Livistona jekinsiana fabricated ZnO nanoparticles and their detrimental effect towards anthropogenic organic pollutants and human pathogenic bacteria

Green route to fabrication of Semal-ZnO nanoparticles for efficient solar-driven catalysis of noxious dyes in diverse aquatic environments

This work successfully demonstrates a sustainable and environmentally friendly approach for synthesizing Semal-ZnO nanoparticles (NPs) using the aqueous leaf extract of Bombax ceiba L. These NPs exhibit an absorption peak at approximately 390 nm in the UV-visible spectrum and an energy gap (Eg) of 3.11 eV. Detailed analyses of the morphology and particle size using various spectroscopic and microscopic techniques, XRD, FE-SEM with EDS, and HR-TEM reveal crystallographic peaks attributable to the hexagonal phase, with an average crystal size of 17 nm. The Semal-ZnO NPs also exhibit a notable photocatalytic efficiency for degrading methylene blue (MB) and methyl orange (MO) under sunlight in different water samples collected from diverse natural sources, indicating that they are promising photocatalysts for environmental remediation. The photocatalytic efficiency of the biofabricated Semal-ZnO NPs is impressive, exhibiting a photodegradation rate of up to 99% for MB and 79% for MO in different water samples under exposure to sunlight. The novel phytofabricated Semal-ZnO NPs are thus a beacon of hope for the environment, with their desirable photocatalytic efficiency, pseudo-first-order kinetics, and ability to break down noxious dye pollutants in various aquatic environments.

Green synthesis of nanocellulose supported cu-bionanocomposites and their profound applicability in the synthesis of amide derivatives and controlling of food-borne pathogens

Copper bionanocomposites (CBNCS) were synthesized using Ipomoea carnea- sourced nanocellulose as support via an eco-friendly and cost-effective method. X-ray Diffractometer (XRD) pattern of CBNCS confirmed the octahedral structure of Cu2O, the face-centered cubic (FCC) crystal structure of Cu(0). XRD also revealed the crystal lattice of cellulose II. Surface Electron Microscope (SEM) and Transmission Electron Microscope (TEM) revealed the uniform distribution of copper nanoparticles (Cu NPs) with an average size of 10 nm due to the presence of nanocellulose. X-ray photoelectron spectroscopy (XPS) provided information about the electronic, chemical state and elemental composition of CBNCS. Thermogravimetric Analysis (TGA) showed the thermal stability of CBNCS. CBNCS catalyzed the rearrangement of oximes to primary amides in a very mild condition with a high yield of up to 92 %. CBNCS effectively inhibited the growth of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) with lower minimum inhibitory concentration MIC values. Antioxidant activity and electrical conductivity of CBNCS were also determined.

Associating Physical and Photocatalytic Properties of Recyclable and Reusable Blast Furnace Dust Waste

Blast furnace dust waste (BFDW) proved efficient as a photocatalyst for the decolorization of methylene blue (MB) dye in water. Structural analysis unequivocally identified α-Fe2O3 as the predominant phase, constituting approximately 92%, with a porous surface showcasing unique 10-30 nm agglomerated nanoparticles. Chemical and thermal analyses indicated surface-bound water and carbonate molecules, with the main phase's thermal stability up to 900 °C. Electrical conductivity analysis revealed charge transfer resistance values of 616.4 Ω and electrode resistance of 47.8 Ω. The Mott-Schottky analysis identified α-Fe2O3 as an n-type semiconductor with a flat band potential of 0.181 V vs. Ag/AgCl and a donor density of 1.45 × 1015 cm-3. The 2.2 eV optical bandgap and luminescence stem from α-Fe2O3 and weak ferromagnetism arises from structural defects and surface effects. With a 74% photocatalytic efficiency, stable through three photodegradation cycles, BFDW outperforms comparable waste materials in MB degradation mediated by visible light. The elemental trapping experiment exposed hydroxyl radicals (OH•) and superoxide anions (O2-•) as the primary species in the photodegradation process. Consequently, iron oxide-based BFDW emerges as an environmentally friendly alternative for wastewater treatment, underscoring the pivotal role of its unique physical properties in the photocatalytic process.

Biosynthesis of ZnO and TiO2 nanoparticles using Ipomoea carnea leaf extract and its effect on black carrot (Daucus carota L.) cv. Pusa Asita

Nano fertilizers (NFs) are now becoming an important tool for plant nutrient management having capabilities to improve soil fertility, crop productivity and quality of agricultural products. Since, they are needed in very small amount, thus, reduces cost of crop production. Among different essential or beneficial plant nutrients, Zn and Ti are important micro nutrients having number of beneficial effect on crop growth, yield, quality and post harvest life. Present experiment was carried out to prepare ZnO and TiO2 nanoparticles (NPs) through green technology by using aqueous extract of Ipomoea carnea (morning glory) leaves. In order to investigate size, morphology, composition, and stability of selected NPs, the detailed characterization was carried out using UV-visible spectroscopy, FTIR, HRTEM, EDX, BET, X-ray diffraction, XPS and particle size distribution studies. Subsequently, the effect of foliar spray of ZnO and TiO2 NPs was evaluated in respect of vegetative growth, yield and quality of black carrot (Daucus carota L.) cv. Pusa Asita in presence of 50% Recommended dose of fertilizer (RDF) to assess their effect on fertilizer use efficiency also. There were 8 treatments viz. Control (no fertilizer), recommended dose of fertilizer (RDF), TiO2 (5, 10 and 15 ppm along with 50% RDF), ZnO (50, 75 and 100 ppm along with 50% RDF)] with 3 replications following Randomised Block Design having 24 plots (1 m × 1 m). The observations were taken for vegetative growth, edible root yield and root quality parameters. Although, the growth, yield and quality parameters were found superior (root yield 43.84 g/plant) under conventional system of recommended dose of fertilizers (RDF) of NPK, however, TiO2 NPs also showed very promising result close to RDF as compared to ZnO NPs. Among them, 5 ppm TiO2 foliar application along with 50% NPK was found to be the best in terms of vegetative growth, root yield (38.73 g/plant) and quality of black carrot. It was also found that higher concentration of TiO2 and ZnO NPs had adverse effect on the plant performance. Therefore, it can be concluded that 5 ppm TiO2 NPs along with 50% RDF was good for black carrot production.

Mechanisms of Metallic Nanomaterials to Induce an Antibacterial Effect

Pathogenic microorganisms, including bacteria, are becoming resistant to most existing drugs, which increases the failure of pharmacologic treatment. Therefore, new nanomaterials were studied to spearhead improvement against the same resistant pathogenic bacteria. This has increased the mortality in the world population, principally in under-developed countries. Moreover, recently there has been research to find new drug formulations to kill the most dangerous microorganisms, such as bacteria cells which should avoid the spread of disease. Therefore, lately, investigations have been focusing on nanomaterials because they can exhibit the capacity to show an antibacterial effect. These studies have been trying oriented in their ability to produce an improvement to get antibacterial damage against the same pathogenic bacteria resistance. However, there are many problems with the use of nanoparticles. One of them is understanding how they act against bacteria, "their mechanism(s) action" to induce reduction or even kill the bacterial strains. Therefore, it is essential to understand the specific mechanism(s) of each nanomaterial used to observe the interaction between bacteria cells and nanoparticles. In addition, since nanoparticles can be functionalized with different antibacterial drugs, it is necessary to consider and distinguish the antibacterial activity of the nanoparticles from the antibacterial activity of the drugs to avoid confusion about how the nanoparticles work. Knowledge of these differences can help better understand the applications of the primary nanoparticles (i.e., Ag, Au, CuO, ZnO, and TiO², among others) described in detail in this review which are toxic against various bacterial strains.

Gómez C, Pérez-Larios A. Study of the Interaction of Ti-Zn as a Mixed Oxide at Different pH Values Synthesized by the Sol-Gel Method and Its Antibacterial Properties

TiO2, ZnO, and their combination (TiO2−ZnO) at different molar ratios and pH values (Ti−Zn A and B 3:1, 1:1, and 1:3) via the sol−gel method were characterized by SEM, XRD, UV-Vis, and FT-IR. Moreover, antibacterial tests of the nanoparticles were conducted against Escherichia coli (E. coli), Salmonella paratyphi (S. paratyphi), Staphylococcus aureus (S. aureus), and Listeria monocytogenes (L. monocytogenes). The indirect bandgap of the Ti−Zn binary oxide synthesized in the basic process at molar ratios of 3:1, 1:1, and 1:3 exhibited a higher eV (3.31, 3.30, and 3.19 eV, respectively) compared to pure TiO2 (3.2 eV) and synthesized in the acid process (3.22, 3.29, and 3.19 eV at same molar ratio, respectively); in addition, the results of the indirect bandgap were interesting due to a difference found by other authors. Moreover, the sol−gel method promoted the formation of a spherical, semi-sphere, and semi-hexagonal shape (TiO2, Ti−Zn 1:1, and Ti−Zn 1:3) with a size ≤ 150 nm synthesized during the acid process, with a crystallite size of ~71, ~12, ~34, and ~21 nm, respectively, while ZnO NPs developed a hexagonal and large size (200−800 nm) under the same synthesis process (acid). Samples were classified as TiO2 anatase phase (basic synthesis); however, the presented changes developed in the rutile phase (24% rutile phase) at an acid pH during the synthesis process. Moreover, Ti−Zn maintained the anatase phase even with a molar ratio of 1:3. The most interesting assessment was the antibacterial test; the Ti−Zn A (1:3) demonstrated a bacteriostatic effect compared with all treatments except ZnO, which showed a similar effect in dark conditions, and only Gram-positive bacteria were susceptible (Listeria monocytogenes > Staphylococcus aureus). Therefore, the Ti−Zn characteristic suggests that the results have potential in treating wastewater as well as in pharmaceutical (as drug carriers) and medical applications.

Effect of green synthesized ZnO nanoparticles using Paspalum scrobiculatum grains extract in biological applications

In this report, ZnO nanoparticles were biosynthesized using Paspalum scrobiculatum grains extract for the first time. GC-MS analysis explicated that diethyl phthalate was the major phytocompound with 94.09% in aqueous extract. ZnO nanoparticles formation was confirmed by various physicochemical analyses. HR-TEM images showed the hexagonal, rectangular shaped nanoparticles in 15-30 nm size. The antioxidant, anti-inflammatory, and anti-diabetic analyses showed the effective bioactivity of ZnO nanoparticles in 80 μg/ml concentration with 95.36%, 94.08%, and 91.96%, respectively. The morphological and tissue changes witnessed in larvicidal and insecticidal activities against Culex tritaeniorhynchus and Tribolium castaneum revealed the efficient nature of ZnO nanoparticles in 100 ppm at 48 h and 100 μg/kg at 72 h, respectively. The morphological changes in antibacterial activity demonstrated the bactericidal nature of ZnO nanoparticles against Salmonella typhi and Staphylococcus aureus in 150 μg/ml concentration. The morphological observations in anticancer activity against HepG2 liver cancer cells showed the potent drug features of ZnO nanoparticles in 100 μg/ml concentration with 97.18% of cytotoxicity. The ZnO nanoparticles showed no toxicity against HDF normal cells in lower concentrations and it explicated the biocompatible features of nanoparticles. The Vigna radiata plant growth was efficiently promoted by low (60 ppm) concentration of nanoparticles. The ZnO nanoparticles divulged effective degradation of IPA, EDTA, BQ, and DPBF in 75%, 45%, 55%, and 80% through ROS formation, respectively. Thus, the synthesized ZnO nanoparticles are biocompatible and inexpensive material compared to the traditional one and can be utilized as an efficient material in biological fields.

Enhanced Spontaneous Antibacterial Activity of δ-MnO2 by Alkali Metals Doping

Recently, the widespread use of antibiotics is becoming a serious worldwide public health challenge, which causes antimicrobial resistance and the occurrence of superbugs. In this context, MnO₂ has been proposed as an alternative approach to achieve target antibacterial properties on Streptococcus mutans (S. mutans). This requires a further understanding on how to control and optimize antibacterial properties in these systems. We address this challenge by synthesizing δ-MnO₂ nanoflowers doped by magnesium (Mg), sodium (Na), and potassium (K) ions, thus displaying different bandgaps, to evaluate the effect of doping on the bacterial viability of S. mutans. All these samples demonstrated antibacterial activity from the spontaneous generation of reactive oxygen species (ROS) without external illumination, where doped MnO₂ can provide free electrons to induce the production of ROS, resulting in the antibacterial activity. Furthermore, it was observed that δ-MnO₂ with narrower bandgap displayed a superior ability to inhibit bacteria. The enhancement is mainly attributed to the higher doping levels, which provided more free electrons to generate ROS for antibacterial effects. Moreover, we found that δ-MnO₂ was attractive for in vivo applications, because it could nearly be degraded into Mn ions completely following the gradual addition of vitamin C. We believe that our results may provide meaningful insights for the design of inorganic antibacterial nanomaterials.

Evaluation of the multifunctional activity of silver bionanocomposites in environmental remediation and inhibition of the growth of multidrug-resistant pathogens

Imperata cylindrica cellulose supported Ag bionanocomposites purified industrial water and controlled the contagious diseases with high potential activity.