A review on chitosan-cellulose blends and nanocellulose reinforced chitosan biocomposites: Properties and their applications

Flexible chitosan-graphene oxide-based biomacroporous cryogel via grafting cryopolymerization for selective recovery of myricetin from food sample

Myricetin has a significant role in pharmacology, specifically in traditional Chinese medicine. The most intriguing pharmacological action of myricetin consists of its multi-pathway anticancer effects. Therefore, rapid and selective isolation of myricetin from garlic and apple juices has notable pharmacological benefits. Chitosan-graphene oxide-based biomacroporous cryogel are highly efficient and environmentally friendly materials for adsorption. The current study involved the synthesis of chitosan-graphene oxide-based biomacroporous cryogel sorbent for the selective recovery of myricetin. The characterization investigation utilizing SEM, XRD, EDS and FTIR demonstrated the successful synthesis of a chitosan-graphene oxide-based biomacroporous cryogel. Additionally, XPS effectively revealed the interaction of functional groups on the biomacroporous cryogel sorbent with myricetin. The maximum adsorption capacity for myricetin, under optimized conditions, was 167 mg g-1 in 60 min. The equilibrium adsorption capacity was achieved at neutral pH with optimal parameters, and the Freundlich isotherm model was followed. The pseudo-second-order model presented better descriptions of the adsorption process. In addition, the chitosan-graphene oxide-based biomacroporous cryogel exhibited remarkable selectivity: due to involvement of two primary factors: the number of hydroxyl-groups and the fact that the extra hydroxyl group at position 5' in ring B allows for a more noticeable transfer of the unshared electron pair from oxygen to the π system of the B ring. The adsorption of myricetin decreases to 2 % after three consecutive cycles, indicating the significant reusability of chitosan-graphene oxide-based biomacroporous cryogel. Additionally, the chitosan-graphene oxide based-biomacroporous cryogel that was produced has been utilized after one month and shown a comprehensive shelf-life. Typical adsorption mechanisms include hydrogen bonding and demonstrates significant potential for the efficient and specific isolation of myricetin in complex mixtures. Furthermore, the chitosan-graphene oxide-based biomacroporous cryogel demonstrated a significant rise in recovery of myricetin flavonoid in real samples of garlic and apple juices, rising from 99.66 % to 114.29 %.

Regulatory effects of different spacer alkyl chains on the in vitro antioxidant and antibacterial activities of chitosan quaternary ammonium/phosphonium salt derivatives

In this study, three chitosan quaternary phosphonium salts and three chitosan quaternary ammonium salts with varying spacer chain lengths were synthesized. Structure characterization of the obtained products was conducted using Fourier-transform infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis, and elemental analysis. Additionally, the in vitro scavenging efficiency of these derivatives against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radicals, as well as their antibacterial activities against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), were evaluated. The results indicated that the scavenging efficiency of the chitosan quaternary phosphonium salt at a concentration of 1.6 mg/mL ranged from 36.9 % to 48.7 % for DPPH free radicals and from 48.3 % to 66.3 % for superoxide free radicals, outperforming that of the chitosan quaternary ammonium salt with long alkyl chains. Furthermore, an increase in the length of the spacer alkyl chain was associated with enhanced antibacterial activities of the corresponding chitosan derivatives. At a concentration of 1.0 mg/mL, the synthesized chitosan derivatives demonstrated antibacterial rates exceeding 90 % against both E. coli and S. aureus. Notably, the CCK-8 assay confirmed that these derivatives are non-toxic to 293 T cells. Among the six derivatives, TPPBOC and DMDOC, characterized by longer spacer alkyl chains, demonstrated superior antioxidant and antibacterial activities. This research establishes a robust theoretical foundation for the development of more effective and safer antioxidants and antibacterial agents, thereby enriching the knowledge base in chitosan chemistry and functional materials, and paving new pathways for the innovation of novel antioxidant and antibacterial materials.

A comprehensive review on nanochitosan and its diverse applications in various industries

Nanochitosan, a nanostructured form of chitosan produced from chitin, has become a widely used material with a wide range of applications in a variety of industries. This review summarizes the study on nanochitosan, including its synthesis techniques, distinct physicochemical characteristics, and uses in medicine, agriculture, cosmetics, and cleaning up the environment. The review also emphasizes the impact of synthesis methods such as nanoprecipitation, electrospinning, and chemical modifications on the material's properties and applications. In agriculture, nanochitosan can be used as a long-lasting biopolymer to support crop growth and health. Because it is mucoadhesive and compatible with living things, it can also enhance the effectiveness of medication. The potential of nanochitosan to enhance skin permeability and encapsulate active chemicals in cosmetics presents exciting opportunities for innovation. Furthermore, nanochitosan effectiveness as a biosorbent and antibacterial agent in wastewater treatment highlights its potential to tackle environmental issues. The present study offers valuable perspectives on the present status of nanochitosan research, highlights significant obstacles, and suggests future avenues for optimizing its industrial applications.

Current Paradigms and Future Challenges in Harnessing Nanocellulose for Advanced Applications in Tissue Engineering: A Critical State-of-the-Art Review for Biomedicine

Nanocellulose-based biomaterials are at the forefront of biomedicine, presenting innovative solutions to longstanding challenges in tissue engineering and wound repair. These advanced materials demonstrate enhanced mechanical properties and improved biocompatibility while allowing for precise tuning of drug release profiles. Recent progress in the design, fabrication, and characterization of these biomaterials underscores their transformative potential in biomedicine. Researchers are employing strategic methodologies to investigate and characterize the structure and functionality of nanocellulose in tissue engineering and wound repair. In tissue engineering, nanocellulose-based scaffolds offer transformative opportunities to replicate the complexities of native tissues, facilitating the study of drug effects on the metabolism, vascularization, and cellular behavior in engineered liver, adipose, and tumor models. Concurrently, nanocellulose has gained recognition as an advanced wound dressing material, leveraging its ability to deliver therapeutic agents via precise topical, transdermal, and systemic pathways while simultaneously promoting cellular proliferation and tissue regeneration. The inherent transparency of nanocellulose provides a unique advantage, enabling real-time monitoring of wound healing progress. Despite these advancements, significant challenges remain in the large-scale production, reproducibility, and commercial viability of nanocellulose-based biomaterials. This review not only underscores these hurdles but also outlines strategic directions for future research, including the need for bioengineering of nanocellulose-based wound dressings with scalable production and the incorporation of novel functionalities for clinical translation. By addressing these key challenges, nanocellulose has the potential to redefine biomedical material design and offer transformative solutions for unmet clinical needs in tissue engineering and beyond.

3D Porous Polycaprolactone with Chitosan-Graft-PCL Modified Surface for In Situ Tissue Engineering

Tissue engineering has emerged as a promising approach for improved regeneration of native tissue and could increase the quality of life of many patients. However, the treatment of injured tissue transitions is still in its early stages, relying primarily on a purely physical approach in medical surgery. A biodegradable implant with a modified surface that is capable of biological active protein delivery via a nanoparticulate release system could advance the field of musculoskeletal disorder treatments enormously. In this study, interconnected 3D macroporous scaffolds based on Polycaprolactone (PCL) were fabricated in a successive process of blending, annealing and leaching. Blending with varying parts of Polyethylene oxide (PEO), NaCl and (powdered) sucrose and altering processing conditions yielded scaffolds with a huge variety of morphologies. The resulting unmodified hydrophobic scaffolds were modified using two graft polymers (CS-g-PCLx) with x = 29 and 56 (x = PCL units per chitosan unit). Due to the chitosan backbone hydrophilicity was increased and a platform for a versatile nanoparticulate release system was introduced. The graft polymers were synthesized via ring opening polymerization (ROP) of ε-Caprolactone using hydroxy groups of the chitosan backbone as initiators (grafting from). The suspected impact on biocompatibility of the modification was investigated by in vitro cell testing. In addition, the CS-g-PCL modification opened up the possibility of Layer by Layer (LbL) coating with alginate (ALG) and TGF-β3-loaded chitosan tripolyphosphate (CS-TGF-β3-TPP) nanoparticles. The subsequent release study showed promising amounts of growth factor released regarding successful in vitro cell differentiation and therefore could have a possible therapeutic impact.

Applications and Advantages of Cellulose-Chitosan Biocomposites: Sustainable Alternatives for Reducing Plastic Dependency

This review presents a comprehensive review of cellulose-chitosan-based biocomposites that have high potential as sustainable alternatives to synthetic polymers. These biocomposites, due to biocompatibility, biodegradability, and antimicrobial properties, attract attention for wide application in various industries. This review includes modern methods for producing cellulose-chitosan composites aimed at improving their mechanical and chemical properties, such as strength, flexibility, and water resistance. Particular attention is paid to the use of composites in packaging materials, where they provide protection and durability of products, and help reduce the environmental footprint. In medicine, such composites are used for drug delivery and tissue engineering, providing controlled release of active substances and tissue regeneration. In addition, their advantages in wastewater treatment are discussed, where the composites effectively remove heavy metal ions and organic pollutants due to their high sorption capacity. This study focuses on the wide potential of cellulose-chitosan biocomposites and their role in solving environmental problems.

Computer-Assisted Strategies as a Tool for Designing Green Monomer-Based Molecularly Imprinted Materials

Molecularly imprinted polymers (MIPs) are defined as artificial receptors due to their selectivity and specificity. Their advantageous properties compared to biological alternatives have sparked interest among scientists, as detailed in numerous review papers. Currently, there is significant attention on adhering to the principles of green chemistry and environmental protection. In this context, MIP research groups have focused on developing eco-friendly procedures. The application of "greener" monomers and reagents, along with the utilization of computational methodologies for design and property analysis, are two activities that align with the green chemistry principles for molecularly imprinted technology. This review discusses the application of computational methodologies in the preparation of MIPs based on eco-friendly non-acrylic/vinylic monomers and precursors, such as alkoxysilanes, ionic liquids, deep eutectic solvents, bio-based molecules-specifically saccharides, and biomolecules like proteins. It provides a brief introduction to MIP materials, the green aspects of MIP production, and the application of computational simulations. Following this, brief descriptions of the studied monomers, molecular simulation studies of green monomer-based MIPs, and computational strategies are presented. Finally, conclusions and an outlook on the future directions of computational analysis in the production of green imprinted materials are pointed out. To the best of my knowledge, this work is the first to combine these two aspects of MIP green chemistry principles.

The incorporation of chitosan nanoparticles enhances the barrier properties and antifungal activity of chitosan-based nanocomposite coating films

The potential alternative of exploring the development of nanocomposites through a single-molecule approach, such as combining chitosan nanoparticles (ChiNP) with chitosan (Chi), remains to be investigated. To maintain the insolubility of the ChiNP filler in the system, the protonation of weakly basic amino groups necessitates the pH of the coating solution above the pKa (6-6.5). This study aimed to evaluate the biofunctional properties improvements of Chi coatings incorporated with ChiNP as filler agents. The coating film forming solution comprised of 0.8 % Chi combined with varying concentrations (0 %, 0.1 %, 0.5 %, and 1 %) of ChiNP. The morphology of ChiNP was characterized via atomic force spectroscopy (AFM). Incorporating the ChiNP (1 %) significantly enhanced antifungal efficacy, i.e., an 88.28 % reduction in fungal activity compared with the control group, and a 65 % reduction compared with pure Chi against Botrytis cinerea. The incorporation of ChiNP improved the ultraviolet and visible light wavelengths, water vapor permeability, hydrophobicity, and thermal properties. Scanning electron microscopy and AFM were performed to assess the surface and internal microstructures of the coating. The findings of this study suggested that the nanocomposite coatings herein presented is potential for use in active packaging, especially in the context of preserving fresh fruit products.

Development and evaluation of amine-functionalized β-cyclodextrin grafted starch as a natural flocculant for turbidity removal in water treatment

Recently, biopolymers have been used as coagulants/flocculants due to their biodegradability, low cost, and renewability. In this study, an environmentally friendly amine-functionalized starch-based flocculant was successfully prepared. Initially, β-cyclodextrin was grafted onto the starch backbone to increase the number of hydroxyl groups, and this composite was named CD-starch. Subsequently, in order to introduce cationic properties and enhance effective flocculation, CD-starch was modified using amine functional groups. The surface functional groups were engineered by introducing different amine to CD-starch ratios (0.5:1, 1:1, 2:1 w/w), named A-CD-starch 0.5, 1 and 2, respectively. Following the characterization of the synthesized substrate, its performance in the flocculation process of a kaolin suspension was investigated. The effects of different parameters, including pH, flocculant dosage, and initial turbidity on wastewater turbidity removal, was investigated. The results showed that a higher ratio of amine to CD-starch leads to a better amination reaction due to the greater availability of nitrogen for alkylation. Jar experiments showed that for initial turbidities of 50, 150 and 300 NTU, the appropriate doses of flocculant were 0.070, 0.085 and 0.130 mg/mL, respectively. For these initial turbidities, the maximum turbidity removal was achieved 80.1 %, 92 %, and 97.8 %, respectively. This work provides an innovative natural flocculant based on starch which can effectively treat turbid wastewaters.

Durable silver nanowire transparent electrodes enabled by biorenewable nanocoating using chitin and cellulose nanofibers for flexible electronics

The protection of silver nanowire (AgNW) networks is crucial for enhancing their durability and applicability to flexible electronics. In this study, we present a sustainable and efficient strategy to protect AgNW-based flexible transparent electrodes (FTEs) using a layer-by-layer (LBL) assembly of biorenewable chitin and cellulose nanofibers (Chi and Cell). These uniform LBL-assembled thin films were successfully fabricated on AgNW FTEs due to their opposite surface charges. The resulting (Chi/Cell)n bilayers, where n is the number of bilayers, did not degrade the optoelectrical properties of AgNW FTEs and significantly enhanced their stability under various harsh conditions. The optimized (Chi/Cell)10@Al-AgNW FTEs exhibited comprehensive stability against UV/O3 treatment for 40 min, thermal treatment at 250 °C for 350 min, Na2S (1%), HCl (10%), and NH3 (30%) treatments for 3, 30, and 105 min, respectively, sonication for 300 min, and 10 000 cycles of bending test. Therefore, the (Chi/Cell)10@Al-AgNW FTEs were successfully applied to transparent heaters (TH) and pressure sensors with remarkably improved applicability, durability, and performance compared to pristine AgNW FTEs, providing a reassuring solution to the stability issues of AgNW-based FTEs.

Preparation, characterization, and application of gallic acid-mediated photodynamic chitosan-nanocellulose-based films

In this study, an active film composed of gallic acid (GA), chitosan (CS), and cellulose nanocrystals (CNC) was prepared using a solution casting method and synergistic photodynamic inactivation (PDI) technology. Characterization of the film showed that the CS-CNC-GA composite film had high transparency and UV-blocking ability. The addition of GA (0.2 %-1.0 %) significantly enhanced the mechanical properties, water resistance, and thermal stability of the film. The tensile strength increased up to 46.30 MPa, and the lowest water vapor permeability was 1.16 × e-12 g/(cm·s·Pa). The PDI-treated CS-CNC-GA1.0 composite film exhibited significantly enhanced antibacterial activity, with inhibition zone diameters of 31.83 mm against Staphylococcus aureus and 21.82 mm against Escherichia coli. The CS-CNC-GA composite film also showed good antioxidant activity. Additionally, the CS-CNC-GA1.0 composite film generated a large amount of singlet oxygen under UV-C light irradiation. It was found that using the CS-CNC-GA1.0 composite film for packaging and storage of oysters at 4 °C effectively delayed the increase in pH, total colony count, and lipid oxidation in oysters. In conclusion, the CS-CNC-GA composite film based on PDI technology has great potential for applications in the preservation of aquatic products.

Lignin Nanoparticles: Transforming Environmental Remediation

In the face of escalating environmental challenges driven by human activities, the quest for innovative solutions to counter pollution, contamination, and ecological degradation has gained paramount importance. Traditional approaches to environmental remediation often fall short in addressing the complexity and scale of modern-day environmental problems. As industries transition towards sustainable paradigms, the exploration of novel materials and technologies becomes crucial. Lignin nanoparticles have emerged as a promising avenue of exploration in this context. Once considered a mere byproduct, lignin's unique properties and versatile functional groups have propelled it to the forefront of environmental remediation research. This review paper delves into the resurgence of lignin from an environmental perspective, examining its pivotal role in carbon cycling and its potential to address various environmental challenges. The paper extensively discusses the synthesis, properties, and applications of lignin nanoparticles in diverse fields such as water purification and soil remediation. Moreover, it highlights the challenges associated with nanoparticle deployment, ranging from Eco toxicological assessments to scalability issues. Multidisciplinary collaboration and integration of research findings with real-world applications are emphasized as critical factors for unlocking the transformative potential of lignin nanoparticles. Ultimately, this review underscores lignin nanoparticles as beacons of hope in the pursuit of cleaner, healthier, and more harmonious coexistence between humanity and nature through innovative environmental remediation strategies.

Natural Rubber Films Reinforced with Cellulose and Chitosan Prepared by Latex Aqueous Microdispersion

In this paper, green composite films comprising natural rubber (NR), cellulose (CE), and chitosan (CS) were successfully fabricated through a simple, facile, cost-effective method in order to improve mechanical, chemical, and antimicrobial properties of NR composite films. Chitosan with a low molecular weight of 30,000-50,000 g/mol (CS-L) and a medium molecular weight of 300,000-500,000 g/mol (CS-M) was used for the fabrication. The composite films were prepared via a latex aqueous microdispersion method with different weight ratios of NR:CE:CS-L/CS-M. Fourier transform infrared spectroscopy (FTIR) results demonstrated strong interactions of hydrogen bonds between CE and CS-L/CS-M in the composite films. The tensile strength and the modulus of the composite films in dried form were found to significantly increase with the reinforcement of CE and CS-L/CS-M. The maximum tensile strength (13.8 MPa) and Young's modulus (12.7 MPa) were obtained from the composite films reinforced with CE at 10 wt.% and CS-L at 10 wt.%. The high elongation of 500-526% was obtained from the composite films reinforced with CE at 10 wt.% and CS (CS-L or CS-M) at 5.0 wt.%. The modification could also significantly promote antimicrobial activities and chemical resistance against non-polar solvents in the composite films. The NR composite films have potential uses as flexible films for sustainable green packaging.

Strategies, Challenges, and Prospects of Nanoparticles in Gynecological Malignancies

Gynecologic cancers are a significant health issue for women globally. Early detection and successful treatment of these tumors are crucial for the survival of female patients. Conventional therapies are often ineffective and harsh, particularly in advanced stages, necessitating the exploration of new therapy options. Nanotechnology offers a novel approach to biomedicine. A novel biosensor utilizing bionanotechnology can be employed for early tumor identification and therapy due to the distinctive physical and chemical characteristics of nanoparticles. Nanoparticles have been rapidly applied in the field of gynecologic malignancies, leading to significant advancements in recent years. This study highlights the significance of nanoparticles in treating gynecological cancers. It focuses on using nanoparticles for precise diagnosis and continuous monitoring of the disease, innovative imaging, and analytic methods, as well as multifunctional drug delivery systems and targeted therapies. This review examines several nanocarrier systems, such as dendrimers, liposomes, nanocapsules, and nanomicelles, for gynecological malignancies. The review also examines the enhanced therapeutic potential and targeted delivery of ligand-functionalized nanoformulations for gynecological cancers compared to nonfunctionalized anoformulations. In conclusion, the text also discusses the constraints and future exploration prospects of nanoparticles in chemotherapeutics. Nanotechnology will offer precise methods for diagnosing and treating gynecological cancers.

Chitosan-based aerogels: A new paradigm of advanced green materials for remediation of contaminated water

Chitosan (CS) aerogels are highly porous (∼99 %), exhibit ultralow density, and are excellent sorbents for removing ionic pollutants and oils/organic solvents from water. Their abundant hydroxyl and amino groups facilitate the adsorption of ionic pollutants through electrostatic interaction, complexation and chelation mechanisms. Selection of suitable surface wettability is the way to separate oils/organic solvents from water. This review summarizes the most recent developments in improving the adsorption performance, mechanical strength and regeneration of CS aerogels. The structure of the paper follows the extraction of chitosan, preparation and sorption characteristics of CS aerogels for heavy metal ions, organic dyes, and oils/organic solvents, sequentially. A detailed analysis of the parameters that influence the adsorption/absorption performance of CS aerogels is carried out and their effective control for improving the performance is suggested. The analysis of research outcomes of the recently published data came up with some interesting facts that the unidirectional pore structure and characteristics of the functional group of the aerogel and pH of the adsorbate have led to the enhanced adsorption performance of the CS aerogel. Finally, the excerpts of the literature survey highlighting the difficulties and potential of CS aerogels for water remediation are proposed.

Development and characterization of three-dimensional antibacterial nanocomposite sponges of chitosan, silver nanoparticles and halloysite nanotubes

In this work, we developed novel nanocomposite three-dimensional (3D) scaffolds composed of chitosan (CTS), halloysite nanotubes (HNTs) and silver nanoparticles (AgNPs) with enhanced antimicrobial activity and fibroblast cell compatibility for their potential use in wound dressing applications. A stock CTS-HNT solution was obtained by mixing water-dispersed HNTs with CTS aqueous-acid solution, and then, AgNPs, in different concentrations, were synthesized in the CTS-HNT solution via a CTS-mediated in situ reduction method. Finally, freeze-gelation was used to obtain CTS-HNT-AgNP 3D porous scaffolds (sponges). Morphology analysis showed that synthesized AgNPs were spherical with an average diameter of 11 nm. HNTs' presence did not affect the AgNPs morphology or size but improved the mechanical properties of the scaffolds, where CTS-HNT sponges exhibited a 5 times larger compression stress than bare-CTS sponges. AgNPs in the scaffolds further increased their mechanical strength in correlation to the AgNP concentration, and conferred them improved antibacterial activity against Gram-negative and Gram-positive bacteria, inhibiting the planktonic proliferation and adhesion of bacteria in a AgNP concentration depending on manner. In vitro cell viability and immunofluorescence assays exhibited that human fibroblast (HF) culture was supported by the sponges, where HF retained their phenotype upon culture on the sponges. Present CTS-HNT-AgNP sponges showed promising mechanical, antibacterial and cytocompatibility properties to be used as potential scaffolds for wound dressing applications.

Modified Cellulose for Adsorption of Methylparaben and Butylparaben from an Aqueous Solution

Emerging contaminants are chemical products that are found in low concentrations, are not regulated by environmental norms, and cause health effects. Among this group of contaminants are parabens, a family of p-hydroxybenzoic acid esters used as preservatives in cosmetics, pharmaceuticals, and food products. Recent research describes parabens as endocrine disruptors that can cause health alterations. Some of the best alternatives for pollutant removal include the adsorption process, which can use materials that are inexpensive, abundant, and susceptible to modifications. In this sense, cellulose can be an option for obtaining materials that can be used in the removal of contaminants. This research investigates the synthesis of benzoic cellulose (MCB) and magnetic cellulose (MCM) as well as its use as an adsorbent for the removal of methylparaben (MP) and butylparaben (BP) from water. Likewise, physicochemical characterization, including Fourier transform infrared (FTIR), scanning electronic microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA), for both cellulose materials was carried out. Moreover, pseudo-first-order, pseudo-second-order, Elovich, Weber, Morris, and Boyd models were used to investigate the adsorption kinetics. As a result, the pseudo-second-order model was favorable for both modified cellulose and the two parabens assayed. Finally, Freundlich, Langmuir, and Sips adsorption isotherm models were investigated; the Langmuir model was the best for the adsorption isotherm data. The adsorption of methylparaben and butylparaben was in the following order: MCM > MCB. The maximum adsorption capacity of MP and BP for MCM was 9.58 and 12.03 mg g-1, respectively. For instance, the results showed that the modified cellulose adsorbed the parabens physically, which could involve electrostatic attraction, hydrogen bonding, π-π bonding, and hydrophobic interactions.

Polymer-Based Wound Dressings Loaded with Essential Oil for the Treatment of Wounds: A Review

Wound healing can result in complex problems, and discovering an effective method to improve the healing process is essential. Polymeric biomaterials have structures similar to those identified in the extracellular matrix of the tissue to be regenerated and also avoid chronic inflammation, and immunological reactions. To obtain smart and effective dressings, bioactive agents, such as essential oils, are also used to promote a wide range of biological properties, which can accelerate the healing process. Therefore, we intend to explore advances in the potential for applying hybrid materials in wound healing. For this, fifty scientific articles dated from 2010 to 2023 were investigated using the Web of Science, Scopus, Science Direct, and PubMed databases. The principles of the healing process, use of polymers, type and properties of essential oils and processing techniques, and characteristics of dressings were identified. Thus, the plants Syzygium romanticum or Eugenia caryophyllata, Origanum vulgare, and Cinnamomum zeylanicum present prospects for application in clinical trials due to their proven effects on wound healing and reducing the incidence of inflammatory cells in the site of injury. The antimicrobial effect of essential oils is mainly due to polyphenols and terpenes such as eugenol, cinnamaldehyde, carvacrol, and thymol.

Recycling and 3D-Printing Biodegradable Membranes for Gas Separation-toward a Membrane Circular Economy

Polymer membranes employed in gas separation play a pivotal role in advancing environmental sustainability, energy production, and gas purification technologies. Despite their significance, the current design and manufacturing of these membranes lack cradle-to-cradle approaches, contributing to plastic waste pollution. This study explores emerging solutions, including the use of biodegradable biopolymers such as polyhydroxybutyrate (PHB) and membrane recycling, with a focus on the specific impact of mechanical recycling on the performance of biodegradable gas separation membranes. This research represents the first systematic exploration of recycling biodegradable membranes for gas separation. Demonstrating that PHB membranes can be recycled and remanufactured without solvents using hot-melt extrusion and 3D printing, the research highlights PHB's promising performance in developing more sustainable CO2 separations, despite an increase in gas permeability with successive recycling steps due to reduced polymer molecular weight. The study emphasizes the excellent thermal, chemical, and mechanical stability of PHB membranes, albeit with a marginal reduction in gas selectivity upon recycling. However, limitations in PHB's molecular weight affecting extrudability and processability restrict the recycling to three cycles. Anticipating that this study will serve as a foundational exploration, we foresee more sophisticated recycling studies for gas separation membranes, paving the way for a circular economy in future membrane technologies.

Chitosan based ethanolicAllium Sativumextract hydrogel film: a novel skin tissue regeneration platform for 2nd degree burn wound healing

This study investigated the potential of ethanolic garlic extract-loaded chitosan hydrogel film for burn wound healing in an animal model. The ethanolic garlic extract was prepared by macerating fresh ground garlic cloves in ethanol for 24 h, followed by filtration and concentration using a rotary evaporator. Hydrogels were then prepared by casting a chitosan solution with garlic extract added at varying concentrations for optimization and, following drying, subjected to various characterization tests, including moisture adsorption (MA), water vapor transmission rate (WVTR), and water vapor permeability rate (WVPR), erosion, swelling, tensile strength, vibrational, and thermal analysis, and surface morphology. The optimized hydrogel (G2) was then analyzedin vivofor its potential for healing 2nd degree burn wounds in rats, and histological examination of skin samples on day 14 of the healing period. Results showed optimized hydrogel (G2; chitosan: 2 g, garlic extract: 1 g) had MA of 56.8% ± 2.7%, WVTR and WVPR of 0.00074 ± 0.0002, and 0.000 498 946 ± 0.0001, eroded up to 11.3% ± 0.05%, 80.7% ± 0.04% of swelling index, and tensile strength of 16.6 ± 0.9 MPa, which could be attributed to the formation of additional linkages between formulation ingredients and garlic extract constituents at OH/NH and C=O, translating into an increase in transition melting temperature and enthalpy (ΔT= 238.83 °C ± 1.2 °C, ΔH= 4.95 ± 0.8 J g-1) of the chitosan moieties compared with blank. Animal testing revealed G2 formulation significantly reduced the wound size within 14 d of the experiment (37.3 ± 6.8-187.5 ± 21.5 mm2) and had significantly higher reepithelization (86.3 ± 6.8-26.8 ± 21.5 and 38.2% ± 15.3%) compared to untreated and blank groups by hastening uniform and compact deposition of collagen fibers at the wound site, cementing developed formulation a promising platform for skin regeneration.

Efficient Cr(VI) remediation by electrospun composite porous nanofibers incorporating biomass with metal oxides and metal-organic framework

To develop a highly efficient adsorbent to remediate and remove hexavalent chromium ions (Cr(VI)) from polluted water, cellulose acetate (CA) and chitosan (CS), along with metal oxides (titanium dioxide (TiO2) and ferroferric oxide (Fe3O4)), and a zirconium-based metal-organic framework (UiO-66) were used to fabricate the composite porous nanofiber membranes through electrospinning. The adsorption performance, influencing factors, adsorption kinetics and isotherms of composite nanofiber membranes were comprehensively investigated. The multi-layer membrane with interpenetrating nanofibers and surface functional groups enhanced the natural physical adsorption and provided potential chemical sites. The thermal stability was improved by introducing TiO2 and UiO-66. CA/CS/UiO-66 exhibited the highest adsorption capacity (118.81 mg g-1) and removal rate (60.76%), which were twice higher than those of the control. The correlation coefficients (R2) of all the composite nanofibers regressed by the Langmuir model were significantly higher than those by the Freundlich model. The pseudo-first-order kinetic curve of CA/CS composite nanofibers showed the highest R2 (0.973), demonstrating that the whole adsorption process involved a combination of strong physical adsorption and weak chemical adsorption by the amino groups of CS. However, the R2 values of the pseudo-second-order kinetic model increased after incorporating TiO2, Fe3O4, and UiO-66 into the CA/CS composite nanofiber membranes since an enhanced chemical reaction with Cr (VI) occured during the adsorption.

Insect cuticle-inspired design of sustainably sourced composite bioplastics with enhanced strength, toughness and stretch-strengthening behavior

Insect cuticles that are mainly made of chitin, chitosan and proteins provide insects with rigid, stretchable and robust skins to defend harsh external environment. The insect cuticle therefore provides inspiration for engineering biomaterials with outstanding mechanical properties but also sustainability and biocompatibility. We herein propose a design of high-performance and sustainable bioplastics via introducing CPAP3-A1, a major structural protein in insect cuticles, to specifically bind to chitosan. Simply mixing 10w/w% bioengineered CPAP3-A1 protein with chitosan enables the formation of plastics-like, sustainably sourced chitosan/CPAP3-A1 composites with significantly enhanced strength (∼90 MPa) and toughness (∼20 MJ m -3), outperforming previous chitosan-based composites and most synthetic petroleum-based plastics. Remarkably, these bioplastics exhibit a stretch-strengthening behavior similar to the training living muscles. Mechanistic investigation reveals that the introduction of CPAP3-A1 induce chitosan chains to assemble into a more coarsened fibrous network with increased crystallinity and reinforcement effect, but also enable energy dissipation via reversible chitosan-protein interactions. Further uniaxial stretch facilitates network re-orientation and increases chitosan crystallinity and mechanical anisotropy, thereby resulting in stretch-strengthening behavior. In general, this study provides an insect-cuticle inspired design of high-performance bioplastics that may serve as sustainable and bio-friendly materials for a wide range of engineering and biomedical application potentials.

A review on the enhancement of circular economy aspects focusing on nanocellulose composites

Researchers are now focusing on using the circular economy model to manufacture nanocellulose composites due to growing environmental issues related to waste management. The circular economy model offers a sustainable solution to the problem by optimizing resource efficiency and waste management by reducing waste, maintaining value over time, minimizing the use of primary resources, and creating closed loops for goods, components, and materials. With the use of the circular economy model, waste, such as industrial, agricultural, and textile waste, is used again to produce new products, which can solve waste management issues and improve resource efficiency. In order to encourage the use of circular economy ideas with a specific focus on nanocellulose composites, this review examines the concept of using circular economy, and explores ways to make nanocellulose composites from different types of waste, such as industrial, agricultural, and textile waste. Furthermore, this review investigates the application of nanocellulose composites across multiple industries. In addition, this review provides researchers useful insights of how circular economics can be applied to the development of nanocellulose composites, which have the goal of creating a flexible and environmentally friendly material that can address waste management issues and optimize resource efficiency.

Degradable chitosan-based bioplastic packaging: Design, preparation and applications

Food packaging is an essential part of food transportation, storage and preservation. Biodegradable biopolymers are a significant direction for the future development of food packaging materials. As a natural biological polysaccharide, chitosan has been widely concerned by researchers in the field of food packaging due to its excellent film-forming property, good antibacterial property and designability. Thus, the application research of chitosan-based food packaging films, coatings and aerogels has been greatly developed. In this review, recent advances on chitosan-based food packaging materials are summarized. Firstly, the development background of chitosan-based packaging materials was described, and then chitosan itself was introduced. In addition, the design, preparation and applications of films, coatings and aerogels in chitosan-based packaging for food preservation were discussed, and the advantages and disadvantages of each research in the development of chitosan-based packaging materials were analyzed. Finally, the application prospects, challenges and suggestions for solving the problems of chitosan-based packaging are summarized and prospected.

Synthesis and characterization of citric acid-modified chitosan Schiff base with enhanced antibacterial properties for the elimination of Bismarck Brown R and Rhodamine B dyes from wastewater

In this study, a new chitosan Schiff base with surface modification using citric acid was synthesized for efficient removal of pernicious dyes, namely Bismarck Brown R (BBR) and Rhodamine B (RhB), from wastewater. The physicochemical properties of the modified chitosan Schiff base were comprehensively investigated. Adsorption studies demonstrated that BBR adsorption occurred through monolayer formation, while RhB adsorption proceeded via multilayer formation on the heterogeneous surface. The synthesized adsorbent exhibited exceptional dye removal efficiency, with a Langmuir saturation capacity of 348 ± 11.0 mg.g-1 for BBR and 145 ± 18.44 mg.g-1 for RhB. Isotherm data fitting revealed consistency with the Langmuir isotherm model for BBR and the Freundlich isotherm model for RhB. Notably, the modified chitosan Schiff base showcased enhanced antibacterial properties, effectively inhibiting both gram-positive and gram-negative bacteria. The study's findings underscore the potential of this novel chitosan-based Schiff base as an efficient adsorbent for the removal of various dyes from wastewater, emphasizing its versatility and practical applicability in water treatment processes.

Promising cellulose-based functional gels for advanced biomedical applications: A review

Novel biomedical materials provide a new horizon for the diagnosis/treatment of diseases and tissue repair in medical engineering. As the most abundant biomass polymer on earth, cellulose is characterized by natural biocompatibility, good mechanical properties, and structure-performance designability. Owing to these outstanding features, cellulose as a biomacromolecule can be designed as functional biomaterials via hydrogen bonding (H-bonding) interaction or chemical modification for human tissue repair, implantable tissue organs, and controlling drug release. Moreover, cellulose can also be used to construct medical sensors for monitoring human physiological signals. In this study, the structural characteristics, functionalization approaches, and advanced biomedical applications of cellulose are reviewed. The current status and application prospects of cellulose and its functional materials for wound dressings, drug delivery, tissue engineering, and electronic skin (e-skin) are discussed. Finally, the key technologies and methods used for designing cellulosic biomaterials and broadening their application prospects in biomedical fields are highlighted.

Recent developments in chitosan based microgels and their hybrids

Chitosan based microgels have gained great attention because of their chemical stability, biocompatibility, easy functionalization and potential uses in numerous fields. Production, properties, characterization and applications of chitosan based microgels have been systematically reviewed in this article. Some of these systems exhibit responsive behavior towards external stimuli like pH, light, temperature, glucose, etc. in terms of swelling/deswelling in an aqueous medium depending upon the functionalities present in the network which makes them a potential candidate for various applications in the fields of biomedicine, agriculture, catalysis, sensing and nanotechnology. Current research development and critical overview in this field accompanying by future possibilities is presented. The discussion is concluded with recommended possible future works for further progress in this field.

Chitosan-encapsulated microbial biofertilizer: A breakthrough for enhanced tomato crop productivity

Encapsulation technology protects the beneficial microorganisms, which are the sources of Nitrogen (N), Phosphorus (P), and Potassium (K), with a carrier material and improves the nutrient uptake from the soil. Pseudomonas fluorescens, gram-negative bacteria, was selected as the microorganism for encapsulation. A chitosan carrier (3 %), a polysaccharide, was chosen for the encapsulation of the bacterial strain to use as biofertilizers by standardization with two carriers, sodium alginate and chitosan. P. fluorescens encapsulated with chitosan showed a higher shelf life than sodium alginate. The shelf life of the encapsulated culture (7 × 1010 CFU/mL) was maintained for ten months. Studies were performed with the encapsulated P. fluorescens to analyze its nature and characteristics. The pot and field studies were conducted with the encapsulated P. fluorescens for the tomato crop. The difference between the treated and control plants was observed based on biometric parameters like shoot length and root length, fruit weight, and number of branches and fruits per plant. This study reveals that encapsulated P. fluorescens improved the yield of the crops. In addition, soil health and fertility were also enhanced. Thus, encapsulated P. fluorescens could be a superior solution for promoting soil health and crop productivity for sustainable agriculture.

An Overview of Biopolymers for Drug Delivery Applications

Nowadays, drug delivery has an important role in medical therapy. The use of biopolymers in developing drug delivery systems (DDSs) is increasingly attracting attention due to their remarkable and numerous advantages, in contrast to conventional polymers. Biopolymers have many advantages (biodegradability, biocompatibility, renewability, affordability, and availability), which are extremely important for developing materials with applications in the biomedical field. Additionally, biopolymers are appropriate when they improve functioning and have a number of positive effects on human life. Therefore, this review presents the most used biopolymers for biomedical applications, especially in drug delivery. In addition, by combining different biopolymers DDSs with tailored functional properties (e.g., physical properties, biodegradability) can be developed. This review summarizes and provides data on the progress of research on biopolymers (chitosan, alginate, starch, cellulose, albumin, silk fibroin, collagen, and gelatin) used in DDSs, their preparation, and mechanism of action.

A hemostatic sponge derived from chitosan and hydroxypropylmethylcellulose

Hemostatic materials are of great significance for rapid control of bleeding, especially in military trauma and traffic accidents. Chitosan (CS) hemostatic sponges have been widely concerned and studied due to their excellent biocompatibility. However, the hemostatic performance of pure chitosan sponges is poor due to the shortcoming of strong rigidity. In this study, CS and hydroxypropylmethylcellulose (HPMC) were combined to develop a safe and effective hemostatic composite sponges (CS/HPMC) for hemorrhage control by a simple mixed-lyophilization strategy. The CS/HPMC exhibited excellent flexibility (the flexibility was 74% higher than that of pure CS sponges). Due to the high porosity and procoagulant chemical structure of the CS/HPMC, it exhibited rapid hemostatic ability in vitro (BCI was shortened by 50% than that of pure CS sponges). The good biocompatibility of the obtained CS/HPMC was confirmed via cytotoxicity, hemocompatibility and skin irritation tests. The CS/HPMC can induced the erythrocyte and platelets adhesion, resulting in significant coagulation acceleration. The CS/HPMC had excellent performance in vivo assessments with shortest clotting time (40 s) and minimal blood loss (166 mg). All above results proved that the CS/HPMC had great potential to be a safe and rapid hemostatic material.

Fungal derived herbicidal metabolite loaded starch-chitosan-gum acacia-agar based bio composite: Preparation, characterization, herbicidal activity, release profile and biocompatibility

Biocomposites based on starch- gum acacia- agar, chitosan- starch- agar, starch- poly vinyl alcohol- agar were synthesized by simple, green route principles and the various characterization techniques like fourier infrared spectroscopy, SEM revealed the highly stable micro dimenstional that specially interacted with functional groups of polymers -herbicidal metabolites. Respective biocomposite was prepared by mixing equal volume of the selected polymer (1;1;1 ratio) with known concentration (100 mg of in distilled water followed by the addition of reconstituted herbicidal metabolites (100 mg or 0.1 g). Though all the biocomposites were capable of inducing herbicidal effect, notable impact was recorded in chitosan- starch- gum acacia treatment. In this case, the necrotic lesions were initiated at the early incubation period (6 h), progressively developing into dark brownish black lesions with 30.0 mm diameter. Release profile of the metabolites from the respective composite was also under in vitro and soil assay. Release profile study under in vitro and soil condition showed the sustained or controlled manner in distilled water and ethyl acetate treatment. No sign of toxic effect on the soil, parameters plant growth, rhizobacteria and peripheral blood cells clearly revealed the best biocompatibility of the presently proposed biocomposite.

Polysaccharides and proteins-based bionanocomposites for microencapsulation of probiotics to improve stability and viability in the gastrointestinal tract: A review

Probiotics have recently received significant attention due to their various benefits, such as the modulation of gut flora, reduction of blood sugar and insulin resistance, prevention and treatment of digestive disorders, and strengthening of the immune system. One of the major issues concerning probiotics is the maintenance of their viability in the presence of digestive conditions and extended shelf life during storage. To address this concern, numerous techniques have been explored to achieve success. Among these methods, the microencapsulation of probiotics has been proposed as the most effective way to overcome this challenge. The combination of nanomaterials with biopolymer coating is considered a novel approach to improve its viability and effective delivery. The use of polysaccharides and proteins-based bionanocomposites for microencapsulation of probiotics has emerged as an efficient and promising approach for maintaining cell viability and targeted delivery. This review article aims to investigate the use of different bionanocomposites in microencapsulation of probiotics and their effect on cell survival in long-term storage and harsh conditions in the gastrointestinal tract.

Enhancing Paper Packaging's Wet Strength Using the Synergy between Chitosan and Nanofibrillated Cellulose Additives

The demand for eco-friendly packaging materials has urged researchers to look for alternatives to petroleum-based polymers. In this regard, paper-based products have turned out to be a promising choice; however, their weak resistance to water has limited their application. The use of various additives to enhance paper's moisture resistance is a common practice. However, considering the growing global agenda for sustainable development, the search for new bio-based paper additives has become increasingly important. This study investigated the potential synergistic impact of the addition of nanofibrillated cellulose (NFC) and chitosan additives (CHIT) to different fiber combinations to improve paper's properties, in particular, their wet strength. The efficacy of the additive application order was examined and was found to be crucial in achieving the desired outcomes. The results showed that incorporating CHIT after NFC enhanced the paper's tensile and burst indicators, as well as the paper stretch in the dry state, by 35-70%, 35-55%, and 20-35%, respectively. In addition, the tensile index and stretch in the wet state improved 9-13 times and 2.5-5.5 times over, respectively. The air permeability decreased 2.5-12 times over. These findings demonstrate that the sequential addition of the NFC and CHIT additives yield a greater enhancement of paper's properties than using each additive separately.

Impact of soybean protein isolate concentration on chitosan-cellulose nanofiber edible films: Focus on structure and properties

Chitosan and cellulose nanofiber films are frequently employed as biodegradable materials for food packaging. However, many exhibit suboptimal hydrophobicity and antioxidant properties. To address these shortcomings, we enhanced the performance by adding different concentrations of soybean protein isolate (SPI) to chitosan-cellulose nanofiber (CS-CNF) films. As SPI concentration varied, the turbidity, particle size, and ζ-potential of the film-forming solutions initially decreased and subsequently increased. This suggests that 1 % SPI augments the electrostatic attraction and compatibility. Rheological analysis confirmed a pronounced apparent viscosity at this concentration. Analyses using Fourier transform infrared spectra, Raman spectra, X-ray diffraction, and Scanning electron microscope revealed the presence of hydrogen bonds and electrostatic interactions between SPI and CS-CNF, indicative of superior compatibility. When SPI concentration was set at 1 %, notable enhancements in film attributes were observed: improvements in tensile strength and elongation at break, a reduction in water vapor permeability by 8.23 %, and an elevation in the contact angle by 18.85 %. Furthermore, at this concentration, the ABTS+ and DPPH scavenging capacities of the film surged by 61.53 % and 46.18 %, respectively. Meanwhile, the films we prepare are not toxic. This research offers valuable insights for the advancement and application of protein-polysaccharide-based films.

Polysaccharide-Based Double-Network Hydrogels: Polysaccharide Effect, Strengthening Mechanisms, and Applications

Polysaccharides are carbohydrate polymers that are major components of plants, animals, and microorganisms, with unique properties. Biological hydrogels are polymeric networks that imbibe and retain large amounts of water and are the major components of living organisms. The mechanical properties of hydrogels are critical for their functionality and applications. Since synthetic polymeric double-network (DN) hydrogels possess unique network structures with high and tunable mechanical properties, many natural functional polysaccharides have attracted increased attention due to their rich and convenient sources, unique chemical structure and chain conformation, inherently desirable cytocompatibility, biodegradability and environmental friendliness, diverse bioactivities, and rheological properties, which rationally make them prominent constituents in designing various strong and tough polysaccharide-based DN hydrogels over the past ten years. This review focuses on the latest developments of polysaccharide-based DN hydrogels to comprehend the relationship among the polysaccharide properties, inner strengthening mechanisms, and applications. The aim of this review is to provide an insightful mechanical interpretation of the design strategy of novel polysaccharide-based DN hydrogels and their applications by introducing the correlation between performance and composition. The mechanical behavior of DN hydrogels and the roles of varieties of marine, microbial, plant, and animal polysaccharides are emphatically explained.

Enhancing the Properties of Polyvinyl Alcohol Films by Blending with Corn Stover-Derived Cellulose Nanocrystals and Beeswax

Coating is a technique to surround a target substance with a thin layer to obtain desirable properties. Polyvinyl alcohols (PVAs) are biodegradable plastics and have shown good applicability as a coating or film material. Cellulose nanocrystals are a promising green nanomaterial that has been shown to enhance the properties of PVA after blending. However, these PVA/CNC films have concerns in a moist environment due to high hydrophilicity. To overcome this issue, the current study incorporated beeswax into PVA/CNC films and investigated the effect of CNC and beeswax on the properties of the coatings and films. Results showed that the addition of corn stover-derived CNCs to PVA films increased tensile strength (from 11 to 25 MPa) and Young's modulus (from 32 to 173 MPa) and reduced water vapor transmission rate (from 25 to 20 g h-1 m-2). Beeswax added to PVA/CNC films further improved water vapor barrier properties (from 20 to 9 g h-1 m-2) and maintained Young's modulus (from 173 to 160 MPa), though it caused a reduction in the tensile strength (from 25 to 11 MPa) of the films. This information can help to select materials for blending with PVAs by obtaining the desirable endmost properties depending on applications.

In situ capping of silver nanoparticles with cellulosic matrices from wheat straws in enhancing their antimicrobial activity: Synthesis and characterization

Silver nanoparticles have gained worldwide attention in the scientific community due to their high antimicrobial activity. However, they tend to agglomerate and lose their shape and properties, thus capping agents necessary to protect their shapes, sizes, and properties. To enhance their antimicrobial activity, this research aimed to cap silver nanoparticles with cellulosic matrices from wheat straws. The wheat straw was delignified with 6% HNO3, and the residual was treated with 1% NaOH and NaClO: CH3COOH (1:1), then used to synthesize cellulose nanocrystals via acid hydrolysis. AgNPs were incorporated into the CPC and CNCs by in-situ synthesis using NaHB4 as the reducing agent. Fourier Transform Infrared, Scanning Electron Microscopy, and X-ray diffraction were used to investigate their features. The findings exhibited crystallinity increased with subsequent treatments, according to XRD analysis. Ultraviolet-visible, FTIR, TEM, and XRD analysis confirmed the capping of AgNPs onto the cellulosic materials. Antibacterial activity against Staphylococcus aureus and Escherichia coli, with CNCs-AgNPs composite, exhibited higher activity compared to CPC-AgNPs composite due to the increased surface area and excellent binding on the surface of the composite.

Bio-based antimicrobial food packaging films based on hydroxypropyl starch/polyvinyl alcohol loaded with the biosynthesized zinc oxide nanoparticles

In the last decades, bio-based active food packaging materials have received much attention. It is known that the utilization of traditional materials for food packaging applications lack some critical characteristics such as resistance to the harmful microbes that cause a damage to the preserved foods. Therefore, the current study aimed to find an alternative packaging films comprises an efficient biopolymers. This research work was designed to prepare film mats using hydroxypropyl starch (HPS), polyvinyl alcohol (PVA), palmitic acid (PA) and biosynthesized zinc oxide nanoparticles (ZnONPs). The fabricated films were coded as 1H, 2H, 3H and 4H based on the utilized concentration of ZnONPs. The biosynthesized ZnONPs and the bio-based films loaded with ZnONPs were characterized. The results revealed that ZnONPs exhibited nearly spherical shape and size ∼40 nm. The surface structure of the produced bioactive packaging films exhibited smooth with homogeneous features, excellent mechanical and thermal stability properties. The prepared bioactive packaging film loaded with ZnONPs (4H) exhibited superior antibacterial activity among other films against Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923 with inhibition zones 15.1 ± 0.76 and 12.1 ± 0.71 mm respectively. Correspondingly, packing film 4H exhibited potential antifungal activity toward Aspergillus niger RCMB 02724, A. flavus RCMB 02782, Penicillium expansum IMI 89372 and Fusarium oxysporum RCMB 001004 with inhibition zones (16 ± 1.0, 22 ± 0.90, 18.0 ± 1.1 and12.3 ± 0.57 mm respectively). Moreover, all prepared films did not show cytotoxicity on the normal cell line (Wi38) and recorded biodegradability properties that reached around 85 % after four weeks in soil. Based on these results, the antimicrobial films comprising HPS/PVA and loaded with the biosynthesized ZnONPs can be considered as a suitable film for food packaging purposes.

Fabrication of Bio-Nanocomposite Packaging Films with PVA, MMt Clay Nanoparticles, CNCs, and Essential Oils for the Postharvest Preservation of Sapota Fruits

Sapota is an important climacteric fruit with limited shelf life. A special system must be employed to extend the shelf life of sapota fruits. In the present study, polyvinyl alcohol (PVA) and montmorillonite clay (MMt)-based bio-nanocomposite films (BNFs) were integrated at various concentrations (2%, 4%, 6%, and 8%) into cellulose nanocrystals (CNCs), produced from garlic peels (GPs). The BNF loaded with 8% CNC has a better crystallinity index and mechanical properties than the other concentrations of CNC. Therefore, the 8% CNC-incorporated BNF (BNF-8) was selected for further packaging studies. The combined effect of BNF-8 with ajwain essential oil (AO) and oregano essential oil (OO) vapors and BNF-8 with carbendazim (commercial fungicide-CARB) were investigated. In this study, the BNF-based packagings are categorized into five types, viz: BNF+8% CNC (BNF-8), BNF-8+AO, BNF-8+OO, BNF-8+CARB and the non-packaged fruits (control). The shelf-life duration, antioxidant activity, firmness, decay index, and sensory quality were evaluated in order to identify the effectiveness of packaging treatment on sapota fruits. BNF-8+CARB, BNF-8+AO, and BNF-8+OO packaging extended the shelf life of sapota fruits to up to 12 days and maintained the overall physiochemical parameters and sensory qualities of the fruits. Therefore, the BNF-8+AO and BNF-8+OO packaging materials are appropriate alternatives to commercial fungicides for the preservation of sapota during postharvest storage.

Valorizing industrial tobacco wastes within natural clays and chitosan nanocomposites for an ecofriendly insecticide

We report the engineering of insecticide films based on two mineral clays, montmorillonite and kaolinite, combined to chitosan and/or cellulose acetate originating from cigarette filter and subsequently impregnated with tobacco essential oil extracted from tobacco dust. Both binary composites, i.e. clay and chitosan or clay and cellulose acetate, and ternary composites containing clay, chitosan and cellulose acetate were prepared and characterized by XRD, DLS, ELS, and IR to investigate the nature of interactions within the composites. The two clay minerals showed different kinds of interaction with chitosan: intercalation in the case of Montmorillonite vs adsorption on the external surface for kaolinite. Secondly, the nicotine release from the composites films at different temperatures was studied by in-situ IR. The Montmorillonite composites, particularly the ternary one, showed a better encapsulation of nicotine which release was limited. Finally, the insecticidal activity of the composites was evaluated against the Tribolium castaneum a common wheat pest. The differences observed between montmorillonite and kaolinite composites were rationalized in relation to the nature of interaction between the components. The fumigant bioassay showed promising insecticidal effects in the case of the ternary composite cellulose acetate/chitosan/montmorillonite. Therefore, these eco-friendly nanocomposites can be used efficiently for the sustainable protection of stored cereals.

Preparation, characterization, and performance evaluation of composite films of polyvinyl alcohol/ cellulose nanofiber extracted from Imperata cylindrica

In recent years, production of cellulose nanofiber (CNF) from waste materials has achieved great interest owing to their renewable nature, biodegradability, high mechanical properties, economic value, and low density. Because Polyvinyl alcohol (PVA) is a synthetic biopolymer with good water solubility and biocompatibility, the composite material formed of CNF and PVA, is a sustainable way of monetizing to address environmental and economic issues. In this work pure PVA, PVA/CNF0.5, PVA/CNF1.0, PVA/CNF1.5, and PVA/CNF2.0 nanocomposite films were produced using the solvent casting approach with the addition of 0, 0.5, 1.0, 1.5, and 2.0 wt% of CNF concentrations respectively. The strongest water absorption behaviour was found as 25.82% for pure PVA membrane, followed by PVA/CNF0.5 (20.71%), PVA/CNF1.0 (10.26%), PVA/CNF1.5 (9.63%), and PVA/CNF2.0 (4.35%). The water contact angle of 53.1°, 47.8°, 43.4°, 37.7°, and 32.3° was formed between water droplet and the solid-liquid interface of pure PVA, PVA/CNF0.5, PVA/CNF1.0, PVA/CNF1.5, PVA/CNF2.0 composite films respectively. The SEM image clearly shows that a network structure like a tree form at the PVA/CNF0.5 composite film, where the sizes and number of pores are apparent. XRD analysis suggested that unique peaks found at 2θ = 17.5°, 28.1°, 33.4°, and 38° for nanocomposites indicating new crystal plane generated upon cross-linking in presence of malic acid. The maximum loss rate temperature (T_d,max) for PVA/CNF0.5, PVA/CNF1.0, PVA/CNF1.5 was determined by TG analysis to be around 273.4 °C. FTIR studies suggested that PVA/CNF0.5 composite film showed the highest peak at 1428 cm^-1 as compared to other PVA/CNF composite films representing the presence of higher crystalline band in the composite film matrix. PVA/CNF0.5 composite film was found to have a surface porosity and mean pore size of 27.35% and 0.19 μm respectively, classifying it in the MF membrane category. The maximum tensile strength (TS) of 5.27 MPa was found for PVA/CNF0.5, followed by PVA/CNF1.0, PVA/CNF1.5, pure PVA, and PVA/CNF2.0. The maximum young's modulus (111 MPa) was found for PVA/CNF1.0, followed by PVA/CNF0.5, PVA/CNF2.0, PVA/CNF1.5, and pure PVA, which could be attributed to the cyclization of the molecular structures by cross-linking. PVA/CNF0.5 exhibits greater elongation at break (21.7) than the other polymers, indicating a material's ability to undergo significant deformation before failure. Performance evaluation of the PVA/CNF0.5 composite film showed that 46.3% and 92.8% yield were found in the retentate for 200 mg/L of BSA, and 5 × 10⁷ CFU/mL respectively. However, more than 90% E. coli was retained by PVA/CNF0.5 composite film, therefore absolute rating of this membrane is 0.22 μm. The size of this composite film may be therefore considered in the range of MF.

Multimodal Biomedical Implant with Plasmonic and Simulated Body Temperature Responses

This work presents a novel nanoparticle-based thermosensor implant able to reveal the precise temperature variations along the polymer filaments, as it contracts and expands due to changes in the macroscale local temperature. The multimodal device is able to trace the position and the temperature of a polypropylene mesh, employed in abdominal hernia repair, by combining plasmon resonance and Raman spectroscopy with hydrogel responsive system. The novelty relies on the attachment of the biocompatible nanoparticles, based on gold stabilized by a chitosan-shell, already charged with the Raman reporter (RaR) molecules, to the robust prosthesis, without the need of chemical linkers. The SERS enhanced effect observed is potentiated by the presence of a quite thick layer of the copolymer (poly(N-isopropylacrylamide)-co-poly(acrylamide)) hydrogel. At temperatures above the LCST of PNIPAAm-co-PAAm, the water molecules are expulsed and the hydrogel layer contracts, leaving the RaR molecules more accessible to the Raman source. In vitro studies with fibroblast cells reveal that the functionalized surgical mesh is biocompatible and no toxic substances are leached in the medium. The mesh sensor opens new frontiers to semi-invasive diagnosis and infection prevention in hernia repair by using SERS spectroscopy. It also offers new possibilities to the functionalization of other healthcare products.

Fabrication and Characterization of Magnetic Cellulose-Chitosan-Alginate Composite Hydrogel Bead Bio-Sorbent

The implementation of inorganic adsorbents for the removal of heavy metals from industrial effluents generates secondary waste. Therefore, scientists and environmentalists are looking for environmentally friendly adsorbents isolated from biobased materials for the efficient removal of heavy metals from industrial effluents. This study aimed to fabricate and characterize an environmentally friendly composite bio-sorbent as an initiative toward greener environmental remediation technology. The properties of cellulose, chitosan, magnetite, and alginate were exploited to fabricate a composite hydrogel bead. The cross linking and encapsulation of cellulose, chitosan, alginate, and magnetite in hydrogel beads were successfully conducted through a facile method without any chemicals used during the synthesis. Energy-dispersive X-ray analysis verified the presence of element signals of N, Ca, and Fe on the surface of the composite bio-sorbents. The appearance and peak's shifting at 3330-3060 cm^-1 in the Fourier transform infrared spectroscopy analysis of the composite cellulose-magnetite-alginate, chitosan-magnetite-alginate, and cellulose-chitosan-magnetite-alginate suggested that there are overlaps of O-H and N-H and weak interaction of hydrogen bonding with the Fe₃O₄ particles. Material degradation, % mass loss, and thermal stability of the material and synthesized composite hydrogel beads were determined through thermogravimetric analysis. The onset temperature of the composite cellulose-magnetite-alginate, chitosan-magnetite-alginate, and cellulose-chitosan-magnetite-alginate hydrogel beads were observed to be lower compared to raw-material cellulose and chitosan, which could be due to the formation of weak hydrogen bonding resulting from the addition of magnetite Fe₃O₄. The higher mass residual of cellulose-magnetite-alginate (33.46%), chitosan-magnetite-alginate (37.09%), and cellulose-chitosan-magnetite-alginate (34.40%) compared to cellulose (10.94%) and chitosan (30.82%) after degradation at a temperature of 700 °C shows that the synthesized composite hydrogel beads possess better thermal stability, owing to the addition of magnetite and the encapsulation in the alginate hydrogel beads.

Chitosan-Based Polymer Blends for Drug Delivery Systems

Polymers have been widely used for the development of drug delivery systems accommodating the regulated release of therapeutic agents in consistent doses over a long period, cyclic dosing, and the adjustable release of both hydrophobic and hydrophilic drugs. Nowadays, polymer blends are increasingly employed in drug development as they generate more promising results when compared to those of homopolymers. This review article describes the recent research efforts focusing on the utilization of chitosan blends with other polymers in an attempt to enhance the properties of chitosan. Furthermore, the various applications of chitosan blends in drug delivery are thoroughly discussed herein. The literature from the past ten years was collected using various search engines such as ScienceDirect, J-Gate, Google Scholar, PubMed, and research data were compiled according to the various novel carrier systems. Nanocarriers made from chitosan and chitosan derivatives have a positive surface charge, which allows for control of the rate, duration, and location of drug release in the body, and can increase the safety and efficacy of the delivery system. Recently developed nanocarriers using chitosan blends have been shown to be cost-effective, more efficacious, and prolonged release carriers that can be incorporated into suitable dosage forms.

Chitosan coated magnetic cellulose nanowhisker as a drug delivery system for potential colorectal cancer treatment

Polysaccharide-based magnetic nanocomposites can eminently illuminate several attractive features as anticancer drug carriers. In this study, rice straw-based cellulose nanowhisker (CNW) was used as solid support for Fe₃O₄ nanofillers to synthesize magnetic CNW. Then, cross-linked chitosan-coated magnetic CNW for 5-fluorouracil carrier abbreviated as CH/MCNW/5FU. Fourier-transform infrared, X-Ray diffraction, and X-ray photoelectron spectroscopy analysis indicated successful fabrication and multifunctional properties of the CH/MCNW/5FU nanocomposites. In addition, CH/MCNW/5FU nanocomposites showed hydrodynamic diameter and zeta potential value of 181.31 ± 3.46 nm and +23 ± 1.8 mV, respectively. Based on images of transmission electron microscopy, magnetic CNW as reinforcement was coated with chitosan to obtain almost spherical CH/MCNW/5FU nanocomposites with an average diameter of 37.16 ± 3.08. The nanocomposites indicated desired saturation magnetization and thermal stability, high drug encapsulation efficiency, and pH-dependent swelling and drug release performance. CH/MCNW/5FU nanocomposites showed potent killing effects against colorectal cancer cells in both 2D monolayer and 3D spheroid models. These findings suggest CH/MCNW as a potential carrier for anticancer drugs with high tumour-penetrating capacity.

Understanding Nanocellulose-Water Interactions: Turning a Detriment into an Asset

Modern technology has enabled the isolation of nanocellulose from plant-based fibers, and the current trend focuses on utilizing nanocellulose in a broad range of sustainable materials applications. Water is generally seen as a detrimental component when in contact with nanocellulose-based materials, just like it is harmful for traditional cellulosic materials such as paper or cardboard. However, water is an integral component in plants, and many applications of nanocellulose already accept the presence of water or make use of it. This review gives a comprehensive account of nanocellulose-water interactions and their repercussions in all key areas of contemporary research: fundamental physical chemistry, chemical modification of nanocellulose, materials applications, and analytical methods to map the water interactions and the effect of water on a nanocellulose matrix.

Chitosan with Natural Additives as a Potential Food Packaging

Recently, the development of materials based on natural polymers have been observed. This is the result of increasing environmental degradation, as well as increased awareness and consumer expectations. Many industries, especially the packaging industry, face challenges resulting from legal regulations. Chitin is the most common biopolymer right after cellulose and is used to produce chitosan. Due to the properties of chitosan, such as non-toxicity, biocompatibility, as well as antimicrobial properties, chitosan-based materials are used in many industries. Many studies have been conducted to determine the suitability of chitosan materials as food packaging, and their advantages and limitations have been identified. Thanks to the possibility of modifying the chitosan matrix by using natural additives, it is possible to strengthen the antioxidant and antimicrobial activity of chitosan films, which means that, in the near future, chitosan-based materials will be a more environmentally friendly alternative to the plastic packaging used so far. The article presents literature data on the most commonly used natural additives, such as essential oils, plant extracts, or polysaccharides, and their effects on antimicrobial, antioxidant, mechanical, barrier, and optical properties. The application of chitosan as a natural biopolymer in food packaging extends the shelf-life of various food products while simultaneously reducing the use of synthetic plastics, which in turn will have a positive impact on the natural environment. However, further research on chitosan and its combinations with various materials is still needed to extent the application of chitosan in food packaging and bring its application to industrial levels.

The use of essential oils in chitosan or cellulose-based materials for the production of active food packaging solutions: a review

In recent decades, interest in sustainable food packaging systems with additional functionality, able to increase the shelf life of products, has grown steadily. Following this trend, the present review analyzes the state of the art of this active renewable packaging. The focus is on antimicrobial systems containing nanocellulose and chitosan, as support for the incorporation of essential oils. These are the most sustainable and readily available options to produce completely natural active packaging materials. After a brief overview of the different active packaging technologies, the main features of nanocellulose, chitosan, and of the different essential oils used in the field of active packaging are introduced and described. The latest findings about the nanocellulose- and chitosan-based active packaging are then presented. The antimicrobial effectiveness of the different solutions is discussed, focusing on their effect on other material properties. The effect of the different inclusion strategies is also reviewed considering both in vivo and in vitro studies, in an attempt to understand more promising solutions and possible pathways for further development. In general, essential oils are very successful in exerting antimicrobial effects against the most diffused gram-positive and gram-negative bacteria, and affecting other material properties (tensile strength, water vapor transmission rate) positively. Due to the wide variety of biopolymer matrices and essential oils available, it is difficult to create general guidelines for the development of active packaging systems. However, more attention should be dedicated to sensory analysis, release kinetics, and synergetic action of different essential oils to optimize the active packaging on different food products. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Eco-friendly and facile preparation of chitosan-based biofilms of novel acetoacetylated lignin for antioxidant and UV-shielding properties

The development of eco-friendly, sustainable, biodegradable, and biocompatible green biopolymer composites is becoming increasingly important. In this study, acetoacetylated lignin (ATL) was obtained via an eco-friendly, facile one-step synthesis reaction, and chitosan (CS)-containing ATL films (CSL) were prepared. The chemical structural analysis of ATL confirmed that the acetoacetyl groups were successfully grafted onto kraft lignin (KL). ATL with adequate acetoacetyl groups exhibited enhanced molecular weight and antioxidant and ultraviolet (UV)-shielding properties. In particular, ATL, with a half maximal inhibitory concentration (IC₅₀) of 23.8 μg·mL^-1, exhibited superior antioxidant activity than butylated hydroxytoluene (38.3 μg·mL^-1) and KL (50.0 μg·mL^-1). When ATL was incorporated into the CS solution to prepare biofilms, the antioxidant activity, UV-shielding property, water resistance, and thermal stability of the CSL greatly improved. Notably, the UV-A and UV-B shielding properties of the 2 % CSL were 130 % and 78 % higher than those of the pure CS film, respectively. Therefore, ATL designed with lignin-derived multifunctional properties has potential applications as an antioxidant and UV-shielding bio-additive and shows significant prospects in food packaging and biomedical applications.