Biopolymer Chitosan Research Articles

Covalent Immobilization of Cellulase Enzyme on Chitosan and Eudragit S-100 Biopolymers for Recovery and Reusability in Denim Fading Application

Covalent Immobilization of Cellulase Enzyme on Chitosan and Eudragit S-100 Biopolymers for Recovery and Reusability in Denim Fading Application

Chemical structure analysis of chitosan-modified road bitumen after de-icing salt treatment

AbstractAsphalt pavements are constantly exposed to many destructive environmental factors including de-icing salts. The problem of the negative effect of salt ions on the performance and consequently the durability of road pavements occurs mainly in temperate climates and regions directly neighboring saline water areas. The salt ions react chemically with the bitumen components, which consequently changes their electronic structure and results in a weakening of the intermolecular interactions occurring between them. Therefore, this study focused primarily on an investigation into the potential for inhibiting the destructive erosion process of bitumen by its modification with chitosan. Studies involving changes in the acidity of the eroding solution as well as chemical and surface properties of the eroded bitumen were carried out for three different salts (NaCl, MgCl2, CaCl2) at varying concentrations, i.e. 5%, 10%, 15% (w/w) after 7 and 28 days of erosion process. Main findings demonstrate that chitosan prevents negative changes in the bitumen physico-chemical properties occurring during the salt erosion process. This effect is especially visible for the bitumen eroded with a solution of MgCl2 and CaCl2. For these salts, chitosan biopolymer reduces the introduction of Cl− ions into the bitumen-building hydrocarbon structures and formation of C–Cl bonds, which is demonstrated by a reduction in the pH changes of the eroding solutions. In addition, chitosan biopolymer inhibits leaching of organic matter from the bitumen, prevents C = O groups formation and reduces the negative effects of de-icing salts on the cohesion energy of the bitumen.

Synthesis and Characterization of Chitosan–Silver Nanocomposite Film: Antibacterial and Cytotoxicity Study

AbstractThis study is aimed at the in situ preparation and antibacterial study of silver nanoparticles within the matrix of an eco‐friendly, biocompatible, biodegradable, and bioavailable biopolymer (chitosan) to form Chi–AgNP film via multiple noncovalent interactions between the organic polymer and the nanoparticles. The film is fully characterized by infrared and ultraviolet spectroscopy, scanning electron microscopy, transmission electron microscopy, X‐ray photoelectron spectroscopy, and thermogravimetric analysis. The characterization confirms the successful incorporation of silver nanoparticles into the polymeric network. Infrared spectroscopy reveals peaks corresponding to the vibration of functional groups present in chitosan with enhanced intensity and blueshifts caused by the presence of silver nanoparticles. Well‐monodispersed spherical silver nanoparticles with an average size of 10 nm are observed in the Chi–AgNP film. The surface plasmon resonance at 447 nm is consistent with a typical silver plasmon. Furthermore, the antibacterial effects on E. coli and S. aureus were determined and attributed to the release of AgNPs observed by UV absorption.

Potential of water-soluble chitosan Schiff bases extracted from Metapenaeus dobsoni shells as effective corrosion inhibitors

Corrosion causes significant economic losses and structural failures in industries, highlighting the need for eco-friendly inhibitors. Chitosan (CS), a biodegradable and non-toxic biopolymer, shows potential, though its limited water solubility restricts its applications. To overcome this challenge, this study presents the synthesis of two water-soluble chitosan Schiff bases (CSBs) derived from the shells of Metapenaeus dobsoni (M. dobsoni). The extracted CS exhibits a remarkable degree of deacetylation exceeding 95 %, which was subsequently modified through reactions with o-vanillin (2-hydroxy-3-methoxybenzaldehyde) (CSB I) and 2,3-dihydroxybenzaldehyde (CSB II). Structural characterization using spectroscopic techniques confirmed the successful formation of CSBs. Electrochemical measurements were employed to assess the corrosion resistance of mild steel in 0.5 M HCl with varying concentrations of CSB I and CSB II. The results revealed superior corrosion inhibition by CSB II (% IE = 94.48 %) compared to CSB I (% IE = 88.80 %). The methoxy group in CSB II contributed to its higher electron density and enhanced adsorption, leading to better surface coverage and corrosion resistance. Both inhibitors followed the Langmuir isotherm, suggesting a mix of physisorption and chemisorption. These CSBs are promising for corrosion control in industries like pipelines, storage tanks, construction materials, and acid pickling.

Dual Loading of Trans-Cinnamaldehyde and Either Paclitaxel or Curcumin in Chitosan Nanoparticles: Physicochemical Characterization and Biological Evaluation Against MDCK and HeLa Cells.

Biopolymer chitosan sub-micron particles (CSMPs) were prepared by the ionic gelation technique crosslinked with sodium tripolyphosphate co-loaded with trans-cinnamaldehyde (TCIN), and either curcumin (CUR) or paclitaxel (PTX). The size of the spherical CSMPs increased from 118 nm to 136 nm and 170 nm after the loading of TCIN and CUR, whereas the loading of PTX led to a slight decrease (114 nm). Polydispersity indexes of all the samples were smaller than 0.4, indicating monodisperse particles. Zeta potential values higher than +40 mV were determined, which is direct proof of the high stability of these nanoparticles. TCIN and PTX release studies in vitro, at pH 6.5 and 7.4, showed a pH dependence on the release rate with a higher value at pH 6.5. However, CUR was not released from CSMPs probably due to strong interactions with CS biopolymer chains. Cytotoxicity studies showed that the systems loaded with TCIN and PTX were more cytotoxic for HeLa cancer cells than for MDCK cells. Moreover, a synergistic effect against HeLa cells was observed for the TCIN-PTX-loaded CSMP samples. The Sensitivity Index indicated that the CSMPs loaded with TCIN have a prospective attraction to carry and release conventional or new chemotherapeutic drugs. This study demonstrates the in vitro efficiency of the obtained drug delivery system, but in vivo studies are necessary to confirm its potential for clinical applications.

Adsorption of amoxicillin by chitosan and alginate biopolymers composite beads.

Due to its widespread use and incomplete breakdown in the human body, amoxicillin has been detected in receiving water bodies. This raises significant concerns, like the promotion of antibiotic resistance, toxicity towards aquatic life, disruption of the natural balance of microbial communities within these water bodies, and the struggle of effectively removal by the traditional wastewater treatment plants. Consequently, exploring new processes to complement the existing methods is crucial. Adsorption, a promising highly efficient, selective, and versatile technique, can effectively remove contaminants, making it useful in various industries such as water treatment, pharmaceuticals, and environmental remediation. Several adsorbents are documented in the literature for drug adsorption; however, their fabrication often involves more complex steps and substances compared to chitosan and alginate, which are natural polymers that are biocompatible, non-toxic, and biodegradable. Their tunable properties and ease of modification enhance their efficacy in environmental remediation. Therefore, the novelty of this article is to understand the interaction of amoxicillin with chitosan and alginate adsorbents easily synthetized using the dripping technique. This approach allows us to explore basic principles that can be applied to more complex systems in future studies. The optimal pH for both beads was found to be 4, with adsorption capacities of 74.2 ± 0.3mgg-1 for alginate and 80.4 ± 0.2mgg-1 for chitosan, using 1g of adsorbent. Kinetics studies indicated that external diffusion governs adsorption for alginate, while internal diffusion governs adsorption for chitosan. This approach underscores the potential of chitosan and alginate beads as effective adsorbents for mitigating antibiotic contamination in water systems, offering a sustainable complement to traditional treatment methods.

ZrO2 nanoparticle embedded reusable and self-standing biopolymeric membrane for efficient piezodynamic eradication of gram-positive and gram-negative coliform bacteria

Bacterial infections pose a significant global threat, especially with the increasing prevalence of antibiotic resistance and multidrug resistance (MDR). To address this challenge, dynamic antibacterial therapies are becoming increasingly important, with piezodynamic therapy emerging as a particularly promising approach due to its non-invasive nature and quick response using mechanical stimuli to target bacterial contaminations. This study, probably for the first-time, introduced an advanced piezo-active membrane, ZrO2 nanoparticle-loaded chitosan biopolymer (ZO@CHS), which utilized piezodynamic therapy to combat both Gram-positive (E. faecalis) and Gram-negative (E. coli) coliform bacteria. By combining the biocompatibility of chitosan with the enhanced physiochemical properties of ZrO2, this self-supporting and non-toxic highly polarized bio-nanocomposite (ZO@CHS) membrane generated a significant piezo-voltage of 4.47 V upon finger tapping and promoted cellular adhesion while enhancing reactive radicals’ production under mild ultrasound (∼15 kHz), eliminating over 96 % of E. coli and 97 % E. faecalis within just 20 minutes, which corroborated well with the statistical analysis. Detailed study, including reactive oxygen species (ROS) assessment through Photoluminescence spectroscopy and bacterial FESEM examination, provided insights into the underlying mechanism. Additionally, the membrane’s robust structure and hydrophobic properties allow for cyclic reuse, retaining over 95 % effectiveness after five cycles. Furthermore, the superior biocompatibility of the membrane, evidenced by a minimal haemolysis rate of 0.11 %, making it suitable for potential in vivo applications. Thus, this novel membrane presented promising applications in healthcare systems and pigment industries, serving as a self-cleaning material.

Effects of Chitosan and N-Succinyl Chitosan on Metabolic Disorders Caused by Oral Administration of Olanzapine in Mice.

The issue of human mental health is gaining more and more attention nowadays. However, most mental disorders are treated with antipsychotic drugs that cause weight gain and metabolic disorders, which include olanzapine (OLZ). The search for and development of natural compounds for the prevention of obesity when taking antipsychotic drugs is an urgent task. The biopolymer chitosan (Chi) and its derivatives have lipid-lowering and anti-diabetic properties, which makes them potential therapeutic substances for use in the treatment of metabolic disorders. The purpose of this work was to analyze the effect of the natural biopolymer Chi, its derivative N-succinyl chitosan (SuChi), and Orlistat (ORL) as a control on the effects caused by the intake of OLZ in a mouse model. Mice were fed with pearl barley porridge mixed with OLZ or combinations OLZ + Chi, OLZ + SuChi, or OLZ + ORL for 2 months. The weight, lipid profile, blood chemokines, expression of genes associated with appetite regulation, and behavior of the mice were analyzed in dynamics. For the first time, data were obtained on the effects of Chi and SuChi on metabolic changes during the co-administration of antipsychotics. Oral OLZ increased body weight, food and water intake, and glucose, triglyceride, and cholesterol levels in blood. ORL and SuChi better normalized lipid metabolism than Chi, decreasing triglyceride and cholesterol levels. OLZ decreased the production of all chemokines tested at the 4th week of treatment and increased CXCL1, CXCL13, and CCL22 chemokine levels at the 7th week. All of the supplements corrected the level of CXCL1, CXCL13, and CCL22 chemokines but did not recover suppressed chemokines. SuChi and ORL stimulated the expression of satiety associated proopiomelanocortin (POMC) and suppressed the appetite-stimulating Agouti-related protein (AgRP) genes. All supplements improved the locomotion of mice. Taken collectively, we found that SuChi more than Chi possessed an activity close to that of ORL, preventing metabolic disorders in mice fed with OLZ. As OLZ carries positive charge and SuChi is negatively charged, we hypothesized that SuChi's protective effect can be explained by electrostatic interaction between OLZ byproducts and SuChi in the gastrointestinal tract.

Chitosan pyrolysis in the presence of a ZnCl2/NaCl salts for carbons with electrocatalytic activity in oxygen reduction reaction in alkaline solutions.

The one-step carbonization of low cost and abundant chitosan biopolymer in the presence of salt eutectics ZnCl2/NaCl results in nitrogen-doped carbon nanostructures(8.5 wt.% total nitrogen content). NaCl yields the spacious 3D structure, which allows external oxygen to easily reach the active sites for the oxygen reductionreaction (ORR) distinguished by their high onset potential and the maximum turnover frequency of 0.132 e site⁻1s⁻1. Data show that the presence of NaCl during the synthesis exhibits the formation of pores having large specific volumes and surface(specific surface area of 1217 m2g-1), and holds advantage by their pores characteristics such as their micro-size part, which provides a platform for mass transport distribution in three-dimensional N-doped catalysts for ORR. It holds benefit over sample pre-treated with LiCl in terms of the micropores specific volume and area, seen as their percentage rate, measured in the BET. Therefore, the average concentration of the active site on the surface is larger.

Antifouling activity of PEGylated chitosan coatings: Impacts of the side chain length and encapsulated ZnO/Ag nanoparticles

PEGylation is regarded as a common antifouling strategy and the effect is normally linked with surface hydrophilicity of the coatings. Herein, the biopolymer chitosan (CS) was grafted by polyethylene glycol (PEG) of different chain lengths (molecular weight 200, 4 k and 100 k Da) to verify if the hydrophilicity of CS-PEG coatings is crucial in determining antifouling activities and if PEG chain length influences biofouling in marine environment. Properties of copolymers such as melting points and crystallinity are affected by grafting PEG. The water contact angle (WCA) of CS-PEG coatings increases with the chain length of grafted PEG, from 27° to 58°. Photocatalyst of zinc oxide-silver (ZnO/Ag) was also studied and its embedment (2 % to CS-PEG) renders the surface of CS-PEG coatings more hydrophobic with WCA increased from 52° to 86°. Antibacterial, anti-diatom, and anti-biofilm activities of the coatings were evaluated in natural sea water. The bacterial density on CS-PEG coatings was dramatically reduced to 4 × 104 compared to the control of 7 × 104 ind/mm2, and further to 2 × 104 for CS-PEG-ZnO/Ag coatings. CS-PEG coatings also strongly inhibit diatoms (120–200 ind/mm2), but the inclusion of ZnO/Ag did not obviously enhance such effect (50–150 ind/mm2). The findings provide useful insights for designing polymer-based antifouling coatings.

Impact of biopolymer-based Trichoderma harzianum seed coating on disease incidence and yield in oilseed crops

The use of microbe-based biological control for crop pests is recognized as an environmentally safe substitute for conventional chemical pesticides. However, the practical application of microbial inoculants in large-scale agriculture is underexplored, impeding their widespread commercial adoption. This study addresses the scarcity of research on effective delivery methods for microbial inoculants, particularly through seed coating, which has the potential to be a cost- and time-efficient strategy in crop management. In this research, the Trichoderma harzianum strain Th4d, a biological control agent (BCA), was incorporated into specially formulated biopolymeric compositions based on chitosan and cellulose. The efficacy of this seed coating approach was tested against various soil- and seed-borne pathogens in oilseed crops, including soybean, groundnut, and safflower. Results indicate that safflower treated with the biopolymer chitosan-based T. harzianum Th4d 1 % liquid formulation blend exhibited a higher seed yield of 793 kg/ha, seed germination of 84.7 %, and a significant reduction in wilt and root rot by 64.7 %. In groundnut crops, the seed coating led to a seed germination rate of 88.6 %, a 72 % reduction in root rot incidence, and a seed yield of 3040 kg/ha. Similarly, soybean crops treated with the biopolymer chitosan and T. harzianum Th4d displayed 83.4 % seed germination, a 70.9 % reduction in root rot, and a seed yield of 1239 kg/ha. Further on-farm evaluations demonstrated promising results, with the biopolymer chitosan-based T. harzianum Th4d 1 % liquid formulation blend seed treatment showing a high incremental cost-benefit ratio in safflower (1:4.5), soybean (1:2.5), and groundnut crops (1:3.3). This study underscores the potential of microbe-based seed coating as a sustainable and economically viable strategy for pest management in oilseed crops."

A new methacrylate-chitosan based blend and its ZnO containing nanocomposites: Investigation of thermal and biological properties.

Biobased materials are an important step towards a sustainable future. The need for these materials, which stand out in terms of their environmental and economic benefits, is increasing daily. This study includes the production of new bio based nanocomposites containing a blend of biopolymer chitosan (CS) and synthetic polymethacrylate derivative poly(2-oxo-2-(3,4,5-trifluoroanilino)ethyl-2-methylprop-2-enoate)(POTFAMA) and biosynthesized zinc oxide nanoparticles (ZnO NPs) by hydrothermal method. POTFAMA, POTFAMA-CS blend, and POTFAMA-CS/ZnO nanocomposites were characterized by FTIR, XRD, SEM, EDX, and TEM techniques. The thermal properties of the materials were determined by TGA and DSC. While POTFAMA reduced the thermal stability of CS, ZnO NPs incorporated into POTFAMA-CS blend increased the thermal stability. POTFAMA-CS blend had a single glass transition temperature (Tg) value at 116°C. The Tg of CS, which was 93°C, increased by 23°C after blending with POTFAMA, and by 34°C with the incorporation of 7% ZnO NPs. The biological properties of the prepared materials have been meticulously investigated. The inhibition zone of CS against C. albicans was 10.66±1.19mm, while that of the POTFAMA-CS blend was 13.70±1.54mm. After standard BHT at a concentration of 120μg/mL, the highest DPPH inhibition percentages belonged to POTFAMA (60.56%) and POTFAMA-CS (52.99%). It was detected that the wound closure rates of POTFAMA (17.51±0.75%) and POTFAMA-CS (15.51±2.52%) were better than the characteristics of CS wound closure (13.61±2.01%). The results suggest that POTFAMA-CS may be a good alternative as a wound-healing agent. Furthermore, nanocomposites containing 5% and 7% ZnO NPs can be an alternative material in healthcare due to their higher antimicrobial activity.

Ionic liquid supported chitosan-g-SPA as a biopolymer-based single ion conducting solid polymer electrolyte for energy storage devices

This article discusses the preparation of different grades of single-ion conducting quasi-solid polymer electrolytes (q-SPE) material (Chit-g-SPA-IL) based on biopolymer (chitosan), polyacrylic acid and DBU-acetate (DBUH+ AcO−) ionic liquid. Chit-SPA-60 %-IL exhibited the highest conductivity within the range of 10−4 S/cm. TGA analysis demonstrated the stability of electrolytes up to a temperature of 120 °C. SEM-EDS analysis unveiled the porous nature of the electrolyte and even distribution of ions throughout the matrix. It exhibited an electrochemical stability window (EWS) of 2.53 V with significant current density and an ionic transference number (ITN) of ~99.9 %. The temperature-dependent conductivity established an Arrhenius-type conduction mechanism with an activation energy of 0.149 eV for ion movement within the electrolyte matrix. The AC conductivity analysis emphasized the time-temperature independence of the ionic conduction mechanism. Dielectric analysis highlighted the capacitive nature of the electrolyte, underlining its substantial capacitance, while modulus studies indicated minimal influence from the electrode-electrolyte interface. Chit-SPA-60 %-IL at 30 °C included a self-diffusion coefficient of 4.57 × 10−5 m2/s, ionic mobility of 1.75 × 10−3 m2/Vs, and drift ionic velocity of 0.44 m/s. These findings makes SPE as a promising candidate for sodium-ion-based energy storage devices.

Polyion Hydrogels of Polymeric and Nanofibrous Carboxymethyl Cellulose and Chitosan: Mechanical Characteristics and Potential Use in Environmental Remediation.

Recently, cellulose and other biomass nanofibers (NFs) have been increasingly utilized in the design of sustainable materials for environmental, biomedical, and other applications. However, the past literature lacks a comparison of the macromolecular and nanofibrous states of biopolymers in various materials, and the advantages and limitations of using nanofibers (NF) instead of conventional polymers are poorly understood. To address this question, hydrogels based on interpolyelectrolyte complexes (IPECs) between carboxymethyl cellulose nanofibers (CMCNFs) and chitosan (CS) were prepared by ele+ctrostatic cross-linking and compared with the hydrogels of carboxymethyl cellulose (CMC) and CS biopolymers. The presence of the rigid CMCNF altered the mechanism of the IPEC assembly and drastically affected the structure of IPEC hydrogels. The swelling ratios of CMCNF-CS hydrogels of ca. 40% were notably lower than the ca. 100-300% swelling of CMC-CS hydrogels. The rheological measurements revealed a higher storage modulus (G') of the CMCNF-CS hydrogel, reaching 13.3 kPa compared to only 3.5 kPa measured for the CMC-CS hydrogel. Further comparison of the adsorption characteristics of the CMCNF-CS and CMC-CS hydrogels toward Cu2+, Cd2+, and Hg2+ ions showed the slightly higher adsorption capacity of CMC-CS for Cu2+ but similar adsorption capacities for Cd2+ and Hg2+. The adsorption kinetics obeyed the pseudo-second-order adsorption model in both cases. Overall, while the replacement of CMC with CMCNF in hydrogel does not significantly affect the performance of such systems as adsorbents, CMCNF imparts IPEC hydrogel with higher stiffness and a frequency-independent loss (G″) modulus and suppresses the hydrogel swelling, so can be beneficial in practical applications that require stable performance under various dynamic conditions.

Sodium alginate- and chitosan-based hydrogels with different network charges for selective removal of cationic and anionic dyes from water

ABSTRACT The grafting of chitosan (CH) and sodium alginate (SA) biopolymers with glycidyl methacrylate (GMA) and acrylamide (AAm) monomers, combined with graphene oxide (GO), led to the formation of bio-based hydrogels. These hydrogels, named CH -GO -hydrogel (GO/CH-g-poly (AAm-co-GMA)), CH -GO -hydrogel (CH-g-poly (AAm-co-GMA)), SA -GO -hydrogel (GO/SA-g-poly(AAm-co-GMA)), and SA -hydrogel (SA-g-poly(AAm-co-GMA)), were tested as selective dye adsorbents. While the chitosan-based hydrogels exhibited positive zeta potential values ranging from +27.5 to +0.1 mV, alginate-based samples had negative values between −10.4 to −41.7 mV in pH conditions from 3.0 to 9.0. Adding GO nano-fillers reduced the swelling capacity of both hydrogels, with water absorption (WA) values for SA -GO -hydrogel and SA -hydrogel recorded at 10.1 and 22.2 g/g, respectively. The ability of these materials to adsorb dyes, specifically crystal violet (cationic) and Congo red (anionic), was confirmed. Factors such as adsorbent dosage, initial pH, dye concentration, shaking time, and temperature were analyzed to determine dye adsorption capacity. Interestingly, the pristine hydrogels, free of GO, performed better than their nanocomposite counterparts. Adsorption capacities (qm) for crystal violet and Congo red with SA -hydrogel, SA -GO -hydrogel, CH -hydrogel, and CH -GO -hydrogel was 909.1, 714.3, 454.5, and 400.0 mg/g, respectively.

Application of chitosan/acid-treated biomass composite for dye wastewater treatment: Adsorption modeling using Box-Behnken Design

The use of chitosan polymer and acid-treated biomass composite as an eco-friendly and cost-effective solution for the removal of synthetic dyes from wastewater is a promising approach for sustainable wastewater treatment. The objective of the present investigation was to create a biocomposite (subsequently referred to as CHI/SFH-SA) by functionalizing chitosan (CHI) biopolymer with acid-treated biomass (sunflower husks-sulphuric acid (H2SO4), SFH-SA). Methods such as pHpzc, XRD, CHNS-O, FTIR, BET, and FESEM were employed to investigate the physicochemical properties of CHI/SFH-SA. The CHI/SFH-SA biocomposite's ability to eliminate brilliant green (BG) dye from aquatic systems was evaluated. To optimize the adsorption efficacy of CHI/SFH-SA, the Box-Behnken Design (BBD) was implemented. The design took into account parameters such as A: CHI/SFH-SA dose (0.02–0.08 g), B: pH (4–10), and C: time (10–60 min). The BBD model results showed that an optimal pH of 9.2, a contact duration of 59.1 min, and a CHI/SFH-SA dosage of 0.061 g were found to be the most effective conditions for achieving maximal BG dye elimination (95.89 %). The Langmuir and Freundlich models agree with the experimental data on BG dye adsorption by CHI/SFH-SA. Negative ΔG° values (−10.67, −12.09, −13.51, −14.93 kJ/mol) indicate spontaneous adsorption. Endothermic adsorption can be estimated with a positive ∆H° value of 31.65 kJ/mol. The adsorption capacity of CHI/SFH-SA was 485.56 mg/g. H-bonding, n-π interactions, and electrostatic forces are the primary factors responsible for the significant adsorption of BG dye onto CHI/SFH-SA. This research offers an environmentally conscious and sustainable approach to fabricating effective adsorbents, thereby establishing a foundation for developing bioadsorbents derived entirely from bioresources (chitosan and biomass), which hold great promise as a substitute for cationic dye removal.

Gastrointestinal-inert prebiotic micro-composites improve the growth and community diversity of mucosal-associated bacteria.

The process of microencapsulation and the development of microparticle-based drug formulations have gained increased pharmaceutical interest, particularly for drug delivery and bacterial-encapsulation purposes for probiotic delivery. Existing studies have examined microcomposite (MC) responses to gastrointestinal (GI) conditions with the aim of controlling disintegration, and thus release, across the small and large bowel. However, the delivery of MCs which remain intact, without degrading, could act as bacterial growth scaffolds or materials providing a prebiotic support, conferring potentially beneficial GI health properties. This present study employs prilling as a method to produce a portfolio of MCs using a variety of biopolymers (alginate, chitosan, pectin and gellan gum) with a range of MC diameters and density compositions. Fluorescent probes are co-encapsulated within each MC to enable flow-cytometry directed release profile assessments following exposure to chemical simulated gastric and intestinal digestion conditions. We observe that MC size, gel-strength, density, and biopolymer material all influence response to gastric and intestinal conditions. Gellan gum (GG) MCs demonstrated complete resistance to disintegration throughout GI-simulation in the stomach and small intestine. Considering these MCs could reach the colon intact, we then examined how such MCs, doped with prebiotic growth supporting carboxymethyl cellulose (CMC) polymers, could impact microbial communities using a bioreactor model of the colonic microbiome. Following supplementation with GGCMC MCs, mucosal bacterial diversity (using 16 s rRNA sequencing and Shannon entropy and observed feature diversity metrics) and taxonomic composition changes were observed. Concentrations of short chain fatty acid (SCFA) metabolites were also found to be altered. This is the first study to comprehensivelyexamine how MC physicochemistry can be manipulated to tailor MCs to have the desired GI release performance and subsequently, how GI-resistant MCs could have influential microbial altering properties and be adopted in novel prebiotic strategies.

Assembly of Chitosan/Caragana Fibers to Construct an Underwater Superelastic 2D Layer-Supported 3D Architecture for Rapid Congo Red Removal.

Developing environmentally friendly bulk materials capable of easily and thoroughly removing trace amounts of dye pollutants from water to rapidly obtain clean water has always been a goal pursued by researchers. Herein, a green material with a 3D architecture and with strong underwater rebounding and fatigue resistance ability was prepared by means of the assembly of biopolymer chitosan (CS) and natural caraganate fibers (CKFs) under freezing conditions. The CKFs can randomly and uniformly distribute in the lamellar structure formed during the freezing process of CS and CKFs, playing a role similar to that of "steel bars" in concrete, thus providing longitudinal support for the 3D-architecture material. The 2D layers formed by CS and CKFs as the main basic units can provide the material with a higher strength. The 3D-architecture material can bear the compressive force of a weight underwater for multiple cycles, meeting the requirements for water purification. The underwater compression test shows that the 3D-architecture material can quickly rebound to its original shape after removing the stress. This 3D-architecture material can be used to purify dye-containing water. When its dosage is 3 g/L, the material can remove 99.65% of the Congo Red (CR) in a 50 mg/L dye solution. The adsorption performance of the 3D architecture adsorbent for CR removal in actual water samples (i.e., tap water, seawater) is superior than that of commercial activated carbon. Due to its porous block characteristics, this material can be used for the continuous and efficient treatment of wastewater containing trace amounts of CR dye to obtain pure clean water, meaning that it has great potential for the effective purification of dye wastewater.

Advanced biopolymer-based Ti/Si-terephthalate hybrid materials for sustainable and efficient adsorption of the tetracycline antibiotic

This study involves the synthesis of an organic-inorganic hybrid material consisting of Ti/Si-terephthalate (Ti-TPA-Si) in a 1:1:1 ratio using sol-gel method and its reaction with cellulose and chitosan (Ti-TPA-Si-C and Ti-TPA-Si-CS). Characterization techniques such as XRD, FTIR, SEM, EDS, XPS, BET, TGA, and DTA were used. The incorporation of biopolymers (cellulose and chitosan) into the Ti/Si-terephthalate structure improved the morphology and textural properties of the hybrid materials, leading to increased adsorption capacity and sustainability. Adsorption experiments reveal that Ti-TPA-Si, Ti-TPA-Si-C, and Ti-TPA-Si-CS hybrid materials exhibit a high affinity towards tetracycline, achieving remarkable adsorption efficiencies of 88.27, 89.60, and 88.98 %, respectively. Isotherm studies indicate that the adsorption process follows both Langmuir (R2 = 0.971, 0.990, and 0.994) and Dubinin-Radushkevich (R2 = 0.922, 0.965, and 0.949) isotherm models. According to the Langmuir model, the maximum adsorption capacity (qm) of Ti-TPA-Si, Ti-TPA-Si-C, and Ti-TPA-Si-CS adsorbents was found to be 24.10, 33.56, and 26.59 mg/g, respectively. Kinetic studies indicate that the adsorption process follows both pseudo-second-order (R2 = 0.998, 0.984, and 0.989) and intra-particle diffusion (R2 = 0.995, 0.994, and 0.988) models. Thermodynamic studies reveal that adsorption processes are spontaneous and endothermic in nature. Reusability studies demonstrate their potential for repeated use without significant loss in performance.

Biomedical applications of chitosan-coated phytogenic silver nanoparticles: An alternative drug to foodborne pathogens

The biogenic synthesis of silver nanoparticles (AgNPs) was performed using crude rosmarinic acid (RA) from plants as a reducing agent and coated with chitosan biopolymer. The prepared particles were characterized by ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). A surface plasmon resonance peak at 430 nm indicates the emergence of AgNPs. XRD showed that the AgNPs were crystalline with an average crystalline size of 30 nm and TEM studies revelad that AgNPs were spherical without aggregation. The prepared CS-AgNPs exhibited good bactericidal properties against foodborne pathogens, such as Escherichia coli, Pseudomonas aeruginosa, and Vibrio parahaemolyticus. In particular, 100 μg/mL CS-AgNPs inhibited the growth of the selected bacteria and controlled their biofilm-forming ability. Band-aid cloth assay confirmed that the CS-AgNPs could be used in the medical field to prevent bacterial infections. The prepared CS-AgNPs increased the survival rate of Artemia species and exhibited antioxidant activity in conjunction with bactericidal properties against selected foodborne pathogens.