Green synthesis and characterizations of Nickel oxide nanoparticles using leaf extract of Rhamnus virgata and their potential biological applications

In the present report, Nickel oxide nanoparticles (NiONPs) were synthesized using Rhamnus virgata (Roxb.) (Family: Rhamnaceae) as a potential stabilizing, reducing and chelating agent. The formation, morphology, structure and other physicochemical properties of resulting NiONPs were characterized by Ultra violet spectroscopy, X‐ray diffraction (XRD), Fourier Transform Infrared analysis (FTIR), Scanning electron microscopy (SEM), Energy‐dispersive‐spectroscopy (EDS), Transmission electron microscopy (TEM), Raman spectroscopy and dynamic light scattering (DLS). Detailed in vitro biological activities revealed significant therapeutic potential for NiONPs. The antimicrobial efficacy of biogenic NiONPs was demonstrated against five different gram positive and gram negative bacterial strains. Klebsiella pneumoniae and Pseudomonas aeruginosa (MIC: 125 μg/mL) were found to be the least susceptible and Bacillus subtilis (MIC: 31.25 μg/mL) was found to be the most susceptible strain to NiONPs. Biogenic NiONPs were reported to be highly potent against HepG2 cells (IC₅₀: 29.68 μg/ml). Moderate antileishmanial activity against Leishmania tropica (KMH₂₃) promastigotes (IC₅₀: 10.62 μg/ml) and amastigotes (IC₅₀: 27.58 μg/ml) cultures are reported. The cytotoxic activity was studied using brine shrimps and their IC₅₀ value was recorded as 43.73 μg/ml. For toxicological assessment, NiONPs were found compatible towards human RBCs (IC₅₀: > 200 μg/ml) and macrophages (IC₅₀: > 200 μg/ml), deeming particles safe for various applications in nanomedicines. Moderate antioxidant activities: total antioxidant capacity (TAC) (51.43%), 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) activity (70.36%) and total reducing power (TRP) (45%) are reported for NiONPs. In addition, protein kinase and alpha amylase inhibition assays were also performed. Our results concluded that Rhamnus virgata synthesized NiONPs could find important biomedical applications with low cytotoxicity to normal cells.     

QbD approached comparison of reaction mechanism in microwave synthesized gold nanoparticles and their superior catalytic role against hazardous nirto‐dye

Microwave irradiation (MI) process characteristically enables extremely rapid “in‐core” heating of dipoles and ions, in comparison to conventional thermal (conductance) process of heat transfer. During the process of nanoparticles synthesis, MI both modulates functionality behaviors as well as dynamic of reaction in favorable direction. So, MI providing a facile, favorable and alternative approach during nanoparticles synthesis nanoparticles with enhanced catalytic performances. Although, conventionally used reducing and capping reagents of synthetic origin, are usually environmentally hazardous and toxic for living organism. But, in absence of suitable capping agent; stability, shelf life and catalytic activity of metallic nanoparticles adversely affected. However, polymeric templates which emerged as suitable choice of agent for both reducing and capping purposes; bearing additional advantages in terms of catalyst free one step green synthesis process with high degree of biosafety and efficiency. Another aspect of current works was to understand role of process variables in growth mechanism and catalytic performances of microwave processed metallic nanoparticles, as well as comparison of these parameters with conventional heating method. However, due to poor prediction ability with previously published architect OFAT (One factor at a time) design with these nanoparticles as well as random selection of process variables with their different levels, such comparison couldn't be possible. Hence, using gum Ghatti (Anogeissus latifolia) as a model bio‐template and under simulated reaction conditions; architect of QbD design systems were integrated in microwave processed nanoparticles to establish mechanistic role these variables. Furthermore, in comparison to conventional heating; we reported well validated mathematical modeling of process variables on characteristic of nanoparticles as well as synthesized gold nanoparticles of desired and identical dimensions, in both thermal and microwave‐based processes. Interestingly, despite of identical dimension, MI processed gold nanoparticles bearing higher efficiency (kinetic rate) against remediation of hazardous nitro dye (4‐nitrophenol), into safer amino (4‐aminophenol) analogues.     

Dinuclear nickel(II) complexes with ONO-pincer and coordinated aquo ligands as a robust homogeneous water oxidation catalyst

Russian Chemical Bulletin - A nickel(II) complex with the newly synthesized dicarboxamide ligand [H2LBZ][(CF3SO3)Cl] was explored as a water oxidation catalysis. All the synthesized compounds were...     

Investigation of 500 keV Si ion induced surface structuring of Ni and Ti for enhancement of field emission properties

The present paper reports the investigation of surface morphology, elemental composition, phase changes and field emission properties of Si ion irradiated nickel (Ni) and titanium (Ti). The Ni and Ti targets have been irradiated with 500 keV Si ions generated by Pelletron accelerator at various fluences ranging from 6.9 × 10¹³ to 77.1 × 10¹³ ions/cm². Stopping range of ions in matter analysis revealed higher values of electronic stopping and sputtering yield for Ni as compared with Ti. For both irradiated metals, electronic energy loss dominant over the nuclear stopping. The growth of induced surface structures have been analysed by using field emission scanning electron microscopy (FESEM) analysis. In case of Ni, as the ion fluence increases from 6.9 × 10¹³ to 65.8 × 10¹³ ions/cm², the formation of spherical particulates, agglomers and sputtering is observed. Although in the case of Ti, with the increase of Si ion fluence from 11.6 × 10¹³ to 77.1 × 10¹³ ions/cm², the formation of irregular-shaped particulates along with crater and sputtered channels is observed. X-ray diffraction (XRD) analysis shows that no new phase is identified. However, a significant increase in peak intensity is observed with increasing ion fluence. The variation in crystallite size and dislocation line density is also observed as a function of Si ion fluence. Fourier transform infrared spectroscopy analysis shows that no bands are formed after the Si ion irradiation. Field emission properties of ion-structured Ni and Ti are well correlated with the growth of surface structures observed by SEM and dislocation line density evaluated by XRD analysis.     

Oxymatrine Loaded Cross-Linked PVA Nanofibrous Scaffold: Design and Characterization and Anticancer Properties

This study focuses on the fabrication, characterization and anticancer properties of biocompatible and biodegradable composite nanofibers consisting of poly(vinyl alcohol) (PVA), oxymatrine (OM), and citric acid (CA) using a facile and high-yield centrifugal spinning process known as Forcespinning. The effects of varying concentrations of OM and CA on fiber diameter and molecular cross-linking are investigated. The morphological and thermo-physical properties, as well as water absorption of the developed nanofiber-based mats are characterized using microscopical analysis, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. In vitro anticancer studies are conducted with HCT116 colorectal cancer cells. Results show a high yield of long fibers embedded with beads. Fiber average diameters range between 462 and 528 nm depending on OM concentration. The thermal analysis results show that the fibers are stable at room temperature. The anticancer study reveals that PVA nanofiber membrane with high concentrations of OM can suppress the proliferation of HCT116 colorectal cancer cells. The study provides a comprehensive investigation of OM embedded into nanosized PVA fibers and the prospective application of these membranes as a drug delivery system.     

Synthesis,Spectroscopy, Semi‐empirical and Biological Activities of Organotin(IV) Complexes with o‐Isopropyl Carbonodithioic Acid

New organotin(IV) complexes have been synthesized by treating potassium o‐isopropyl carbonodithioate with R₂SnCl₂/R₃SnCl in 1 : 2/1 : 1 M/L ratio. All complexes have been characterized by IR and NMR (¹H, ¹³C) spectroscopy. IR results shows that ligand acts as bidentate which is also confirmed by semi‐empirical study. NMR data reveals four coordinated geometry in solution. Computed positive heat of formation shows that complex 5 is thermodynamically unstable. UV/visible spectroscopy was used to assess the mode of interaction and binding of the complexes with DNA which shows that complex 5 exhibits higher binding constant as compared to complex 3 . In protein kinase inhibition assay, compound 3 was found most active, while other biological activities shows that triorganotin(IV) complexes are biologically more active as compared to diorganotin(IV) complexes.     

Rapid preparative isolation of erythrocentaurin from Enicostemma littorale by medium‐pressure liquid chromatography,its estimation by high‐pressure thin‐layer chromatography,and its α‐amylase inhibitory activity

Erythrocentaurin is a relatively simple natural product present among the members of Gentianaceae. A preparative method for the isolation of erythrocentaurin from the ethyl acetate fraction of Enicostemma littorale using medium‐pressure liquid chromatography has been reported. The method consisted of a simple step gradient from 10 to 20% ethyl acetate in n‐hexane. Using a 70 × 460 mm Si60 column, this method is capable of processing 20 g of material in <3 h (purity ≈ 97%). The recovery of erythrocentaurin was 87.77%. Estimation of erythrocentaurin in extracts and fractions based on high‐pressure thin‐layer chromatography was carried out on silica gel 60 F₂₅₄ plates with toluene/ethyl acetate/formic acid (80:18:2 v/v/v) as the mobile phase. The densitometric analysis was performed at 230 nm. A well‐separated compact band of erythrocentaurin appeared at R_f 0.54 ± 0.04. The analytical method showed good linearity in the concentration range of 200–1500 ng/band with a correlation coefficient of 0.99417. The limits of detection and quantification were found to be ≈60 and ≈180 ng/band, respectively. Erythrocentaurin exhibited a concentration‐dependent α‐amylase inhibition (IC₅₀ 1.67 ± 0.28 mg/mL). The outcome of the study should be considered for pharmacokinetic and biotransformation studies involving E. littorale.     

Improving the sensitivity of cellulose fiber-based lateral flow assay by incorporating a water-dissolvable polyvinyl alcohol dam

Cellulose - Lateral flow assay (LFA) is an important point-of-care (POC) test platform due to the associated portability, on-site testing, and low cost for diagnosis of pathogen infections and...     

Bacilli as Biological Nano-factories Intended for Synthesis of Silver Nanoparticles and Its Application in Human Welfare

The search of eco-friendly technologies for nano-synthesis is significant to expand their applications in human welfare. Nowadays, various inorganic nanoparticles with beneficial features have been synthesized via physical, chemical, and biological means. Significant biological applications of silver nanoparticles include on-infectious microbes, target drug delivery, cancer and vector-borne disease control. Their syntheses have been tested from plant fungi, bacteria, and viruses. The bacterial mediated synthesis of silver, gold, zinc and other metal leads to a milestone in nano-medicines. Thus, in this review, we focus on the contribution of Bacilli in the synthesis of silver nanoparticles, the mechanism of action and their potential application in the welfare of human beings.     

Design of donor–acceptor–donor (D–A–D) type small molecule donor materials with efficient photovoltaic parameters

Four Donor–Acceptor–Donor (D–A–D) type of donor molecules (M1‐M4) with triphenylamine (TPA) as donor moiety, thiophene as bridge, and thiazolothiazole as acceptor unit were designed and its photovoltaic parameters were equated with reference molecule “R.” DFT functional CAM‐B3LYP/6‐31G (d,p) was found best for geometry optimization and TD‐CAM‐B3LYP/6‐31G (d,p) was found suitable for excited state calculations. Among designed donor molecules, M4 manifests suitable lowest band gap of 4.73 eV, frontier molecular orbital energy levels as well as distinctive broad absorption of 455.3 nm due to the stronger electron withdrawing group. The electron‐withdrawing substituents contribute to red shifts of absorption spectra and better stabilities for designed molecules. The theoretically determined reorganization energies of designed donor molecules suggested excellent charge mobility property. The lower λ_e values in comparison with λ_h illustrated that these four donor materials would be ideal for electron transfer and M4 would be best amongst the investigated molecules with lowest λ_e of 0.0177. Furthermore, the calculated Voc of M4 is 2.04 V with respect to PC₆₀BM (phenyl‐C61‐butyric acid methyl ester). This study revealed that the designed donor materials are suitable and recommended for high performance organic solar cell devices.