained by applying simple deacidification and simultaneous deacidification-reduction on laboratory paper samples that were artificially aged and then re-measured after 10 and 15 years of natural aging. Results show that all alcoholic treatments are very effective: papers are stable also after a long period of both artificial and natural aging.

The upturn of viscose fiber market has triggered an augmented dissolving pulp usage over the last decade. Dissolving pulp is feasible to obtain from kraft pulp after two essential steps including hemicellulose removal and subsequent pulp activation. Prerequisite of conversion being hemicellulose reduction can be gently done by using xylanase treatment prior to alkali extraction. Herein, the significance of xylanase treatment and the optimum xylanase dose required in conjunction with subsequent alkali extraction was investigated. An increase in xylanase dose prior to alkali extraction had no significant effect on pentosans while the Fock reactivity and viscosity both improved at the dose of 50AXU/g. Also, alkali extraction without xylanase pretreatment resulted in decreased Fock reactivity, alpha cellulose, brightness and viscosity of paper grade pulp. A moderate dose of xylanase prior to alkali extraction can thus be used to facilitate the hemicellulose removal while simultaneously protecting the native structure of cellulose.

Bacterial cellulose (BC) samples were obtained using two culture media (glucose and glucose+fructose) and two bacteria (Komagataeibacter rhaeticus and Komagataeibacter hansenii). Nanopaper was obtained from the BC through oxidation and both were studied to determine the impact of culture media and bacteria strain on nanofiber structure and mechanical properties. AFM and SEM were used to investigate fibre dimensions and network morphology; FTIR and XRD to determine cellulose purity and crystallinity; carboxyl content, degree of polymerisation and zeta potential were used to characterise nanofibers. Tensile testing showed that nanopaper has up to 24 times higher Young's modulus (7.39GPa) than BC (0.3GPa). BC displayed high water retention values (86-95%) and a degree of polymerisation up to 2540. Nanofibers obtained were 80-120nm wide and 600-1200nm long with up to 15% higher crystallinity than the original BC. It was concluded that BC is an excellent source for easily obtainable, highly crystalline and strong nanofibers.

An effective method of preparing composites containing inorganic (Ag) and organic (beeswax) particles was established in this study. Ag nanoparticles were first immobilized on the cellulose nanocrystals (CNC) during the reduction of AgNO3 in the presence of CNC, then mixed with beeswax by high speed stirring. Scanning transmission electron microscopy (STEM) images indicated that Ag and beeswax particles were uniformly dispersed and stable in the network structure formed by CNC. Upon coating on a paper surface, a layer of beeswax film was evident based on scanning electron microscopy (SEM) images. The dynamic contact angle and antibacterial activity tests indicated that the contact angle of coated paper reached 113.06° and the growth inhibition of Escherichia coli increased to 99.96%, respectively, at a coating amount of 21.53 g/m(2). When applied onto paper surface by coating, the CNC/Ag/beeswax composites can impact paper with antibacterial property and improved water resistance.

This work reports on the development of a 3D microfluidic paper-based device (3D µPAD) for glucose detection using organic-inorganic hybrid nanoflower technology to immobilize the bi-enzymatic system (glucose oxidase and horseradish peroxidase). The system is based on nanoflowerssupported on cellulose paper (the microreactor zone) coupled to 3,3',5,5'-tetramethylbenzidine (TMB) as the colorimetric probe in the detection zone. We used a digital camera for the quantitative analysis of glucose with the S coordinate of the HSV color space as the analytical parameter. Under optimal operational conditions, linearity was observed for glucose concentrations up to 300 μM, with a detection limit of 15.6 µM. The biosensor is reusable and remains stable for 75 days in conventional storage conditions.

Recycled paper needs a lot of mechanical/chemical treatments for its re-use in the papermaking process. Some of these ones produce considerable rejected waste fractions, such as "screen rejects", which include both cellulose fibers and non-fibrous organic contaminants, or "stickies", these last representing a shortcoming both for the papermaking process and for the quality of the final product. Instead, the accepted fractions coming from these unit operations become progressively poorer in contaminants and richer in cellulose. Here, input and output streams coming from mechanical screening systems of a papermaking plant using recycled paper for cardboard production were sampled and analyzed directly and after solvent extraction, thus confirming the abundant presence of styrene-butadiene rubber (SBR) and ethylene vinyl acetate (EVA) copolymers in the output rejected stream and cellulose in the output accepted one. Despite some significant drawbacks, the "screen reject" fraction could be traditionally used as fuel for energy recovery within the paper mill, in agreement with the integrated recycled paper mill approach. The waste, which still contains a cellulose fraction, can be also exploited by means of the hydrothermal route to give levulinic acid, a platform chemical of very high value added.

Paper-based sensors gained almost explosive attention during the last few years. A large number of systems, often destined to resource limited settings is based on enzymatic reactions. Choice of an adequate immobilization method could significantly prolong the shelf-life of such sensors, especially in applications, where exposure to high temperatures during storage and transport is more than a threat. We are seeking to compare a variety of immobilization methods based on different phenomena (adsorption, entrapment in gel, microencapsulation, covalent linkage), with total of 33 methods tested. Glucose oxidase was used as a model enzyme. Enzymatic activity of immobilized samples was accompanied for a period of 24 weeks considering two sets of samples, one stored in 4 °C and other in ambient temperature.

Carbon-based aerogel fabricated from waste biomass is a potential absorbent material for solving organic pollution. Herein, the lightweight, hydrophobic and porous carbon aerogels (CAs) have been synthesized through freezing-drying and post-pyrolysis by using waste newspaper as the only raw materials. The as-prepared CAs exhibited a low density of 18.5 mg cm(-3) and excellent hydrophobicity with a water contact angle of 132° and selective absorption for organic reagents. The absorption capacity of CA for organic compounds can be 29-51 times its own weight. Moreover, three methods (e.g., squeezing, combustion, and distillation) can be employed to recycle CA and harvest organic pollutants. Combined with waste biomass as raw materials, green and facile fabrication process, excellent hydrophobicity and oleophilicity, CA used as an absorbent material has great potential in application of organic pollutant solvents absorption and environmental protection.

Taking advantage of the self-assembly between the components, novel stable antibacterial nanoparticles were efficiently fabricated via a facile one-step co-polymerization of acrylic acid (AA) and N,N'-methylenebisacrylamide (MBA) on a mixed aqueous solution of poly(hexamethylene guanidine hydrochloride) (PHMG) and hydroxyethylcellulose (HEC). The z-average hydrodynamic diameters of the nanoparticles ranged from 220 nm to 450 nm. The inner layer of the nanoparticles is composed of water-insoluble interpolymer complexes of PHMG and PAA networks, while the outer layer is composed of PHMG and HEC. The nanoparticles are stabilized by electrostatic interactions, hydrogen bonding interactions, and the chemical bonds. The nanoparticle solution remained stable in a wide pH range of 2.0-12.0 and at salt concentrations below 0.25 mol/L. The nanoparticles were incorporated into handsheets using a dipping treatment. The resulted handsheets exhibited excellent antimicrobial activities even after multiple water washing treatments. The nanoparticles are promising in fabricating paper, water-based coatings and textiles with permanent antibacterial activity.

A new concept of composite filler was developed by using cellulose nanofibrils (CNF), precipitated calcium carbonate (PCC) and cationic starch (C-starch). In this study, cellulose nanofibrils were utilized in two different ways: a PCC-CNF composite filler and a papermaking additive in sheet forming. The aim was to elucidate their effects on flocculation, filler retention and the strength and optical properties of handsheets. The highest filler retention was obtained by using the PCC-CNF composite filler in paper sheets. The paper filled with the composite fillers had much higher bursting and tensile strengths than conventional PCC loading. It was also found that the paper prepared with PCC-CNF composite fillers became denser with increasing the filler content of paper.

To better assess the stabilization effects of chemical treatments on Cu(II)-catalyzed cellulose degradation, we developed Cu(II)-containing model rag paper with typical copper corrosion characteristics using e-beam radiation. The paper can be prepared homogeneously and quickly compared to tedious pre-aging methods. Using the Cu(II)-containing model rag paper, the stabilization effects of various chemicals on Cu(II)-catalyzed degradation of cellulose were tested. Benzotriazol was highly effective in retarding the degradation of the Cu(II)-containing model rag paper under hot and humid aging condition, as well as under photo-oxidative stress. Tetrabutylammonium bromide reduced Cu(II)-catalyzed degradation of cellulose, but its efficacy was dependent on the accelerated aging conditions. The results with the alkaline treatments and gelatin treatment suggested that their roles in the degradation mechanisms of cellulose in the presence of Cu(II) differ from those of benzotriazol and tetrabutylammonium bromide.

Paper made of cellulose has the advantages of substantial resource, good biocompatibility, large operation scale, and low production cost, however, it is usually hindered to replace plastic due to its inferior stability to water and poor mechanical strength. Herein, commercial filter paper (FP) was reacted with methylene diphenyl diisocyanate (MDI) to fabricate modified paper with tunable hydrophobicity and enhanced wet tensile strength. Due to the formation of urethane linkages in the reaction, both hydrophobicity and wet mechanical properties can be tuned and improved by varying the MDI cross-linking agent, exhibiting highest water contact angle of 137.0° and wet tensile strength of 4.8 MPa. In addition, the modified MDI-FPs exhibited excellent antibacterial performance against Escherichia coli compared with the original FP. Overall, this study provides a more simple approach to modify cellulose paper to produce versatile cellulose-based materials that can potentially replace the non-biodegradable plastics.

Fluorescent nanoparticles are widely exploited as probes in cell tracking, drug delivery systems and high-performance security devices nowadays. Herein, we report the synthesis of novel 7-acryloxycoumarin (7-AC) through modification reaction of 7-hydroxycoumarin with acryloyl chloride and its copolymerization with methyl methacrylate and glycidyl methacrylate to produce epoxy-functionalized fluorescent polymer nanoparticles through emulsion polymerization. Chemical modification of cellulose pulp papers with the as-prepared fluorescent latex nanoparticles was also assessed. Spherical nanoparticles with average particle size of 40-93 nm and their diffusion into cellulosic fibers with excellent wetting and coating were monitored. Fluorimetery analysis demonstrated that immobilization of 7-AC into the hydrophobic acrylic copolymer substrate enhanced its emission intensity significantly with respect to its molecularly solution due to the elimination of unwanted environmental effects and non-radiative processes such as probable internal conversions. The obtained products exhibited intensified fluorescence emission with potentiality of being used in anticounterfeiting inks and security documents.

Pulp and paper mill sludge is a waste stream derived from the pulp and paper making industry, comprised of organic and inorganic material in the form of cellulose, hemicellulose, lignin and ash. In South Africa, approximately fivefour hundred thousand wet tonnes are produced per annum and is currently disposed via landfilling or incineration. However, these disposal methods raise environmental and financial concerns. This waste stream is an attractive feedstock for fermentable sugars, mainly glucose, recovery and can be redirected for valorisation as a feedstock for microbial fermentation to produce value-added products. Sugar recovery by enzymatic hydrolysis, as opposed to acidic hydrolysis, is a promising approach but is hampered by the lignin and inorganic material found in pulp and paper mill sludge. Several treatment steps to reduce or remove these components prior to enzymatic hydrolysis are assessed in this review. Pretreatment improves hydrolysis of cellulosic fibres and ensures a substantial yield of sugars.