Sonal Thakore

The Maharaja Sayajirao University of Baroda, Baroda, Gujarāt, India

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Publications (22)36.62 Total impact

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    ABSTRACT: 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 50nm 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 (3T3L1cells).
    Materials Science and Engineering C 11/2014; 44:209–215. · 2.40 Impact Factor
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    ABSTRACT: 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.
    RSC Advances 09/2014; 4(77). · 3.71 Impact Factor
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    ABSTRACT: 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.
    Catal. Sci. Technol. 08/2014;
  • Sonal Thakore
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    ABSTRACT: Cellulose nanoparticles (CelNPs) prepared by an acid hydrolysis process were acetylated under ambient conditions to retain the nanosize and to obtain hydrophobic nanosized derivatives. Green nanocomposites of natural rubber (NR) with more than 50 phr of cellulosic fillers were successfully developed by a commercial dry mixing process. The incorporation of cellulose acetate nanofiller up to 40 phr led to an almost linear increase in both the tensile and elongation properties, which were higher than even those of a composite with the conventional filler carbon black (CB). This was further supported by the almost uniform single-phase morphology of the nanobiocomposite revealed by scanning electron microscopy and the high thermal stability. The results indicate the high degree of compatibility between the hydrophobic nanosized filler and the NR matrix. Although a drop in the mechanical strength was observed above 50 phr, the cellulose derivatives were expected to prove to be promising substitutes for the hazardous filler CB even at higher loadings. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40632.
    Journal of Applied Polymer Science 03/2014; · 1.40 Impact Factor
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    ABSTRACT: Ethylenediamine provides excellent activity under ambient conditions when assisted by metal nanoparticles for the transesterification of higher to lower esters and vice versa. This is the first report on room temperature conversion of diethylmalonate to dimethylmalonate using this novel catalytic system. The nanoparticles were successfully recycled up to 24 cycles (although with an increase in reaction time) with no compromise in the yield. Various primary alcohols were used for transesterification. The scope was extended to aliphatic, heterocyclic and aromatic esters with various functional groups.
    Journal of Molecular Catalysis A Chemical 10/2013; 377:129–136. · 3.19 Impact Factor
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    ABSTRACT: Aloe vera has been used as a cosmetic and medical remedy since ancient times and has gained increasing popularity in recent years. Despite its widespread use, reports on biodiesel from Aloe vera seeds are lacking. The present investigation reports the fatty acid composition of Aloe vera seed oil (AVSO) and addresses the feasibility of using AVSO as a source of biodiesel. A novel ecofriendly catalyst was developed using triacetin as a model. Interestingly, the room-temperature conversion of AVSO and other nonedible oils to methyl esters could be achieved using this novel catalytic system consisting of ethylene diamine in the presence of nickel nanoparticles (NiNPs). The metal core, capping agent, and amine concomitantly contribute to make the system an effective catalyst.
    Energy & Fuels. 04/2013; 27(5):2776–2782.
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    ABSTRACT: 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 S2O 3−2. 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
    Catalysis Letters 01/2013; · 2.24 Impact Factor
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    ABSTRACT: Ag and Cu nanoparticles were immobilized into crosslinked polyurethane (PU) membranes by taking advantage of the swelling characteristics of the membranes. The formation, shape and size of the nanoparticles inside the post-swollen PU membranes were observed by transmission electron microscopy and atomic force microscopy. X-ray diffraction indicated the presence of the pure Ag and Cu embedded in the amorphous PU matrix. Because of their compatibility, the nanoparticles improved the thermal stability and increased the glass transition temperature of PU. The membranes exhibited interesting conducting behavior with increasing temperature. The metal immobilization increased the ionic conductivity which further increased with temperature, with an activation energy of 0.15 eV indicating a thermally activated conduction mechanism. The optical and electrical properties of these starch-based membranes can be utilized in the development of novel sensors for biomedical applications. Copyright © 2012 Society of Chemical Industry
    Polymer International 12/2012; 61(12). · 2.13 Impact Factor
  • Mayur Valodkar, Sonal Ishit Thakore
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    ABSTRACT: Biocomposites of natural rubber (NR) blends were prepared with a variety of fillers obtained from renewable resources by a mastication technique. They were characterized for their mechanical properties and morphologies and compared with composites of the conventional filler carbon black (c‐black). The biopolymers exhibited an interesting trend and imparted strength to NR that was quite comparable to c‐black. Up to 30 phr of the fillers could be successfully incorporated; this led to enhancements in the mechanical strength. The properties were found to vary with the type and ratio of filler, namely, starch, cellulose, and chitin. The optimum mechanical strength of the biocomposites was observed at 10 phr. The results were interpreted on the basis of the morphology by scanning electron microscopy, which revealed strong filler–polymer interactions. The moisture‐uptake characteristics of the composites were studied. It was found that addition of biofillers did not lead to a significant increase in the moisture absorption. Furthermore, as the adhesion between the polymer matrix and fillers increased, the water uptake decreased. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
    Journal of Applied Polymer Science 01/2012; 124(5). · 1.40 Impact Factor
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    ABSTRACT: 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.
    Journal of hazardous materials 12/2011; 201-202:244-9. · 4.33 Impact Factor
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    ABSTRACT: Organically modified silver nanoparticles were prepared by biosynthetic route induced by stem latex of a medicinally important plant, Euphorbia nivulia. The reduction and stabilization is assisted by certain peptides and terpenoids present within the latex. The aqueous formulation of latex capped silver nanoparticles (LAgNPs) being completely free of toxic chemicals can be directly used for administration/in vivo delivery of nanoparticles. The in vitro cytotoxicity evaluation of the latex capped nanoparticles was carried out using human lung carcinoma cells (A549) by MTT cell viability assay. Further, possible cytotoxic mechanisms were evaluated using various biomarkers for cytotoxicity and oxidative stress viz. extracellular lactate dehydrogenase (LDH) release, reactive oxygen species (ROS) generation, intracellular reduced glutathione (GSH), malondialdehyde (MDA), superoxide generation and acridine orange/ethedium bromide staining. It can be concluded from the present study that LAgNP formulation is toxic to A549 cells in a dose dependent manner. Thus plant latex solubilizes the AgNPs in water and acts as a biocompatible vehicle for transport of AgNPs to tumor/cancer cells.
    Materials Science and Engineering C 12/2011; 31(8):1723-1728. · 2.40 Impact Factor
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    ABSTRACT: This study elucidates the process of synthesis of copper (Cu) nanorods using almond skin extract as stabilizing cum capping agent. These nanorods were (about 200 nm long and 40 nm wide) characterized by transmission electron microscopy (TEM). Further, cytotoxicity potential of these nanorods was evaluated in A549 cells (Human lung carcinoma cell line) via cell viability assay and extracellular lactate dehydrogenase (LDH) release. Also, reduced glutathione (GSH), lipid peroxidation (LPO), cellular oxidative stress (Rhodamine 123 florescence) and apoptosis (Annexin V FITC/Propidium iodide staining) were also investigated in control and treated cells. Results indicated that Cu nanorods induced apoptotic death of cancer cells by induction of oxidative stress, depletion of cellular antioxidants and mitochondrial dysfunction. This study reports a novel process of synthesis of almond skin extract capped Cu nanorods and its potential as an anticancer agent against A549 lung carcinoma cells.
    Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association 07/2011; 49(11):2990-6. · 2.99 Impact Factor
  • Mayur Valodkar, Sonal Thakore
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    ABSTRACT: Organic modification of starch nanoparticles was carried out at room temperature to obtain nanosized hydrophobic derivatives. The particle size of the modified starch nanoparticles obtained by transmission electron microscopy (TEM) and X-ray diffraction (XRD) was found out to be around 50nm. The hydrophobic starch derivatives were used to prepare bionanocomposites of natural rubber by mastication process. The properties were compared with composites obtained from untreated starch nanoparticles and carbon black. Up to 30phr of the fillers were successfully incorporated leading to an enhancement in mechanical as well as thermal properties. Scanning electron microscopy (SEM) revealed single phase morphology of nanobiocomposites indicating compatibility of the filler and matrix. Dynamic mechanical properties were seen as a broad tan delta peak over a large range of temperature. It was observed that modified starch nanoparticles could be a potential substitute for carbon black as reinforcing agents and as promising materials for vibration damping applications.
    Carbohydrate Polymers - CARBOHYD POLYM. 01/2011; 86(3):1244-1251.
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    ABSTRACT: The stem latex of a medicinally important plant, Euphorbia nivulia was successfully used to induce room temperature/microwave synthesis of silver and copper nanoparticles even at high concentrations. The major component of the latex, Euphol, is assumed to be the reducing moiety; while stabilization is assisted by certain peptides and terpenoids present within the latex as supported by the FT-IR analysis. The fast and simple process has high reproducibility and leads to formation of nanoparticles with 5–10nm diameter. The one step synthesis can be extended for other metals. The nanoparticle solutions being completely free of toxic chemicals can be directly used for antimicrobial tests. The as synthesized solutions of both metals exhibited excellent bactericidal action against both gram negative and gram positive bacteria well below the in vitro cytotoxic concentration. The non-cytotoxic metal–latex aqueous solution offers a rational approach towards antimicrobial application and for integration to biomedical devices.
    Colloids and Surfaces A-physicochemical and Engineering Aspects - COLLOID SURFACE A. 01/2011; 384(1):337-344.
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    ABSTRACT: Extracellular synthesis of copper nanoparticles was carried out using stem latex of a medicinally important plant, Euphorbia nivulia. The nanoparticles were stabilized and subsequently capped by peptides and terpenoids present within the latex. The protein capping is a promising biocompatible vehicle for destruction of tumor/cancer cells. The cytotoxicity potential of the plant protein capped nanoparticles was evaluated using various parameters like MTT cell viability assay and extracellular lactate dehydrogenase (LDH) release in cancer cell line. Other parameters that determine the oxidative stress viz., reactive oxygen species (ROS) generation, intracellular reduced glutathione (GSH), malondialdehyde (MDA), superoxide generation and acridine orange/ethidium bromide staining were also investigated. The present study led to the conclusion that copper nanoparticles are toxic to A549 cells in a dose dependent manner. The non-toxic aqueous formulation of latex capped copper nanoparticles can be directly used for administration/in vivo delivery of nanoparticles for cancer therapy.Highlights► Protein capped copper nanoparticles were obtained by simple and rapid biosynthetic approach. ► In vitro Cytotoxicity of nanoparticles assessed in human lung carcinoma cells. ► Elevated indices of oxidative stress and cellular damages in A549 cells were recorded. ► This biocompatible nanoparticle formulation effective as delivery system against cancer cells.
    Materials Chemistry and Physics 01/2011; 128:83-89. · 2.07 Impact Factor
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    ABSTRACT: Metallic and bimetallic nanoparticles of copper and silver in various proportions were prepared by microwave assisted chemical reduction in aqueous medium using the biopolymer, starch as a stabilizing agent. Ascorbic acid was used as the reducing agent. The silver and copper nanoparticles exhibited surface plasmon absorption resonance maxima (SPR) at 416 and 584 nm, respectively; while SPR for the Cu–Ag alloys appeared in between depending on the alloy composition. The SPR maxima for bimetallic nanoparticles changes linearly with increasing copper content in the alloy. Transmission electron micrograph (TEM) showed monodispersed particles in the range of 20 ± 5 nm size. Both silver and copper nanoparticles exhibited emission band at 485 and 645 nm, respectively. The starch-stabilized nanoparticles exhibited interesting antibacterial activity with both gram positive and gram negative bacteria at micromolar concentrations.Graphical abstractResearch highlights▶ Synthesis of novel nanosized copper-silver alloys of different compositions. ▶ Completely green approach for synthesis of water soluble bimetallic nanoparticle. ▶ Interesting anti-bacterial activity of as synthesized metal and alloy nanoparticle.
    Materials Research Bulletin. 01/2011; 46(3):384-389.
  • Mayur Valodkar, Angshuman Pal, Sonal Thakore
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    ABSTRACT: Cuprous oxide (Cu2O) dendrites were prepared by simple hydrothermal route at two different temperatures using starch as reducing and stabilizing agent. Scanning Electron Microscopy (SEM) revealed the alterations in morphology with reaction temperature and time. The spherical nanoparticles obtained at lower reaction temperature self-assembled into distinct dendritic nanostructures at high temperature. The mechanism of formation of dendrite over the polysaccharide template has been discussed. Transmission Electron Microscopy (TEM) revealed that the crystalline size of these dendrites in one dimension is about 50nm. The nanoparticles were characterized by UV–vis and photoluminescence (PL) spectroscopy, X-ray diffraction (XRD), FT-IR and Thermal Gravimetry Analyzer (TGA). Impedance analysis of the nanostructures showed conductivity to be a function of temperature.
    Journal of Alloys and Compounds 01/2011; 509(2):523-528. · 2.73 Impact Factor
  • Mayur Valodkar, Sonal Thakore
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    ABSTRACT: Hydrophobic nanoparticles and nanocomposite films of 1,4-hexamethylene diisocyanate (HMDI)-modified starch nanoparticles (SNPs) have been synthesized at ambient temperatures. The platelet-like starch nanocrystals become pseudospherical after modification with HMDI and the size increases or decreases depending on diisocyanate concentration compared to the ungrafted particles as revealed by transmission electron microscopy (TEM) results. The obtained nanocrystals were characterized by means of the FT-IR and X-ray diffraction (XRD) techniques. When compared with the hydrophobic performance of the unmodified starch nanocrystals, that of crosslinked starch nanocrystals significantly increased. X-ray diffraction reveals that the crystalline structure of modified starch nanocrystals was preserved. The resulting hydrophobic starch nanoparticles are versatile precursors to the development of nanocomposites. The polyether-polyurethane crosslinked with SNPs nanocomposite film exhibited thermo-responsive electrical conductivity.
    Carbohydrate research 11/2010; 345(16):2354-60. · 2.03 Impact Factor
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    ABSTRACT: Silver nanoparticles were prepared by a simple hydrothermal route and chemical reduction using carbohydrates (sucrose, soluble and waxy corn starch) as reducing as well as stabilizing agents. The crystallite size of these nanoparticles was evaluated from X-ray diffraction (XRD) and transmission electron microscopy (TEM) and was found to be 25nm. The effect of carbohydrates on the morphology of the silver nanocomposites was studied using scanning EM (SEM). The nanocomposites exhibited interesting inhibitory as well as bactericidal activity against both Gram positive and Gram negative bacteria. Incorporation of silver also increased the thermal stability of the carbohydrates.
    Carbohydrate research 08/2010; 345(12):1767-73. · 2.03 Impact Factor
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    ABSTRACT: Silver nanowires were prepared on a waxy corn starch matix by a simple and green hydrothermal route. Infrared (IR) spectroscopy and X-ray diffraction (XRD) confirmed the presence of nanostructured cubic silver embedded in waxy starch matrix. The particle size by Scherrer’s equation is calculated to be about 32 nm. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed a uniform morphology, indicating intimate association of the metal-polysaccharide composite. The nanocomposites exhibited bactericidal effect and electrical conductivity, which was observed to be a function of temperature and metal concentration. The eco-friendly nanocomposites could be of potential biomedical application.
    International Journal of Green Nanotechnology: Physics and Chemistry. 01/2010; 2(1):10-19.