Enhanced antimicrobial efficacy of biogenic ZnO nanoparticles through UV-B activation: A novel approach for textile garment.

Zinc oxide nanoparticles (ZnO NP) are characterized by novel properties which have been attracting the attention of different lines of research due to their wide applicability. Obtaining this nanomaterial is strongly linked to biogenic synthesis methods, which have also been developed in this research, using Coriandrum sativum extract as a reducing agent. ZnO NPs have been properly characterized by techniques to evaluate their morphology by transmission electron microscopy (TEM) and elemental analysis by EDX. The evaluation of the antimicrobial and antifungal effects is linked to the use of a system provided by "locker sanitizer" equipment, which has been designed and built as part of this research, and is intended to treat textile garments by nebulizing the ZnO NP colloid (99.08 µg/mL) + UV-B, water + UV-B, and UV-B only, and also to evaluate the influence of the treatment time for 1, 2 and 3 min. In this sense, it is known that the nanomaterial used shows a better response to UV light because more hydroxyl radicals are produced, leading to a higher reaction rate, which results in greater efficiency in inhibitory processes. The results show that the use of the locker sanitizer is more efficient when using ZnO NP + UV-B light since it achieved 100 % growth inhibition against E. coli, C. albicans, and A. brasiliensis, and >99 % against S. aureus, after 3 min of treatment.

Optimization of the biosynthesis of silver nanoparticles using bacterial extracts and their antimicrobial potential.

In the present study, silver nanoparticles (AgNPs) were biosynthesized using the supernatant and the intracellular extract of Cupriavidus necator, Bacillus megaterium, and Bacillus subtilis. The characterization of the AgNPs was carried out using UV-Vis spectroscopy, FTIR, DLS and TEM. Resazurin microtiter-plate assay was used to determine the antimicrobial action of AgNPs against Escherichia coli. UV-Visible spectra showed peaks between 414 and 460 nm. TEM analysis revealed that the synthesized AgNPs showed mostly spherical shapes. DLS results determined sizes from 20.8 to 118.4 nm. The highest antimicrobial activity was obtained with the AgNPs synthesized with supernatant rather than those using the intracellular extract. Therefore, it was determined that the bacterial species, temperature, pH, and type of extract (supernatant or intracellular) influence the biosynthesis. This synthesis thus offers a simple, environmentally friendly, and low-cost method for the production of AgNPs, which can be used as antibacterial agents.

Evaluation of the antiviral activity of ultraviolet light and zinc oxide nanoparticles on textile products exposed to Avian coronavirus.

This research has developed a piece of sanitizing locker-model equipment for textiles exposed to avian coronavirus, which has been put under the influence of UV light, UV + zinc oxide nanoparticles (phytosynthesized ZnONP), and water + UV, and, in turn, under the influence of the exposure time (60, 120, 180 s). The results linked to the phytosynthesis of ZnONP indicate a novel method of fabricating nanostructured material, nanoparticles with spherical morphology and an average size of 30 nm. The assays were made based on the viral viability of avian coronavirus according to the mortality of SPF embryonated eggs and a Real-Time PCR for viral load estimation. This was a model to evaluate the sanitizing effects against coronaviruses since they share a very similar structure and chemistry with SAR-CoV-2. The influence of the type of textile treatment evidenced the potential effect of the sanitizing UV light, which achieved 100% of embryo viability. The response of the ZnONP + UV nebulization showed a notorious influence of photoactivation according to the exposure time, and the 60-s treatment achieved a decrease of 88.9% in viral viability, compared to 77.8% and 55.6% corresponding to the 120 and 180-s treatments, respectively. Regarding the decrease in viral load between the types of treatments, UV 180 s reduced 98.42% and UV 60 s + ZnONP reduced 99.46%, respectively. The results show the combinatorial effect of UV light and zinc nanoparticles in decreasing the viral viability of avian coronavirus, as a model of other important coronaviruses in public health such as SARS-CoV-2.

ZnO Nanoparticles Obtained by Green Synthesis as an Alternative to Improve the Germination Characteristics of L. esculentum.

Tomato is an important crop due to its nutritional contributions and organoleptic properties, which make it an appetizing vegetable around the world. In its sowing, the use of seed is the most accessible propagation mechanism for farmers. However, the induction to germination and emergence is often limited in the absence of stimulants that promote the development and growth of the seedling, added to the interference of infectious agents that notoriously reduce the vitality and viability of the seed. Given this, it was proposed as a research objective to determine the effect of zinc oxide nanoparticles (ZnO NPs) mediated by a green route on the germinative characteristics of Lycopersicon esculentum Mill. 1768 "tomato". The experimental phase consisted of the synthesis of ZnO NPs and its subsequent characterization. After its synthesis, its inoculation was conducted during the germination of seeds of L. esculentum, considering six sample groups for the treatment with zinc nanoparticles (T1: Control; T2: 21.31 ppm; T3: 33.58 ppm; T4: 49.15 ppm; T5: 63.59 and T6: 99.076 ppm). The results indicate that concentrations close to 100 ppm of ZnO NPs are ideal in the treatment of L. esculentum seeds, due to the promotion of enzymatic and metabolic activity to achieve cell elongation; likewise, the biosynthesized nanoparticles showed no phytotoxicity, due to the fact that, in all the treatments, there were processes of germination and emergence. This was linked to the generation of a Zn0-phenolate complex through a chelating effect, which generates compatibility with the seed and, compared to classic inorganic synthesis, usually shows phytotoxicity. In this sense, green synthesis is presented as a great alternative in this type of application.

Topical Chitosan-Based Thermo-Responsive Scaffold Provides Dexketoprofen Trometamol Controlled Release for 24 h Use.

Chronic and non-healing wounds demand personalized and more effective therapies for treating complications and improving patient compliance. Concerning that, this work aims to develop a suitable chitosan-based thermo-responsive scaffold to provide 24 h controlled release of Dexketoprofen trometamol (DKT). Three formulation prototypes were developed using chitosan (F1), 2:1 chitosan: PVA (F2), and 1:1 chitosan:gelatin (F3). Compatibility tests were done by DSC, TG, and FT-IR. SEM was employed to examine the morphology of the surface and inner layers from the scaffolds. In vitro release studies were performed at 32 °C and 38 °C, and the profiles were later adjusted to different kinetic models for the best formulation. F3 showed the most controlled release of DKT at 32 °C for 24 h (77.75 ± 2.72%) and reduced the burst release in the initial 6 h (40.18 ± 1.00%). The formulation exhibited a lower critical solution temperature (LCST) at 34.96 °C, and due to this phase transition, an increased release was observed at 38 °C (88.52 ± 2.07% at 12 h). The release profile for this formulation fits with Hixson-Crowell and Korsmeyer-Peppas kinetic models at both temperatures. Therefore, the developed scaffold for DKT delivery performs adequate controlled release, thereby; it can potentially overcome adherence issues and complications in wound healing applications.

Green Synthesis of Gold and Silver Nanoparticles from Plant Extracts and Their Possible Applications as Antimicrobial Agents in the Agricultural Area.

Currently, metal nanoparticles have varied uses for different medical, pharmaceutical, and agricultural applications. Nanobiotechnology, combined with green chemistry, has great potential for the development of novel and necessary products that benefit human health, environment, and industries. Green chemistry has an important role due to its contribution to unconventional synthesis methods of gold and silver nanoparticles from plant extracts, which have exhibited antimicrobial potential, among other outstanding properties. Biodiversity-rich countries need to collect and convert knowledge from biological resources into processes, compounds, methods, and tools, which need to be achieved along with sustainable use and exploitation of biological diversity. Therefore, this paper describes the relevant reported green synthesis of gold and silver nanoparticles from plant extracts and their capacity as antimicrobial agents within the agricultural field for fighting against bacterial and fungal pathogens that can cause plant, waterborne, and foodborne diseases. Moreover, this work makes a brief review of nanoparticles' contribution to water treatment and the development of "environmentally-friendly" nanofertilizers, nanopesticides, and nanoherbicides, as well as presenting the harmful effects of nanoparticles accumulation in plants and soils.

Organic amendments exacerbate the effects of silver nanoparticles on microbial biomass and community composition of a semiarid soil.

Increased utilization of silver nanoparticles (AgNPs) can result in an accumulation of these particles in the environment. The potential detrimental effects of AgNPs in soil may be associated with the low fertility of soils in semiarid regions that are usually subjected to restoration through the application of organic amendments. Microbial communities are responsible for fundamental processes related to soil fertility, yet the potential impacts of low and realistic AgNPs concentrations on soil microorganisms are still unknown. We studied the effects of realistic citrate-stabilized AgNPs concentrations (0.015 and 1.5 µg kg-1) at two exposure times (7 and 30 days) on a sandy clay loam Mediterranean soil unamended (SU) and amended with compost (SA). We assessed soil microbial biomass (microbial fatty acids), soil enzyme activities (urease, ß-glucosidase, and alkaline phosphatase), and composition of the microbial community (bacterial 16S rRNA gene and fungal ITS2 sequencing) in a microcosm experiment. In the SA, the two concentrations of AgNPs significantly decreased the bacterial biomass after 7 days of incubation. At 30 days of incubation, only a significant decrease in the Gram+ was observed at the highest AgNPs concentration. In contrast, in the SU, there was a significant increase in bacterial biomass after 30 days of incubation at the lowest AgNPs concentration. Overall, we found that fungal biomass was more resistant to AgNPs than bacterial biomass, in both SA and SU. Further, the AgNPs changed the composition of the soil bacterial community in SA, the relative abundance of some bacterial taxa in SA and SU, and fungal richness in SU at 30 days of incubation. However, AgNPs did not affect the activity of extracellular enzymes. This study demonstrates that the exposure time and organic amendments modulate the effects of realistic concentrations of AgNPs in the biomass and composition of the microbial community of a Mediterranean soil.

Environmentally relevant concentrations of silver nanoparticles diminish soil microbial biomass but do not alter enzyme activities or microbial diversity.

The increasing use of silver nanoparticles (AgNPs) due to their well-known antimicrobial activity, has led to their accumulation in soil ecosystems. However, the impact of environmental realistic concentrations of AgNPs on the soil microbial community has been scarcely studied. In this work, we have assessed the impact of AgNPs, that mimic real concentrations in nature, on tropical soils cultivated with Coffea arabica under conventional and organic management systems. We evaluated the biomass, extracellular enzyme activities, and diversity of the soil microbial community, in a microcosm experiment as a function of time. After seven days of incubation, we found an increase in microbial biomass in an AgNPs-concentration-independent manner. In contrast, after 60-day-incubation, there was a decrease in Gram+ and actinobacterial biomass, in both soils and all AgNPs concentrations. Soil physico-chemical properties and enzyme activities were not affected overall by AgNPs. Regarding the microbial community composition, only some differences in the relative abundance at phylum and genus level in the fungal community were observed. Our results suggest that environmental concentrations of AgNPs affected microbial biomass but had little impact on microbial diversity and may have little effects on the soil biogeochemical cycles mediated by extracellular enzyme activities.