Cu Nanoparticles absorbed on chitosan hydrogels positively alter morphological, production, and quality characteristics of tomato

Use of nanoparticles as nano copper (nCu) may be useful in agriculture. The objective of the present study was to evaluate responses in plant growth and antioxidants in tomato fruits upon application of nCu absorbed on chitosan hydrogels. The study was performed in two stages. The first stage, with tomato seedlings, was done to determine the most appropriate nCu concentration. nCu was absorbed on a chitosan hydrogel at 100 mg nCu kg-1 of hydrogel, and five different treatments of hydrogel were applied to the substrate prior to transplantation: 0.3, 0.15, 0.06, 0.03 and 0.015 g L-1, plus a control. The second stage evaluated the best treatment results from the previous stage, a chitosan treatment without nCu and a control. Effects of the treatments on antioxidants in the leaves and fruit were evaluated, along with fruit quality. The results from the first stage demonstrated that 0.06 g L-1 nCu-chitosan hydrogel treatments had better results. Outcomes from the second stage demonstrated that treatment with nCu had the best results for most of the plant growth variables, with differences in catalase activity in the leaves and lycopene concentration in the fruit. Application of chitosan hydrogels with nCu was favorable to tomato growth and quality

Synthesis of Copper Nanoparticles Coated with Nitrogen Ligands

The synthesis of copper nanoparticles was studied by wet chemical methods using copper sulfate pentahydrate (CuSO4·5H2O) and nitrogen ligands allylamine (AAm) and polyallylamine (PAAm) as stabilizers. The results suggest that the use of these ligands leads to the exclusive formation of metallic copper nanoparticles (Cu-NPs). The use of partially crosslinked polyallylamine (PAAmc) leads to nanoparticles (NPs) with low yields and high coating content, while linear PAAm leads to NPs with high yields and low coating content. The chemical composition of the particles was determined by XRD and average particle diameters were determined by the Debye-Scherrer equation. TGA analysis provided evidence of the content and thermal stability of the coating on the nanoparticles and PAAm. The morphology, particle size distribution, and presence of PAAm coating were observed through TEM. The use of AAm in the synthesis of NPs could be a good alternative to reduce costs. By using TGA, TEM, and DSC techniques, it was determined that synthesized NPs with AAm presented a coating with similar characteristics to NPs with PAAm, suggesting that AAm underwent polymerization during the synthesis

Antibacterial activity of chitosan and the interpolyelectrolyte complexes of poly(acrylic acid)-chitosan

The antimicrobial activity of chitosan and water soluble interpolyelectrolyte complexes of poly(acrylic acid)-chitosan was studied. Chitosans of two different molecular weights were tested at different concentration for 0.5 to 5 g·L-1 as antimicrobial agents against P. aeruginosa and P. oleovorans. In both cases, the best microbial inhibition was obtained with the concentration of 5 g·L-1. However, the interpolyelectrolyte complexes of poly(acrylic acid)-chitosan with composition φ =2 produced higher antibacterial activity than the two chitosans at the concentration of 0.5 g·L-1. The NPEC2 complex was more effective than chitosans. This could be attributed to the number of moles of the amino groups of chitosan and the carboxylic acid groups of the interpolyelectrolyte complexes poly(acrylic acid).A atividade antimicrobiana de quitosana e complexos interpolieletrolíticos hidrossoluvéis de poli(ácido acrílico)-quitosana foi estudada. Quitosanas de dois diferentes pesos moleculares foram testados em diferentes concentrações, 0,5 a 5 g • L-1, como agentes antimicrobianos nas P. aeruginosa e P. oleovorans. Em ambos os casos, obteu-se a melhor inibição microbiana com a concentração de 5 g • L-1, no entanto os complexos interpolieletrolíticos de poli (ácido acrílico)-quitosana com composição φ = 2 apresentaram maior atividade antibacteriana do que os dois quitosans na concentração de 0,5 g • L-1. O complexo NPEC2 foi mais eficaz do que as quitosanas, sendo que o resultado pode ser atribuído ao número de moles dos grupos aminos da quitosana e aos grupos carboxílicos dos complexos de poli(ácido acrílico)

PLA-ZnO/TiO2 Nanocomposite Obtained by Ultrasound-Assisted Melt-Extrusion for Adsorption of Methylene Blue

Access to fresh water is an increasing concern worldwide. The contamination of this vital liquid is largely caused by discharges of pollutants into rivers and seas from different types of industries. Waste dyes from different industries have been classified as harmful to health. In this study, polymeric nanomaterials based on polylactic acid (PLA) and nanoparticles of titanium dioxide (TiO2) and zinc oxide (ZnO) modified by ultrasound-assisted extrusion were obtained. These materials were evaluated by FTIR, DRX, TGA, DSC, SEM and methylene blue adsorption. From the results of the physicochemical characterizations, it was possible to observe the presence of TiO2 and ZnO nanoparticles dispersed in the polymeric matrix, increasing the crystallinity and thermal stability of the polymer. In addition, a good dispersion of the nanoparticles could be seen by means of SEM, due to the extrusion assisted by ultrasound. The methylene blue dye adsorption tests revealed that the best result was 98% dye adsorption in a time of 13 min for the 1.5% PZT sample. Additionally, this material could be used for 3 adsorption cycles without affecting its adsorbent properties

Impact of Calcium-Silicon nanoparticles on flower quality and biochemical characteristics of Lilium under salt stress

Lilium plants are one of the most important and widely distributed ornamental crops in the world. However, these plants are also susceptible to salinity, an environmental factor that is one of the main ones worldwide. Salinity negatively affects the development and productivity of plants, in addition to the fact that it can affect the quality of flowers in ornamental crops. The use of nanotechnology can be a useful tool to counteract the negative effects of salinity, since the application of nanoparticles can function as a biostimulant and induce positive responses against different types of abiotic stress. In the present study, the foliar application of two types and concentrations of calcium-silicon nanoparticles (Ca-Si NPs) (500 and 750 mg L−1) in lilium plants grown with or without stress and under saline stress (30 mM NaCl) was evaluated. The differences between both nanoparticles were the size and content of inorganic residues, where CaSi-1 had a size of 23.29 nm and a content of inorganic residues of 62.0 %, while CaSi-2 had a size of 15.29 nm and a content of inorganic residues of 87.0 %. The results showed that salinity affected the quality of the flowers, as well as the biochemical parameters of the plants. In contrast, the application of Ca-Si NPs induced positive effects on flower quality, improved flower size and fresh biomass. Under salt stress conditions, the application of Ca-Si NPs in lilium improved the biochemical parameters, increased the content of chlorophylls (up to 38.1 %), vitamin C (9.4 %), and antioxidant capacity (19.2-23.8 %) in the leaves. Regarding the stress indicators in the leaves, the hydrogen peroxide (H2O2) was not affected by salinity or by the Ca-Si NPs, while the malondialdehyde (MDA) increased by the application of the NPs, however, under saline stress there were no differences. In lilium flowers without salt stress, both H2O2 and MDA increased by the application of Ca-Si NPs, while under salt stress only MDA increased. The use of Ca-Si NPs can be an alternative to counteract the harmful effects of salinity stress in plants

Complejo PVA-quitosán-nCu mejora el rendimiento y la respuesta de defensa en tomate

Currently the use of nanotechnology is revolutionizing agricultural production. Copper nanoparticles have been shown to influencethe growth and development of different plant species, in addition tooperating as stress resistance inducers. The objective of the present research was to evaluate the response in growth and yield,as well as the activation of the defense system of tomato plants. The treatments evaluated were a complex of polyvinyl alcohol-chitosan-copper nanoparticles (PVA-Cts-nCu), another complex of PVA-Cts and an absolute control (T0). The treatments were applied via foliar in tomato plants under greenhouse conditions. During the crop cycle, agronomic variables were determined, and the activity of enzymes related to stress tolerance such as β-1,3 glucanase, chitinase and phenylalanine ammonia lyase (PAL), as well as the expression of the PR1 gene. The PVA-Cts-nCu complex increased yield, number of fruits, average fruit weight, aerialfresh weight and root freshweight, in addition, it promoted the defense system by increasing the PAL enzyme activity, as well as the overexpression of the PR1 geneActualmente el uso de la nanotecnología está revolucionando la producción agrícola. Se ha demostrado que las nanopartículas de cobre tienen un efecto en el crecimiento y desarrollo de las diferentes especies vegetales, además de operar como inductores de resistencia al estrés. El objetivo del presente trabajo fue evaluar la respuesta en el crecimiento y rendimiento, así como la activación del sistema de defensa de plantas de tomate. Los tratamientos evaluados fueron un complejo de alcohol polivinílico-quitosán-nanopartículas de cobre (PVA-Cts-nCu), otro complejo de PVA-Cts y un testigo absoluto (T0). Los tratamientos se aplicaron vía foliar en plantas de tomate bajo condiciones de invernadero. Durante el ciclo del cultivo, se determinaron variables agronómicas, y la actividad de enzimas relacionadas a la tolerancia a estrés como β-1,3 glucanasa, quitinasa y fenilalanina amonio liasa (PAL), así como la expresión del gen PR1. El complejo PVA-Cts-nCu incrementó el rendimiento, número de frutos, peso promedio de fruto, peso fresco aéreo y peso fresco de la raíz, además, promovió el sistema de defensa mediante el aumento en la actividad enzimática PAL, así como la sobreexpresión del gen PR1

Influence of Modified Carbon Black on Nylon 6 Nonwoven Fabric and Performance as Adsorbent Material

The number of chronic kidney disease (CKD) persons continues to rise in Mexico. They require renal replacement therapy, and in the absence of it, hemodialysis is the major option for their survival. The uremic toxins present in the blood are removed by hemodialysis, which involve membranes. In this study, nonwoven fabrics with modified carbon black nanoparticles in a matrix polymer of Nylon 6 were obtained and evaluated as an adsorbent material of uremic toxins. All nonwoven fabrics were characterized by FTIR, XRD, TGA, SEM, and contact angle measurements and were evaluated as an adsorbent material for the urea toxin and as an albumin retainer. The findings suggest their potential application as a hemodialysis membrane. Nanocomposites had a higher hydrophilic characteristic compared to pure Nylon 6. The average diameter size of the fibers was in the range of 5 to 50 μm. All nanocomposites nonwoven fabrics showed high removal percentages of inulin in a range of 80–85% at 15 min of contact. Most Ny6 Zytel/CB nanocomposites showed a high percentage of urea removal (80 to 90%)

Effects of Chitosan–PVA and Cu Nanoparticles on the Growth and Antioxidant Capacity of Tomato under Saline Stress

Chitosan is a natural polymer, which has been used in agriculture to stimulate crop growth. Furthermore, it has been used for the encapsulation of nanoparticles in order to obtain controlled release. In this work, the effect of chitosan–PVA and Cu nanoparticles (Cu NPs) absorbed on chitosan–PVA on growth, antioxidant capacity, mineral content, and saline stress in tomato plants was evaluated. The results show that treatments with chitosan–PVA increased tomato growth. Furthermore, chitosan–PVA increased the content of chlorophylls a and b, total chlorophylls, carotenoids, and superoxide dismutase. When chitosan–PVA was mixed with Cu NPs, the mechanism of enzymatic defense of tomato plants was activated. The chitosan–PVA and chitosan–PVA + Cu NPs increased the content of vitamin C and lycopene, respectively. The application of chitosan–PVA and Cu NPs might induce mechanisms of tolerance to salinity

Graphene–Cu Nanocomposites Induce Tolerance against <i>Fusarium oxysporum</i>, Increase Antioxidant Activity, and Decrease Stress in Tomato Plants

The tomato crop is susceptible to various types of stress, both biotic and abiotic, which affect the morphology, physiology, biochemistry, and genetic regulation of plants. Among the biotic factors, is the phytopathogen Fusarium oxysporum f. sp. lycopersici (Fol), which can cause losses of up to 100%. Graphene–Cu nanocomposites have emerged as a potential alternative for pathogen control, thanks to their antimicrobial activity and their ability to induce the activation of the antioxidant defense system in plants. In the present study, the effect of the Graphene–Cu nanocomposites and the functionalization of graphene in the tomato crop inoculated with Fol was evaluated, analyzing their impacts on the antioxidant defense system, the foliar water potential (Ψh), and the efficiency of photosystem II (PSII). The results demonstrated multiple positive effects; in particular, the Graphene–Cu nanocomposite managed to delay the incidence of the “vascular wilt” disease and reduce the severity by 29.0%. This translated into an increase in the content of photosynthetic pigments and an increase in fruit production compared with Fol. In addition, the antioxidant system of the plants was improved, increasing the content of glutathione, flavonoids, and anthocyanins, and the activity of the GPX, PAL, and CAT enzymes. Regarding the impact on the water potential and the efficiency of the PSII, the plants inoculated with Fol and treated with the Graphene–Cu nanocomposite responded better to biotic stress compared with Fol, reducing water potential by up to 31.7% and Fv/Fm levels by 32.0%