Single Step Fabrication of Chitosan Nanocrystals Using Penaeus semisulcatus: Potential as New Insecticides, Antimicrobials and Plant Growth Promoters

Synergic effect and biosafety of chitosan/zinc complex nanoparticle-based carboxymethyl cellulose coatings for postharvest strawberry preservation

Nanotechnology represents a burgeoning field that revolutionizes various industries and sectors, including food applications. In this study, chitosan nanoparticles (CS NPs), zinc oxide nanoparticles (ZnO NPs), and chitosan-zinc complex nanoparticles (CS/Zn NPs) were prepared and incorporated into carboxymethyl cellulose (CMC) coatings to examine their strawberry preservation efficiency. CS NPs, synthesized via ionic gelation, appeared with a spherical shape and a relatively uniform size below 50 nm. ZnO NPs, produced through a green electrochemical method, formed larger aggregates. CS/Zn NPs were formed due to the chelation of CS NPs with Zn2+ present in the fresh zinc electrochemical solution. In antibacterial tests against Escherichia coli and Staphylococcus aureus, CS/Zn NPs exhibited significantly lower MIC and MBC values compared to CS NPs and ZnO NPs individually, indicating a synergistic antibacterial effect between the components. CMC coatings containing these nanoparticles were applied to strawberry surfaces and the fruits were stored at room temperature (25 °C) and in a refrigerator (5 °C). The CS/Zn-CMC coating demonstrated the most pronounced effect in preventing weight loss and decrease of titratable acidity (TA) and ascorbic acid (AA) content over storage. It effectively preserved the original appearance of strawberries, delaying browning until day 15, while the control and other coated samples were completely spoiled within this period. The cytotoxicity assessment indicated the safety of CS/ZnO-CMC coating, suggesting its potential application in fruit preservation.

Epoxy-Affixed ZIF-8/CS/Cellulase: a Sustainable Approach for Hydrolysis of Agricultural Waste to Reducing Sugars

Cellulase was effectively immobilized onto an epoxy-bound chitosan-modified zinc metal-organic framework (epoxy/ZIF-8/CS/cellulase) support, yielding a conjugation rate of 0.64 ± 0.02 mg/cm2 and retaining 80.01 ± 0.01% of its specific activity. The bare and cellulase-bound supports was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy and energy-dispersive X-ray spectroscopy. The immobilized enzyme exhibited optimal activity at pH 5.5 and a temperature of 70 ℃. The efficiency, stability and reactivity of the enzyme improved after immobilization, as evidenced by a decrease in activation energy, enthalpy and Gibbs free energy along with an increase in entropy change. The epoxy-affixed ZIF-8/CS/cellulase strip was successfully employed for rice husk hydrolysis achieving an impressive conversion efficiency of 95%. The method demonstrated a linear range from 0.1 to 0.9% (0.1 × 10-2 to 0.9 × 10-2 mg/ml) and exhibited a strong correlation (R2 = 0.998) with the widely adopted 3, 5-dinitrosalicylic acid method. The epoxy/ZIF-8/CS bound cellulase exhibited remarkable thermal stability, retaining 100% of its activity at 70 °C, in contrast to just 53% for the free enzyme and displayed a half-life of 21 days after storage at 4 °C compared to 9 days for the free enzyme. Furthermore, it retained over 95% activity after 12 h at pH levels of 4.5 and 5.5 and showcased excellent reusability, maintaining activity over 25 cycles. Overall, this method offers high conversion efficiency and selectivity under benign conditions, with no undesirable by-products, making it a cost-effective solution for the routine hydrolysis of lignocellulosic biomass feedstock.

Cellulase immobilization on nano-chitosan/chromium metal-organic framework hybrid matrix for efficient conversion of lignocellulosic biomass to glucose

In the current work, cellulase from Aspergillus niger was successfully immobilized on a novel epoxy-affixed chromium metal-organic framework/chitosan (Cr@-MIL-101/CS) support via covalent method using glutaraldehyde as a crosslinker. The bare and cellulase-bound support was characterized by using various microscopic and spectroscopic techniques. Immobilized cellulase exhibited a high immobilization yield of 0.7 ± 0.01 mg/cm2, retaining 87.5 ± 0.04% of its specific activity and displaying enhanced catalytic performance. The immobilized enzyme was maximally active at pH 5.0, temperature 65 °C and 0.9 × 10-2 mg/ml saturating substrate concentration and the half-lives of free and immobilized cellulases were approximately 9 and 19 days, respectively. The decrease in activation energy, enthalpy change, and Gibbs free energy change, coupled with an increase in entropy change upon immobilization, indicated that the enzyme's efficiency, stability, and spontaneity in catalyzing the reaction were enhanced by immobilization. Additionally, the immobilized cellulase efficiently converted rice husk cellulose to glucose, with a quantification limit of 0.05%, linear measurement ranging from 0.1 to 0.9%, and 8.5% conversion efficiency. The present method exhibited a strong correlation (R2 = 0.998) with the DNS method, validating its reliability. Notably, the epoxy/Cr@-MIL-101/CS-bound cellulase demonstrated impressive thermal and pH stabilities, retaining 50% of its activity at 75 °C and over 96% at pH levels of 4.5 and 5.0 after 12 h. Furthermore, it showed excellent reusability, preserving 80% of its activity after 15 cycles and maintaining 50% of its activity even after 20 days of storage. These results suggest that epoxy/Cr@-MIL-101/CS/cellulase composites could be very effective for large-scale cellulose hydrolysis applications.

Biosynthesized Chitosan-Coated Silver Nanoparticles: Insecticide Activity and Sublethal Effects Against Drosophila suzukii (Diptera: Drosophilidae)

The overuse of synthetic pesticides has triggered resistance in insect pests and caused severe environmental impacts, emphasizing the urgent need for sustainable alternatives in Integrated Pest Management (IPM). This study aimed to biosynthesize and characterize chitosan-coated silver nanoparticles (AgChNPs) using Galega officinalis leaf extract and evaluate their insecticidal effects against Drosophila suzukii (Diptera: Drosophilidae), a key pest of fruit crops worldwide. The biosynthesized AgChNPs (257.2 nm) were polydisperse, crystalline, and stable, as confirmed by UV-vis spectroscopy, dynamic light scattering (DLS), X-ray diffraction (XRD), and transmission electron microscopy (TEM). AgChNPs exhibited strong toxicity across multiple developmental stages. Combined larvicidal and pupicidal activity reached 48.3% and 73.3% at 500 and 1000 ppm, respectively, significantly affecting immature stages. As a consequence, adult emergence declined to 46.7%, 51.7%, and 26.7% at 250, 500, and 1000 ppm. Among emerged adults, 71.7% displayed sublethal effects, with 62.8% showing morphological malformations (deformed wings, dehydration) and 37.2% presenting cuticle demelanization. Adulticidal bioassays revealed progressive mortality over 48 h, with 96% mortality at 1000 ppm. Overall, AgChNPs caused acute and chronic toxicity, reduced adult emergence, and induced severe morphological alterations, demonstrating their potential as a sustainable nanotechnological tool for effective pest control within IPM programs.

Comparison on the performance of green and conventional magnetic chitosan-based composites in the removal of complex dyes: Synergetic effect, experimental and theoretical studies

The presence of complex dyes, which possess four or more aromatic rings, is pervasive in environmental matrices. Nanomaterials offer a promising avenue for their removal. In this study, we synthesized novel magnetic nanocomposites comprising nanochitosan (nCS) and iron nanoparticles through the application of green and conventional protocols. In the preparation of the green composite, designated as G-nCS@FeNPs, eucalyptus leaves extract and proanthocyanidins were employed as reducing and crosslinking agents, respectively. In contrast, the conventional composite, designated as C-nCS@FeNPs, utilized ammonia and glutaraldehyde as the reducing and crosslinking agents, respectively. The G-nCS@FeNPs exhibited a more electropositive surface, and prominent magnetic properties. The zeta potential measurements of the G-nCS@FeNPs (ranging from +36 to +30 mV) were more positive than those of the C-nCS@FeNPs (+35 to -2.79 mV). Additionally, the C content in C-nCS@FeNPs was less (36.4 %) than in G-nCS@FeNPs (57.2 %), which is likely due to the higher nanochitosan content and the presence of proanthocyanidins in the green nanocomposite. The G-nCS@FeNPs exhibited a tridimensional porous structure, whereas the conventional composite appeared to form a CS film with an uneven surface and embedded FeNPs. G-nCS@FeNPs demonstrated remarkable potential as an adsorbent material for the removal of anionic reactive dyes, namely orange 122 (RO122) and red 250 (RR250). It exhibited an exceptional adsorption capacity of 3005 mg.g-1 for RO122. A DFT study revealed that the RO122 molecule displays enhanced reactivity towards the adsorbent surface. Moreover, experiments conducted in saline media and XPS and FTIR analyses post-adsorption indicated that 78.8 % of the interactions between RO122 and the adsorbent are based on electrostatic and ion exchange, while the remaining 22.2 % are attributed to π-π and hydrogen bonds. Also, G-nCS@FeNPs demonstrated a synergistic effect on the removal of the cationic dye safranin in multicomponent systems, exhibiting an increase in removal capacity from 0 to 169 mg.g-1.

Facile fabrication of a novel chitosan/carboxymethyl cellulose/bentonite/CuO nanocomposite for enhanced photocatalytic and antibacterial applications

In this study, an eco-friendly chitosan/carboxymethyl cellulose/bentonite/CuO nanocomposite (CS/CMC/BN/CuO NC) was synthesized utilizing algal-mediated copper oxide nanoparticles (CuO NPs). The resulting hybrid nanocomposite was thoroughly characterized using advanced techniques, including XRD, FTIR, UV-vis, FE-SEM, HR-TEM, and BET analysis. The photocatalytic activity of the hybrid nanocomposite was assessed by the degradation of brilliant cresyl blue (BCB) dye under visible light irradiation, while the antibacterial activity of the hybrid nanocomposite was evaluated against both Gram-positive and Gram-negative bacterial strains. XRD analysis confirmed the successful synthesis of the hybrid nanocomposite (CS/CMC/BN/CuO NC) with a crystallite size of 9.66 nm. The UV-vis analysis and Tauc plot revealed that the hybrid nanocomposite exhibited an absorbance peak at 249 nm and a band gap of 2.81 eV, respectively. FE-SEM and HR-TEM analysis highlighted its unique broken-tile structure. Furthermore, the hybrid nanocomposite exhibited outstanding photocatalytic performance, achieving 98.38% degradation of BCB dye within 60 min under optimal conditions. The scavenging experiments showed that electrons (e-) and superoxide anion radicals (O2˙-) are the major reactive species involved in the degradation of BCB dye. Additionally, it demonstrated remarkable antibacterial efficacy, showing a 40 mm zone of inhibition (ZOI) against the Gram-negative Pseudomonas aeruginosa strain. The findings indicate that the synthesized CS/CMC/BN/CuO NC holds significant promise for the photodegradation of organic dyes. Furthermore, it exhibits strong antibacterial properties, making it a potential disinfectant for treating wastewater contaminated with pathogenic bacteria.

Nano-chitosan-coated, green-synthesized selenium nanoparticles as a novel antifungal agent against Sclerotinia sclerotiorum: in vitro study

Chemical fungicides have been used to control fungal diseases like Sclerotinia sclerotiorum. These fungicides must be restricted because of their toxicity and the development of resistance strains. Therefore, utilizing natural nanoscale materials in agricultural production is a potential alternative. This work aimed to investigate the antifungal properties of a nanocomposite (nano-chitosan-coated, green-synthesized selenium nanoparticles) against the plant pathogenic fungus S. sclerotiorum. Chemical reduction was used to produce selenium nanoparticles from citrus peel extracts, and ionotropic gelation was used to produce chitosan nanoparticles. The nanocomposite has been produced using selenium nanoparticles stabilized by chitosan and cross-linked with sodium tripolyphosphate. Transmission electron microscopy, dynamic light scattering, X-ray diffraction, UV-VIS spectroscopy, and Fourier transform infrared spectroscopy were used to characterize all produced nanostructures. The in vitro antifungal activity and minimum inhibitory concentration of all bulk and nanostructures are investigated at (0.5, 1, 5, 10, 50, 100) ppm concentrations. Scanning electron microscopy was used to detect structural deformations in the fungal mycelium. The findings support the successful synthesis and characterization of all nanoparticles. Lemon peel extract produced smaller, more stable, and distributed selenium nanoparticles (42.28 ± 18.5 nm) than orange peel extract (85.7 ± 140.22 nm). Nanostructures, particularly nanocomposite, have shown a considerable increase in antifungal efficacy compared to bulk structures. At a minimum inhibitory concentration of 0.5 ppm, the nanocomposite exhibited 100% inhibitory activity. The nanocomposite with a concentration of 0.5 ppm exhibited the lowest average fungal biomass (0.32 ± 0.05 g) among all tested nanostructures. Fungal hyphae treated with 0.5 ppm of nanocomposite within 18 h of treatment revealed substantial damage and deformation. These results provide new insights into the nanocomposite as an eco-friendly and promising antifungal agent against other plant pathogenic fungi.

Alleviation of drought stress in tomato by foliar application of seafood waste extract

To manage the adverse effects of garbage pollution and avoid using chemicals, a natural extract of seafood shells was obtained and explored for its beneficial role. Physical characterization highlighted that its active compounds correspond to chitin and its derivative, chitosan. The ability of the extracted biostimulant to foster tomato tolerance was tested on drought-stressed plants. Along with changes in morphological parameters, the accumulation of chlorophyll and carotenoids was improved. The biostimulant also mediates the accumulation of osmoprotectants and an increased leaf water content. Furthermore, the biostimulant effectively promotes tolerance by increasing drought-stress SIERF84 Transcription factor and decreasing both SIARF4 and SlWRKY81 transcript levels, which in turn, mediates stomatal closure. In addition, the up-regulation of key genes related to NO3- uptake (NTR1.1/2) and assimilation (NR) coupled with the downregulation of ammonium transporters' genes (AMT1.1/2), allowed the uptake of NO3- over NH4+ in the tolerant genotype which is likely to be associated with drought tolerance. Overall, the biostimulant was effective in alleviating water stress and showed similar effects to commercial chitosan. Besides the benefits of a circular economy framework, this biostimulant-based approach is innovative to promote a sustainable eco-agriculture, in the face of persistent water scarcity.

Bile acid conjugated chitosan nanoparticles promote the proliferation and epithelial-mesenchymal transition of hepatocellular carcinoma by regulating the PI3K/Akt/mTOR pathway

Bile acids have been known to play significant roles at certain physiological levels in gastrointestinal metabolism. Yet, they are known to be carcinogenic and aid in tumor progression in most cases, although the roles remain uncertain. Hence, we tested the cytotoxic potential of cholic acid (CA) loaded chitosan nanoparticles (CNPs) on Hep3B cells. The physicochemical properties of the CNPs synthesized with CA load (CA-CNPs) were determined using standard techniques such as ultraviolet-visible spectrophotometry (UV-Vis), fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS) and transmission electron microscopy (TEM). The characteristic peak for chitosan nanoparticles were observed for plain CNPs (pCNPs) and CA-CNPs at around 300 nm as per UV-Vis analysis. FTIR analysis indicated the possible trapping of CA onto CNPs as certain peaks were retained and some peaks were shifted. XRD analysis determined that the peaks representing CA and pCNPs were collectively obtained in CA-CNPs. As per DLS analysis, the particle size, PDI and ζ-potential of the CA-CNPs were 259 nm, 0.284 and 30.4 mV. Further, the CA-CNPs were non-cytotoxic on Hep3B cells at the maximum tested concentration of 500 μg/mL. The viability at 500 μg/mL of CA-CNPs was two-fold higher than 500 μg/mL of pCNPs. Also, the pCNPs were not hemolytic and therefore could not have played a role in the increase of viability after treatment with CA-CNPs, which indicates that CA posed a major role in increased viability of Hep3B cells. As per quantitative PCR (qPCR), the upregulated gene expressions of PI3K, Akt, mTORC2, cMyc, Fibronectin, hVPS34, Slug and ZEB1 and the downregulated expression of the tumor suppressor PTEN indicates that PI3K/Akt/mTOR pathway mediated the induction of epithelial-to-mesenchymal transition (EMT) in response to CA-CNPs treatment on Hep3B cells.

Chitosan-based insecticide formulations for insect pest control management: A review of current trends and challenges

Future agricultural practices necessitate green alternatives to replace hazardous insecticides while distinguishing between pests and beneficial insects. Chitosan, as a biological macromolecule derived from chitin, is biodegradable and exhibits low toxicity to non-target organisms, making it a sustainable alternative to synthetic pesticides. This review identifies chitosan-derivatives for insecticidal activity and highlights its efficacy including genotoxicity, defense mechanism, and disruption of insect's exoskeleton at different concentrations against several insect pests. Similarly, synergistic effects of chitosan in combination with natural extracts, essential oils, and plant-derived compounds, enhances insecticidal action against various pests was evaluated. The chitosan-based insecticide formulations (CHIF) in the form of emulsions, microcapsules, and nanoparticles showed efficient insecticide action on the targeted pests with less environmental impact. The current challenges associated with the field-trial application were also recognized, by optimizing potent CHIF-formulation parameters, scaling-up process, and regulatory hurdles addressed alongside potential solutions. These findings will provide insight into achieving the EU mission of reducing chemical pesticides by 50 %.

5-Fluorouracil-loaded green chitosan nanoparticles/ guar gum nanocomposite hydrogel in controlled drug delivery

In recent years nanotechnologies have been applied to human health with promising results, especially in the field of drug delivery. Polymeric nanoparticles (NPs) have garnered much importance in controlled drug delivery owing to their size. Chitosan (Cs) is a well-recognized biopolymer and Cs NPs have been widely explored in drug delivery. Nonetheless, reports pertaining to green synthesis of Cs NPs are scarce. Thus, in this study, green synthesis of Cs NPs was accomplished from raw mango peel extract. Spherical Cs NPs with positively charged surface of 33.4 mV was accomplished by this process. Cs NPs, in varied content, were integrated in a guar gum network matrix resulting in a nanocomposite hydrogel. The mechanical and thermal stability of the hydrogel improved upon addition of Cs NPs. The hydrogel exhibited smart swelling, good antioxidant and anti-inflammatory propensities. Cs NPs encapsulating 5-Fluorouracil demonstrated a controlled release drug profile in the colorectum and the kinetics implied the anomalous nature of drug release mechanism. The exposure of the drug-loaded nanocomposite hydrogel displayed improved anticancer effects in HT-29 colon cancer cells. Taken altogether, this study puts forth the greater efficacy of Cs NPs in controlled drug delivery for anticancer therapy.

Novel algae-mediated biosynthesis approach of chitosan nanoparticles using Ulva fasciata extract, process optimization, characterization and their flocculation performance

Chitosan nanoparticles (CNPs) are promising biopolymeric nanoparticles with excellent physicochemical, antimicrobial, and biological properties. In this investigation, CNPs were produced using Ulva fasciata biomass extract as a reducing agent. The SEM micrograph revealed that the biosynthesized CNPs appeared to be spheres with a mean size of 32.49 nm. The ζ-potential pattern of CNPs has a single peak at +33.1 mV, indicating a positively charged surface. The X-ray diffraction pattern of the biosynthesized CNPs exhibited three different peaks at 2θ = 25.24, 52.96, and 72.28°. The FTIR analysis identifies various functional groups. The thermogravimetric analyses demonstrate that CNPs have high thermal stability. Additionally, the highest biosynthesis of CNPs (8.96 mg CNPs/mL) was obtained via FCCD when the initial pH level was 4, Ulva fasciata extract concentration was 45 %, v/v, and chitosan concentration was 0.9 %. Algae-mediated synthesized CNPs were used as coagulating/flocculating agents. By using the jar test, CNPs exhibited superior flocculation performance compared to commercial coagulants like alum, FeCl3, and chitosan in bulk form. Further, different parameters were screened, and the maximum flocculating activity (FA) recorded was 83.58 ± 0.47 % at 500 mg/L of CNPs, 1-5 % clay suspension at pH and temperature ranges of 6-8 and 10-80 °C, respectively. CNPs displayed eminent performance in water clarification.

Preparation and characterization of chitosan-coated noisomal doxorubicin for enhanced its medical application

This study aimed to synthesize and characterize chitosan-coated noisomal doxorubicin for the purpose of enhancing its medical application, particularly in the field of cancer treatment. Doxorubicin, a potent chemotherapeutic agent, was encapsulated within noisomes, which are lipid-based nanocarriers known for their ability to efficiently deliver drugs to target sites. Chitosan, a biocompatible and biodegradable polysaccharide, was used to coat the surface of the noisomes to improve their stability and enhance drug release properties. The synthesized chitosan-coated noisomal doxorubicin was subjected to various characterization techniques to evaluate its physicochemical properties. Transmission electron microscopy (TEM) revealed a spherical structure with a diameter of 500-550 ± 5.45 nm and zeta potential of +11 ± 0.13 mV with no aggregation or agglomeration. Chitosan-coated noisomes can loaded doxorubicin with entrapping efficacy 75.19 ± 1.45%. While scanning electron microscopy (SEM) revealed well-defined pores within a fibrous surface. It is observed that chitosan-coated niosomes loading doxorubicin have optimum roughness (22.88 ± 0.71 nm). UV spectroscopy was employed to assess the drug encapsulation efficiency and release profile. Differential scanning calorimetry (DSC) helped determine the thermal behavior, which indicated a broad endotherm peak at 52.4 °C, while X-ray diffraction (XRD) analysis provided information about the crystallinity of the formulation with an intense peak at 23.79°. Fourier-transform infrared spectroscopy (FTIR) indicated the formation of new bonds between the drug and the polymer. The findings from this study will contribute to the knowledge of the physical and chemical properties of the synthesized formulation, which is crucial for ensuring its stability, drug release kinetics, and biological activity. The enhanced chitosan-coated noisomal doxorubicin has the potential to improve the effectiveness and safety of doxorubicin in cancer treatment, offering a promising strategy for enhanced medical applications.

Coating based on chitosan/vancomycin nanoparticles: Patterns of formation in a water-carbon dioxide biphase system and in vivo stability

The patterns of formation of chitosan nanoparticles doped with vancomycin and coatings based on them in carbonate solutions have been investigated for the first time in this study. Using a technique of radioactive indicators, it was found that at a CO2 pressure of 30 MPa, the yield of the nanoparticles was ∼85 %, and a maximum antibiotic encapsulation efficiency of ∼30 % was achieved. By spectrophotometric and high-resolution microscopy, it was found that the coating of stabilized xenopericardial tissue of bioprosthetic heart valve, based on chitosan nanoparticles doped with vancomycin with a zeta potential |ζ| ∼20 mV completely covers collagen fibers by depositing about 60 nm nanoparticles onto them under direct deposition from carbonic acid at a pressure of 30 MPa CO2. The coating preserves the mechanical strength characteristics of collagen tissue and completely suppresses the growth of S. aureus pathogenic biofilm. This is consistent with the observed increase in antibiotic release of 15 % when the medium was acidified. Histological study demonstrated that the structure of pericardial tissues was not significantly altered by the deposition nanoparticles from carbonic acid. It was found that the rate of biodegradation of polymers and vancomycin in the coating differs by half (16 weeks for the rat model). A significantly lower degradation rate of antibiotics (∼50 % of vancomycin total remaining mass and ∼25 % of chitosan) was associated with its reliable encapsulation into nanoparticles.

Ruthenium complex based nanocomposite film with enhanced and selective electrochemical sensing of bifenthrin pesticide

Bifenthrin (BF), a widely used pyrethroid pesticide in farming, lacks highly sensitive and selective sensors despite its extensive application. Ruthenium complexes are very effective for selective sensing applications but suffer from structural instability at elevated conditions, electrochemical activity, and the use of costly electrolytes. This work improves their electrochemical activity and mechanical strength by incorporating silver nanowires and replacing the costly electrolyte with abundant KCl + PBS, resulting in enhanced signal performance. Herein, a ruthenium complex containing composite film was immobilized on a platinum (Pt) electrode using Langmuir Blodgett technique. The fabricated sensor has been characterized by differential pulse voltammetry (DPV) based electrochemical technique. The BF pesticide sensing parameters, including the limit of detection (LOD), linear range (LR), and sensitivity, were evaluated using SWV, DPV, and CV techniques. Among these, the DPV technique demonstrated the best performance, achieving a sensitivity of 0.648 μA cm-2 μM-1, a LR of 1-10 μM, and a LOD of 1 μM. The relative standard deviation (RSD) values using DPV are found to be 6.3% (repeatability study), 3% (reproducibility study), 8% (metal ion interference), 5% (organic species interference), and 2% (real sample study), which are much lesser than the World Health Organization (WHO) recommendation of RSD value on the pesticide (i.e. 20%). The BF sensor demonstrated a selectivity of 2× difference of peak height response compared to similar pesticides. The reported pesticide sensor will open new options for sensor research using metal complex-based LB film nanocomposite.

Termiticidal Effects and Morpho-Histological Alterations in the Subterranean Termite (Odontotermes formosanus) Induced by Biosynthesized Zinc Oxide, Titanium Dioxide, and Chitosan Nanoparticles

Recently, nanoparticles have been widely used in agricultural pest control as a secure substitute for pesticides. However, the effect of nanoparticles on controlling the subterranean termite Odontotermes formosanus (O. formosanus) has not been studied yet. Consequently, this study aimed to evaluate the effectiveness of some nanomaterials in controlling O. formosanus. The results showed that zinc oxide nanoparticles (ZnONPs), titanium dioxide nanoparticles (TiO2NPs), and chitosan nanoparticles (CsNPs) biosynthesized using the culture filtrate of Scedosporium apiospermum (S. apiospermum) had an effective role in controlling O. formosanus. Moreover, the mortality rate of O. formosanus after 48 h of treatment with ZnONPs, TiO2NPs, and CsNPs at a 1000 µg/mL concentration was 100%, 100%, and 97.67%, respectively. Furthermore, using ZnONPs, TiO2NPs, and CsNPs on O. formosanus resulted in morpho-histological variations in the normal structure, leading to its death. X-ray diffraction, UV-vis spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, dynamic light scattering, energy dispersive spectroscopy, and the Zeta potential were used to characterize the biosynthesis of ZnONPs, TiO2NPs, and CsNPs with strong activity against O. formosanus termites. Overall, the results of this investigation suggest that biosynthesized ZnONPs, TiO2NPs, and CsNPs have enormous potential for use as innovative, ecologically safe pesticides for O. formosanus control.

Size-controlled synthesis of La and chitosan doped cobalt selenide nanostructures for catalytic and antibacterial activity with molecular docking analysis

Co-precipitation method was adopted to synthesize ternary heterostructure catalysts La/CS-CoSe NSs (lanthanum/chitosan‑cobalt selenide nanostructures) without the use of a surfactant. During synthesis, a fixed amount (3 wt%) of CS was doped with 2 and 4 wt% La to control the growth, recombination rate and stability of CoSe NSs. The doped samples served to enhance the surface area, porosity and active sites for catalytic degradation of rhodamine B dye and antibacterial potential against Staphylococcus aureus (S. aureus). Additionally, the synthesized catalysts were examined for morphological, structural and optical characteristics to assess the influence of dopants to CoSe. XRD spectra verified the hexagonal and cubic structure of CoSe, whereas the porosity of the undoped sample (CoSe) increased from 45 to 60 % upon incorporation of dopants (La and Cs). Among the samples analyzed during this study, 4 % La/CS-CoSe exhibited significant bactericidal behavior as well as the highest catalytic reduction of rhodamine B dye in a neutral environment. Molecular docking analysis was employed to elucidate the underlying mechanism behind the bactericidal activity exhibited by CS-CoSe and La/CS-CoSe NSs against DHFRS. aureus and DNA gyraseS. aureus.

Bee chitosan nanoparticles loaded with apitoxin as a novel approach to eradication of common human bacterial, fungal pathogens and treating cancer

Antimicrobial resistance is one of the largest medical challenges because of the rising frequency of opportunistic human microbial infections across the globe. This study aimed to extract chitosan from the exoskeletons of dead bees and load it with bee venom (commercially available as Apitoxin [Api]). Then, the ionotropic gelation method would be used to form nanoparticles that could be a novel drug-delivery system that might eradicate eight common human pathogens (i.e., two fungal and six bacteria strains). It might also be used to treat the human colon cancer cell line (Caco2 ATCC ATP-37) and human liver cancer cell line (HepG2ATCC HB-8065) cancer cell lines. The x-ray diffraction (XRD), Fourier transform infrared (FTIR), and dynamic light scattering (DLS) properties, ζ-potentials, and surface appearances of the nanoparticles were evaluated by transmission electron microscopy (TEM). FTIR and XRD validated that the Api was successfully encapsulated in the chitosan nanoparticles (ChB NPs). According to the TEM, the ChB NPs and the ChB NPs loaded with Apitoxin (Api@ChB NPs) had a spherical shape and uniform size distribution, with non-aggregation, for an average size of approximately 182 and 274 ± 3.8 nm, respectively, and their Zeta potential values were 37.8 ± 1.2 mV and - 10.9 mV, respectively. The Api@ChB NPs had the greatest inhibitory effect against all tested strains compared with the ChB NPs and Api alone. The minimum inhibitory concentrations (MICs) of the Api, ChB NPs, and Api@ChB NPs were evaluated against the offer mentioned colony forming units (CFU/mL), and their lowest MIC values were 30, 25, and 12.5 μg mL-1, respectively, against Enterococcus faecalis. Identifiable morphological features of apoptosis were observed by 3 T3 Phototox software after Api@ChB NPs had been used to treat the normal Vero ATCC CCL-81, Caco2 ATCC ATP-37, and HepG2 ATCC HB-8065 cancer cell lines for 24 h. The morphological changes were clear in a concentration-dependent manner, and the ability of the cells was 250 to 500 μg mL-1. These results revealed that Api@ChB NPs may be a promising natural nanotreatment for common human pathogens.

Fabrication of chitosan/fibrin-armored multifunctional silver nanocomposites to improve antibacterial and wound healing activities

A wound healing substitute promotes rapid tissue regeneration and protects wound sites from microbial contamination. The silver-based antiseptic frequently moist skin stains, burns and irritation, penetrates deep wounds and protects against pathogenic infections. Thus, we formulated a novel fibrin/chitosan encapsulated silver nanoparticle (CH:F:SPG-CH:SNP) composites bandage accelerating the polymicrobial wound healing. Electrospinning method was employed to form the nano-porous, inexpensive, and biocompatible smart bandages. The structural, functional, and mechanical properties were analyzed for the prepared composites. The biological capacity of prepared CH:F:SPG-CH:SNP bandage was assessed against NIH-3 T3 fibroblast and HaCaT cell lines. In vitro hemolytic assays using red blood cells were extensively studied and explored the low hemolytic effect (4.5 %). In addition, the improved drug delivery nature captured for the CH:F:SPG-CH:SNP composite bandage. Antibacterial experiments were achieved against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and Lactobacillus bulgaricus using zone inhibition method. Moreover, in-vivo wound healing efficacy of fabricated smart bandage was evaluated on the albino Wistar rats which revealed the significant improvement on the postoperative abdomen wounds.

Mitigating Global Challenges: Harnessing Green Synthesized Nanomaterials for Sustainable Crop Production Systems

Green nanotechnology, an emerging field, offers economic and social benefits while minimizing environmental impact. Nanoparticles, pivotal in medicine, pharmaceuticals, and agriculture, are now sourced from green plants and microorganisms, overcoming limitations of chemically synthesized ones. In agriculture, these green-made nanoparticles find use in fertilizers, insecticides, pesticides, and fungicides. Nanofertilizers curtail mineral losses, bolster yields, and foster agricultural progress. Their biological production, preferred for environmental friendliness and high purity, is cost-effective and efficient. Biosensors aid early disease detection, ensuring food security and sustainable farming by reducing excessive pesticide use. This eco-friendly approach harnesses natural phytochemicals to boost crop productivity. This review highlights recent strides in green nanotechnology, showcasing how green-synthesized nanomaterials elevate crop quality, combat plant pathogens, and manage diseases and stress. These advancements pave the way for sustainable crop production systems in the future.

Synthesis and characterization of chitosan-corn starch-SiO2/silver eco-nanocomposites: Exploring optoelectronic and antibacterial potential

This work discusses the physicochemical and antimicrobial characteristics of chitosan-corn starch eco-nanocomposites integrated with silica@Ag nano-spheres. These composites were synthesized through sol-gel polymerization and subsequently exposed to simulated body fluid (SBF). The incorporation of Ag into the eco-nanocomposites led to a decrease in diffuse reflectance across the entire wavelength range. The dielectric permittivity exhibited an increase up to 52.1 at a frequency of 100 kHz, while the ac conductivity reached a value of 5.2 ∗ 10-6 (S cm-1) at the same frequency for the sample with the highest Ag content. The study utilized XRD and FTIR techniques to examine the materials before and after in vitro testing and evaluated the antibacterial properties of the eco-nanocomposites against several pathogenic microorganisms, including Staphylococcus haemolyticus, Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli, using the agar diffusion method. The eco-nanocomposites demonstrated bioactivity by forming a hydroxy appetite layer on their surfaces and were capable of releasing silver (Ag) at concentrations of 1.3, 1.9, and 2.5 mol%. This study suggests that chitosan-corn starch-SiO2-based doped with Ag eco-nanocomposite has the potential for various applications, including biomedical and environmental fields, where their antibacterial properties can be utilized to combat harmful microorganisms.

Synthesis of chitosan based reduced graphene oxide-CeO2 nanocomposites for drug delivery and antibacterial applications

In this study, the unique characteristics of chitosan, reduced graphene oxide (rGO) and cerium oxide (CeO2) based hybrid bionano-composites make a carrier for various drug delivery and antimicrobial applications. The recent literatures shown that addition of biopolymers to rGO and CeO2 based nanocomposites exhibit excellent performance in design and development of biosensors, wound dressings, electrodes, microfluidic chips, drug delivery systems and energy storage applications. Chitosan (CS), reduced graphene oxide (rGO) mixed with cerium oxide (CeO2) to form CS-rGO and CS-rGO-CeO2 hybrid bionano-composites using precipitation method. The physiochemical characterization of casted nanocomposite sheet was done using FTIR, XRD, UV-Vis spectrum, SEM and TGA. The XRD results of CS-rGO-CeO2 revealed that the nanoparticle was found to be crystalline structure. FTIR revealed that nitrogen functionalities of CS interacted with rGO-CeO2 to form hybrid nanocomposites. The thermal gravimetric analysis (TGA) showed that the CS-rGO-CeO2 has better thermal stability up to 550 °C. The SEM confirms the surface morphology of CS-rGO-CeO2 has large surface area with smooth surface. Moreover, the antibacterial properties of nanocomposites exhibit excellent zone of inhibition against Staphylococcus aureus and Escherichia coli. The NIH3T3 cell line evaluations showed superior cell adhesion on hybrid nanocomposites. Hence bionano-composite based on CS, rGO and CeO2 are potential biomaterials for drug delivery and antibacterial applications.

Novel jointured green synthesis of chitosan‑silver nanocomposite: An approach towards reduction of nitroarenes, anti-proliferative, wound healing and antioxidant applications

Here we present the simple green synthesis of chitosan‑silver nanocomposite (CS-Ag NC) by employing kiwi fruit juice as reducing agent. The structure, morphology, and composition of CS-Ag NC were determined using characterization techniques such as XRD, SEM-EDX, UV-visible, FT-IR, particle size, and zeta potential. The prepared CS-Ag nanocomposite was effectively used as catalyst in the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of NaBH4 as reductant, in aqueous medium at room temperature. The toxicity of CS-Ag NC was assessed on Normal (L929) cell line, Lung cancer (A549) cell line and Oral cancer (KB-3-1) cell line and their respective IC50values observed were 83.52 μg/mL, 66.74 μg/mL and 75.11 μg/mL. The CS-Ag NC displayed significant cytotoxic activity and the cell viability percentage for normal, lung and oral cancer cell lines were found to be 42.87 ± 0.0060, 31.28 ± 0.0045 and 35.90 ± 0.0065 respectively. Stronger cell migration was exemplified by CS-Ag NC and the percentage of wound closure (97.92%) was substantially identical to that of the standard drug ascorbic acid (99.27%). Further CS-Ag nanocomposite was subjected for in vitro antioxidant activity.

Nanocatalytic performance of pectinase immobilized over in situ prepared magnetic nanoparticles

Immobilization of enzymes is one of the protein engineering methods used to improve their thermal and long-term stabilities. Immobilized pectinase has become an essential biocatalyst for optimization in the food processing industry. Herein, nanostructured magnetic nanoparticles were prepared in situ for use as supports to immobilize pectinase. The structural, morphological, optical and magnetic features and the chemical compositions of the nanoparticles were characterized. Nanoparticle agglomeration and low porosity were observed due to the synthetic conditions. These nanoparticles exhibited superparamagnetic behavior, which is desirable for biotechnological applications. The maximum retention rate for the enzyme was observed at pH 4.5 with a value of 1179.3 U/mgNP (units per milligram of nanoparticle), which was equivalent to a 65.6% efficiency. The free and immobilized pectinase were affected by the pH and temperature. The long-term instability caused 40% and 32% decreases in the specific activities of the free and immobilized pectinase, respectively. The effects of immobilization were analyzed with kinetic and thermodynamic studies. These results indicated a significant affinity for the substrate, a decreased reaction rate, and improved thermal stability of the immobilized pectinase. The reusability of the immobilized pectinase was preserved effectively during cycling, with only a 21.2% decrease in activity observed from the first to the last use. Therefore, alternative magnetic nanoparticles are presented for immobilizing and maintaining the thermostability of pectinase.

Antimicrobial activity of nanocellulose composite hydrogel isolated from an agricultural waste

Infectious diseases and antimicrobial resistance have become one of the extreme health threats of this century. Overuse of antibiotics leads to pollution. To overcome this threat, the current strategy is to develop a substitute for these antibiotics that are extracted from natural sources. In this study, nanocellulose (NC) was isolated from an agricultural waste (wheat straw) and then oxidized with the help of sodium periodate to obtain dialdehyde nanocellulose (DA-NC). Then, chitosan (Ch) and DA-NC are both crosslinked with each other in different weight ratios, to obtain NC/Ch composite hydrogels. The resulted hydrogel is also characterized to confirm its structure, morphology and composition. The hydrogel was also tested for antimicrobial activities against bacteria, algae as well as fungal species to check its applicability for biomedical applications. The six microbes used for the ananlysis are Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis, Candida albicans, Aspergillus niger and Fusarium solani. The antimicrobial assessment of the hydrogel is evaluated via inhibition zone and optical density analysis. The resulted nanocellulose/chitosan (NC/Ch) hydrogel shows the uniform distribution of nanocellulose in the composite and the synergistic effect of their properties. Hydrogel serves excellent antimicrobial results which makes it a promising candidate for various biomedical applications.

Application of depolymerized chitosan in crop production: A review

Currently, chitosan (CHT) is well known for its uses, particularly in veterinary and agricultural fields. However, chitosan's uses suffer greatly due to its extremely solid crystalline structure, it is insoluble at pH levels above or equal to 7. This has sped up the process of derivatizing and depolymerizing it into low molecular weight chitosan (LMWCHT). As a result of its diverse physicochemical as well as biological features which include antibacterial activity, non-toxicity, and biodegradability, LMWCHT has evolved into new biomaterials with extremely complex functions. The most important physicochemical and biological property is antibacterial, which has some degree of industrialization today. CHT and LMWCHT have potential due to the antibacterial and plant resistance-inducing properties when applied in crop production. This study has highlighted the many advantages of chitosan derivatives as well as the most recent studies on low molecular weight chitosan applications in crop development.

Chitosan nanocomposite as an effective carrier of potential herbicidal metabolites for noteworthy phytotoxic effect against major aquatic invasive weed water hyacinth (Eichhornia crassipes)

In this current work, the herbicidal activity of fungal metabolites stacked chitosan nanocomposite against significant aquatic invasive weed Eichhornia crassipes (water hyacinth) was examined. Herbicidal metabolites from the fungal strain Allophoma oligotrophica were extracted and purified under standard condition. Altered ionic gelation technique was received for the amalgamation of chitosan nanocomposite fabricated with herbicidal metabolites. Synthesized nanocomposite incited checked herbicidal impact on the leaflets of water hyacinth. Synthesized nanocomposite induced marked herbicidal effect on the tested leaflets of water hyacinth. Necrotic development on the tested leaflets at earlier incubation period followed by progressive enhancement of necrotic lesion reveals the noteworthy herbicidal activity of the synthesized nanocomposite. Parenchymal, mesenchymal tissue disintegration, reduction of total chlorophyll content, elevated anti oxidative enzymes and changes in qualitative protein profiling of tested leaflets reveals the nanocomposite induced noteworthy morphometric and functional effects. Effect of solvents on the release profile demonstrates that ethyl acetate treatment brought about controlled or sustained release of metabolites. No sign of toxic effect on the zebra fish embryonic developmental stages revealed biocompatibility of the nanocomposite.

Molecular Docking and Efficacy of Aloe vera Gel Based on Chitosan Nanoparticles against Helicobacter pylori and Its Antioxidant and Anti-Inflammatory Activities

The medicinal administration of Aloe vera gel has become promising in pharmaceutical and cosmetic applications particularly with the development of the nanotechnology concept. Nowadays, effective H. pylori treatment is a global problem; therefore, the development of natural products with nanopolymers such as chitosan nanoparticles (CSNPs) could represent a novel strategy for the treatment of gastric infection of H. pylori. HPLC analysis of A. vera gel indicated the presence of chlorogenic acid as the main constituent (1637.09 µg/mL) with other compounds pyrocatechol (1637.09 µg/mL), catechin (1552.92 µg/mL), naringenin (528.78 µg/mL), rutin (194.39 µg/mL), quercetin (295.25 µg/mL), and cinnamic acid (37.50 µg/mL). CSNPs and A. vera gel incorporated with CSNPs were examined via TEM, indicating mean sizes of 83.46 nm and 36.54 nm, respectively. FTIR spectra showed various and different functional groups in CSNPs, A. vera gel, and A. vera gel incorporated with CSNPs. Two strains of H. pylori were inhibited using A. vera gel with inhibition zones of 16 and 16.5 mm, while A. vera gel incorporated with CSNPs exhibited the highest inhibition zones of 28 and 30 nm with resistant and sensitive strains, respectively. The minimal inhibitory concentration (MIC) was 15.62 and 3.9 µg/mL, while the minimal bactericidal concentration (MBC) was 15.60 and 7.8 µg/mL with MBC/MIC 1 and 2 indexes using A. vera gel and A. vera gel incorporated with CSNPs, respectively, against the resistance strain. DPPH Scavenging (%) of the antioxidant activity exhibited an IC₅₀ of 138.82 μg/mL using A.vera gel extract, and 81.7 μg/mL when A.vera gel was incorporated with CSNPs. A.vera gel incorporated with CSNPs enhanced the hemolysis inhibition (%) compared to using A.vera gel alone. Molecular docking studies through the interaction of chlorogenic acid and pyrocatechol as the main components of A. vera gel and CSNPs with the crystal structure of the H. pylori (4HI0) protein supported the results of anti-H. pylori activity.

High-Power Laser Deposition of Chitosan Polymers: Medical and Environmental Applications

High-power laser irradiation interaction with natural polymers in biocomposites and Laser-Induced Chitin Deacetylation (LICD) was studied in this work, in order to produce thin films consisting of chitosan composite. The new method can lead to a cutting-edge technology, as a response to the concern regarding the accumulation of “natural biological waste” and its use. The process consists of high-power laser irradiation applied on oyster shells as the target and deposition of the ablated material on different substrates. The obtained thin films we analyzed by FTIR, UV-VIS and LIF spectroscopy, as well as SEM-EDS and AFM. All the results indicated that chitin was extracted from the shell composite material and converted to chitosan by deacetylation. It was, thus, evidenced that chemical transformation in the chitin polymer side-chain occurs during laser irradiation of the oyster shell and in the resulted plasma plume of ablation. The numerical simulation in COMSOL performed for this study anticipates and confirms the experimental results of chitin deacetylation, also providing information about the conditions required for the physico-chemical processes involved. The high sorption properties of the thin films obtained by a LICD procedure is evidenced in the study. This quality suggests that they should be used in transdermal patch construction due to the known hemostatic and antibacterial effects of chitosan. The resulting composite materials, consisting of the chitosan thin films deposited on hemp fabric, are also suitable for micro-filters in water decontamination or in other filtering processes.

The Chitosan-Based System with Scutellariae baicalensis radix Extract for the Local Treatment of Vaginal Infections

Scutellarie baicalensis radix, as a flavone-rich source, exhibits antibacterial, antifungal, antioxidant, and anti-inflammatory activity. It may be used as a therapeutic agent to treat various diseases, including vaginal infections. In this study, six binary mixtures of chitosan with stable S. baicalensis radix lyophilized extract were obtained and identified by spectral (ATR-FTIR, XRPD) and thermal (TG and DSC) methods. The changes in dissolution rates of active compounds and the significant increase in the biological properties towards metal chelating activity were observed, as well as the inhibition of hyaluronic acid degradation after mixing plant extract with chitosan. Moreover, the combination of S. baicalensis radix lyophilized extract with a carrier allowed us to obtain the binary systems with a higher antifungal activity than the pure extract, which may be effective in developing new strategies in the vaginal infections treatment, particularly vulvovaginal candidiasis.

Current trends and challenges in the synthesis and applications of chitosan-based nanocomposites for plants: A review

Chitosan, a low-cost and multipurpose polymer with numerous desired physicochemical and biological properties has been tested for various applications in agriculture, pharmacy, and biomedicine industries. The availability of functional groups along the backbone makes chitosan readily available for other polymers and metal ions to form bio-nanocomposites. Different types of chitosan-based nanocomposites have been designed and tested for the enhancement of chitosan efficiency and ultimately widening the application areas of chitosan in plants. These nanocomposites serve different purposes such as eliciting plant's defence systems against different threats (pathogen attack), antimicrobial agent against bacteria, fungi and viruses, enhancement of nutrient uptake by plants, control release of micro/macronutrients, fungicides and herbicides. In this review, an extensive outlook has been provided (mainly in the last five years) to recent trends and advances in the fabrication and application of chitosan-based composites. Finally, current challenges and future development opportunities of chitosan-based nanocomposites for plants are discussed.

Seafood Waste as Attractive Source of Chitin and Chitosan Production and Their Applications

Chitosan is a cationic polymer obtained by deacetylation of chitin, found abundantly in crustacean, insect, arthropod exoskeletons, and molluscs. The process of obtaining chitin by the chemical extraction method comprises the steps of deproteinization, demineralization, and discoloration. To obtain chitosan, the deacetylation of chitin is necessary. These polymers can also be extracted through the biological extraction method involving the use of microorganisms. Chitosan has biodegradable and biocompatible properties, being applied in the pharmaceutical, cosmetic, food, biomedical, chemical, and textile industries. Chitosan and its derivatives may be used in the form of gels, beads, membranes, films, and sponges, depending on their application. Polymer blending can also be performed to improve the mechanical properties of the bioproduct. This review aims to provide the latest information on existing methods for chitin and chitosan recovery from marine waste as well as their applications.

Isolation, structure elucidation and antibacterial activity of methyl-4,8-dimethylundecanate from the marine actinobacterium Streptomyces albogriseolus ECR64

Around 120 actinobacterial colonies were isolated from various regions of marine East coast region of Tamil Nadu, India. Among them, 33 were morphologically distinct and they were preliminarily screened for their antibacterial activity against Pseudomonas fluorescens, Vibrio cholerae, V. parahaemolyticus, V. alginolyticus, and Aeromonas hydrophila by cross-streak plate technique. Among the isolated, the isolate ECR64 exhibited maximum zone of inhibition against fish pathogenic bacteria. The crude bioactive compounds were extracted from the isolate ECR64 using different organic solvents which exhibited maximum antibacterial activity. Separation and purification of the bioactive compounds were made by column chromatography which yielded 27 fractions and were re-chromatographed to obtain the active compound. Ultra violet (UV), Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectral studies were used to predict the structure of the active compound which was identified as methyl-4,8-dimethylundecanate. The potential isolate ECR64 was identified as Streptomyces albogriseolus by phylogenetic, phenotypic and genotypic (16S rRNA gene sequence) analyses. The identified compound methyl-4,8-dimethylundecanate can be used as potential and alternative drug in disease management of aquaculture.