Browsing by Author "Kislay Singh"

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A reduced graphene oxide ceramic electrode modified with one MoNomer doubly imprinted acryloylated tetraamine cobalt phthalocyanine polymer for the simultaneous analysis of anticancerous drugs
(Elsevier B.V., 2019) Sana Fatma; Bhim Bali Prasad; Kislay Singh; Richa Singh; Swadha Jaiswal
The present work illustrates a novel technique for the development of One MoNomer dual imprinted polymer, utilizing acryloylated tetraamine cobalt phthalocyanine as a tetrafunctional monomer, on the surface of a reduced graphene oxide ceramic electrode. This electrode was used for the simultaneous analysis of a mixture of anticancerous drugs, chlorambucil and dacarbazine, at ultra-trace level in real samples. The acryloylated tetraamine cobalt phthalocyanine was typically selected in this work for polymerization because it served both as a monomer and a crosslinker, with higher electroconductivity. The detection sensitivity of the measurement was realized to be 0.041 ng mL−1 and 0.017 ng mL−1 for chlorambucil and dacarbazine, respectively in the aqueous environment. The complex matrices of blood plasma, urine and pharmaceutics were examined which yielded the validated results without any effects of matrix complications including cross-reactivity, and false-positives. The therapeutic ranges of the test analyte(s) (chlorambucil 0.159–28.524 ng mL−1, dacarbazine 0.063–37.286 ng mL−1) were realized to be larger demonstrating perfect linearity (R2 = 0.99) with the improved voltammetric response. This work merits special significance to decide the adequate supplementation of drug(s) in combined therapy for cancer treatment. © 2018 Elsevier B.V.
An electroconducting copper (II) imprinted sensor using algae as cheap substitute of multiwalled carbon nanotubes
(Elsevier Ltd, 2016) Bhim Bali Prasad; Kislay Singh
A typical, reproducible, and rugged "complex-template" imprinted polymer-based pencil graphite electrode was fabricated for differential pulse anodic stripping voltammetric analysis of copper (II) (limit of detection, 0.004 ng mL-1, S/N = 3) in real-world samples. In this work, copper (II) ion mediated imprinting in alga (Aulosira sp.)-based molecularly imprinted polymer actually helped upbringing electro-conducting characteristics in the film. The modified electrode quantitatively responded copper (II), without any cross-reactivity and false-positives. Herein, encapsulated algal stains extended their carboxylate groups to imprint copper (II) in cooperation with an assistant monomer, N-methacryloylglutamic acid. The imprinted system simultaneously restricted the metal biosorption (non-specific adsorption) in acidic medium. The most interesting feature of algal stains was their ability to serve as an in-expensive alternative to the costly multi-walled carbon nanotubes. The results obtained by the proposed sensor could be utilized for the assessment of Cu (II) supplementation in metal-deficient patients and to estimate endogenous concentrations of Cu (II) in environmental, biological, and pharmaceutical samples. © 2015 Elsevier Ltd. All rights reserved.
Biomimetic Polymer-Based Electrochemical Sensor Using Methyl Blue-Adsorbed Reduced Graphene Oxide and Functionalized Multiwalled Carbon Nanotubes for Trace Sensing of Cyanocobalamin
(American Chemical Society, 2018) Richa Singh; Swadha Jaiswal; Kislay Singh; Sana Fatma; Bhim Bali Prasad
The paper reports a three-dimensional cyanocobalamin (Cbl)-selective biomimetic imprinted polymer. For this, a methyl blue-adsorbed reduced graphene oxide (rGO) and functionalized multiwalled carbon nanotubes (f-MWCNTs) composite, duly functionalized with acryloylurea, was used. This exhibited higher electroconductivity and larger surface area in comparison to either pristine carbon nanotubes or graphene. It is the first synthetic biomimetic polymer of Cbl, grown on the surface of a pencil graphite electrode. In this work, the adsorption of methyl blue over the rGO sheets improved its solubility, conductivity, and self-assembly properties. Such assemblies of rGO sheets and f-MWCNTs provide enhanced kinetics and conductivity to the entire architectural design of a molecularly imprinted polymer. The ultratrace detection of Cbl was feasible by differential-pulse voltammetric transduction. This sensor exhibited high sensibility and selectivity for Cbl detection, especially in real samples. © 2018 American Chemical Society.
Development of highly electrocatalytic and electroconducting imprinted film using Ni nanomer for ultra-trace detection of thiamine
(Elsevier B.V., 2017) Bhim Bali Prasad; Richa Singh; Kislay Singh
The present work describes a new molecularly imprinted polymer-based electrochemical sensor for thiamine (vitamin B1), which has been fabricated exploiting both surface imprinting and nanotechnology. Of two monomers used in this work, N-methacryloylglutamic acid served as a biocompatible and bio-adhesive material, whereas the assistant monomer, acryloylated nickel nanoparticles-functionalized multiwalled carbon nanotubes (Ni nanomer) induced large electro-catalytic and conducting activities to the molecularly imprinted polymer film. The polymer synthesis was carried out, following the ‘surface grafting from’ protocol, with the free radical polymerization directly on the surface of Ni nanomer modified pencil graphite electrode. The presence of functionalized-MWCNTs in the polymer film was inevitable to render stability to the coating via aromatic π − π interactions at the film-nanomer modified electrode interface. Thiamine, being electrochemically inactive, was estimated indirectly by a probe, hexamine ruthenium (II) chloride, with signal transduction via differential pulse anodic stripping voltammetric technique. The limits of detection were in the range 0.17–0.2 ng mL−1(S/N = 3) in aqueous, multi-vitamin tablet, urine, and human blood serum, without any cross-reactivity and false- positives. The proposed sensor assures a reliable estimation of thiamine in the patients suffering from its acute deficiency. © 2017
Electrochemical simultaneous analysis of dopamine and epinephrine using double imprinted One MoNomer acryloylated graphene oxide-carbon black composite polymer
(Elsevier Ltd, 2019) Sana Fatma; Bhim Bali Prasad; Swadha Jaiswal; Richa Singh; Kislay Singh
A novel One MoNomer dual imprinted graphene oxide/carbon black composite polymer was developed applying ‘surface-grafting from’ approach on the screen printed carbon electrode for the electrochemical sensing of dopamine and epinephrine. Acryloylated-graphene oxide/carbon black was synthesized for the first time. This served both as a crosslinker and monomer leading to the fast electron transfer from the redox centre to the electrode. The oxidation peak potentials of both the targets were found separated by 200 mV which enabled their simultaneous analysis in real world samples, without any cross reactivity, interferences, and false-positives. The detection limits realized by the proposed sensor, under optimized analytical conditions, were found to be as low as 0.028, 0.028,0.061 and 0.029 ng mL −1 for dopamine and 0.017, 0.018, 0.019 and 0.020 ng mL −1 for epinephrine (S/N = 3) in aqueous, blood serum, urine and pharmaceutical samples. Such sensor could be considered suitable for the primitive diagnosis of several chronic diseases, manifested at ultra-trace level. © 2019
Enantioselective analysis of D- and L- Serine on a layer-by-layer imprinted electrochemical sensor
(Elsevier Ltd, 2019) Swadha Jaiswal; Richa Singh; Kislay Singh; Sana Fatma; Bhim Bali Prasad
The present work describes a new, simple, and easy method of generating acrylamide functionalised reduced graphene oxide-fullerene layer-by-layer assembled dual imprinted polymers to quantify D- and L-Serine at ultra trace level in aqueous and real samples. Herein, the pencil graphite electrode was initially spin coated with D-Serine imprinted acrylamide functionalized reduced graphene oxide. After 10 min thermal treatment (50 °C), this electrode was again modified with L-Serine imprinted acrylamide functionalized fullerene molecules. This bilayer assembly was finally made thermally stable by 60 °C exposure for 3 h. The proposed sensor showed better electronic properties with an improved synergism. We have compared this modified electrode with other modified pencil graphite electrodes like single layered acrylamide functionalised reduced graphene oxide or fullerene, single layered acrylamide functionalised reduced graphene oxide-fullerene composite and double layered acrylamide functionalised reduced graphene oxide or fullerene molecules, which yielded very inferior sensitivity due to possible agglomeration and decreased synergism. The chosen system demonstrated a very good analytical figures of merit with differential pulse anodic stripping voltammetry and cyclic voltammetry transduction, showing lower limits of detection (0.24 ng mL −1 , S/N = 3) for both isomers. The proposed sensor assures practical applications as disease biomarker, manifesting several diseases at very ultra-trace level. © 2018 Elsevier B.V.
Molecularly imprinted polymer-based core-shells (solid vs hollow) @ pencil graphite electrode for electrochemical sensing of certain anti-HIV drugs
(Elsevier B.V., 2017) Bhim Bali Prasad; Kislay Singh
The present work describes a new, simple, and easy method for the fabrication of molecularly imprinted polymer-based core-shells (solid and hollow) @ pencil graphite electrode for sensing anti-HIV drugs, lamivudine and zidovudine, in real samples. For this, an imprinted polymer was developed on the surface of vinylated silica nanospheres to obtain modified solid as well as hollow core-shells. In this work, respective electrodics in terms of analyte diffusion for binding and electrode kinetics of both modified solid and hollow core-shells were compared using a ferricyanide probe with cyclic voltammetric and differential pulse anodic stripping voltammetric methods of transduction. Whereas modified solid core-shells evolved unilateral diffusion of probe/analyte molecules, the corresponding hollow core-shells were found to be relatively better owing to their bilateral diffusions into molecular cavities. Indirect detections of electroinactive targets chosen were feasible with the help of probe using imprinted hollow core shells modified electrode with limits of detection as low as 2.23 and 1.26 (aqueous sample), 2.45 and 1.88 (blood serum), and 2.52 and 1.77 ng mL−1(pharmaceutics) for lamivudine and zidovudine, respectively. © 2016
One-by-one imprinting in two eccentric layers of hollow core-shells: Sequential electroanalysis of anti-HIV drugs
(Elsevier Ltd, 2018) Kislay Singh; Swadha Jaiswal; Richa Singh; Sana Fatma; Bhim Bali Prasad
Double layered one-by-one imprinted hollow core-shells@ pencil graphite electrode was fabricated for sequential sensing of anti-HIV drugs. For this, two eccentric layers were developed on the surface of vinylated silica nanospheres to obtain double layered one-by-one imprinted solid core-shells. This yielded hollow core-shells on treatment with hydrofluoric acid. The modified hollow core-shells (single layered dual imprinted) evolved competitive diffusion of probe/analyte molecules. However, the corresponding double layered one-by-one imprinted hollow core-shells (outer layer imprinted with Zidovudine, and inner layer with Lamivudine) were found relatively better owing to their bilateral diffusions into molecular cavities, without any competition. The entire work is based on differential pulse anodic stripping voltammetry at double layered one-by-one imprinted hollow core-shells. This resulted in indirect detection of electro inactive targets with limits of detection as low as 0.91 and 0.12 (aqueous sample), 0.94 and 0.13 (blood serum), and 0.99 and 0.20 ng mL-1 (pharmaceutics) for lamivudine and zidovudine, respectively in anti-HIV drug combination. © 2018 Elsevier B.V.
Ultra-trace analysis of D-and L-aspartic acid applying one-by-one approach on a dual imprinted electrochemical sensor
(Elsevier B.V., 2017) Bhim Bali Prasad; Swadha Jaiswal; Kislay Singh
An enantiomeric pair imprinted polymeric film, with embedded functionalized multiwalled carbon nanotubes, was developed following the ‘surface grafting from’ approach onto a gold nanoparticles decorated pencil graphite electrode. Double imprinting of chiral molecules in a single polymer motif, as a sensory platform, for the one-by-one evaluation of individual components of a racemic mixture, is a challenging task. The underlying state-of-art proposed for this purpose is novel and if this works well, any two simple molecules could be used as templates. In this work, a pencil graphite electrode was first dipped for the overnight in the aqueous suspension of gold nanoparticles. The electrode was then subjected to spin coating with a pre-polymerization mixture consisting a monomer (N-acryloyl-pyrrolidine-2,5-dione), templates (D- and L-Aspartic acid), a cross-linker (ethylene glycol dimethacrylate) in the presence of an initiator (α,α′-azoisobutyronitrile). As aspartic acid isomers have been found to be electro-inactive, their evaluation was feasible indirectly with the help of a potassium ferricyanide probe. The quantitation ability of the proposed sensor, with differential pulse anodic stripping voltammetric transduction, was found to be in the tune of 4.08 ng mL−1 (S/N = 3) for both the enantiomers in the real samples, which reportedly manifest several chronic diseases at their stringent limits. © 2016