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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., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Here, we designed paper sheets coated with chitosan, bacterial cellulose (nanofibers), and ZnO with boosted antibacterial and mechanical activity. We investigated the compositions, with ZnO exhibiting two different sizes/shapes: (1) rods and (2) irregular sphere-like particles. The proposed processing of bacterial cellulose resulted in the formation of nanofibers. Antimicrobial behavior was tested using E. coli ATCC ® 25922™ following the ASTM E2149-13a standard. The mechanical properties of the paper sheets were measured by comparing tearing resistance, tensile strength, and bursting strength according to the ISO 5270 standard. The results showed an increased antibacterial response (assigned to the combination of chitosan and ZnO, independent of its shape and size) and boosted mechanical properties. Therefore, the proposed composition is an interesting multifunctional mixture for coatings in food packaging applications.

We developed a simple method to achieve semiquantitative detection of an amphiphilic biosample through measuring the length of flow on a microfluidic analytical device (μPAD) based on paper. When an amphiphilic sample was dripped into a straight microchannel defined with a printed wax barrier (hydrophobic) on filter paper (hydrophilic), the length of flow was affected by the reciprocal effect between the sample, the filter-paper channel and the wax barrier. The flow length decreased with increasing concentration of an amphiphilic sample because of adsorption of the sample on the hydrophobic barrier. Measurement of the flow length enabled a determination of the concentration of the amphiphilic sample. The several tested samples included surfactants (Tween 20 and Triton X-100), oligonucleotides (DNA), bovine serum albumin (BSA), human albumin, nitrite, glucose and low-density lipoprotein (LDL). The results show that the measurement of the flow length determined directly the concentration of an amphiphilic sample, whereas a non-amphiphilic sample was not amenable to this method. The proposed method features the advantages of small cost, simplicity, convenience, directness, rapidity (<5 min) and requirement of only a small volume (5 μL) of sample, with prospective applications in developing areas and sites near patients for testing at a point of care (POCT).

Recovery of cellulose fibres from paper mill effluent has been studied using common polysaccharides or biopolymers such as Guar gum, Xanthan gum and Locust bean gum as flocculent. Guar gum is commonly used in sizing paper and routinely used in paper making. The results have been compared with the performance of alum, which is a common coagulant and a key ingredient of the paper industry. Guar gum recovered about 3.86mg/L of fibre and was most effective among the biopolymers. Settling velocity distribution curves demonstrated that Guar gum was able to settle the fibres faster than the other biopolymers; however, alum displayed the highest particle removal rate than all the biopolymers at any of the settling velocities. Alum, Guar gum, Xanthan gum and Locust bean gum removed 97.46%, 94.68%, 92.39% and 92.46% turbidity of raw effluent at a settling velocity of 0.5cm/min, respectively. The conditions for obtaining the lowest sludge volume index such as pH, dose and mixing speed were optimised for guar gum which was the most effective among the biopolymers. Response surface methodology was used to design all experiments, and an optimum operational setting was proposed. The test results indicate similar performance of alum and Guar gum in terms of floc settling velocities and sludge volume index. Since Guar gum is a plant derived natural substance, it is environmentally benign and offers a green treatment option to the paper mills for pulp recycling., (Copyright © 2014. Published by Elsevier B.V.)

The present comment concerns some doubtful results included in the above paper., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

For proper treatment, recycling, or disposal of the pulp and paper mill secondary sludge qualitative and quantitative determination of its characteristics are necessary. Chemical extraction, quantitative characterization, and spectroscopic experiments have been performed to determine the molecular composition and chemical functionality of a pulp and paper mill secondary sludge. In order to extract the low-molecular-weight substances, soxhlet extraction with polar and non-polar solvents was performed where most of the target substances (17±1.3%.) were extracted after 2 hours. Over time, this extraction followed a first-order kinetics. Fiber analyses have shown 12±3% lignin, 28±3% cellulose, and 12±4% hemicelluloses content. The ash content was about 17±0.5%. In this work, 7 and 16% intra- and extracellular polymeric substances, respectively, were extracted from the secondary sludge. EPS and mixture of intra- and extracellular biopolymers have shown similar chemical functionalities. These analyses confirmed that the paper secondary sludge consisted mainly of wood fiber, i.e. lignocellulosic substances, along with proteins and polysaccharides originated from microorganisms.

Much recent research has focused on electrochemical biosensors to meet the growing demands for rapid and accurate diagnostic tests for diseases, detecting toxic molecules present in the environment, and biomolecules used as in pharmaceuticals. Carbon nanotubes (CNTs) have been shown to be effective for electrochemical biosensors because of their favorable chemical, physical and electrical properties. Here we report the use of a two-dimensional entangled mat of CNTs, known as buckypaper, as electrodes for electrochemical biosensors. The buckypaper electrodes exhibit superior sensitivity towards tryptophan, L-carnitine, tyrosine and myoglobin. When engineered with metals or other specific molecules, the buckypaper shows an up to 1000-fold increase in the signal compared with electrodes based on glassy carbon. This enhanced electrochemical performance of the modified buckypaper demonstrates potential for a new platform for electrochemical biosensor technologies.

Nonwoven membranes based on electrospun fibers are of great interest in applications such as biomedical, filtering, and protective clothing. The poor mechanical performance is a limitation, as is some of the electrospinning solvents. To address these problems, porous nonwoven membranes based on nanofibrillated cellulose (NFC) modified by a hydroxyethyl cellulose (HEC) polymer coating are prepared. NFC/HEC aqueous suspensions are subjected to simple vacuum filtration in a paper-making fashion, followed by supercritical CO(2) drying. These nonwoven nanocomposite membranes are truly nanostructured and exhibit a nanoporous network structure with high specific surface area, as analyzed by nitrogen adsorption and FE-SEM. Mechanical properties evaluated by tensile tests show high strength combined with remarkably high strain to failure of up to 55%. XRD analysis revealed significant fibril realignment during tensile stretching. After postdrawing of the random mats, the modulus and strength are strongly increased. The present preparation route uses components from renewable resources, is environmentally friendly, and results in permeable membranes of exceptional mechanical performance.

Assuming dipole-dipole interaction as the dominant relaxation mechanism of protons of water molecules adsorbed onto macromolecule (biopolymer) surfaces we have been able to model the dependences of relaxation rates on temperature and frequency. For adsorbed water molecules the correlation times are of the order of 10(-5)s, for which the dispersion region of spin-lattice relaxation rates in the rotating frame R(1)(ρ)=1/T(1)(ρ) appears over a range of easily accessible B(1) values. Measurements of T(1)(ρ) at constant temperature and different B(1) values then give the "dispersion profiles" for biopolymers. Fitting a theoretical relaxation model to these profiles allows for the estimation of correlation times. This way of obtaining the correlation time is easier and faster than approaches involving measurements of the temperature dependence of R(1)=1/T(1). The T(1)(ρ) dispersion approach, as a tool for molecular dynamics study, has been demonstrated for several hydrated biopolymer systems including crystalline cellulose, starch of different origins (potato, corn, oat, wheat), paper (modern, old) and lyophilized proteins (albumin, lysozyme)., (Copyright © 2010 Elsevier Inc. All rights reserved.)

High-pressure size-exclusion liquid chromatography and infrared microscopy were coupled to investigate the molecular weight and nature of extracellular polymeric substances (EPS) from various activated sludges. Six main families of compounds (proteins, polysaccharides, organic acids, lipids, mineral phases) were found either as a single molecule or as associations. The molecular weight of proteins varied from small (10 kDa) to large (600 kDa) sizes, while all polysaccharides were smaller than 1 kDa. Association of different molecules implied the presence of species large in size. The EPS chromatographic fingerprints of sludge from various origins remained stable in normal operating conditions, but were drastically modified during settling crises. In poor settling conditions, the EPS with smaller molecular sizes always prevailed and large polymers were underrepresented. The EPS identified in activated sludge were collected in a chemical database which provides the basis for comparison of municipal and industrial wastewater treatment plants (WWTP).

Biocompatible materials for the fabrication of tissue substitutes are crucially important in the advancement of modern medicinal biotechnology. These materials, to serve their function, should be similar in physical, chemical, biological, and structural properties to native tissues which they are aimed to mimic. The porosity of artificial scaffolds is essential for normal nutrient transmission to cells, gas diffusion, and cell attachment and proliferation. Nanoscale inorganic additives and dopants are widely used to improve the functional properties of the polymer materials for tissue engineering. Among these inorganic dopants, halloysite nanotubes are arguably the most perspective candidates because of their biocompatibility and functional properties allowing to enhance significantly the mechanical and chemical stability of tissue engineering scaffolds. Here, this vibrant field of biotechnology for regenerative medicine is overviewed., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The past decade has seen a revolution in our understanding of how the cellular environment is organized, where an incredible body of work has provided new insights into the role played by membraneless organelles. These rapid advancements have been made possible by an increasing awareness of the peculiar physical properties that give rise to such bodies and the complex biology that enables their function. Viral infections are not extraneous to this. Indeed, in host cells, viruses can harness existing membraneless compartments or, even, induce the formation of new ones. By hijacking the cellular machinery, these intracellular bodies can assist in the replication, assembly, and packaging of the viral genome as well as in the escape of the cellular immune response. Here, we provide a perspective on the fundamental polymer physics concepts that may help connect and interpret the different observed phenomena, ranging from the condensation of viral genomes to the phase separation of multicomponent solutions. We complement the discussion of the physical basis with a description of biophysical methods that can provide quantitative insights for testing and developing theoretical and computational models., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Natural fibers are available as an essential substitute for synthetic fiber in many applications. However, the sensitivity of Chinese Windmill Palm or Trachycarpus Fortune Fiber (TFF) to water causes low interfacial bonding between the matrix and the fiber and at the end reduces the mechanical properties of the composite product. Alkaline treatment improves mechanical properties and does not affect water absorption. Hence, additional treatment in the coating is required. This study uses alkaline treatment and coating modification using blended chitosan and Acrylated Epoxidized Soybean Oil (AESO). Blend coating between AESO and chitosan is performed to increase water absorption and mechanical properties. TFF water resistance improved significantly after the coating, with water absorption of the alkaline/blend coating-TFF of 3.98 % ± 0.52 and swell ability of 3.156 % ± 0.17. This indicated that blend coating had formed a cross-link of fiber and matrix after alkalization. Thus, the single fiber tensile strength increased due to the alkaline treatment, and water absorption decreased due to the coating. The combination of alkaline treatment and blend coating on TFF brings excellent properties, as shown by the increase in tensile strength in both single fiber test and composite., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Biomass from four different Nordic microalgal species, grown in BG-11 medium or synthetic wastewater (SWW), was explored as inexpensive carbohydrate-rich feedstock for polyhydroxybutyrate (PHB) production via microbial fermentation. Thermochemical pre-treatment (acid treatment followed by autoclavation) with 2% hydrochloric acid or 1% sulphuric acid (v/v) was used to maximize sugar yield prior to fermentation. Pre-treatment resulted in ∼5-fold higher sugar yield compared to the control. The sugar-rich hydrolysate was used as carbon source for the PHB-producing extremophilic bacterium Halomonas halophila. Maximal PHB production was achieved with hydrolysate of Chlorococcum sp. (MC-1) grown on BG-11 medium (0.27 ± 0.05 g PHB/ g DW), followed by hydrolysate derived from Desmodesmus sp. (RUC-2) grown on SWW (0.24 ± 0.05 g PHB/ g DW). Nordic microalgal biomass grown on wastewater therefore can be used as cheap feedstock for sustainable bioplastic production. This research highlights the potential of Nordic microalgae to develop a biobased economy., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Activated sludge (AS) offers great potential for resource recovery considering its high organic and nutrient content. However, low recovery efficiency and high costs are directing the focus toward the high-valuable resource recovery. This study extracted 71.5 ± 5.9 mg/g VSS of alginate-like exopolysaccharides from AS (ALE/AS) and applied it to mortar as a novel biopolymer agent for crack self-healing. With a mortar crack of 120 μm, addition of 0.5 wt% ALE/AS yielded a high crack closure ratio of 86.5 % within 28 days. In comparison to commercial healing agents, marginal flexural strength reduction with ALE/AS addition (17.9 % vs 30.2-50.5 %) was demonstrated. The abundance of COO - group in GG blocks of ALE/AS resulted in a higher cross-link capacity with Ca 2+ , while the reduction of hydrophilic residues (e.g., COO - and OH) after complexation engendered a lower swelling capacity, which facilitated self-healing and flexural strength maintenance. Molecular dynamics (MD) revealed that lower Ca 2+ diffusivity, arising from the stronger electrostatic interactions between the COO - groups and Ca 2+ , resulted in a high Ca 2+ concentration around the cracks, leading to CaCO 3 deposition and healed cracks. The outcomes of this study provided light on ALE-based mortar crack healing and presented a possibility for multi-level AS resource recovery., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Super adsorbents exhibit great potential to remove pollutants from media or store considerable amounts of water, which may undermine the pressure triggered by environmental pollution and shortage of water resources. Super adsorbents made from biopolymers have been an attractive topic because of biodegradability, renewability and outstanding adsorption capacity. Hemicelluloses are a type of biopolymers very abundant in agricultural, forestry and pulping industrial wastes. Hemicellulose-based bio-adsorbents are thriving because the inherent chemical structures and physical properties of hemicelluloses make themselves easy to be processed into matrix materials applicable in super adsorbents. This review summarizes recent studies in hemicellulose-based bio-adsorbents, i.e. hydrogels and activated carbons, from the perspectives of types, applications, fabrication methods, the elements affecting the adsorption performance and the kinetics of adsorption process, which thus helps to further improve the properties of hemicellulose-based bio-adsorbents and to promote the industrial production and utilization of hemicelluloses and hemicellulose-based bio-adsorbents., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Contamination caused by the accumulation of petrochemical-based plastics has reached worrying magnitudes and led to the development of biopolymers as an option to mitigate the problem. This work thus presents a bibliometric analysis of all that concerns the development of such bionanocomposite materials, using ScientoPy and SciMAT software to establish associations between the number of published documents, countries, institutions and most relevant topics. The bionanocomposites topic was found to throw up the biggest number of documents associated (2008) with the different types of raw materials and methods used to obtain nanoparticles and their combination with biopolymeric materials, the result known as a "bionancomposite*". Analysis of the documents related to the application for development of packaging materials from biological molecules, carbohydrate polymers, compounds, conjugates, gels, glucans, hydrogels, membranes, mucilage (source unspecified), mucoadhesives, paper, polymers, polysaccharide, saccharides etc, is also presented, emphasizing mechanical, thermal and barrier properties, which, due to the inclusion of nanoparticles mainly from natural sources of cellulose, show increases of up to 30%. The inclusion of nanoparticles, especially those derived from cellulose sources, generally seeks to increase the properties of bionanocomposite materials. Regarding an increase in mechanical properties, specifically tensile strength, inclusions at percentages not exceeding 10 wt% can register increases that exceed 30% were reported., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Nanostructured materials along with an added value of polymers-based support carriers have gained high interest and considered ideal for enzyme immobilization. The recently emerged nanoscience interface in the form of nanostructured materials combined with immobilized-enzyme-based bio-catalysis has now become research and development frontiers in advance and applied bio-catalysis engineering. With the involvement of nanoscience, various polymers have been thoroughly developed and exploited to nanostructured engineer constructs as ideal support carriers/matrices. Such nanotechnologically engineered support carriers/matrix possesses unique structural, physicochemical, and functional attributes which equilibrate principal factors and strengthen the biocatalysts efficacy for multipurpose applications. In addition, nano-supported catalysts are potential alternatives that can outstrip several limitations of conventional biocatalysts, such as reduced catalytic efficacy and turnover, low mass transfer efficiency, instability during the reaction, and most importantly, partial, or complete inhibition/deactivation. In this context, engineering robust and highly efficient biocatalysts is an industrially relevant prerequisite. This review comprehensively covered various biopolymers and nanostructured materials, including silica, hybrid nanoflower, nanotubes or nanofibers, nanomembranes, graphene oxide nanoparticles, metal-oxide frameworks, and magnetic nanoparticles as robust matrices for cellulase immobilization. The work is further enriched by spotlighting applied and industrially relevant considerations of nano-immobilized cellulases. For instance, owing to the cellulose-deconstruction features of nano-immobilized cellulases, the applications like lignocellulosic biomass conversion into industrially useful products or biofuels, improved paper sheet density and pulp beat in paper and pulp industry, fruit juice clarification in food industry are evident examples of cellulases, thereof are discussed in this work., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The biomedical and therapeutic importance of chitosan and chitosan derivatives is the subject of interdisciplinary research. In this analysis, we intended to consolidate some of the recent discoveries regarding the potential of chitosan and its derivatives to be used for biomedical and other purposes. Why chitosan? Because chitosan is a natural biopolymer that can be obtained from one of the most abundant polysaccharides in nature, which is chitin. Compared to other biopolymers, chitosan presents some advantages, such as accessibility, biocompatibility, biodegradability, and no toxicity, expressing significant antibacterial potential. In addition, through chemical processes, a high number of chitosan derivatives can be obtained with many possibilities for use. The presence of several types of functional groups in the structure of the polymer and the fact that it has cationic properties are determinant for the increased reactive properties of chitosan. We analyzed the intrinsic properties of chitosan in relation to its source: the molecular mass, the degree of deacetylation, and polymerization. We also studied the most important extrinsic factors responsible for different properties of chitosan, such as the type of bacteria on which chitosan is active. In addition, some chitosan derivatives obtained by functionalization and some complexes formed by chitosan with various metallic ions were studied. The present research can be extended in order to analyze many other factors than those mentioned. Further in this paper were discussed the most important factors that influence the antibacterial effect of chitosan and its derivatives. The aim was to demonstrate that the bactericidal effect of chitosan depends on a number of very complex factors, their knowledge being essential to explain the role of each of them for the bactericidal activity of this biopolymer.

We present facile methods to obtain purified sporopollenin exine capsules, and provide mass balances for classical and novel purification procedures. An ionic liquid, tetrabutyl phosphonium hydroxide turned out to be the most effective in removing the intine wall. The sporopollenin capsules were investigated by fluorescent microscopy, AFM, solid-state NMR and infrared Raman spectroscopy. The latter two methods showed that sunflower and rape exines have different proportions of O-aliphatic and aromatic constituents. Purified exine capsules were coated with functionalized fluorophores. The procedures presented in this paper could contribute to further spread of the applications of this hollow, and chemically highly resistant material.

Several technologies have been proposed to preserve fruits and to avoid postharvest losses. The degradation of ethylene produced by the fruits using TiO 2 photocatalysis has shown to be a good option to delay the ripening of fruits. This paper proposed a new application of biopolymers-TiO 2 nanocomposites developed to extend the shelf-life of fruits. Photocatalytic coatings were applied on the expanded polyethylene foam nets to degrade ethylene. Gelatin and hydroxypropyl methylcellulose (HMPC) were tested as hydrophobic and hydrophilic matrices for the TiO 2 incorporation. First, nanocomposite films prepared by casting were evaluated with regards to their photocatalytic properties. Both matrices, which were loaded with 1 wt% TiO 2 , degraded 40% of the ethylene injected in a batch reactor. By Langmuir-Hinshelwood model, ethylene degradation using gelatin-TiO 2 films (k app  = 0.186 ± 0.021 min -1 ) was faster than the HPMC-TiO 2 films (k app  = 0.034 ± 0.003 min -1 ). Then, gelatin-TiO 2 dispersion was applied as a coating on the foam nets by dip coating. The gelatin-TiO 2 bilayer exhibited higher concentration of ethylene degraded per photocatalytic area and photocatalyst mass unit (13.297 ± 0.178 ppmv m 2 [Formula: see text] ) than its film form (18.212 ± 1.157 ppmv m 2 [Formula: see text] ), which makes gelatin-TiO 2 /foam nets a promising composite design for fruit postharvest application., Competing Interests: Declaration of competing interest None., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Modified biopolymer chitosan namely 2-hydroxy-1-naphthaldehyde chitosan (CTS-Nap) has been synthesized for the removal of toxic chromium from aqueous solutions. In an attempt to enhance the adsorption capacity of toxic chromium on the prepared modified biopolymer, magnetic Fe 3 O 4 nanoparticles have been loaded on the modified adsorbent to form the magnetite adsorbent (Fe 3 O 4 @CTS-Nap). The adsorption mechanism of both adsorbents is explored by batch experiments, FT-IR, SEM, TEM, XRD, VSM, and EDS. The optimum adsorption is achieved at pH 1.5 for CTS-Nap and 1.0 for Fe 3 O 4 @CTS-Nap. Pseudo second order illustrated the best description for the adsorption process with correlation coefficient R 2 = 0.999 and the film diffusion or chemisorption is the rate-limiting step. The equilibrium data is analyzed using five isotherm models, the experimental data agreed well with the Freundlich model with a maximum adsorption capacity of 78.12 mg g-1 and 57.14 mg g-1 for CTS-Nap and Fe 3 O 4 @CTS-Nap, respectively. However, this unexpected result revealed that the presence of magnetic nanoparticles does not always enhance the adsorption process and many other factors could control the adsorption process. Generally, these outcomes revealed that the unmagnetite modified adsorbent CTS-Nap have practical greater influence on wastewater treatment management rather than the magnetic modified chitosan Fe 3 O 4 @CTS-Nap., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

An enhancement of environmental concern lately has improved the awareness of researchers in employing eco-friendly solvents for processing biopolymers. Recently, ionic liquids have been utilized to prepare biopolymer blends as they are non-volatile and recyclable. Biopolymers such as cellulose, chitin, chitosan, keratin, lignin, silk, starch, and zein are widely used for the preparation of biopolymer blends via dissolution in ionic liquids, followed by coagulation procedure. In this concise review, three types of ionic liquids based on imidazolium cations combined with different counter anions that are frequently utilized to prepare biopolymer blends are described. Moreover, three types of biopolymer blends that are prepared in ionic liquids were classified, specifically polysaccharide/polysaccharide blends, polysaccharide/polypeptide blends, and polysaccharide/bioplastic blends. The physicochemical properties of biopolymer blends prepared in different imidazolium-based ionic liquids are also concisely reviewed. This paper may assist the researchers in the polymer blend area and generate fresh ideas for future research.

The study of the high-performance of biopolymers and current eco-friendly have recently emerged. However, the micro-behavior and underlying mechanisms during the test are still unclear. In this study, we conducted experimental and numerical tests in parallel to investigate the impact of different xanthan gum biopolymer contents sand. Then, a numerical simulation of the direct tensile test under different tensile positions was carried out. The micro-characteristics of the biopolymer-treated sand were captured and analyzed by numerical simulations. The results indicate that the biopolymer can substantially increase the uniaxial compressive strength and tensile strength of the soil. The analysis of the microparameters demonstrates the increase in the contact bond parameter values with different biopolymer contents, and stronger bonding strength is provided with a higher biopolymer content from the microscale. The contact force and crack development during the test were visualized in the paper. In addition, a regression model for predicting the direct tensile strength under different tensile positions was established. The numerical simulation results explained the mechanical and fracture behavior of xanthan gum biopolymer stabilized sand under uniaxial compression, which provides a better understanding of the biopolymer strengthening effect., Competing Interests: The authors declare no conflict of interest.

Here, firstly lignin sulfonate was produced from sulfite liquor provided by Mazandaran wood & paper industries (Chookam). Then, the role of effective parameters including reaction temperature, duration time, and amounts of pyridine and acetic anhydride respectively as the catalyst and the esterification agent on the acetylation rate of lignin sulfonate were studied and the process parameters were optimized through multiple experiments. In this investigation, using 1 g lignin sulfonate, the effect of various levels of temperature (ranged from room temperature to 140 °C), reaction time (12-72 h), pyridine volume (0-30 mL), and acetic anhydride volume (5-30 mL) were evaluated. Based on the results of several esterification processes, the optimal values of temperature and reaction time were obtained to be 100 °C and 48 h, respectively, and the optimal volumes of acetic anhydride and pyridine were 20 mL (with equal amounts). Besides, the characterization tests of lignin sulfonate and acetylated lignin sulfonate were performed using FT-IR and NMR techniques. Also in this paper, the morphology and crystallinity/amorphicity of lignin sulfonate and acetylated lignin sulfonate were examined using SEM images and XRD patterns., Competing Interests: Declaration of competing interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2020 Elsevier B.V. All rights reserved.)

In this paper, the production and the characterization of poly (lactic) acid (PLA)-based composites containing different amounts (from 10 wt.% to 25 wt.%) of ultra-short cellulose fibers (Arbocel 600 BE/PU) have been investigated. On the basis of a previous study, it was observed that the addition of the cellulose fibers led to an embrittlement of the composite. Consequently, in order to obtain a composite with enhanced impact resistance and elongation at break, the effect of the Einar 101 addition (a bio-based dispersing aid additive) was analyzed. The role of the adhesion between the fiber and the matrix, coupled with a better fiber dispersion, was thus evaluated. Also, the consequences on the final mechanical properties (tensile and impact test) caused by the Einar addition were investigated. Analytical models were also applied in order to obtain an evaluation of the variation of the interfacial shear stress (IFSS) (strictly correlated to the fiber-matrix adhesion) caused by the Einar introduction. Furthermore, due to the very low aspect ratio of the Arbocel fibers, a suitable Bader and Boyer model variation was adopted in order to have a better quantitative estimation of the IFSS value.

All materials respond heterogeneously at small scales, which limits what a sensor can learn. Although previous studies have characterized measurement noise arising from thermal fluctuations, the limits imposed by structural heterogeneity have remained unclear. In this paper, we find that the least fractional uncertainty with which a sensor can determine a material constant λ 0 of an elastic medium is approximately [Formula: see text] for a ≫ d ≫ ξ, [Formula: see text], and D > 1, where a is the size of the sensor, d is its spatial resolution, ξ is the correlation length of fluctuations in λ 0 , Δ λ is the local variability of λ 0 , and D is the dimension of the medium. Our results reveal how one can construct devices capable of sensing near these limits, e.g. for medical diagnostics. We use our theoretical framework to estimate the limits of mechanosensing in a biopolymer network, a sensory process involved in cellular behavior, medical diagnostics, and material fabrication.

Cellulose nanocrystals (CNC) have attracted the attention of many engineering fields and offered excellent mechanical and physical properties as polymer reinforcement. However, their application in composite products with high material demand is complex due to the current production costs. This work explores the use of cellulose microfibers (MF) obtained by a straightforward water dispersion of kraft paper to reinforce polyhydroxyalkanoate (PHA) and polylactic acid (PLA) films. To assess the influence of this type of filler material on the properties of biopolymers, films were cast and reinforced at different scales, with both CNC and MF separately, to compare their effectiveness. Regarding mechanical properties, CNC has a better reinforcing effect on the tensile strength of PLA samples, though up to 20 wt.% of MF may also lead to stronger PLA films. Moreover, PHA films reinforced with MF are 23% stronger than neat PHA samples. This gain in strength is accompanied by an increment of the stiffness of the material. Additionally, the addition of MF leads to an increase in the crystallinity of PHA that can be controlled by heat treatment followed by quenching. This change in the crystallinity of PHA affects the hygroscopicity of PHA samples, allowing the modification of the water barrier properties according to the required features. The addition of MF to both types of polymers also increases the surface roughness of the films, which may contribute to obtaining better interlaminar bonding in multi-layer composite applications. Due to the partial lignin content in MF from kraft paper, samples reinforced with MF present a UV blocking effect. Therefore, MF from kraft paper may be explored as a way to introduce high fiber concentrations (up to 20 wt.%) from other sources of recycled paper into biocomposite manufacturing with economic and technical benefits.

Latent membrane protein 1 (LMP1) is a gene product of the Epstein-Barr virus (EBV), a widely spread virus present in 90-95% of the world's population. EBV can lead to several malignancies, in which LMP1 was shown to play a key role. LMP1 is active only in the oligomeric form and its fifth transmembrane domain (TMD-5) is critical for the oligomerization, with D150 identified as a key residue for LMP1 activation. Here we propose an NMR-based approach to treat the complex oligomerization equilibria with slow conformational exchange. Using this method we investigate the TMD-5 in DPC micelles. We show that the pKa of D150 equals 7.4. Uncharged form of TMD-5 associates into dimers and trimers, deprotonation of D150 induces the high-order oligomerization of the protein and enhances dramatically its trimerization. Pentamidine interacts mainly with the charged TMD-5, destroying the oligomers and stabilizing the monomer and trimer. Using computer simulations we investigate the structural basis of TMD-5/pentamidine interaction. Our data suggest that D150 is likely charged in the full-length LMP1 under native conditions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Biopolymers have generated mounting interest among researchers and industrialists over the recent past. Rising consciousness on the use of eco-friendly materials as green alternatives for fossil-based biopolymers has shifted the research focus towards biopolymers. Advances in technologies have opened up new windows of opportunities to explore the potential of biopolymers. In this context, this review presents a critique on applications of biopolymers in relation to antioxidant and antimicrobial activities. Some biopolymers are reported to contain inherent antioxidant and antimicrobial properties, whereas, some biopolymers, which do not possess such inherent properties, are used as carriers for other biopolymers or additives having these properties. Modifications are often performed in order to improve the properties of biopolymers to suit them for different applications. This review aims at presenting an overview on recent advances in the use of biopolymers with special reference to their antioxidant and antimicrobial applications in various fields., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Controlled release technology has a great potential in pharmaceutical and medical applications to ensure high efficacy of treatment, reduces the aggressive action of the medicines per patient, decreases the cost of treatment and reduces the side effects of the drug as well. In this research, hydrogels from biopolymers were designed for potential use in the drug release systems. The main objective was the manipulation of alginate and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) - oxidized cellulose nanofibers hydrogels crosslinking density by changing the biopolymer and crosslinker concentrations. Rheological measurements of prepared hydrogels were performed to determine the viscosity as a biomedical applicability factor and for determining shear modulus as a basis for theoretical mesh size calculations. The homogeneity of the hydrogel was confirmed by NMR verifying the validity of the mesh size calculations at the same time. In the last stage, the improved mathematical model was developed taking into account the concentration of crosslinker and the concentration of biopolymer in hydrogel as well. The designed model is the first step for the preparation of hydrogels with specific properties., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

New details of chemical structure of Araucaria lignin are the focus of this paper, since Araucaria is a relict plant which fossils are dated by the Permian period. Quantitative chemical analysis, FTIR, EPR and 2D NMR spectroscopies, Py-GC/MS and nitrobenzene oxidation have been used to characterize the Araucaria lignin. This work highlighted the structural features of the lignin of Araucaria, which distinguish it from modern coniferous (gymnosperm) lignins. This lignin exhibits pronounced paramagnetic properties with the concentration of paramagnetic centers of 3.0 × 10 17  spin/g, the value of g-factor of 2.0036 corresponds to the phenoxyl radical. The Araucaria lignin is apparently unique since it does not belong to the known G, GS or GSH types. For the first time it was quantitatively proven that he lignin of Araucaria was assigned to compositionally heterogeneous GH lignins, which is not typical for modern lignins., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The increasing concern about environmental degradation and resource depletion has inspired the analytical chemistry community to develop analytical methods that comply as much as possible with the principles of Green Analytical Chemistry. Significant progress has been made in greening sample preparation strategies by miniaturizing sampling devices and decreasing the amount of sorptive phase needed for efficient extraction of targeted molecules. In this context, the use of natural sorbents represents an additional and convenient option for green sample preparation. The advantages of using natural sorbents for extraction include their availability from renewable sources, low toxicity and biodegradability. In this review, we describe the use of various natural sorbents for metals and organic molecules extraction, focusing on the most innovative applications within the decade 2009-2019. Particular emphasis is given to the description of commonly used biopolymers - e.g. cellulose, chitin, and lignin - and their use in a variety of sample preparation strategies. We also refer to different functionalization approaches that enhance the extraction efficiency of natural sorbents., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Nowadays, many of the tropical fruits have been commercialized worldwide due to increasing demand. In 2018, global tropical fruit has reached an unprecedented peak of 7.1 million tonnes. As such, a lot of large scale farming has been initiated to cultivate the fruit for commercialization. The nature of tropical fruit is perishable make the fruit easily undergo post-harvest losses especially when the fruit travels in a long distance for distribution. Losses of tropical fruit is estimated around 18-28% after harvesting. Then, the losses will continually develop during the trading process. Applying fruit coating on the fruit can minimize substantial privation. This article compendiously reviews the needs of coating and discuss different types of coating materials. The efficiency of different coating materials; polysaccharide, protein, lipid and composite based coating on tropical fruit is highlighted. There are various types of coating available for major fruit such as banana, mango, pineapple and avocado that can effectively extend the post-harvest life, minimize water loss, reduce chilling injuries and fight against post-harvest disease. Coating from minor fruit such as durian, rambutan, passion-fruit and mangosteen are still limited especially made from lipid and protein coating. In choosing the most appropriate coating for tropical, the nature of fruit needs to be understood. In addition, the chemistry of coating components and techniques of application is important in modulating the fruit quality., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Among other polysaccharides, levan is a fructan with great potential in biotechnological applications due to its functional properties. The levan has only been available in small quantities because of its high cost. Here, a levan-producing microorganism was isolated from soil and identified as Pseudomonas mandelii. TGA, SEM, FTIR, 1 H NMR, 13 C NMR and Zetasizer analyses were used to characterize thermal properties and the morphology of the levan. It is the first time, the levan synthesized from P. mandelii is reported as nano sized. The culture conditions were optimized. It is the most comprehensive optimization study regarding levan production of P. mandelii up to the present. The optimum conditions found for levan production were 37 °C, at pH 8, under static conditions, with 15% sucrose and 1.5% mannitol as the C sources and yeast extract as the N source. In addition, the levan production yield was calculated at optimum conditions. Antibacterial activity of levan was evaluated against bacteria and the largest zone of inhibition was observed against E. coli at a concentration of 1000 μg/mL. Antibiofilm activity of levan was evaluated, and we found that all levan concentrations inhibited biofilm formation of all microorganisms in the study. We have shown that the levan from Pseudomonas mandelii induce cytotoxicity breast (MCF-7) cells in a dose-dependent manner., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In a world that canopies numerous opportunities to advance towards a green sustainable life, biopolymer development offers a platform that fits into the paradigm of achieving an eco-friendly environment whilst reducing reliance on the scarce fossil fuel elements for the fabrication of day-to-day products. Today's technological improvements have aided biopolymer end-products to escalate to higher purposes and soon may have their performance level in par with the petroleum-based synthetic polymers. The motive of this paper is to shimmer light on some aspects of biopolymers that include its classes, properties, composites and applications. Depending on the type of class on the basis of various categories, many enthralling chemistries of polymer composition can be substantiated. Essential properties can imparted to the ensuing biopolymer by altering its chemical configuration and method of synthesis while also focusing on its functional purpose. Nowadays, biopolymer composites blend qualities of one biopolymer with another to acquire an enhanced component that showcases unique explicit attributes. There are several techniques to process biopolymer composites, of which in-situ, infiltration and electrospinning methods have captured considerable limelight. Biopolymers and its composites have embarked captivating impressions in regions of biomedical, packaging, agricultural and automotive applications. Although their efficacy is yet to reach their fossil fuel counterparts, biopolymers have laid a distinguishing mark that will continue to inspire creation of novel substances for many years to come., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The stroma is one of the 5 layers of the cornea that comprises more than 90% of the corneal thickness, and is the most important layer for the transparency of cornea and refractive function critical for vision. Any significant damage to this layer may lead to corneal blindness. Corneal blindness refers to loss of vision or blindness caused by corneal diseases or damage, which is the 4th most common cause of blindness worldwide. Different approaches are used to treat these patients. Severe corneal damage is traditionally treated by transplantation of a donor cornea or implantation of an artificial cornea. Other alternative approaches, such as cell/stem cell therapy, drug/gene delivery and tissue engineering, are currently promising in the regeneration of damaged cornea. The aim of tissue engineering is to functionally repair and regenerate damaged cornea using scaffolds with or without cells and growth factors. Among the different types of scaffolds, polymer-based scaffolds have shown great potential for corneal stromal regeneration. In this paper, the most recent findings of corneal stromal tissue engineering are reviewed.

In this review, the recent applications of power ultrasound technology in improving the functional properties and biological activities of biopolymers are reviewed. The basic principles of ultrasonic technology are briefly introduced, and its main effects on gelling, structural, textural, emulsifying, rheological properties, solubility, thermal stability, foaming ability and foaming stability and biological activity are illustrated with examples reviewing the latest published research papers. Many positive effects of ultrasound treatment on these functional properties of biopolymers have been confirmed. However, the effectiveness of power ultrasound in improving biopolymers properties depends on a variety of factors, including frequency, intensity, duration, system temperature, and intrinsic properties of biopolymers such as macromolecular structure. In order to obtain the desired outcomes, it is best to apply optimized ultrasound processing parameters and use the best conditions in terms of frequency, amplitude, temperature, time, pH, concentration and ionic strength related to the inherent characteristics of each biopolymer. This will help employ the full potential of ultrasound technology for generating innovative biopolymers functionalities for various applications such as food, pharmaceuticals, and other industries., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Biopolymer complexes fabricated by proteins and neutral polysaccharides may have some specific or innovative functionalities. However, only little is known about the structural characteristics and molecular interaction mechanisms of proteins-neutral polysaccharides biopolymer complexes. Understanding these informations is of major interest for the design of new proteins-polysaccharides biopolymer complexes with specific and/or innovative functionalities. Thus, the aim of the present study was to investigate the structural characteristics and molecular interaction mechanisms of lactoferrin (LF) and oat β-glucan (OG) with and without heat treatment at different OG concentrations (0.2, 0.5 and 0.9%, w/v). Isothermal titration calorimetry (ITC) results showed that LF and OG could interact with each other. The binding behavior between LF and OG at 25 °C was a spontaneous process, and electrostatic interactions, hydrogen bonding and van der Waals forces contributed to the LF-OG self-assembling behavior. OG concentration influenced the thermodynamic characterization of interactions between LF and OG. LF was susceptible to aggregation and thermal denaturation in the presence of OG. The increased turbidity and particle size of LF-OG complexes suggested the formation of large complexes in aqueous solution. SEM results showed that LF-OG self-assembles exhibited physically cross-linked networks at low OG concentration, while formed some spherical complexes at high OG concentration; LF-OG thermally modified complexes exhibited the honeycomb-like structures with different particle sizes in a concentration-dependent manner. Fluorescence spectroscopy results indicated that OG can change the structure of LF, leading to the exposure of Trp residues of LF molecules toward a more polar microenvironment. Raman difference spectra and circular dichroism revealed that the addition of OG could alter the secondary structure of LF, and the most noticeable changes were in the regions connected β-structures. The apparent viscosity of LF-OG complexes were higher than that of LF or OG alone, indicating that there was synergism between LF and OG. Overall, the self-assembling complexes and thermal complexes of LF and OG can be formed at 25 °C and 90 °C, respectively. These formed LF-OG nanocomplexes and microcomplexes (both the self-assembling and thermal complexes) with unique structures can be widely used in food, pharmaceutical and cosmetic industries, which will be suitable for encapsulation and transportation of bioactive compounds, or as fat substitutes., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Biopolymer composites based on two types of chitosan (chitosan succinate and low-molecular weight chitosan) with single-walled carbon nanotubes (SWCNT) were created by laser printing. SWCNT have good dispersibility in chitosan solutions and therefore, can form relatively homogeneous films that was shown in scanning electron microscopy images. For the studies film composites were formed under the action of laser radiation on aqueous dispersion media. Study of the nonlinear optical process during the interaction of laser radiation with a disperse media has shown that low-molecular chitosan has a large nonlinear absorption coefficient of 17 cm/GW, while the addition of SWCNT lead to a significant increase up to 902 cm/GW. The threshold intensity for these samples was 5.5 MW/cm 2 with nanotubes. If intensity exceeds the threshold value, nonlinear effects occur, which, in turn, lead to the transformation of a liquid into a solid phase. Characterization of films by FTIR and Raman spectroscopy indicated arising molecular interactions between chitosan and SWCNT detected as a small frequency shift and a change in the shape of radial breathing mode (RBM). The results indicate the possibility using aqueous dispersion media based on chitosan and SWCNT to create three-dimensional films and scaffolds for tissue engineering by laser printing., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Great efforts have been devoted to the invention of environmental sensors as the amount of water pollution has increased in recent decades. Chitosan, cellulose and nanocrystalline cellulose are examples of biopolymers that have been intensively studied due to their potential applications, particularly as sensors. Furthermore, the rapid use of conducting polymer materials as a sensing layer in environmental monitoring has also been developed. Thus, the incorporation of biopolymer and conducting polymer materials with various methods has shown promising potential with sensitively and selectively toward heavy metal ions. In this feature paper, selected recent and updated investigations are reviewed on biopolymer and conducting polymer-based materials in sensors aimed at the detection of heavy metal ions by optical methods. This review intends to provide sufficient evidence of the potential of polymer-based materials as sensing layers, and future outlooks are considered in developing surface plasmon resonance as an excellent and valid sensor for heavy metal ion detection.

Hydrogels are cross-linked networks of macromolecular compounds characterized by high water absorption capacity. Such materials find a wide range of biomedical applications. Several polymeric hydrogels can also be used in cosmetics. Herein, the structure, properties and selected applications of hydrogels in cosmetics are discussed in general. Detailed examples from scientific literature are also shown. In this review paper, most common biopolymers used in cosmetics are presented in detail together with issues related to skin treatment and hair conditioning. Hydrogels based on collagen, chitosan, hyaluronic acid, and other polysaccharides have been characterized. New trends in the preparation of hydrogels based on biopolymer blends as well as bigels have been shown. Moreover, biopolymer hydrogels employment in encapsulation has been mentioned.

This paper reports on the preparation, characterization, and photoluminescence properties of novel hybrid materials, in which the EDTA-Ln-L complexes (where L: H 2 O, acac, bzac, dbm, and tta ligands, and Ln: Eu, Gd, and Tb) were covalently linked to the precursor medium molecular weight chitosan surface (CS) matrices or on the chitosan surfaces previously crosslinked with epichlorohydrin (CSech). The emission spectra of these materials were characterized by intraconfigurational-4fN transitions centred on the Eu 3+ and Tb 3+ ions. Some broad bands from the polymeric matrix were also observed in the emission spectra, however the relative intensities of the intraconfigurational bands increased significantly for systems containing diketonate ligands when the antenna effect became more efficient. The values of the radiative rates (A rad ) were higher for crosslinked hybrid systems with epichlorohydrin, while nonradiative rates (A nrad ) presented the opposite behaviour. These data contributed to an increase in the values of emission quantum efficiency (η) for crosslinked materials. The effect of the modification process and antenna ligand on the values of intensities, intensity parameters Ω 2 e Ω 4 of the Eu 3+ complexes were also investigated. The results showed that the crosslinked biopolymer surfaces have great potential for applications in molecular devices light converters., (© 2020 John Wiley & Sons, Ltd.)

Currently, radioactive waste is disposed primarily by burial in a deep geological repository. Microorganisms thriving in such contaminated environment show tolerance to radionuclides. In the present study the bacterial flora, from soil sample collected from an area around atomic power station exposed to radionuclides and heavy metals, was cultivated and assessed for thorium (Th) tolerance. Of all the isolates, strain AM7 identified as O. intermedium was selected since it could thrive at high levels of Th (1000 mg L -1 ). AM7 was characterized physico-chemically and its culture medium was optimized using central composite design of response surface methodology for assessing its growth properties in presence of Th. The strain also showed exceptional exopolysaccharide (EPS) production and its yield was further analyzed using one factor study to investigate the influence of each medium component. On supplementing the EPS medium with Th, no significant decrease in yield was observed. FTIR spectroscopy revealed the functional groups of EPS involved in EPS-Th binding. To the best of our knowledge, this is the first report showing exceptional Th-tolerance by any bacteria. Such study will help other researchers to strategize an environment-friendly way of radwaste disposal., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Polyacrylamide graft Jhingan gum (Jh-g-PAMs) was synthesized adopting microwave assisted graft co-polymerization technique. The synthesized graft copolymer was characterized by various analytical techniques such as Elemental analysis, FTIR, TGA, XRD and NMR. Following standard protocol, drug matrix tablets using 5-Aminosalicylic Acid (5-ASA) were prepared and swelling and erosion studies were carried out in different pH dissolution media. The result revealed that maximum swelling and erosion took place in pH 7.4 while the lowest was recorded in pH 1.2. The 'in vitro' drug release studies revealed that grades with higher grafting % exhibited more sustained release. The highest sustained release was observed in Jh-g-PAM 3 (%G 1231) in pH 1.2 while the least was observed in native gum in pH 7.4. Furthermore, the kinetic studies revealed that 'n' values in all dissolution media lies within 0.5-1.0 which suggested non-Fickian diffusion mode of release. From the above results, it can be said that controlled release of 5-ASA using graft material was successful and hence it can be explored for treatment of colon related diseases., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier B.V.)

Human bones have unique structures and characteristics, and replacing a natural bone in the case of bone fracture or bone diseases is a very complicated problem. The main goal of this paper was to summarize the recent research on polymer materials as bone substitutes and for bone repair. Bone treatment methods, bone substitute materials as well as their advantages and drawbacks, and manufacturing methods were reviewed. Biopolymers are the most promising materials in the field of artificial bones and using biopolymers with the shape memory effect can improve the integration of an artificial bone into the human body by better mimicking the structure and properties of natural bones, decreasing the invasiveness of surgical procedures by producing deployable implants. It has been shown that the application of the rapid prototyping technology for artificial bones allows the customization of bone substitutes for a patient and the creation of artificial bones with a complex structure.

In heterogeneous catalysis, ease of separation of the catalyst is considered to be important for its effective re-use. In this paper, we report a synthesis of carboxymethyl cellulose stabilized cobalt nanoparticles (CMC-Co) catalyst and their coating on the bacterial cellulose nanofibers (BCN) as high surface area support to prepare the CMC-Co-BCN dip-catalyst strips. The samples were characterized by scanning electron microscopy for surface morphology, X-ray diffraction spectrometry for crystal structure and thermogravimetric analysis for the thermal behavior and estimation of the Co content in the CMC-Co-BCN. The CMC-Co-BCN samples were used as dip-catalysts for the 2,6-dinitrophenol and methylene blue dye reduction reactions by sodium borohydride. The catalytic results of CMC-Co-BCN dip-catalyst were compared with the CMC-Co suspension. Both the pollutants were reduced at faster reaction rates by CMC-Co as compared to the CMC-Co-BCN but the latter had advantage of easy recovery for repeated use. The effects of catalyst amount, combination of the two pollutants in a solution, and repeatability tests were also performed and results were discussed., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Electrospun nanofibers are known as the advanced means for wound dressing. They have represented remarkable potency to encapsulate and deliver biomolecules promoting the wound healing process. Compared to synthetic polymers, naturally derived polymers (NDP) are more qualified candidates for fabrication of biomedical electrospun scaffolds. Not only nanofibers of NDP illustrate higher biocompatibility and biodegradability rates, but also they mimic the native extracellular matrix more closely, which leads to the wound closure acceleration by enhancing tissue regeneration. Aside, incorporation of bioactive molecules and therapeutic agents into the nanofibers can generate innovative bioactive wound dressings with significantly improved healing potentials. This paper starts with a brief discussion on the steps and factors influencing the wound healing process. Then, the recent applications of electrospun nanofibers as wound dressing with healing accelerating properties are reviewed. Further, the various healing agents and alternative strategies for modification and functionalization of bioactive naturally-derived electrospun nanofibers are discussed., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background and objectives : Cancer is the second leading cause of death globally, an alarming but expected increase. In comparison to other types of cancer, malignant bone tumors are unusual and their treatment is a real challenge. This paper's main purpose is the study of the potential application of composite scaffolds based on biopolymers and calcium phosphates with the inclusion of magnetic nanoparticles in combination therapy for malignant bone tumors. Materials and Methods: The first step was to investigate if X-rays could modify the scaffolds' properties. In vitro degradation of the scaffolds exposed to X-rays was analyzed, as well as their interaction with phosphate buffer solutions and cells. The second step was to load an anti-tumoral drug (doxorubicin) and to study in vitro drug release and its interaction with cells. The chemical structure of the scaffolds and their morphology were studied. Results: Analyses showed that X-ray irradiation did not influence the scaffolds' features. Doxorubicin release was gradual and its interaction with cells showed cytotoxic effects on cells after 72 h of direct contact. Conclusions : The obtained scaffolds could be considered in further studies regarding combination therapy for malignant bone tumors.