Formulating of the sustained release of Tebuconazole pesticide using chitosan aerogel reinforced NFC/CaCO3 nanocomposite

Chitosan-based aerogels were fabricated through utilizing of nanofibrillated cellulose (NFC)/CaCO3 composites. Chitosan aerogel and extra three aerogels loaded different concentrations of NFC/CaCO3 were investigated to explore their release efficiency of Tebuconazole pesticides. Results obtained from ATR-FTIR showed a remarkable decline of the characterized chitosan hydroxyl group peak prolonging with appearance of new peaks assigned to the inclusion of inorganic calcium element. Also, SEM images showed chitosan aerogel with regular porous structure increased by incorporation with of NFC/CaCO3 nanocomposite, while EDS affirmed the presence of calcium element rather pristine chitosan aerogel. In addition to this, the physical characterizations showed significant improvement in swelling properties for aerogels incorporated NFC/CaCO3 nanocomposite at low ratios. Chitosan aerogel reinforced NFC/CaCO3 nanocomposite exhibited benefit on loading and release efficiency of Tebuconazole. All samples showed accessibility to column release method with fastest release at low slow rate 2 mL/min as giving chance for diffusion and solubility of ingredient, while release increase as heat increase as result of pore expansion. In conclusion, chitosan aerogels incorporated calcium carbonate showed better-sustained release of Tebuconazole pesticides than pristine chitosan aerogel. The produced aerogels loaded NFC/CaCO3 nanocomposite could be promising for controlled release of pesticides at water-streams in agriculture sector.

Thermoresponsive nanofibers loaded with antimicrobial α-aminophosphonate-o/w emulsion supported by cellulose nanocrystals for smart wound care patches

Long-term topical application of antibiotics on wounds has led to the emergence of drug-resistant bacterial infections. Antibiotic incorporation into the wound dressing requires enormous advancement of the field to ensure that the needed dose is released when the infection arises. This study synthesized a series of antimicrobial α-aminophosphonate derivatives, and the most effective compound was incorporated into thermoresponsive wound dressing patches. Wound dressing mats were fabricated by needleless electrospinning, and the resultant nanofiber mats were coated with a thermoresponsive eicosane/cellulose nanocrystals o/w system loaded with active α-aminophosphonate derivatives. Chemical, physical, thermal, and antimicrobial properties of the wound dressings were characterized wound dressings. Using SEM analysis, Nanofibers spun with 20 % w/v solutions were selected for drug-emulsion loading since they showed lower diameters with higher surface area. Furthermore, the drug-emulsion coating on the electrospun dressings improved the hydrophilicity of the wound dressings, and the thermoresponsive behavior of the mats was proved using differential scanning calorimetry data. Finally, the drug-loaded electrospun meshes were found active against tested microorganisms, and clear inhibition zones were observed. In conclusion, this novel approach of synthesizing a new family of antimicrobial molecules and their incorporation into nanofibers from renewable sources exhibits great potential for smart and innovative dressings.

Size-tunable effect of CaCO3/nanocellulose hybrid composites on the removal of paracetamol from aqueous solution

Paracetamol is a ubiquitous drug used by animals and humans but is not fully metabolized within their bodies, and thus often finds its way into raw wastewater. This study represents a new class of adsorbent nanocomposite with high adsorption capacity towards paracetamol removal. Herein, both the kinetic study and the removal of paracetamol from aqueous solutions were investigated in terms of diverse CaCO₃/nanocellulose composites with different surface charges and different particle sizes. To fine-tune these parameters, the latter was hydrothermally synthesized by manipulating of three nanocelluloses types. Precisely, micro-crystalline cellulose (MCC), nano-crystalline cellulose (CNC), and nano-fibrillated cellulose (NFC) were used as templates for precipitating CaCO₃ particles from CaCl₂ solution with the aid of Na₂CO₃. Results revealed the successful in situ deposition of calcite form of CaCO₃ with size varied relying on the base of nanocellulose. For MCC, CNC, and NFC, the size of CaCO₃ was disclosed in the range of 850-1200 nm, 350-600 nm, and 150-200 nm, respectively, regarding their surface charge. While the process of paracetamol adsorption was described by Freundlich and Langmuir isotherms, it was observed that, for MCC, the best fit of the experimental data was achieved with the Freundlich model, while the Langmuir model was the most appropriate for CNC and NFC. Also, the highest max adsorption capacities of paracetamol varied respectively to both size and surface charge of hybrid composite used. Among them, MCC/CaCO₃ composite exhibited the highest max adsorption capacity at 428 mg g^-1, clarifying that the low surface zeta potential of the latter hybrid nanocomposite is responsible for the accumulation of CaCO₃ at a bigger size with a higher affinity to adsorb paracetamol with the highest capacity due to its weak repulsion. Results also demonstrated that the material is highly effective and economical for removal of paracetamol and reusability with marginal diminishing in adsorption capacity up to 10% after five reuse cycles.

In vivo assessment of the durable, green and in situ bio-functional cotton fabrics based carboxymethyl chitosan nanohybrid for wound healing application

Herein, a newly developed approach for durable antibacterial cotton fabrics coated carboxymethyl chitosan (CMCs) via ionic crosslinking driven by cationization of cotton surface (CC) with 3-chloro-2-hydroxyl propyl-trimethyl ammonium chloride (CHTAC). In this regard, the novelty was extended to impart a highly antibacterial activity through harnessing of the as-functionalized CMCs/CC in situ preparation of AgNPs, without using of hazardous reductants. The antibacterial activity of the in situ prepared AgNPs onto CMCs/CC as well as the in vivo study on the rat lab were investigated to evaluate their healing efficiency, pathological tissues and biomarkers. Results affirmed that the treatment of CC with 10% of CMCs was adequate to achieve the highest swelling ratio which, in turns, is able to in situ deposition of AgNPs with a size range of 2-10 nm onto CC/CMCs rendering them a highly durable antibacterial activity against both Gram +Ve and Gram -Ve bacteria, which had a bacterial reduction of 98% to 86% after 20 washing cycles. Furthermore, the in vivo study revealed effectively the advantageous uses of the cotton functionalized with AgNPs compared to CC/CMCs in wound healing via alleviating the oxidative stress and promoting hyaluronic acid in wounded skin as well as increasing RUNX2 in healed skin tissues.

Design of a dual pH and temperature responsive hydrogel based on esterified cellulose nanocrystals for potential drug release

In this study, new stimuli - responsive hybrid hydrogels were achieved via succinylated cellulose nanocrystals (Su-CNC). The innovation was concerned with the inclusion of Su-CNC, at different degree of substitution (DS), into hydrogel network to render it pH and thermo-responsive characters through free radical polymerization reaction with poly(N-isopropylacrylamide) (PNIPAm). The prepared hydrogel was also examined for the in vitro release of Famotidine at different pH values. As clearly evident from the results, all the hydrogels prepared with different DS of Su-CNC, which were nominated as Su-CNC / PNIPAm (1-3), showed a high response to temperature change since their swelling behavior and hydrophilicity were decreased at 35 °C and upwards. This led to the more hydrophobicity character and thus the hydrogel shrinkage occurred. On the other hand, at pH 6, the hydrogels exhibited a significant Equilibrium Swelling Ratio (ESR) attaining 18.1, 17.3 and 16.8 (g/g) for Su-CNC / PNIPAm (1-3), respectively. However, Su-CNC / PNIPAm 2 hydrogel showed a significant response to the pH change from 8 to 2 which was advised to be selected as a potential pH responsive hydrogel for the in vitro Famotidine release.

Formulation of re-dispersible dry o/w emulsions using cellulose nanocrystals decorated with metal/metal oxide nanoparticles

This study describes for the first time the preparation of re-dispersible surfactant-free dry eicosane oil emulsion using cellulose nanocrystals (CNCs) using the freeze-drying technique. Surface properties of CNCs constitute a critical point for the stability of o/w emulsions and thus can affect both the droplet size and dispersion properties of the emulsion. Therefore, surface modification of CNCs was performed to understand its effect on the size of the obtained re-dispersible dry o/w eicosane emulsion. Decoration of the CNC surface with metal and metal oxide nanoparticles was conducted through the available alcoholic groups of glycosidic units of CNC, which played a dual role in reducing and stabilizing nanoparticles. Of these nanoparticles, silver (AgNPs), gold (AuNPs), copper oxide (CuO-NPs), and iron oxide (Fe₃O₄-NPs) nanoparticles were prepared via a facile route using alkali activated CNCs. Thorough characterizations pertaining to the as-prepared nanoparticles and their re-dispersible dry eicosane o/w emulsions were investigated using UV-vis spectroscopy, TEM, XRD, particle size, zeta potential, and STEM. Results confirmed the ability of CNCs to stabilize and/or reduce the formed nanoparticles with different sizes and shapes. These nanoparticles showed different shapes and surface charges accompanied by individual morphologies, reflecting on the stability of the re-dispersed dry eicosane emulsions with droplet sizes varying from 1.25 to 0.5 μm.

Schematic diagram for the detailed preparation of dry eicosane o/w emulsions.

Endophytic Streptomyces laurentii Mediated Green Synthesis of Ag-NPs with Antibacterial and Anticancer Properties for Developing Functional Textile Fabric Properties

Improvement of the medical textile industry has received more attention recently, especially with widespread of microbial and viral infections. Medical textiles with new properties, such as bacterial pathogens self-cleaning, have been explored with nanotechnology. In this study, an endophytic actinomycetes strain of Streptomyces laurentii R-1 was isolated from the roots of the medicinal plant Achillea fragrantissima. This is used as a catalyst for the mediated biosynthesis of silver nanoparticles (Ag-NPs) for applications in the textile industry. The biosynthesized Ag-NPs were characterized using UV-vis spectroscopy, Fourier transform infrared (FT-IR), transmission electron microscopy (TEM), and X-ray Diffraction (XRD), which confirmed the successful formation of crystalline, spherical metal nanoparticles. The biosynthesized Ag-NPs exhibited broad-spectrum antibacterial activity. Our data elucidated that the biosynthesized Ag-NPs had a highly cytotoxic effect against the cancerous caco-2 cell line. The selected safe dose of Ag-NPs for loading on cotton fabrics was 100 ppm, regarding their antibacterial activity and safe cytotoxic efficacy. Interestingly, scanning electron microscope connected with energy dispersive X-ray spectroscopy (SEM-EDX) of loaded cotton fabrics demonstrated the smooth distribution of Ag-NPs on treated fabrics. The obtained results highlighted the broad-spectrum activity of nano-finished fabrics against pathogenic bacteria, even after 5 and 10 washing cycles. This study contributes a suitable guide for the performance of green synthesized NPs for utilization in different biotechnological sectors.

In-Vitro cytotoxicity, antibacterial, and UV protection properties of the biosynthesized Zinc oxide nanoparticles for medical textile applications

Nowadays, medical textiles have become the most essential and developing part in human healthcare sector. This work was undertaken with a view to harness the bio-active macromolecules secreted by fungi e.g. proteins and enzymes in bio-synthesis of ZnO nanoparticles for multifunctional textiles such as antibacterial activity and UV protection with considering the cytotoxicity limitation. Herein, the isolated fungus, Aspergillus terreus, was allowed to produce proteins which has affinity to cape ZnO-NPs. Various factors affecting the behavior of the secreted proteins on the formed nanoparticles were investigated. Thorough characterizations of the protein capped ZnO-NPs were performed by the using of UV-Visible spectroscopy, transmission electron microscope (TEM) Fourier Transform-Infra Red (FT-IR) spectroscopy, X-ray diffraction (XRD) analysis and Dynamic light scattering analysis (DLS). Prior treatment of cotton fabrics with ZnO-NPs, the cytotoxicity of the protein capped ZnO-NPs was examined. After that, the antibacterial activity of the ZnO-NPs before and after treating of cotton fabrics, besides, the UV-protection (UPF) properties were investigated. Results obviously demonstrated the ability of the bio-secreted protein to cape and reduce ZnO to spherical ZnO-NPs with particle size lied around 10-45 nm, as indicated form UV-vis., spectra TEM, Zeta sizer, FTIR and XRD. Regarding to the results of cytotoxicity, the treatment of the cotton fabrics with ZnO-NPs were performed at safe dose (20 ppm). At this dose, ZnO-NPs loaded samples exhibited reasonable antibacterial activity against both Gram positive and Gram negative bacteria; besides, good UV-protection with reasonable increase in UVA and UVB blocking values. Indeed, nanotechnology based microbiological active molecules opens up new opportunities for us to explore novel applications in terms of green technology.