Chitin and chitosan polymers: Chemistry, solubility and fiber formation

Biopolymers to composite adsorbents for sulfate removal: From conventional to sustainable systems

Addressing elevated water salinity is a global water security issue listed among the UN's Sustainable Development Goals (UN-SDGs). Sulfate is a contributor to water salinity due to its high solubility and is a pollutant of increasing global concern. While various water treatment technologies are currently available, the high capital infrastructure and operational costs of such advanced methods have sustainability limits for their widespread adoption. By contrast, adsorption science and technology offers facile treatment and a sustainable mitigation strategy for the removal of oxyanions such as sulfate. A key challenge in adsorption science and technology relates to the molecular selective uptake of sulfate. This has catalysed significant effort towards achieving improved adsorption properties and the development of sustainable adsorbent technology. This review provides coverage of recent literature on synthetic adsorbents to current research on biosorbents that contain chitosan due to its multifunctional colloid and interface properties. The shift from conventional synthesis to green synthetic strategies are highlighted by the preparation of advanced biocomposite materials with unique sulfate adsorption properties. Diverse types of materials from inorganic minerals to polymer-based adsorbents (e.g., polycaprolactones, waste-based materials from fly ash, etc.) is described to highlight their sulfate adsorption properties. Specifically, chitosan and agricultural biomass waste in the form of lignocellulose materials are abundant and promising renewable platforms for the preparation of sulfate adsorbents. In particular, the adsorption properties of chitosan biocomposites are highlighted by its efficacy for adsorption-based remediation of sulfate oxyanions that reveal its promising utility as sulfate adsorbents with unique colloidal and interface properties.

Chitosan-metal and metal oxide nanocomposites for active and intelligent food packaging; a comprehensive review of emerging trends and associated challenges

In recent years, significant advancements in biopolymer-based packaging have emerged as a response to the environmental challenges posed by traditional petroleum-based materials. The drive for sustainable, renewable, and degradable alternatives to fossil-based components in the packaging industry has led to an increased focus on chitosan, the second most abundant biopolymer after cellulose. Chitosan offers intrinsic properties such as biodegradability, biocompatibility, antimicrobial activity, excellent barrier and film-forming capabilities, positioning it as an ideal candidate for food packaging applications. However, limitations including inferior mechanical, thermal, barrier properties, and brittleness compared to conventional plastics have limiting its widespread adoption in the food packaging industry. Chitosan has been extensively utilized in various forms, particularly as nanocomposites incorporating metal nanoparticles, leading to chitosan-based nanocomposite films/coatings that synergistically combine the advantageous properties of both chitosan and metal nanoparticles. Through an in-depth analysis of the current research (primarily the last 5 years), this review delves into the physicochemical, mechanical, sensing, and antimicrobial properties of chitosan nanocomposite as an innovative food packaging material. This review will provide insights into the potential toxicity and environmental impact of nanoparticle migration, as well as the prospects and challenges associated with chitosan-metal/metal oxide nanocomposite films in the development of sustainable packaging solutions.

Diabetic wound healing breakthrough: theaflavin-3, 3'-digallate nanoparticles@hydrogel activates the TGF-β1/SMAD3 pathway

BACKGROUND

Diabetes patients face an elevated wound infection susceptibility and delayed healing processes. Currently, no existing literature has reported on the effect and mechanism of theaflavin-3, 3'-digallate nanoparticles (TFDG NPS) and TFDG NPS@hydrogels on diabetic wounds.

PURPOSE

Given that the treatment options for diabetic wound are limited, the aim of this study is to develop an innovative therapeutic approach to address diabetic wounds.

METHODS

The TFDG NPS were prepared using ionic cross-linking, and they were then characterized. The biocompatibility of the TFDG NPS and TFDG NPS@hydrogel was assessed using a Cell Counting Kit-8 (CCK-8) assay and live/dead staining on HK-2 cells in vitro. Diabetic ICR mice were induced through intraperitoneal injection of streptozocin (STZ). They were then subjected to the creation of two full-thickness wounds on their dorsal areas. The effect and mechanism of the TFDG NPS and TFDG NPS@hydrogel on wound healing in diabetic mice were evaluated using a histological analysis, a western blot analysis, and molecular docking.

RESULTS

The optimal TFDG NPS proportion was found to be TFDG:Gelatin (Gel):Chitosan (CS) = 2:1:1. Images photographed using a transmission electron microscope (TEM) revealed that the TFDG NPS appeared spherical, with a diameter of approximately 140 ± 20 nm. The favorable bio-compatibility of the TFDG NPS and TFDG NPS@hydrogel was confirmed using cell experiments. Animal studies demonstrated that both the TFDG NPS and TFDG NPS@hydrogel enhanced collagen fiber accumulation and new blood vessel density, reduced F4/80 infiltration, and upregulated the expression levels of TGF-β1, SMAD3, Collagen I, and α-SMA. The potential mechanism may involve activation of the TGF-β1/SMAD3 pathway, stimulating the secretion of Collagen I and α-SMA, and thereby facilitating wound closure in diabetic mice. The molecular docking results confirmed a high affinity between TFDG and TGF-β1/SMAD3.

CONCLUSION

TFDG NPS and TFDG NPS@hydrogel promoted wound closure in diabetic mice through the TFG-β1/SMAD3 pathway, thus exhibiting promising therapeutic potential for diabetic wound treatment.

Quaternary ammonium salts of chitosan containing aromatic ring: Synthesis, characterization, antimicrobial, antioxidant and cytotoxicity

Quaternary ammonium salts of chitosan have been widely used in the development of anti-microbial biomaterials for their important role in inhibiting the growth of microorganisms. However, it is important to modify its structure to obtain more efficient and biologically active derivatives. Herein, a series of chitosan derivatives with antibacterial, antifungal, antioxidant, and non-cytotoxic properties was synthesized. These four quaternary ammonium salts of chitosan were prepared by incorporating 2-thiophenecarboxaldehyde, 2-furancarboxaldehyde, 2-pyridinecarboxaldehyde and benzaldehyde to form Schiff bases, followed by a reductive amination to obtain the chitosan N-derivatives, and quaternized by iodomethane. The inhibition rate of thiophenecarboxaldehyde chitosan trimethyl ammonium iodide (TpTMC) to B. cinerea could reach 93.78 % and the inhibition ability of pyridinecarboxaldehyde chitosan trimethyl ammonium iodide (PyTMC) to F. graminearum could reach 98.08 % at the concentration of 1.0 mg/mL. Furthermore, furancarboxaldehyde chitosan trimethyl ammonium iodide (FrTMC) exhibited a strong ability to scavenge hydroxyl radicals and DPPH radicals, especially the DPPH radicals scavenging ability was comparable to that of l-ascorbic acid at the concentration of 1.6 mg/mL. The B3LYP/6-311++G (d,p) basis set was employed to determine electronic properties, including HOMO-LUMO energies, and to analyze the chemical reactivity of the compounds. L929 cells were used to evaluate the cytotoxicity of the compounds at different concentrations (1-1000 μg/mL). The results demonstrated the diverse applications of aromatic ring-modified quaternary ammonium salts of chitosan, along with their significant antioxidant and antifungal effects against plant fungi. Therefore, these compounds have potential applications in the preparation of agricultural, biological, and medical materials.

Biopolymer based Fibrous Aggregate Materials for Diagnosis and Treatment: Design, Manufacturing, and Applications

Biopolymer-based fibrous aggregate materials (BFAMs) have gained increasing attention in biomedicine due to their excellent biocompatibility, processability, biodegradability, and multifunctionality. Especially, the medical applications of BFAMs demand advanced structure, performance, and function, which conventional trial-and-error methods struggle to provide. This necessitates the rational selection of materials and manufacturing methods to design BFAMs with various intended functions and structures. This review summarizes the current progress in raw material selection, structural and functional design, processing technology, and application of BFAMs. Additionally, the challenges encountered during the development of BFAMs are discussed, along with perspectives for future research offered.

Removal of Fluoride by Modified Adsorbents: A Review of Modification Methods and Adsorption Mechanisms

Fluoride is ubiquitously present in the natural environment, and its excessive levels can pose serious threats to human health and industrial production. Among various fluoride pollution control methods, adsorption is recognized for its optimal cost-effectiveness and adaptability. The mechanism of fluoride adsorption and the adsorption capacities of various modified adsorbents have been comparatively analyzed :natural minerals, biomass materials, metal oxides, and several emerging types of adsorbents, among which metal-based adsorbents show the best performance. Four modification methods to enhance the performance of adsorbents have been summarized: acid activation, thermal activation, surface functional group modification, and composite materials. Ultimately, this paper identifies the current limitations of adsorption methods for fluoride removal, including insufficient adsorption capacity and a narrow pH range of applicability. These findings are expected to offer valuable insights for the advancement of adsorbent materials research.

Controlled biodegradation of AZ31 alloy by chitosan/Fe-doped bioactive glass composite coating deposited via electrophoretic deposition for orthopaedic implants

The fast degradation rate of implants of AZ 31 alloy in the physiological body fluid is a critical problem for orthopaedic applications. The surface modification of AZ 31 can regulate fast degradation by depositing a biocompatible composite coating. Herein, chitosan/ iron-doped bioactive glass (Fe-doped BG) particles were deposited on AZ 31 via electrophoretic deposition (EPD) at optimized parameters (electric field 15 V/cm with 5 min as deposition time). Scanning electron microscopy (SEM) images revealed that the composite coating exhibited uniform morphology with a thickness of 32.5 ± 2.5 μm, while energy dispersive spectroscopy (EDS) and X-ray fluorescence (XRF) confirmed the presence of Fe, Ca, and Si in the composite coating. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of the functional groups of the composite coating. The composite coating exhibited the average roughness (Ra) of 1.32 ± 0.03 μm with a moderate hydrophilic nature (contact angle 68 ± 2.5°) which would be favorable for a cellular response. The composite coating exhibited 3 N adhesion strength evaluated by scratch test. The turbidity test revealed the antibacterial nature of the composite coating. The alkaline phosphate (ALP) activity was also assessed to confirm the bioactive nature of the composite coating. Electrochemical impedance spectroscopy (EIS) showed improved barrier properties by increased charge transfer resistance. The composite coating controlled the degradation rate of AZ 31 (best results compared to the literature) for orthopaedic applications.

Harnessing the immunomodulatory potential of chitosan and its derivatives for advanced biomedical applications

The success of biomaterial applications in medicine, particularly in tissue engineering, relies on achieving a balance between promoting tissue regeneration and controlling the immune response. Due to its natural origin, high biocompatibility, and versatility, chitosan has emerged as a promising biomaterial especially for immunomodulation purposes. Immunomodulation, refers to the deliberate alteration of the immune system's activity to achieve a desired therapeutic effect either by enhancing or suppressing the function of specific immune cells, signaling pathways, or cytokine production. This modulation opens up the unlimited possibilities for the use of biomaterials, especially about the use of natural polymers such as chitosan. Although numerous chitosan-based immunoregulatory strategies have been demonstrated over the past two decades, the lack of in-depth exploration hinders the full potential of strategies that include chitosan and its derivatives in biomedical applications. Thus, in this review, the possible immunomodulatory effects of chitosan, chitosan derivatives and their potential combined with various agents and therapies are investigated in detail. Moreover, this report includes agents for localized immune response control, chitosan-based strategies with complementary immunomodulatory properties to create synergistic effects that will influence the success of cell therapies for enhanced tissue acceptance and regeneration. Finally, the challenges and outlook of chitosan-based therapies as a powerful tool for improving immunomodulatory applications are discussed for paving the way for further studies.

Nanochitin From Crab Shells: Production, Chemical Modification, Composite Materials, and Physiological Functions

Large quantities of crab shells are generated in food-processing plants. In this review, the authors summarize a series of research findings on the production of nanochitin, its physical properties, chemical modifications, and functions, which have not been fully addressed in existing literature. Nanochitin, which has a width of 10 nm, is derived from chitin, the main component of crab shells, using a technology similar to that used to produce nanocellulose from wood. Unlike conventional chitin, nanochitin is well dispersed in water, making it easy to mold and process into various products for different applications. They can also be modified for specific uses through processes such as acylation and etherification to enhance their physical properties and add functionality. Nanochitin, which are known for their exceptional mechanical strength, can be blended with resins to create composite films with improved strength and elasticity. These films maintain the transparency of the resin, reduce its thermal expansion, and offer reinforcement. Chitin and its derivative chitosan are used as wound dressings, hemostatic agents, and health foods. Nanochitin and its deacetyl derivatives have diverse functions such as topical medicine for the skin, ingestion as a health food, and use as pesticides or fertilizers for plants.

Comparative evaluation of chitligsan nanosuspension gel and spray for enhancing full-thickness wound healing in a rat model

Introduction: This study explores the wound healing potential of Chitligsan (CHG), a novel formulation derived from the enzymatic and fossil-based components of Sahara soil, in nanosuspension-based gel and spray forms. Using a full-thickness wound model in Wistar rats, CHG's efficacy was compared with saline (control) and terramycin treatments.

Methods: A total of 48 rats were divided into four groups: Control (saline), Spray (CHG spray), Gel (CHG gel), and Terramycin pomad. Wound areas were measured at days 3, 7, 14, and 21.

Results: By day 21, CHG spray reduced wound size to 0.08 ± 0.01 cm2, while the gel achieved 0.09 ± 0.01 cm2, outperforming both control (0.34 ± 0.02 cm2) and terramycin (0.14 ± 0.05 cm2, p < 0.05). Histopathological analysis demonstrated superior epithelial regeneration, dense collagenization, and minimal inflammation in CHG-treated groups compared to others. The nanoscale size of CHG particles (89.6 ± 0.26 nm) and their stable zeta potential (-26.1 ± 1.5 mV) contributed to enhanced bioavailability and wound healing efficiency. Morphological and FTIR analyses confirmed the stability and compatibility of the nanosuspension.

Conclusions: This study highlights CHG's potential as a biocompatible and effective wound care solution, offering significant advantages in granulation tissue formation and keratinization compared to conventional treatments.

Post-harvest quality preservation of red globe grapes using grape juice-based edible coatings combined with UVC treatment

This study assesses the impact of grape juice-based alginate or chitosan edible coatings, followed by UVC treatment, on the preservation of post-harvest quality of Red Globe grapes. Coated grapes were stored at 5 °C for 28 days, and their physical, chemical, microbiological, and sensory properties were assessed during the storage period. Films were prepared with grape juice using alginate and chitosan and exposed to 32.4 J/m2 UVC irradiation, then characterized for thickness, color, puncture resistance, elongation at break, permeability, and water solubility. Alginate films were more resistant, soluble, and permeable than chitosan films. Coated and/or UVC-treated grapes showed reduced weight loss, minimal color changes, pH, titratable acidity, total soluble solids, and decreased microbial count compared to uncoated grapes. Sensory attributes remained stable for seven days, while control grapes' firmness significantly decreased (p < 0.05). This sustainable approach enhances the preservation of Red Globe, appealing to consumers who prefer natural preservatives.

Characterization of Thin Polymer Layer Prepared from Liposomes and Polyelectrolytes for TGF-β3 Release in Tissue Engineering

Implant-integrated drug delivery systems that enable the release of biologically active factors can be part of an in situ tissue engineering approach to restore biological function. Implants can be functionalized with drug-loaded nanoparticles through a layer-by-layer assembly. Such coatings can release biologically active levels of growth factors. Sustained release is desired for many in vivo applications. The layer-by-layer technique also allows for the addition of extra layers, which can serve as "barriers" to delay the release. Electrospun Polycaprolactone (PCL) fiber mats are modified with a Chitosan (CS) grafted with PCL sidechains (CS-g-PCL24) and coated with transforming growth factor beta 3 (TGF-β3) loaded Chitosan/tripolyphosphate nanoparticles as a drug delivery system. Additional layers including polystyrene sulfonate, alginate, carboxymethyl cellulose, and liposomes (phosphatidylcholine) are applied. Streaming potential and X-ray photoelectron spectroscopy (XPS) measurements indicated a strong interpenetration of the chitosan and polyanion layers, while liposomes formed separate layers, which are more promising for sustained release. All samples release TGF-β3 at different cumulative levels without altering release kinetics. Variations in layer structure, interpenetration, and stability depending on the chitosan used are observed, which ultimately has minimal impact on the release kinetics. Polyelectrolyte layers strongly interpenetrated the active layers and therefore do not act as effective diffusion barriers, while the liposome layer, though separated, lacked sufficient stability.

Environmental monitoring for Ascaris egg remediation: a critical review

Ascariasis affects up to 1.2 billion people globally, with a significant burden in low-income regions. Despite high prevalence and substantial morbidity, existing monitoring and intervention strategies are insufficient due to sample extraction and quantification inaccuracies. This review underscores the need for enhanced environmental monitoring to improve Ascaris egg remediation and reduce disease incidence. We critically reviewed existing environmental monitoring practices and explored advanced technologies like lab-on-a-disk for rapid detection and quantification of Ascaris eggs. A meta-analysis and meta-regression of studies on Ascaris egg recovery revealed significant variability in recovery rates, with the best methods achieving less than 60% efficiency. Advanced imaging analyses and lab-on-a-disk technologies show promise for rapid detection and viability assessment. By identifying gaps in current methodologies, we recommend more effective environmental interventions. The review incorporated high-quality data adhering to PRISMA guidelines, ensuring comprehensive coverage of the latest methodologies. Integrating improved detection methods and environmental control strategies can significantly reduce ascariasis incidence, especially in endemic regions. Future efforts should focus on refining these technologies and validating their application in real-world settings for sustainable disease control.

Selective nucleation of chitin nanocrystals in the crystallization of poly(ε-caprolactone-b-l-lactide) diblock copolymer composites

Rod-like chitin nanocrystals (ChNCs) filled biodegradable aliphatic polyesters are of great interest because as-obtained nanocomposites are all-degradable. In this work, we prepared a poly(ε-caprolactone-b-l-lactide) (PCL-b-PLA) copolyester nanocomposite with ChNCs and carried out a crystallization study. The results disclosed that the roles of ChNCs played during crystallization of copolyester matrices were very attractive: as heterogeneous nucleator of PLA phase, whereas as inert filler for PCL phase. Thus, the overall crystallization kinetics of PLA phase were accelerated. The heterogeneous nucleation led to the formation of more amounts of crystallized PLA domains, which favored nucleating following crystallization of PCL phase. In addition, the presence of ChNCs did not strongly influence the microphase-segregated structure of PCL-b-PLA, and had good reinforcements to matrix copolymer. The selective nucleation ability of ChNCs reported in this study is valuable for regulating the structures and properties of nanocomposites based on the ChNCs-filled aliphatic diblock copolyester with double crystalline blocks.

How Molar Mass, Acid Type, and Coagulation Bath Composition Influence Coagulation Kinetics, Mechanical Properties, and Swelling Behavior of Chitosan Filaments: A Full Factorial Approach

In this study, a full multilevel factorial design (21 × 31 × 21) × 2 was conducted to investigate the effects of molar mass of chitosan (CS), the type of acid used for dissolution, and the composition of the coagulation bath on the coagulation, mechanical properties, and swelling of the filaments. The results showed the statistical significance of the factors in the characteristics of these filaments. The coagulation followed Fick's second law of diffusion, with an increase in the chitosan molar mass reducing the coagulation rate, as did the use of acetic acid instead of lactic acid. CS with higher molar mass produced filaments with larger diameters, but without a proportional increase in tensile strength. Swelling was influenced by the acid and composition of the coagulation bath. The interaction of CS with acid and the CS molar mass factor were the terms of greatest statistical significance. Crystallinity was higher for samples dissolved in aqueous solutions of acetic acid and coagulated with ethanol, while lactic acid induced greater structural disorder. Samples coagulated with ethanol presented more homogeneous surfaces, while methanol resulted in rougher filaments. These findings emphasize the critical role of processing conditions in tailoring the properties of CS filaments, providing valuable insights for their optimization for biomedical applications.

ZIF-8-Modified Multifunctional Hydrogel Loading siRNA and DOX for Postoperative Therapy of Maxillofacial Osteosarcoma and Bone Repair

The primary clinical challenges associated with postoperative maxillofacial osteosarcoma include high mortality rates and significant local recurrence. Additionally, patients often exhibit substantial bone defects that are incapable of self-healing, necessitating the implantation of scaffolds. Multifunctional hydrogels, which enable sustained local release of therapeutic agents and enhance scaffold surface properties, demonstrate significant potential for the postoperative management of maxillofacial osteosarcoma. In this study, doxorubicin (DOX) and PD-L1 siRNA were initially loaded into ZIF-8 to synthesize highly stable nanocomplex RNA-DOX@ZIF-8 (RDZ). Subsequently, a multifunctional hydrogel (Gel@RDZ) was fabricated by uniformly mixing RDZ with catechol-modified chitosan. Gel@RDZ exhibits a high drug-loading capacity, excellent viscoelasticity, and strong scaffold adhesion. In a rat femoral defect model, the Gel@RDZ-coated scaffold group demonstrated superior bone regeneration capabilities. Furthermore, in a murine osteosarcoma recurrence model, Gel@RDZ exhibited optimal immune cell infiltration, substantially reduced tumor recurrence, and markedly enhanced the tumor-killing efficacy of CD8+ T cells. Therefore, the development of a multifunctional hydrogel system (Gel@RDZ) provides a comprehensive treatment for postoperative maxillofacial osteosarcoma.

Chitosan hydrochloride coated and nonionic surfactant modified niosomes: a better way for oral administration of semaglutide

Diabetes is now a global chronic disease, with the number of people with diabetes expected to reach 643 million by the end of 2030. Semaglutide, a human glucagon-like peptide-1 (GLP-1) analogue with 94% similarity to human GLP-1, can promote insulin secretion and repress glucagon secretion in a glucose concentration-dependent manner, resulting in substantial improvement of blood glucose levels and reducing the risk of hypoglycemia in patients with type 2 diabetes. To improve the absorption efficiency of semaglutide in oral delivery, we developed chitosan hydrochloride-coated and nonionic surfactant-modified niosomes (CS.HCL-NSPEs-NIO) as a new way to encapsulate it. The results showed that CS.HCL-NSPEs-NIO could efficiently penetrate the cell junctions in the intestinal endothelium and therefore promote drug absorbance. In addition, gastrointestinal distribution studies revealed that CS. HCL-NSPEs-NIO could stay in the intestine for more than 4 h, thus allowing for long-term glucose regulation. Effective reduction of blood glucose levels and weight loss were observed in db/db mice while no toxicity was detected in major organs. On the whole, our recommendation is that CS.HCL-NSPEs-NIO shows promise as an oral delivery tool for enhancing the hypoglycemic effects of semaglutide.

Natural Feed Supplements From Crustacean Processing Side Streams for Improved Growth of Finfishes and Crustaceans: A Review

Natural feed additives of plant/animal/microbial origin are researched as supplements in aquaculture to improve the properties of feed, minimize the usage of chemical alternatives, reduce food safety risks and ensure sustainability to combat global food and nutritional security. Side streams generated during shellfish processing possess valuable ingredients: protein, lipids, carotenoids, minerals and chitins. Considering the current trend of organic farming and antibiotic-free fish and shellfish, crustacean processing side streams and their derivatives seem promising and emerging resources as natural additives/supplements for formulating high-quality feeds with superior benefits. Lower concentrations of chitin and chitosan in diets are reported to stimulate the growth of shellfish and finfish under controlled conditions. Oligomers of chitosan and nano-chitosan are also the other potential derivatives as natural supplements in feed for better growth performance of aquaculture varieties. This review focuses on the significance of crustacean processing side streams and their derivatives, especially shrimp head meal, chitin, chitosan and chitosan oligosaccharides as potential natural additives in aquafeeds for promoting the growth performance of cultured fin fishes and shell fishes. Utilization in aquafeeds and the development of natural value-added supplements from crustacean processing side streams, especially shrimp head and shell leftover, offer an answer to the negative environmental impact due to its dumping; reduce the dependency on food fish for fish meal production & fishmeal for aquafeeds; solution to maintain the economic viability of the fish farmers & industry as well as to ensure the supply of safer and healthy aquatic foods to meet the objectives of sustainable development goals.

Effective removal of As5+ from aqueous medium using date palm fiber biochar/chitosan/glutamine nanocomposite: kinetic and thermodynamic studies

In the current work, three adsorbent materials were developed: biochar derived from date palm fiber (C), date palm fiber biochar/chitosan nanoparticles (CCS), and biochar/chitosan nanoparticle composite supplemented with glutamine (CCSG). These compounds were used as solid adsorbents to remove As5+ from polluted water. Several characterization approaches were used to investigate all the synthesized solid adsorbents, including thermogravimetric analysis, N2 adsorption/desorption isotherm, scanning electron microscopy, transmission electron microscopy (TEM), attenuated total reflectance with Fourier transform infrared, and zeta potential. Date palm fiber biochar/chitosan/glutamine nanocomposite (CCSG) demonstrated good thermal stability, with a maximum specific surface area of 518.69 m2/g, a mesoporous size of 2.06 nm, total pore volume of 0.25 cm3/g, TEM average particle size of 38 nm, and pHPZC of 6.9. Contact time (5-60 min), pH (1-9), starting As5+ concentration (50-500 mg/L), adsorbent dose (0.1-2.0 g/L), temperature (27-45 °C), and ionic strength (0.05-0.40 mol/L) were among the sorption parameters that were investigated in order to improve the adsorption conditions. It is observed that the modified samples were effectively able to remove As5+ (CCS; 256.0 and CCSG; 376.0 mg/g) than unmodified ones (C; 150.5 mg/g). The As5+ removal procedure corresponded well with Langmuir isotherm model. Thermodynamic and kinetic experiments show that the Elovich, pseudo-first order, and Van't Hoff plot with endothermic, spontaneous, and physisorption nature are the best fitted models. EDTA has the highest desorption efficiency percentage (98.8%). CCSG demonstrated enhanced reusability after six application cycles of As5+ adsorption/desorption, with only a 4% decrease in the efficiency of adsorption. This work shows that adding glutamine to the DPF biochar/chitosan composite reinforces it, resulting in the fabrication of a solid adsorbent that shows promise for use in water remediation.

Propionate-functionalized chitosan hydrogel nanoparticles for effective oral delivery of insulin

Oral delivery of macromolecular drugs is often hampered by the harsh gastrointestinal environment, which makes the drugs have poor bioavailability. Insulin, the most used drug for diabetes, also faces the same challenge for oral administration. Hence, we decorated microbial metabolite propionate on chitosan (CS) to fabricate insulin-loaded propionate-modified CS hydrogel nanoparticles (IN-CS/PA HNPs). The prepared IN-CS/PA HNPs exhibited high encapsulation efficiency (> 95 %) and loading capacity (∼10 %) for insulin. The system provided better protection for insulin in gastrointestinal environment compared to unmodified IN-CS HNPs. Moreover, the active functional group of propionate can be recognized and transported by mono-carboxylate transporter protein 1 (MCT1) targeting. Thus, in both Caco-2 cells and the ligated intestinal loops of rats, IN-CS/PA HNPs significantly improved permeability and uptake of insulin on intestinal epithelium, which was attributed to MCT1-mediated endocytosis. In type 1 diabetic (T1D) rats, oral delivery of IN-CS/PA HNPs with 60 IU/kg insulin led to more stable and long-lasting hypoglycemic effect than a 5IU/kg dose of subcutaneously injected insulin. It also generated 2.29-fold and 11.88-fold higher relative oral bioavailability compared with empty IN-CS HNPs and free insulin, respectively. This study demonstrated that propanoic acid-functionalized chitosan hydrogel nanoparticles could improve the oral absorption of insulin by overcoming multiple barriers in gastrointestinal tract, providing a promising active targeting strategy for the oral delivery of macromolecules drugs.

Isolation, characterization, and mycostimulation of fungi for the degradation of polycyclic aromatic hydrocarbons at a superfund site

Mycoremediation is a biological treatment approach that relies on fungi to transform environmental pollutants into intermediates with lower environmental burden. Basidiomycetes have commonly been used as the target fungal phylum for bioaugmentation in mycoremediation, however this phylum has been found to be unreliable when used at scale in the field. In this study, we isolated, characterized, and identified potential polycyclic aromatic hydrocarbon (PAH) degrading fungal isolates from creosote-contaminated sediment in the Elizabeth River, Virginia. Our goal was to identify non-basidiomycete PAH degrading fungi. A total of 132 isolates were isolated, of which the overwhelming majority belonged to the phylum Ascomycota. Isolates were screened for their ability to produce known PAH degrading enzymes, particularly laccase and manganese-dependent peroxidases, and to transform model PAH compounds [fluoranthene, phenanthrene, pyrene and benzo(a)pyrene]. Fungal isolates were subsequently biostimulated using complex amendments including chicken feathers, wheat seeds, grasshoppers, and maple saw dust. Following biostimulation, laccase expression and PAH transformation were assessed. The grasshopper amendment was found to yield the highest laccase upregulation improvement with a maximum increase of 18.9% for the Paraphaeosphaeria isolate. The Septoriella and Trichoderma isolates exposed to the chitin-based grasshopper amendment demonstrated an increase in PAH removal. Septoriella sp. increased its transformation of fluoranthene (44%), pyrene (54.2%, and benzo(a)pyrene (48.7%), while there was a 58.3% increase in the removal of benzo(a)pyrene by Trichoderma sp. While the results from this study demonstrate the potential of indigenous fungi to be biostimulated for the removal of PAHs, additional investigation is needed to determine if the response to the chitin-based grasshopper mycostimulation can be translated from the bench to the field.

Chitin isolation from crustaceans and mushrooms: The need for quantitative assessment

This review examines key journal articles on the isolation of chitin from mushroom biomass comparing these findings to those related to crustacean chitin. It highlights the need for standardizing chitin characterization, emphasizing that chitin comprises a family of polymers with variations in molecular weight (Mw), degree of acetylation (%DA), and acetylation patterns (PA), leading to diverse physicochemical properties and biological activities. The review positions fungi and mushrooms as emerging sources of 'vegan' chitin, being non-animal and free from allergenic proteins. Their ability to be cultivated year-round, along with rapid growth and low-cost biowaste substrates, makes them attractive alternatives to crustacean chitin. Market adoption of mushroom chitin will depend on its potential applications in high-value products. Traditionally, chitin characterization has been semi-qualitative, but there is now a growing recognition of how sample inconsistencies impact research quality. This review underscores the importance of quantitative analysis for achieving practical, repeatable, and reproducible results while addressing the challenges in characterizing fungal chitin. We argue that accurately determining the properties of fungal chitin is essential and should be a fundamental aspect of every study, as these properties significantly influence the polymer's characteristics and biological activity.

Fruit Vinegars as Natural and Bioactive Chitosan Solvents in the Production of Chitosan-Based Films

Natural fruit vinegars, derived from various fruits, enhance culinary experience and offer potential health benefits due to their bioactive compounds. In this study, fruit vinegars (apple, blackcurrant, and cherry) were used as natural solvents for producing chitosan films, introducing an environmentally friendly approach. Fruit vinegars and chitosan-based solutions were examined for their antioxidant and antimicrobial properties. In turn, the obtained chitosan films were characterized by their antimicrobial, mechanical, and structural properties. Both fruit vinegars and film-forming chitosan solutions showed antioxidant activity, and chitosan-cherry vinegar solutions exhibited the highest antiradical and ferrous ion-chelating effect. All solvents and chitosan-based solutions were characterized by antimicrobial properties, especially against Pseudomonas aeruginosa (inhibition zone > 28 mm). Antimicrobial activity was also preserved in the case of chitosan-based film, especially when produced with cherry vinegar, which showed activity against the broadest spectrum of bacteria. The largest zone of inhibition for all samples was observed for P. aeruginosa in the range of 19 mm from the inhibition zone to >28 mm, depending on the type of vinegar used as a solvent. The conducted tests showed that the type of vinegar used also affects the mechanical parameters of the films obtained, such as elongation at break, for which values were recorded from 3.97 to 4.93 MPa, or tensile strength, for which the values were recorded from 48.48 to 70.58 MPa. The results obtained demonstrate that natural fruit vinegars, serving as chitosan solvents, can be an alternative to traditionally used acidic solvents, yielding films with favorable properties.

Hydrophobization of Chitin Nanofibers by Grafting of Partially 2-Deoxygenated Amyloses Through Enzymatic Approach

In recent years, increased attention has been given to the effective use of chitin nanofibers (ChNFs). We have developed a method to fabricate thinner chitin nanomaterials, called scale-down chitin nanofibers (SD-ChNFs), by a bottom-up procedure at the nanoscale level, with subsequent disintegration by electrostatic repulsion. The surface modification of SD-ChNFs is anticipated to provide new properties and functions for their practical applications. Inspired by our previous reports, which found hydrophobicity in partially 2-deoxygenated (P2D-) amylose obtained by the glucan phosphorylase (GP)-catalyzed enzymatic copolymerization of α-d-glucose 1-phosphate/d-glucal as comonomers, this work investigated the hydrophobization of SD-ChNFs via an enzymatic approach. After the modification of maltooligosaccharide primers on SD-ChNFs was performed by a reductive alkylation toward ChNFs, the grafting of the P2D-amyloses was performed by GP-catalyzed enzymatic copolymerization. 1H NMR analysis supported the production of P2D-amylose-grafted SD-ChNFs with different d-glucose/2-deoxy-d-glucose unit ratios on SD-ChNFs. The X-ray diffraction analysis of the products confirmed that the chain lengths and unit ratios of the grafted polysaccharides strongly affected the entire crystalline structures. Water contact angle measurements of the cast films of the products indicated that successful hydrophobization was achieved by the grafting of P2D-amylose chains with a sufficient chain length, a relatively high 2-deoxy-d-glucose unit ratio, and low crystallinity.

Carboxymethyl cellulose-chitosan edible films for food packaging: A review of recent advances

Polysaccharide-based edible films have been widely developed as food packaging materials in response to the rising environmental concerns caused by the extensive use of plastic packaging. In recent years, the integration of carboxymethyl cellulose (CMC) and chitosan (CS) for a binary edible film has received considerable interest because this binary edible film can retain the advantages of both constituents (e.g., the great oxygen barrier ability of CMC and moderate antimicrobial activity of CS) while mitigating their respective disadvantages (e.g., the low water resistance of CMC and poor mechanical strength of CS). This review aims to present the latest advancements in CMC-CS edible films. The preparation methods and properties of CMC-CS edible films are comprehensively introduced. Potential additives and technologies utilized to enhance the properties are discussed. The applications of CMC-CS edible films on food products are summarized. Literature shows that the current preparation methods for CMC-CS edible film are solvent-casting (main) and thermo-mechanical methods. The CMC-CS binary films have superior properties compared to films made from a single constituent. Moreover, some properties, such as physical strength, antibacterial ability, and antioxidant activity, can be greatly enhanced via the incorporation of some bioactive substances (e.g. essential oils and nanomaterials). To date, several applications of CMC-CS edible films in vegetables, fruits, dry foods, dairy products, and meats have been studied. Overall, CMC-CS edible films are highly promising as food packaging materials.

Ionically-crosslinked carboxymethyl chitosan scaffolds by additive manufacturing for antimicrobial wound dressing applications

Chitosan chemical functionalization is a powerful tool to provide novel materials for additive manufacturing strategies. The main aim of this study was the employment of computer-aided wet spinning (CAWS) for the first time to design and fabricate carboxymethyl chitosan (CMCS) scaffolds. For this purpose, the synthesis of a chitosan derivative with a high degree of O-substitution (1.07) and water soluble in a large pH range allowed the fabrication of scaffolds with a 3D interconnected porous structure. In particular, the developed scaffolds were composed of CMCS fibers with a small diameter (< 60 μm) and a hollow structure due to a fast non solvent-induced coagulation. Zn2+ ionotropic crosslinking endowed the CMCS scaffolds with stability in aqueous solutions, pH-sensitive water uptake capability, and antimicrobial activity against Escherichia coli and Staphylococcus aureus. In addition, post-printing functionalization through collagen grafting resulted in a decreased stiffness (1.6 ± 0.3 kPa) and a higher elongation at break (101 ± 9 %) of CMCS scaffolds, as well as in their improved ability to support in vitro fibroblast viability and wound healing process. The obtained results encourage therefore further investigation of the developed scaffolds as antimicrobial wound dressing hydrogels for skin regeneration.

Novel ionic chitosan derivatives based on pyridinium sulfonate: Synthesis, characterization, and studies on antimicrobial, antioxidant, and biocompatibility properties

To improve the solubility, antimicrobial efficacy, antioxidant capacity, and biocompatibility of chitosan for broader applications, a series of novel ionic chitosan derivatives were synthesized in this study by amidating chitosan with carboxyl pyridinium sulfonate. These derivatives were characterized through various analytical techniques, including FTIR, 1H NMR, UV, TGA, and XRD. Proton NMR was particularly utilized to determine the degree of substitution. The modified chitosans showed improved water solubility. Their antimicrobial activity against gram negative E. coli and gram positive S. aureus was evaluated in vitro through inhibition rates, minimum inhibitory concentrations (MIC), and minimum bactericidal concentrations (MBC), demonstrating high effectiveness at low concentrations. Additionally, antioxidant tests indicated that these derivatives possess significantly greater antioxidant activities compared to original chitosan, particularly the 5OHNASCS derivative which showed exceptional radical scavenging and reducing capabilities. Furthermore, the CCK-8 assay was employed to assess cytotoxicity in 293 T cells (human embryonic kidney cells), with all samples exhibiting no toxicity. Hemolysis tests were also conducted, revealing that the newly synthesized series of ionic chitosan derivatives showed no hemolytic activity, indicating good biocompatibility and potential for application as wound dressings. In summary, these newly developed ionic chitosan derivatives demonstrated excellent water solubility, antimicrobial activity, antioxidant capacity, and biocompatibility, suggesting their potential use in food and biomedical materials.

Revivable self-assembled supramolecular biomass fibrous framework for efficient microplastic removal

Microplastic remediation in aquatic bodies is essential for the entire ecosystem, but is challenging to achieve with a universal and efficient strategy. Here, we developed a sustainable and environmentally adaptable adsorbent through supramolecular self-assembly of chitin and cellulose. This biomass fibrous framework (Ct-Cel) showcases an excellent adsorption performance for polystyrene, polymethyl methacrylate, polypropylene, and polyethylene terephthalate. The affinity for diverse microplastics is attributed to the transformation of multiple intermolecular interactions between different microplastics and Ct-Cel. Meanwhile, the strong resistance of Ct-Cel to multiple pollutants in water enables an enhanced adsorption when coexisting with microorganisms and Pb2+. Moreover, Ct-Cel can remove 98.0 to 99.9% of microplastics in four types of real water and maintains a high removal efficiency of up to 95.1 to 98.1% after five adsorption cycles. This work may open up prospects for functional biomass materials for cost-efficient remediation of microplastics in complex aquatic environments.

Efficient fabrication of chitin-based films with high UV-blocking and fluorescence via Hantzsch reaction

As the second most abundant polysaccharide on earth, chitin-based films are promising packaging and biomedical materials. However, the lack of special function (especially UV-blocking properties and fluorescence) usually restricts their further and high-value applications. Herein, high UV-blocking and fluorescence chitin-based films were fabricated via surface modification using acetoacetation and the Hantzsch reaction. The structure and properties of the films were characterized by NMR, FTIR, fluorescence spectrum, and tensile tests. The results showed that the benzene ring and 1,4-dihydropyridine ring (DHP) were successfully grafted on the films in the mild process. Besides, the degree of substitution of DHP (DSDHP) increased with the reaction time, temperature, and substrate concentration. Moreover, the modification followed a first-order reaction at 20 °C with a rate constant of 2.1 × 10-4. When the DSDHP was over 0.029, the films exhibited 100 % UV shielding. The fluorescence spectrum demonstrated that the films had excellent solvent and temperature resistance. In addition, the films exhibited excellent mechanical strength with tensile strength up to 85.2 MPa. This work provides a facile and environmentally friendly strategy to fabricate a functional chitin-based film with potential applications in UV protection, medical packaging, and fluorescent materials.

Versatile Biopolymers for Advanced Lithium and Zinc Metal Batteries

Lithium (Li) and zinc (Zn) metals are emerging as promising anode materials for next-generation rechargeable metal batteries due to their excellent electronic conductivity and high theoretical capacities. However, issues such as uneven metal ion deposition and uncontrolled dendrite growth result in poor electrochemical stability, limited cycle life, and rapid capacity decay. Biopolymers, recognized for their abundance, cost-effectiveness, biodegradability, tunable structures, and adjustable properties, offer a compelling solution to these challenges. This review systematically and comprehensively examines biopolymers and their protective mechanisms for Li and Zn metal anodes. It begins with an overview of biopolymers, detailing key types, their structures, and properties. The review then explores recent advancements in the application of biopolymers as artificial solid electrolyte interphases, electrolyte additives, separators, and solid-state electrolytes, emphasizing how their structural properties enhance protection mechanisms and improve electrochemical performance. Finally, perspectives on current challenges and future research directions in this evolving field are provided.

A Review of Chitosan-Based Materials for Biomedical, Food, and Water Treatment Applications

Chitosan, a natural biopolymer with excellent biocompatibility, biodegradability, and modifiable structure, has broad applications in regenerative medicine, tissue engineering, food packaging, and environmental technology. Its abundance, solubility in acidic solutions, and capacity for chemical modification make it highly adaptable for creating specialized derivatives with enhanced properties. Recent advances have demonstrated chitosan's efficacy in composite systems for tissue regeneration, drug delivery, and antimicrobial applications. This review examines chitosan's unique properties, with a focus on its antibacterial activity as influenced by factors like pH, concentration, molecular weight, and deacetylation degree. Additionally, chitosan's potential as a sustainable, non-toxic material for eco-friendly packaging and water treatment is explored, highlighting the growing interest in chitosan composites with other polymers and metallic nanoparticles for enhanced biomedical and environmental applications.

Recent advancements and perspectives on processable natural biopolymers: Cellulose, chitosan, eggshell membrane, and silk fibroin

With the rapid development of the global economy and the continuous consumption of fossil resources, sustainable and biodegradable natural biomass has garnered extensive attention as a promising substitute for synthetic polymers. Due to their hierarchical and nanoscale structures, natural biopolymers exhibit remarkable mechanical properties, along with excellent innate biocompatibility and biodegradability, demonstrating significant potential in various application scenarios. Among these biopolymers, proteins and polysaccharides are the most commonly studied due to their low cost, abundance, and ease of use. However, the direct processing/conversion of proteins and polysaccharides into their final products has been a long-standing challenge due to their natural morphology and compositions. In this review, we emphasize the importance of processing natural biopolymers into high-value-added products through sustainable and cost-effective methods. We begin with the extraction of four types of natural biopolymers: cellulose, chitosan, eggshell membrane, and silk fibroin. The processing and post-functionalization strategies for these natural biopolymers are then highlighted. Alongside their unique structures, the versatile potential applications of these processable natural biopolymers in biomedical engineering, biosensors, environmental engineering, and energy applications are illustrated. Finally, we provide a summary and future outlook on processable natural biopolymers, underscoring the significance of converting natural biopolymers into valuable biomaterial platforms.

Immobilized chitosan as an efficient adsorbent for columnar adsorption of Cr (VI) from aqueous solution

The current effort focuses on creating an effective adsorbent for Cr (VI) adsorption due to the growing need to address Cr (VI) pollution in aqueous solutions. Chitosan, a biopolymer and polysaccharide with several functional sites, is immobilized on alginate using the ion exchange technique. Both prior to and following Cr (VI) adsorption, the material's shape, crystallinity, and functional groups are reported. Immobilized chitosan was employed to adsorb Cr (VI) in a fixed bed column with variable operational parameters (flow rate, initial chromium content, and bed height). The analysis of breakthrough curves showed that at a flow rate of 10 mL/min, Cr (VI) concentration of 50 mg/L and a bed height of 18 cm, a maximum adsorption of 78.41 % was achieved. The adsorption system and the breakthrough curves were thoroughly understood by using Thomas, Yoon-Nelson and Adams-Bohart kinetic models. There is promise for the large-scale use of synthesized immobilized chitosan because the current adsorption process fits the Thomas and Yoon-Nelson model well and confirms the homogenous bed, low mass transfer resistance, and constant operating conditions throughout the experiment. Furthermore, an exploration of the adsorption mechanism is undertaken and the outcomes are compared with existing literature. The regeneration and reuse tests up to four cycles provided insight into the immobilized chitosan's stability, dependability, and potential for scaling up.

Functionalized chitosan-inspired (nano)materials containing sulfonic acid groups: Synthesis and application

Nature-inspired chitosan (CS) materials show a high potential for the design/fabrication of sustainable heterogeneous (nano)materials with extraordinary structural/physical features, such as superior biodegradability/biocompatibility, simplicity of chemical modification, environmental safety, high availability, cost-effectiveness, high electrochemical activity, good film-forming ability, and antioxidant, antimicrobial/antibacterial, and anticoagulant activities. Industrialization and growth of industrial wastes or by-products induce an increasing demand for the development of clean, low-cost, and renewable natural systems to minimize or eliminate the utilization of environmentally toxic compounds. The preparation of novel heterogeneous functionalized polysaccharide-inspired bio(nano)materials via chemical modifications of natural CS to improve its physicochemical/biochemical properties has recently become tremendously attractive for many researchers. The most abundantly available and cost-effective functionalized CS-inspired (nano)materials are considerably valuable in terms of the economic aspects of production of (nano)catalysts, (nano)hydrogels, (nano)composite/blend membranes, and thus their commercialization. In this respect, the preparation of functionalized CS-inspired (nano)materials containing -SO3H groups has been represented as a valid alternative to the homogenous unmodified biomaterials for various applications. Sulfonated derivatives of CS-inspired (nano)materials may possess huge surface areas, catalytic activity, adsorption, and biological/biomedical properties. This review article is aimed at the investigation of different methods and potential applications of sulfonated CS-inspired (nano)materials in catalysis, fuel cells, adsorption of ions, membranes, and biological applications.

Extraction, characterization and evaluation of antimicrobial activity of chitosan from adult Zophobas morio (Fabricius, 1776) (Coleoptera: Tenebrionidae)

The increasing demand for chitosan has led to the exploration of alternative sources, including insects. In this study, chitosan was extracted from Zophobas morio beetles with 19.17 % yield. FTIR and Raman Spectroscopy showed similar peaks in Z. morio chitosan (ZC) and commercial chitosan (CC). ZC showed low crystallinity (40.96 %) and high thermal residual mass (42.7 %) than CC. SEM imaging of ZC displayed pores ranging from 10 μm to 0.3 μm. EDX mapping revealed the homogenous presence of C, N and O elements. ZC exhibited low molecular weight (435.95 kDa) and low intrinsic viscosity (317.95 cm3/g) than CC (680.20 kDa and 480.87 cm3/g, respectively). Degree of deacetylation of ZC and CC was 96.24 % and 78.26 %, respectively. ZC showed antimicrobial activity against Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC 13883), Proteus mirabilis (ATCC 29906), Staphylococcus aureus (ATCC 25923), Enterococcus faecalis (ATCC 29212) and Candida albicans (ATCC 90028) with zones of inhibition ranging from 5 mm to 11 mm. The minimum bactericidal concentration of ZC against K. pneumoniae and P. mirabilis was lower than CC. This study suggests the applicability of insect chitosan as an antimicrobial agent in the food and pharmaceutical industries.

Biopolymeric 3D printed implantable scaffolds as a potential adjuvant treatment for acute post-operative pain management

BACKGROUND

Pain is characterized as a major symptom induced by tissue damage occurring from surgical procedures, whose potency is being experienced subjectively, while current pain relief strategies are not always efficient in providing individualized treatment. 3D printed implantable devices hold the potential to offer a precise and customized medicinal approach, targeting both tissue engineering and drug delivery.

RESEARCH DESIGN AND METHODS

Polycaprolactone (PCL) and PCL - chitosan (CS) composite scaffolds loaded with procaine (PRC) were fabricated by bioprinting. Geometrical features including dimensions, pattern, and infill of the scaffolds were mathematically optimized and digitally determined, aiming at developing structurally uniform 3D printed models. Printability studies based on thermal imaging of the bioprinting system were performed, and physicochemical, surface, and mechanical attributes of the extruded scaffolds were evaluated. The release rate of PRC was examined at different time intervals up to 1 week.

RESULTS

Physicochemical stability and mechanical integrity of the scaffolds were studied, while in vitro drug release studies revealed that CS contributes to the sustained release dynamic of PRC.

CONCLUSIONS

The printing extrusion process was capable of developing implantable devices for a local and sustained delivery of PRC as a 7-day adjuvant regimen in post-operative pain management.

Fine-tuning the cytotoxicity profile of N,N,N-trimethyl chitosan through trimethylation, molecular weight, and polyelectrolyte complex nanoparticles

N,N,N-trimethyl chitosan (TMC) is a promising biopolymer for pharmaceutical applications due to its enhanced solubility and bioadhesive properties, though its cytotoxic limitations necessitate careful modification to ensure safety and efficacy. This study sought to investigate whether nanoparticle (NP) formation could reduce the anticipated cytotoxic effects of TMC, thus improving its applicability across a wider spectrum of pharmaceutical uses. TMC's capability to form NPs with anionic polyelectrolytes led to the application of chondroitin sulfate (ChS) in this study. Five TMC samples, varying in degree of trimethylation (DTM 23, 32, 46, 50 and 99 %) and molecular weight (Mw, 66-290 kDa) were synthesized, and their biocompatibility with human umbilical vein endothelial cells (HUVECs) was assessed. The results revealed a discernible impact of both DTM and Mw on cell viability, with higher DTM and lower Mw correlating with increased toxicity. Cytotoxicity studies against ovarian cancer cell lines SKOV-3 and OVISE showed a clear indication of a higher cytotoxic effect of TMC samples against cancer cells compared to healthy cells (HUVEC). The cytotoxicity against cancer cells also indicated an optimal DTM for maximum efficacy, deviating from a linear trend. The effects of Mw were cell-dependent, introducing complexity to the observed relationship. Additionally, TMC-ChS NPs were successfully prepared, demonstrating a substantial reduction in cytotoxicity compared to TMC alone in all tested cells. This promising outcome suggests the potential of NP formation to fine-tune the cytotoxicity profile of TMC, paving the way for the development of safer and more effective pharmaceutical formulations.

A chemometric approach using I-optimal design for optimising Pb(II) removal using bentonite-chitosan composites and beads

This paper reports adsorption studies of Pb(II) ions onto Bentonite-Chitosan (Bt-Ch) composites or beads when using an I-optimal design experiment approach. Three adsorption factors (pH, adsorbent dosage, and initial concentration) were optimised whilst simultaneously investigating multiple adsorbents. The Bt-Ch composites and beads (type A and B) adsorbents were made using weight ratios 90%/10% and differed characteristically due to their preparation methods of solution blending and precipitation, respectively. A batch procedure was used for adsorption experiments, and the amounts of Pb(II) ions (adsorbed onto Bt-Ch composites/beads) were analysed using inductively coupled plasma optical emission spectrometry (ICP-OES). Adsorption experimental parameters were analysed and optimised by using a response surface method (I-optimal design) generated from Design-Expert® 13.0 software. The main achievements of this study were to intensify the understanding and application of I-optimal experimental designs, which allow simultaneous determination of adsorption capacities and efficiencies across multiple adsorbents in an economical manner. A reduced quadratic model provided the best fit for the experimental data and exhibited minimal deviation between predicted and experimental values. This was evidenced by the very small covariance (CV) values of 1.81% and 1.33% observed for adsorption capacity and adsorption efficiency, respectively, also suggesting high reproducibility. It was observed that the adsorption factors studied (pH, adsorbent dose, and initial concentration) have a more pronounced effect on the adsorption capacity (F-value = 714.37) compared to adsorption efficiency (F-value = 140.62). Adsorbent dosage was found to have the greatest effect on adsorption capacity, while the initial pH of Pb(II) solution had the greatest effect on adsorption efficiency. Under optimal conditions, the adsorption capacities of beads-A (73.2 mg/g) and beads-B (77.6 mg/g) were found to be higher than that of the corresponding composite (51.7 mg/g). Whilst the optimum adsorption efficiency values for all three adsorbents were ∼100% (with ranges of pH 2-5, initial concentrations 50-200 mg/L, and adsorbent dosage 0.05-0.5 mg). The desirability indexes for the optimised conditions for these respective responses (and each adsorbent) were found to be within the ranges of 0.892-0.974 and 0.945-0.967 for adsorption capacity and adsorption efficiency, respectively. These high desirability index values for both responses indicate that the optimised conditions lead to very good performance for both measures. The information obtained in this study provides detailed understanding of the adsorption phenomena of the adsorbents studied. It gives confidence in the use of I-optimal designs to be applied as a chemometric tool for the specific adsorbents studied herein and others.

Chitosan-based electrospun fibers for bone-tissue engineering: Recent research advancements

Chitosan, a sustainable and highly abundant animal-derived biopolymer, possesses versatile properties, such as solubility, film-forming ability, viscosity, ion binding, and antimicrobial qualities, which are suitable for biomedical applications. Due to its charged nature, chitosan is a lucrative biopolymer for scaffold fabrication, especially for bone-tissue engineering applications, using the electrospinning method, which is an industrially suitable, scalable, and swift method for fabricating porous nanocomposite structures. Despite a lot of research being conducted on chitosan-based electrospun materials for bone tissue engineering, the research on this topic has not been thoroughly reviewed. This review article aims to fill this knowledge gap and provides an in-depth discussion of the research on this topic. To start with, a brief overview of bone tissue engineering has been provided, followed by the properties of chitosan, which make it an important biopolymer for this application. Also, the important factors that must be considered while electrospinning chitosan, especially considering its application in bone tissue engineering, have been debated. Further, the type of chitosan-based electrospun material has been discussed along with the recent advancements in this research area. Finally, a brief perspective on the future of this technology has been provided.

Biocompatible chitin-based Janus hydrogel membranes for periodontal repair

Periodontal defects caused by severe periodontitis are a widespread issue globally. Guided tissue regeneration (GTR) using barrier membranes for alveolar bone repair is a common clinical treatment. However, most commercially available collagen barrier membranes are expensive and lack the antibacterial properties essential for effective bone regeneration. Herein, we report a natural polysaccharide chitin hydrogel barrier membrane with a Janus structure (ChT-PDA-p-HAP), featuring high antibacterial and protein-repelling activity on the outer side and good osteogenesis ability on the inner side. This multifunctional membrane is fabricated though a three-step process: (i) dissolution and regeneration of chitin, (ii) co-deposition with polydopamine (PDA) and poly(sulfobetaine methacrylate) (pSBMA), and (iii) coating with gelatin-hydroxyapatite (gelatin-HAP). In vitro cell experiments demonstrated the membrane's high biocompatibility and significant osteogenic activity. In vivo implantation in rats with periodontal defects revealed that the cemento-enamel junction index of the ChT-PDA-p-HAP membrane (1.165 mm) was superior to that of the commercial Bio-Gide® membrane (1.350 mm). This work presents a method for fabricating a chitin-based Janus barrier membrane, potentially expanding the use of chitin in tissue engineering. STATEMENT OF SIGNIFICANCE: This study introduces a Janus hydrogel membrane based on chitin, tailored for guided tissue regeneration in periodontal defects. By combining antibacterial properties and osteogenic capabilities in a single membrane, the ChT-PDA-p-HAP membrane represents a significant advancement over traditional collagen barriers. Its outer surface, enhanced by Cu2+ and PDA-pSBMA coatings, resists bacterial colonization and protein adhesion effectively, while the inner side, coated with gelatin-HAP, promotes robust bone formation. In vitro experiments demonstrate high biocompatibility and substantial osteogenic differentiation, while in vivo testing in rat models confirms good therapeutic efficacy compared to commercial membranes. This multifunctional approach not only utilizes chitin's abundant natural resource but also integrates simple coating techniques to enhance therapeutic outcomes in periodontal tissue engineering, offering promising avenues for broader biomedical applications.

Valorization of diverse waste-derived nanocellulose for multifaceted applications: A review

The study underscores the urgent need for sustainable waste management by focusing on circular economy principles, government regulations, and public awareness to combat ecological threats, pollution, and climate change effects. It explores extracting nanocellulose from waste streams such as textile, paper, agricultural matter, wood, animal, and food waste, providing a detailed process framework. The emphasis is on waste-derived nanocellulose as a promising material for eco-friendly products. The research evaluates the primary mechanical and thermal properties of nanocellulose from various waste sources. For instance, cotton-derived nanocellulose has a modulus of 2.04-2.71 GPa, making it flexible for lightweight applications. Most waste-derived nanocelluloses have densities between 1550 and 1650 kg/m3, offering strong, lightweight packaging support while enhancing biodegradability and moisture control. Crystallinity influences material usage: high crystallinity is ideal for packaging (e.g., softwood, hardwood), while low crystallinity suits textiles (e.g., cotton, bamboo). Nanocelluloses exhibit excellent thermal stability above 200 °C, useful for flame-retardant coatings, insulation, and polymer reinforcement. The research provides a comprehensive guide for selecting nanocellulose materials, highlighting their potential across industries like packaging, biomedical, textiles, apparel, and electronics, promoting sustainable innovation and a more eco-conscious future.

Recent advances in sustainable nature-based functional materials for biomedical sensor technologies

The lightweight, low-density, and low-cost natural polymers like cellulose, chitosan, and silk have good chemical and biodegradable properties due to their individually unique structural and functional elements. However, the mechanical properties of these polymers differ from each other. In this scenario, chitosan lacks good mechanical properties than cellulose and silk. The synthesis of nano natural polymer and reinforcement with suitable chemical compounds as the development of nanocomposite gives them promising multidisciplinary applications. Many kinds of research are already published with innovative bio-derived polymeric functional materials (Bd-PFM) applications. Most research interest is carried out on health concerns. Lots of attention has been paid to biomedical applications of Bd-PFM as biosensors. This review aims to provide a glimpse of the nanostructures Bd-PFM biosensors.

Recent progresses in bentonite/lignin or polysaccharide composites for sustainable water treatment

Today, with the growth of the human population, industrial activities have also increased. Different industries such as painting, cosmetics, leather, etc. have broadly developed, and as a result, they also produce a lot of pollutants. These pollutants can enter the environment and pollute water, air, and soil. Organic dyes, nitro compounds, drug residues, pesticides and herbicides are pollutants that should be removed from the environment. Natural polymers or biopolymers are important types of organic materials that are broadly applied for different applications. Among them, polysaccharides and lignin, which are two types of biopolymers, have attracted much consideration owing to their advantages such as biocompatibility, environmental friendly, safety, availability, etc. Polysaccharides include cellulose, gum, starch, alginate (Alg), chitin, and chitosan (CS). On the other hand, bentonite is one of the types of clays, which owing to their properties like large specific surface area, adsorption performance, naturally available, etc., have drawn the interest of many researchers. As a result, the synthesis of a composite including polysaccharide/lignin and bentonite can be very efficient for different applications, especially environmental ones. In this review, we instigated the preparation of these composites as well as the removal performance of them. In fact, we reported recent advancements in the synthesis of lignin- and polysaccharide-bentonite composites for the removal of diverse kinds of contaminants like organic dyes, nitro compounds, and hazardous materials.

Chitin nanofibers promote rhizobial symbiotic nitrogen fixation in Lotus japonicus

Chitin, an N-acetyl-D-glucosamine polymer, has multiple functions in living organisms, including the induction of disease resistance and growth promotion in plants. In addition, chitin oligosaccharides (COs) are used as the backbone of the signaling molecule Nod factor secreted by soil bacteria rhizobia to establish a mutual symbiosis with leguminous plants. Nod factor perception triggers host plant responses for rhizobial symbiosis. In this study, the effects of chitins on rhizobial symbiosis were examined in the leguminous plants Lotus japonicus and soybean. Chitin nanofiber (CNF), retained with polymeric structures, and COs elicited calcium spiking in L. japonicus roots expressing a nuclear-localized cameleon reporter. Shoot growth and symbiotic nitrogen fixation were significantly increased by CNF but not COs in L.japonicus and soybean. However, treatments with chitin and cellulose nanofiber, structurally similar polymers to CNF, did not affect shoot growth and nitrogen fixation in L.japonicus. Transcriptome analysis also supported the specific effects of CNF on rhizobial symbiosis in L.japonicus. Although chitins comprise the same monosaccharides and nanofibers share similar physical properties, only CNF can promote rhizobial nitrogen fixation in leguminous plants. Taking the advantages on physical properties, CNF could be a promising material for improving legume yield by enhancing rhizobial symbiosis.

Chitosan-based sustainable packaging and coating technologies for strawberry preservation: A review

Strawberry fruits are popular all over the world due to their rich organoleptic properties and enormous health benefits. However, it is highly susceptible to postharvest spoilage due to various factors, including moisture loss, nutrient oxidation, and microbial spoilage. Recently, various researchers have studied the effect of chitosan-based flexible films and surface coatings on the shelf life of strawberries. Despite various reviews providing general information on the effects of chitosan-based films and coatings on various food products, no review has focused solely on their effects on postharvest preservation and the shelf life of strawberries. The purpose of this review is to summarize the current research on chitosan-based formulations for extending the shelf life of strawberries. Chitosan, a cationic carbohydrate polymer, possesses excellent properties such as film formation, mechanical strength, non-toxicity, biodegradability, edibility, UV-blocking ability, antioxidant activity, and antibacterial functionality, justifying its potential as packaging/coating material for fresh agricultural products, including strawberries. This review covers the various factors responsible for strawberry spoilage and the properties of chitosan that help counteract these factors. Additionally, the advantages of chitosan-based preservation technology compared to existing strawberry preservation methods were explained, efficiency was evaluated, and future research directions were suggested.

The Phylogenomic Characterization of Planotetraspora Species and Their Cellulases for Biotechnological Applications

This study aims to evaluate the in silico genomic characteristics of five species of the genus Planotetraspora: P. kaengkrachanensis, P. mira, P. phitsanulokensis, P. silvatica, and P. thailandica, with a view to their application in therapeutic research. The 16S rRNA comparison indicated that these species were phylogenetically distinct. Pairwise comparisons of digital DNA-DNA hybridization (dDDH) and OrthoANI values between these studied type strains indicated that dDDH values were below 62.5%, while OrthoANI values were lower than 95.3%, suggesting that the five species represent distinct genomospecies. These results were consistent with the phylogenomic study based on core genes and the pangenome analysis of these five species within the genus Planotetraspora. However, the genome annotation showed some differences between these species, such as variations in the number of subsystem category distributions across whole genomes (ranging between 1979 and 2024). Additionally, the number of CAZYme (Carbohydrate-Active enZYme) genes ranged between 298 and 325, highlighting the potential of these bacteria for therapeutic research applications. The in silico physico-chemical characteristics of cellulases from Planotetraspora species were analyzed. Their 3D structure was modeled, refined, and validated. A molecular docking analysis of this cellulase protein structural model was conducted with cellobiose, cellotetraose, laminaribiose, carboxymethyl cellulose, glucose, and xylose ligand. Our study revealed significant interaction between the Planotetraspora cellulase and cellotetraose substrate, evidenced by stable binding energies. This suggests that this bacterial enzyme holds great potential for utilizing cellotetraose as a substrate in various applications. This study enriches our understanding of the potential applications of Planotetraspora species in therapeutic research.

Stretchable hydrogels of chitosan/hyaluronic acid induced by polyelectrolyte complexation around neutral pH

In this work, we propose the formation of stretchable hydrogels at neutral pH from the physical crosslinking of chitosan (CS) and hyaluronic acid (HA) by polyelectrolyte complexation. A mixture of CS (Mw ≈ 600 kg/mol, degree of acetylation ≈ 50 %) solution and HA (Mw ≈ 77 kg/mol) solution was prepared with an excess of salts screening the electrostatic interactions CS/HA. In a controlled manner, the polyelectrolyte complexation was induced through the progressive dialysis of the salted polymer mixture against a sodium acetate solution (AcONa, 0.01 M) for 7 days. Depending on [HA], various materials were obtained: viscous solutions at [HA] = 0.75 % (w/v); hydrogels at [HA] = 1.50-2.24 % (w/v) with Young modulus of 14 kPa and stretchable to 200 %. The small angle X-ray scattering characterization of the hydrogels revealed a multiscale organization related to the conformation of the polymers induced by the physical interactions. The dialysis process with AcONa was optimized by adding a dialysis step against a zinc acetate solution containing Zn2+. The combination of polyelectrolyte complexation between CS/HA and metal complexation between Zn2+ and the polymers led to an enhancement of the hydrogel stretchability up to 400 %.

O-carboxymethyl chitosan in biomedicine: A review

O-carboxymethyl chitosan (O-CMC) is a chitosan derivative produced through the substitution of hydroxyl (-OH) functional groups in glucosamine units with carboxymethyl (-CH2COOH) substituents, effectively addressing the inherent solubility issues of chitosan in aqueous solutions. O-CMC has garnered significant interest due to its enhanced solubility, elevated viscosity, minimal toxicity, and advantageous biocompatibility properties. Furthermore, O-CMC demonstrates antibacterial, antifungal, and antioxidant characteristics, rendering it a promising candidate for various biomedical uses such as wound healing, tissue engineering, anti-tumor therapies, biosensors, and bioimaging. Additionally, O-CMC is well-suited for the fabrication of nanoparticles, hydrogels, films, microcapsules, and tablets, offering opportunities for effective drug delivery systems. This review outlines the distinctive features of O-CMC, offers analyses of advancements and future potential based on current research, examines significant obstacles for clinical implementation, and foresees its ongoing significant impacts in the realm of biomedicine.

Chitosan composite with mesenchymal stem cells: Properties, mechanism, and its application in bone regeneration

Bone defects resulting from trauma, illness or congenital abnormalities represent a significant challenge to global health. Conventional treatments such as autographs and allografts have limitations, leading to the exploration of bone tissue engineering (BTE) as an alternative approach. This review aims to provide a comprehensive analysis of bone regeneration mechanisms with a focus on the role of chitosan-based biomaterials and mesenchymal stem cells (MSCs) in BTE. In addition, the physiochemical and biological properties of chitosan, its potential for bone regeneration when combined with other materials and the mechanisms through which MSCs facilitate bone regeneration were investigated. In addition, different methods of scaffold development and the incorporation of MSCs into chitosan-based scaffolds were examined. Chitosan has remarkable biocompatibility, biodegradability and osteoconductivity, making it an attractive choice for BTE. Interactions between transcription factors such as Runx2 and Osterix and signaling pathways such as the BMP and Wnt pathways regulate the differentiation of MSCs and bone regeneration. Various forms of scaffolding, including porous and fibrous injections, have shown promise in BTE. The synergistic combination of chitosan and MSCs in BTE has significant potential for addressing bone defects and promoting bone regeneration, highlighting the promising future of clinical challenges posed by bone defects.

Isolation of chitosan and hydroxyapatite from waste edible white garden snail shells and their sensing applications towards industrial Congo red dye detection: Greener approach

Biomaterials like chitosan, hydroxyapatite have been used in biomedical and pharmaceutical field, due to its valuable biochemical and physiological properties. In current work firstly our group has isolated a polysaccharide chitosan along with hydroxyapatite biomaterial from the same source by varying the process condition via greener approach. We have adapted greener approach for the isolation of chitosan within a short period of time and this is the very first report for the isolation of both chitosan and hydroxyapatite simultaneously from the same waste edible garden snail shells. Both these materials were thoroughly characterized by using UV, FT-IR, SEM techniques. Among synthetic colourants, congo red dye is recognized as carcinogens, which are usually used in the textile manufacturing. Interestingly, one of our biomaterial hydroxyapatite has shown good selectivity towards Congo red dye. The sensitivity range was obtained from 10 to 100 μM within the LOD of 101.52 nM. The developed sensor has been tested for various industrial effluents and shown good agreement with our results. Meanwhile these chitosan and hydroxyapatite have also been used as capping agent for the preparation of stable gold nanoparticles.