Chitosan-polyvinyl Alcohol Hydrogel Research Articles

Preparation of Polyvinyl Alcohol–Chitosan Nanocellulose–Biochar Nanosilver Composite Hydrogel and Its Antibacterial Property and Dye Removal Capacity

In this research, silver-loaded biochar (C-Ag) was acquired from a waste fish scale, and nanocellulose (CNF) was prepared from the waste wheat stalk. Then C-Ag was loaded into chitosan-polyvinyl alcohol hydrogel (CTS-PVA) with CNC as a reinforcement agent, and a novel nanocomposite material was acquired, which could be efficiently applied for antibacterial and dye removal. By plate diffusion analysis, the inhibition areas of C-Ag-CTS-PVA-CNF (C/CTS/PVA/CNF) hydrogel against E. coli ATCC25922, S. aureus ATCC6538, and P. aeruginosa ATCC9027 could reach 22.5 mm, 22.0 mm, and 24.0 mm, respectively. It was found that the antibacterial rate was 100% in the water antibacterial experiment for 2 h, and the antibacterial activity was more than 90% within 35 days after preparation, and the antibacterial rate was more than 90% after repeated antibacterial tests for five times. Through swelling, water adsorption, water loss rate, and water content tests, the hydrogel manifested good moisturizing properties and could effectually block the loss of water and improve the stability of the C/CTS/PVA/CNF hydrogel. The pseudo-first-order and pseudo-second-order models were built, and the adsorption capacity of hydrogel to dye was analyzed, and the dye removal was more consistent with the pseudo-first-order kinetic model. The best removal effect for Congo red was 96.3 mg/g. The C/CTS/PVA/CNF hydrogel had a remarkable removal efficacy on Malachite green, Methyl orange, Congo red, and Methylene blue. As a result, the C/CTS/PVA/CNF hydrogels had robust antibacterial properties and reusability. In addition, the present research developed a facile strategy for effectual dyes removal from the aqueous medium.

Silver nanoparticles stabilized by chitosan-polyvinyl alcohol polymers mediated by Pistacia extract for treatment of functional dyspepsia and gastric cancer

The impact of the nanoparticles on the dyspepsia mice gut microbiota is evaluated through the utilization of the 16S rRNA technique. Various methods were employed to characterize the NPs. In the textile, culinary, paper, leather, and printing sectors, synthetic dyes are frequently employed as coloring agents. Because these dye molecules are harmful to both the environment and living things, it is difficult to remove them sustainably. Here, we have produced nanoparticles embedded in chitosan-polyvinyl alcohol hydrogel (CS-PVA) by using bark's Pistacia under ultrasonic irradiation. The reduction of Ag + ions into Ag0 NPs was detected by a visual change in the colors. UV–Vis analysis indicated that the characteristic SPR band appeared near ∼440–450 nm. UV/Vis, EDX-elemental mapping, SEM, TEM, ICP-OES, and XRD analysis were applied to characterize the Ag NPs/CS-PVA nanocomposite. The recent study focused on the cellular and molecular aspects. The MTT assay was conducted for 48 h to evaluate the anti-human gastric cancer and cytotoxicity efficacies of the treated cells with nanocomposite. The assessment was performed on normal (HUVEC) and gastric cancer cells, namely MKN45 and NCI–N87. The IC50 values of nanocomposite against MKN45 and NCI–N87 were 180 and 151 μg/mL, respectively. The dose-dependent reduction in malignant gastric cell viability was observed in the nanocomposite presence. Furthermore, the nanocomposite induced cell apoptosis by 40–50%, leading to an increase in the expression of pro-apoptotic markers (Bax and cleaved caspase-8) and a decrease in the expression of the anti-apoptotic marker, Bcl-2. Furthermore, the nanocomposite showed inhibitory effects on colony formation. Our results indicate that the nanocomposite can increase p53 expression and decrease the expression of STAT3 in treated cells. This indicates that p53 and STAT3 play crucial roles in the biological effects induced by the extract in human gastric carcinoma cells. The data from the gut microbiome suggested that nanocomposites have the ability to control the rebalancing of homeostasis and microbiome composition by decreasing the levels of harmful bacteria, and at the same time, increasing the levels of beneficial bacteria. Following the introduction of nanocomposite, there was an observed rise in the levels of gastrointestinal hormones in the serum, including gastrin and motilin, while the levels of vasoactive intestinal peptide decreased. The application of nanocomposite led to an improvement in gastrointestinal movement, encompassing a rise in the rate of transit through the small intestine and the rate of gastric emptying. These findings offer that the Ag NPs/CS-PVA nanocomposite could be a promising anticancer treatment for functional dyspepsia and gastric cancer.

All-weather-available down carbon fiber hydrogel with enhanced mechanical properties for simultaneous efficient clean water generation and dye adsorption from dye wastewater

Solar-driven photothermal conversion can produce clean water from dye wastewater while leaving the dye in the evaporation medium. Herein, a biomass-based composite hydrogel via down-fiber carbon (DFC) aerogel modified with chitosan-polyvinyl alcohol (CS-PVA) hydrogel was designed to address the aforementioned problem. The CS-PVA@DFC hydrogel integrated the capacity of simultaneous clean water production/dye adsorption during the day and continuous dye adsorption during the night. Furthermore, the modification of the CS-PVA hydrogel endowed the composite hydrogel with enhanced compression stress of 190.07 kPa (76.03 times that of DFC aerogel of 2.50 kPa) and impressive resilient recovery. Moreover, the CS-PVA@DFC hydrogel possessed solar light absorption of 99.56 % and strengthened water replenishment capacity due to the high porosity and CS-PVA hydrophilic network structure. The CS-PVA@DFC hydrogel demonstrated a stable, high evaporation rate of 2.34 kg·m−2·h−1 and simultaneous dye adsorption capacity of 70.39 % for treating methyl orange dye solution within 5 h. Additionally, the 24-h outdoor test showed that the CS-PVA@DFC hydrogel possessed excellent clean water production capacity during the daytime (reaching 4.17 kg·m−2·h−1 at 1:00p.m.) and continuous satisfactory dye adsorption capacity all day (89.68 %). These findings will inspire researchers seeking opportunities to improve the mechanical properties of aerogel and its application for treating wastewater, especially wastewater with harmful dyes.

Gelatin–chitosan–PVA hydrogels and their application in agriculture

AbstractBACKGROUNDHydrogels are materials with great potential in agricultural applications. Biodegradable hydrogels are used as preparations, for example to increase the substratum water capacity, and improve soil structure or agrochemical‐controlled release. This work aimed to develop biodegradable hydrogels based on chitosan, gelatin and polyvinyl alcohol (PVA) for releasing inulin isolated from Dahlia tubers to induce protection in chili plants against Phytophthora capsici. The hydrogels were characterized by water absorption capacity, Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and stereomicroscopy microscopy, and degradation capacity using the soil burial test with sterile and inoculated soil.RESULTSThis work demonstrated the ability of a fabrication process in the preparation of gelatin‐chitosan‐PVA hydrogels for potential agricultural applications. The hydrogels showed a dense, tridimensional, interconnected and reticulated structure that was more evident in the hydrogel loaded with inulin. The hydrogels showed a water absorption capacity of ≤12 times its mass. FTIR and light microscopy demonstrated that the hydrogels were biodegradable. The percentage of degradation of hydrogels in inoculated soil was higher than in sterile soil using the soil burial test. Hydrogel loaded with inulin was found to be capable of inducing resistance in chili plants against Phytophthora capsici.CONCLUSIONThe hydrogels prepared for the described methodology have great potential for use in the agricultural sector as a reservoir for agrochemicals and inductors in plant resistance treatments. Furthermore, the hydrogels were proven to be biodegradable, offering a promising tool in crop protection. © 2019 Society of Chemical Industry

Sonochemically Synthesized Lignin Nanoparticles and its Application in the Development of Nanocomposite Hydrogel

Abstract The hydrophilic gels or hydrogels are chemically or physically crosslinked polymeric network which are capable in absorbing a large quantity of water in their three-dimensional polymeric network. In contrast with synthetic polymer hydrogels, biopolymeric hydrogels are biocompatible, flexible, biodegradable, and non-toxic, hence they have received a great attention in numerous biomedical, engineering, and industrial applications. Conventionally developed synthetic polymer [i.e., polyvinyl alcohol (PVA)] and biopolymer [i.e., chitosan (CS)] hydrogels have insignificant physical as well as chemical properties, which can be overcome by the development of these hydrogels in association with nanoparticles. The present study focuses on the synthesis of lignin nanoparticles derived from natural resources by using ultrasound and its application in the development of CS–PVA hydrogel. The nanoparticles were found to be in the range of 10–50 nm. Physical crosslinking method has been adopted for the development of hydrogel. Further to examine the thermal stability of hydrogel TGA was performed. Post addition of nanoparticles in CS–PVA hydrogel manifested a significant increase in the thermal stability. Considering numerous advantages of the proposed nanocomposite hydrogel, this could be possibly used in drug delivery, food packaging and wound dressing