This study sought to develop a biodegradable material that can be a substitute for conventional plastics and is sustainable and eco-friendly. The research's primary focus was the conversion of carboxymethyl cellulose (CMC) derived from agricultural waste into a bioplastic film that is satisfactory for use in packaging. The weak mechanical stability and excessive water sensitivity of CMC films limit their widespread use. To overcome these limitations, therefore, CMC films were reinforced with varying concentrations (0, 5, 10, 15, 20, and 25%) of zinc oxide nanoparticles (ZnO NPs), using a solution casting method. The films were also surface-modified by spray coating with a 1:1 composite mixture of poly(dimethylsiloxane) (PDMS) and starch. An array of analyses were used to investigate the films' properties. Structural characterization employing Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) confirmed the successful incorporation of ZnO and uniformity of PDMS/starch coating on the films. Thermogravimetric analysis (TGA) and mechanical testing revealed that the films' thermal and mechanical properties were improved by the incorporation of ZnO, with the film CZ20-C exhibiting the highest value of tensile strength--14.029 MPa--and 27.59% elongation at break. The films exhibited excellent water resistance, as evidenced by a remarkable increase in their water contact angle to 152.04 degrees. Furthermore, biodegradability studies demonstrated that the films degraded by 84.78% in soil within 20 days, under ambient conditions. Films with these desirable characteristics are therefore producible through the study's facile strategy for preparing CMC-based eco-friendly composite films that have excellent potential to replace conventional plastic in the packaging industry.
Nanoparticles can easily reach soil,water and foodstuffs. The zinc oxide nanoparticle (ZnONP), which is a type of nanoparticle with known antiviral/microbial properties used frequently in cosmetic UV protection products, can damage the cell membrane/wall complex in Saccharomyces cerevisiae after exposure. However, the capacity of hsp150, an o-mannosylated heat shock protein needed for the strength of the S. cerevisiae cell wall, to prevent ZnONP toxicity/genotoxicity has not been investigated before. In this study, HSP150 gene of S. cerevisiae cells was deleted and the effects on the toxicity caused by ZnONPs were investigated by MTT, cell wall/membrane damage analyses and zymolyase susceptibility test. In addition, the level of oxidative DNA damage was determined by 8-OHdG test in the HSP150 deficient cells (hsp150 Delta). IC50 values observed in hsp150 Delta cells were lower than the wild type cells. In addition, the lowest dose of ZnONPs (250 mu g/mL) was significant enough to damage the cellular integrity in hsp150 Delta cells and DNA damage levels observed in the hsp150 Delta cells exposed to the lowest dose of the nanoparticles were nearly 2.5 times higher than the wild type cells. Therefore, it can be concluded that the HSP150 gene is needed for the cellular protection against ZnONP toxicity and genotoxicity.
This research explores the synthesis of carboxymethyl cellulose (CMC) for the development of a cost-effective bioplastic film that can serve as a sustainable alternative to synthetic plastic. Replacing plastic packaging with CMC-based films offers a solution for mitigating environmental pollution, although the inherent hydrophilicity and low mechanical strength of CMC present significant challenges. To address these limitations, zinc oxide nanoparticles (ZnO NPs) were employed as a biocompatible and non-toxic reinforcement filler to improve CMC's properties. A solution casting method which incorporated varying concentrations of ZnO NPs (0%, 5%, 10%, 15%, 20%, and 25%) into the CMC matrix allowed for the preparation of composite bioplastic films, the physicochemical properties of which were analyzed using scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The results revealed that the ZnO NPs were well-integrated into the CMC matrix, thereby improving the film's crystallinity, with a significant shift from amorphousness to the crystalline phase. The uniform dispersion of ZnO NPs and the development of hydrogen bonding between ZnO and the CMC matrix resulted in enhanced mechanical properties, with the film CZ20 exhibiting the greatest tensile strength-15.12 +/- 1.28 MPa. This film (CZ20) was primarily discussed and compared with the control film in additional comparison graphs. Thermal stability, assessed via thermogravimetric analysis, improved with an increasing percentage of ZnO Nps, while a substantial decrease in water vapor permeability and oil permeability coefficients was observed. In addition, such water-related properties as water contact angle, moisture content, and moisture absorption were also markedly improved. Furthermore, biodegradability studies demonstrated that the films decomposed by 71.43% to 100% within 7 days under ambient conditions when buried in soil. Thus, CMC-based eco-friendly composite films have the clear potential to become viable replacements for conventional plastics in the packaging industry.
Nanomaterials play a crucial role in various applications, but their environmental impact necessitates effective recycling strategies. This study investigates the effects of different ZnO nanoparticles (ZnO-NPs) sizes (0, 30, 50, and 90 nm) on Agrostis stolonifera, focusing on physiological and biochemical responses, root exudate, and microbial community structure. The results showed that the most optimal physiological and biochemical responses, including enhanced plant growth and increased activities of superoxide dismutase, peroxidase, and catalase, were observed at 50 nm ZnO-NPs. Agrostis stolonifera accumulated more ZnO-NPs at 30 nm, with Zn content in root and leaf tissues reaching 186 mg/kg and 294 mg/kg, respectively. Meanwhile, SEM-Mapping and TEM analyses confirmed the absorption and transport of ZnO-NPs within Agrostis stolonifera. Furthermore, root exudates analysis revealed an increase in the types of organic matter secreted by roots at 30 nm and 50 nm ZnO-NPs, while 90 nm ZnO-NPs had the opposite effect. 16S rRNA gene sequencing showed that the species diversity and uniformity of root microorganisms exhibited contrasting trends with increasing ZnO-NPs size, with roots exposed to 50 nm ZnO-NPs showed higher species richness than those exposed to 30 nm or 90 nm. However, beneficial microorganisms such as Bryobacter and Methylophilus were inhibited by 90 nm ZnO-NPs. This study provides novel insights into a potential ZnO-NPs recycling strategy in soil using Agrostis stolonifera, offering a means to mitigate nanoparticle-induced damage to soil and crops.
Pythium irregulare (P. irregulare) is one of the soil-borne pathogens that is the primary cause of damage to several plants each year. The novelty and originality of this work were the ability of Streptomyces gancidicus (S. gancidicus OR229936) to synthesize bimetallic zinc oxide-boron oxide nanoparticles (ZnO-B2O3 NPs) for reducing P. irregulare growth and safeguarding pea plant from damping off disease. The produced bimetallic ZnO-B2O3 NPs' XRD results highlighted the ZnO diffraction peaks at 2 = 27.50 degrees, 31.15 degrees, 45.15 degrees, 56.89 degrees, 67.98 degrees, and 75.25 degrees, which are complemented by the standard card JCPDS number 361451 and correspond to (002), (101), (102), (110), (103), and (201) Bragg's reflections. Along with the standard card JCPDS number 300019, they additionally include the B2O3 NP diffraction peaks at 2 = 15.25 degrees, 28.69 degrees, 31.99 degrees, and 41.28 degrees. Bimetallic ZnO-B2O3 NPs were tested against P. irregular for their antifungal activities. The findings indicated that ZnO-B2O3 NPs exhibited potential anti P. irregulare activity, with an inhibition zone of 33 mm at a concentration of 1000 mu g/mL and a promising MIC of 0.01 mu g/mL. Bimetallic ZnO-B2O3 NPs (0.01 ppm) application appeared to significantly lessen the severity of the pea post-emergence damaging off disease by 10% and to provide significant protection by 88%. In comparison to fungicide (difenoconazole 25%) treatments, all metabolic resistance indicators significantly enhanced after the usage of bimetallic ZnO-B2O3 NPs, ZnO NPs, and B2O3 NPs with ethyl acetate extract of S. gancidicus. The beneficial impacts of the bimetallic ZnO-B2O3 NPs, ZnO NPs, and B2O3 NPs have been broadened to increase the enzyme activities of peroxidase (POD) and polyphenol oxidase (PPO) in both healthy and infected pea plant in comparison to control. Reduction of Malondialdehyde content (MDA) in response to S. gancidius filtrate, bimetallic ZnO-B2O3 NPs, ZnO NPs, B2O3 NPs, and difenoconazole by 41.68%, 36.51%, 26.15, 26.15, and 15.25%, respectively. Also, contents of H2O2 in infected pea plant were diminished by 50%, 45%, 40%, 37.5%, and 22.5% at bimetallic ZnO-B2O3 NPs, S. gancidicus filtrate, ZnO NPs, difenoconazole, and B2O3 NPs comparing to P. irregular-infected pea plant is strong evidence to induce disease recovery. The application of bimetallic ZnO-B2O3 NPs seems to be a significant approach to relieve the toxic influences of P. irregulare on infected pea plant as green and alternative therapeutic nutrients of chemical fungicides.
Carboxymethyl cellulose (CMC) bioplastic shows great promise for sustainable food packaging. This study synthesized zinc oxide nanoparticles (ZnO NPs) from pineapple waste via green synthesis and incorporated them into CMC to develop enhanced nanocomposite films. Key steps included preparing ZnONP powder and formulating ZnONP-CMC (ZCMC) (1.0% w/v) solutions for film fabrication. The nanocomposites were characterized using FTIR, XRD, SEM-EDX, TGA, and DSC to assess structural integrity and thermal stability. Physical properties showed enhancement, including a thickness of 0.17.05 mm, opacity of 17%, moisture content of 52.38%, and water solubility of 64.52%. The mechanical properties also improved significantly, with a tensile strength of 26.30 MPa and elongation at a break of similar to 50%. FTIR and XRD confirmed the successful incorporation of ZnO NPs, which improved the crystallinity and structural integrity of the CMC matrix. Notably, the ZCMC nanocomposite exhibited rapid biodegradation within 9 days under soil conditions, highlighting its potential for reducing environmental impact. In conclusion, adding ZnO NPs to CMC films notably improves their physical, mechanical, and thermal characteristics, rendering them ideal for food packaging. While the mechanical and biodegradation properties are promising for food packaging applications, future research should focus on evaluating the antimicrobial properties and practical applications of the ZCMC films in food preservation.
This study investigated potato starch/agar-based bioplastics' structure, properties, and biodegradability by adding ZnO nanoparticles (NPs) biogenically synthesized using Coriandrum sativum extract. ZnO NPs presented crystalline structure, good optical properties, and a size of 6.75 +/- 1.4 nm, which were added at various concentrations (419.66-104.23 ppm) in bioplastics and their presence was confirmed via EDS elemental analysis and X-ray fluorescence. The highest NPs concentration contributed to a smoother surface, while FTIR and Raman analyses suggested interactions between the NPs and functional groups of the biopolymeric matrix. ZnO NPs addition slightly reduced bioplastic transparency but significantly improved UV-A and UV-B blocking capacities. It also increased hydrophobicity, evidenced by a 22 % reduction in water absorption and a 55 % increase in contact angle. Thermogravimetric analysis (TGA) indicated that NPs raised the bioplastic's thermal stability. Mechanical property tests showed that ZnO NPs concentrations had negligible or negative effects probably due to the heterogeneous distribution of NPs, or the non-isotropic characteristic of the bioplastic. Finally, biodegradability assays in seawater and soil revealed over 43.5 % and 66 % degradation after 15 and 28 days, respectively. Therefore, biosynthesized ZnO NPs mainly enhanced the bioplastic's UV-blocking capacity, hydrophobicity, and thermal properties, offering an eco-friendly option for future studies/applications.
Silty clay is widely distributed in seasonally frozen zones in China and frequently engages in engineering projects. Nevertheless, it exhibits significant frost susceptibility and generates substantial related freezing damage. To address this problem, this study investigates the impact of nano-zinc oxide (ZnO) on silty clay's frost heave characteristic. We conducted tests on silty clay with varying nano-ZnO contents, assessing plasticity limit, liquid limit, frost heave, and uniaxial compressive strength. The findings reveal that: (1) the addition of nano-ZnO can decrease the free water content, and result in both the plastic limit and the liquid limit increase, and further accelerate the freezing process, which is helpful to mitigate the frost heave caused by water migration; (2) the frost heave ratio decreases with increasing nano-ZnO content within the tested range, 4.0% addition of nano-ZnO can significantly reduce frost heave by 66.96%, and transform the silty clay from extreme frost heave to frost heave; (3) with the nano-ZnO content increases, the uniaxial compressive strengths of the specimen initially increases (0%-3.0%) and subsequently decreases (4.0%), and the brittleness also becomes more pronounced. According to the results of mechanical and frost heave tests, the optimal content of nano-ZnO is ascertained to be 3.0%. The results of this study provide a promising solution to mitigate the frost heave of silty clay, particularly in regions with limited coarse-grained soil.
Poly(butylene succinate) (PBS)-based nanocomposites, reinforced and toughened with ZnO-coated multi-walled carbon nano-tubes (MWCNT-ZnO), demonstrate significantly enhanced properties, making them ideal for potential applied in food packaging applications. This study explores the effects of varying proportions of MWCNT-ZnO on the overall characteristics of these composites. The addition of 0.1 parts per hundred (phr) MWCNT-ZnO optimizes the nanocomposites' mechanical properties, crystallinity, melting temperature, thermal stability, and barrier performance. Specifically, the composite exhibits a 22% increase in tensile strength, a 28.4% rise in yield strength, and a remarkable 95.7% enhancement in the material's elongation at break, compared to the pure PBS matrix. Moreover, these nanocomposites exhibit excellent antibacterial properties, crucial for food preservation and safety. The soil burial test indicates that, except for the addition of 0.1phr which is lower than pure PBS, the biodegradation rate increases with the increasing addition of MWCNT-ZnO. This further suggests that a low nanoparticle filler content can enhance structural compactness, thereby improving the mechanical stability. The study also reveals notable preservation benefits for vegetables. When used for beef packaging, this composite material successfully extends the meat's freshness period, substantially curtails bacterial proliferation, and ensures the beef remains within safe consumption parameters. The combination of enhanced mechanical, thermal, barrier, and antibacterial properties makes PBS/MWCNT-ZnO nanocomposites promising candidates for sustainable and efficient food packaging materials.
Zinc oxide nanoparticles (ZnO NPs) are inorganic compounds listed as generally recognized as safe (GRAS) materials and have been used in plant production as well as for plant disease control. This study investigated the antibacterial efficacy of ZnO NPs with various surface areas against Xanthomonas campestris pv. campestris, assessed the effectiveness of ZnO NPs in controlling black rot disease in Chinese kale, and examined the influence of ZnO NPs application on soil bacterial communities. The results showed that ZnO NPs with high surface area effectively inhibited X. campestris pv. campestris by restraining growth and causing cell damage. Seed treatment and foliar spray application of high surface area ZnO NPs at 250 mu g/mL significantly reduced the disease severity of black rot. Furthermore, in the greenhouse experiment, the soil bacterial communities in the treatment of plants applied with ZnO NPs did not differ from those in soil of nontreated plants. Therefore, ZnO NPs have the potential to serve as an alternative substance for plant disease management.