Puran Singh Rathore

Cytotoxicity evaluation and antimicrobial studies of starch capped water soluble copper nanoparticles

Water soluble monodisperse copper nanoparticles of about 10nm diameter were prepared by microwave irradiation using starch as green capping agent. The resulting Cu-starch conjugate were characterized by FTIR and energy dispersive X-ray analysis (EDX). The study confirmed the presence of copper embedded in polysaccharide matrix. The aqueous solution of starch capped copper nanoparticles (SCuNPs) exhibited excellent bactericidal action against both gram negative and gram positive bacteria. The in vitro cytotoxicity evaluation of the nanoparticles was carried out using mouse embryonic fibroblast (3T3L1) cells by MTT cell viability assay, extracellular lactate dehydrogenase (LDH) release and dark field microscopy imaging. The capped nanoparticles exhibited cytotoxicity at much higher concentration compared to cupric ions. Minimum bactericidal concentration (MBC) of SCuNPs was well below the in vitro cytotoxic concentration. Statistical analysis demonstrated p<0.05 for significant results and p>0.05 for non-significant ones as compared to untreated cells. The non-cytotoxic green Cu-starch conjugate offers a rational approach towards antimicrobial application and for integration to biomedical devices.

Magnetically separable core–shell iron oxide@nickel nanoparticles as high-performance recyclable catalysts for chemoselective reduction of nitroaromatics

A magnetically separable core–shell iron oxide@nickel (IO@Ni) nanocatalyst was synthesized by reduction of Ni2+ ions in the presence of iron oxide (Fe2+, Fe3+) by a simple one-pot synthetic route using NaBH4 as a reducing agent and starch as a capping agent. The synthesized nanoparticles (NPs) were characterized by several techniques such as X-ray diffraction (XRD), high resolution transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED), and energy dispersive X-ray spectroscopy (EDS). The core–shell iron oxide@nickel nanoparticles (IO@NiNPs) were found to have excellent activity for the hydrogenation reactions of aromatic nitro compounds under mild conditions using water as a green solvent. Excellent chemoselectivity and recyclability up to 30 cycles for the nitro group reduction was demonstrated.

Sunflower oil mediated biomimetic synthesis and cytotoxicity of monodisperse hexagonal silver nanoparticles.

In this work, sunflower oil was utilized for the biomimetic synthesis of silver (Ag) nanoparticles (NPs), leading to highly mono-dispersed hexagonal-shaped silver nanoparticles (NPs) at various concentrations. It was found that the biomolecules of the oil not only have the capability to reduce silver ions, due to its extended phenolic system, but also appear to recognize and affect the Ag nanocrystal growth on the (110) face, leading to hexagonal growth of the NPs of 50 nm size. Initially, some spherical AgNPs of less than 10nm diameter were observed; however, over a longer period of time, a majority of hexagonal-shaped nanocrystals were formed. The one step synthesis can be extended for other metals. The as prepared sunflower oil capped AgNPs being completely free of toxic chemicals can be directly utilized for in vitro studies and offer a more rational approach for cellular applications. The NP solution exhibited dose-dependent cytotoxicity in human lung carcinoma cells and physiologically relevant cell model (3T3L1 cells).

Nanoparticle-supported and magnetically recoverable organic–inorganic hybrid copper(II) nanocatalyst: a selective and sustainable oxidation protocol with a high turnover number

A magnetically recoverable copper-based nanocatalyst was prepared from inexpensive starting materials. With a particle size between 20 to 30 nm, it was shown to catalyze the oxidation of benzylic alcohols. The catalyst exhibited a high turnover number (TON) and excellent selectivity. The catalyst was characterized by several techniques, such as XRD, HR-TEM, SAED, EDS, FT-IR, VSM, and BET surface area. Factors affecting the reaction parameters, such as the substrate to oxidant molar ratio, weight of the catalyst, reaction time, etc., were investigated in detail. The reusability of the catalyst was examined by conducting repeat experiments with the same catalyst; it was observed that the catalyst displayed no significant changes in its activity even after seven cycles for the aerobic, as well as for the peroxide, oxidation of benzyl alcohol. Furthermore, the heterogeneous nature, easy recovery, and reusability, makes the present protocol highly beneficial for addressing environmental concerns and industrial requirements.

Nickel Nanoparticles as Efficient Catalyst for Electron Transfer Reactions

The catalytic efficiency of nickel nanoparticles was investigated in some electron transfer reactions. The nanoparticles brought about rapid room temperature reduction of a number of nitro aromatics in an aqueous medium with high chemoselectivity and also helped to speed up redox reaction of Fe(CN)6−3 and S2O3−2. In addition, interesting results were obtained for microwave assisted decolourization of azo dye. The reactions were monitored through UV–Vis spectroscopy. The present study has additional advantages of reusability of catalysts and aqueous medium. The ultimate goal was to assess the suitability of low cost nanocatalyst for electron transfer reactions under aqueous conditions.Graphical Abstract

Synthesis and cytotoxicity evaluation of novel acylated starch nanoparticles.

Starch nanoparticles (StNPs) were acylated under ambient conditions to obtain various nanosized derivatives formed stable suspension in water and soluble in organic solvents. The degree of substitution (DS) was determined using (1)H NMR technique. The cytotoxicity potential of the derivatised StNPs was evaluated in mouse embryonic fibroblast (3T3L1) cells and A549 tumor cell line using MTT cell viability assay. Other parameters that determine the oxidative stress viz., reactive oxygen species (ROS) generation, intracellular reduced glutathione (GSH), superoxide generation and acridine orange/ethidium bromide staining were also investigated. The present study led to the conclusion that cytotoxic activity of acylated starch nanoparticles was dependent on their dosage, DS and type of substitution. The non-toxic nature in non-cancerous cells reveals that the nanoparticles (NPs) can be used for cancer therapy and drug delivery. The nanoparticles also offered reasonable binding propensity with CT-DNA.