Gurukar Shivappa Suresh
Bar-Ilan University
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Gurukar Shivappa Suresh.
Talanta | 2012
Revanasiddappa Manjunatha; Gurukar Shivappa Suresh; Jose Savio Melo; S.F. D'Souza; T. V. Venkatesha
Cholesterol oxidase (ChOx) and cholesterol esterase (ChEt) have been covalently immobilized onto functionalized graphene (FG) modified graphite electrode. Enzymes modified electrodes were characterized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). FG accelerates the electron transfer from electrode surface to the immobilized ChOx, achieving the direct electrochemistry of ChOx. A well defined redox peak was observed, corresponding to the direct electron transfer of the FAD/FADH(2) of ChOx. The electron transfer coefficient (α) and electron transfer rate constant (K(s)) were calculated and their values are found to be 0.31 and 0.78 s(-1), respectively. For the free cholesterol determination, ChOx-FG/Gr electrode exhibits a sensitive response from 50 to 350 μM (R=-0.9972) with a detection limit of 5 μM. For total cholesterol determination, co-immobilization of ChEt and ChOx on modified electrode, i.e. (ChEt/ChOx)-FG/Gr electrode showed linear range from 50 to 300 μM (R=-0.9982) with a detection limit of 15 μM. Some common interferents like glucose, ascorbic acid and uric acid did not cause any interference, due to the use of a low operating potential. The FG/Gr electrode exhibits good electrocatalytic activity towards hydrogen peroxide (H(2)O(2)). A wide linear response to H(2)O(2) ranging from 0.5 to 7 mM (R=-0.9967) with a sensitivity of 443.25 μA mM(-1) cm(-2) has been obtained.
Bioelectrochemistry | 2016
Seetharamaiah Nandini; Seetharamaiah Nalini; M. B. Madhusudana Reddy; Gurukar Shivappa Suresh; Jose Savio Melo; Pathappa Niranjana; Jakkid Sanetuntikul; Sangaraju Shanmugam
This manuscript reports a new approach for the synthesis of one dimensional gold nanostructure (AuNs) and its application in the development of cholesterol biosensor. Au nanostructures have been synthesized by exploiting β-diphenylalanine (β-FF) as an sacrificial template, whereas the Au nanoparticles (AuNPs) were synthesized by ultrasound irradiation. X-ray diffractometer (XRD), scanning electron microscope (SEM) and energy dispersive analysis of X-rays (EDAX) have been employed to characterize the morphology and composition of the prepared samples. With the aim to develop a highly sensitive cholesterol biosensor, cholesterol oxidase (ChOx) was immobilized on AuNs which were appended on the graphite (Gr) electrode via chemisorption onto thiol-functionalized graphene oxide (GO-SH). This Gr/GO-SH/AuNs/ChOx biosensor has been characterized using cyclic voltammetry (CV), electrochemical impedance spectroscopy and chronoamperometry. CV results indicated a direct electron transfer between the enzyme and the electrode surface. A new potentiostat intermitant titration technique (PITT) has been studied to determine the diffusion coefficient and maxima potential value. The proposed biosensor showed rapid response, high sensitivity, wide linear range and low detection limit. Furthermore, our AuNs modified electrode showed excellent selectivity, repeatability, reproducibility and long term stability. The proposed electrode has also been used successfully to determine cholesterol in serum samples.
Russian Journal of Electrochemistry | 2013
Simson Prasanna Kumar; Revanasiddappa Manjunatha; T. V. Venkatesha; Gurukar Shivappa Suresh
Graphite electrode is modified by casting multi-walled carbon nanotubes (MWCNTs) wrapped with polystyrene sulphonate (PSS) onto the surface of the bare graphite electrode. The modified electrode was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The behavior of the modified electrode towards the oxidation of ascorbic acid (AA), dopamine (DA) and uric acid (UA) has been determined by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry (CA). The modified electrode showed better electrocatalytic activity towards AA, DA and UA compared to bare graphite electrode. The electrochemical oxidation signals of AA, DA and UA are well separated into three distinct peaks with peak potential difference of 222, 128 and 350 mV between AA-DA, DA-UA and AA-UA respectively in CV studies and corresponding peak potential separation in DPV are 228, 120 and 348 mV. This modified electrode was successfully used for simultaneous determination of AA, DA and UA in ternary mixture.
Analytical Methods | 2014
Seetharamaiah Nandini; Seetharamaiah Nalini; Sangaraju Shanmugam; Pathappa Niranjana; Jose Savio Melo; Gurukar Shivappa Suresh
A novel natural immobilizing matrix for the immobilization of glucose oxidase (GOx) and horseradish peroxidase (HRP) is presented in this article. The electrochemical biosensor was constructed by immobilizing the enzymes on Rhoeo discolor (Rd) leaf extract with 2.5% glutaraldehyde (GLD) on functionalized multiwalled carbon nanotubes (f-MWCNTs) modified graphite (Gr) electrode. The Gr/f-MWCNTs/(Rd-GLD)/GOx and Gr/f-MWCNTs/(Rd-GLD)/HRP biosensors showed excellent electrocatalytic activity concerning the detection of glucose and hydrogen peroxide. The physical morphology of the biosensors was studied using SEM and EDX. The electrochemical performance of the proposed biosensors was evaluated using cyclic voltammetry, differential pulse voltammetry and chronoamperometry. The effects of experimental variables such as pH, temperature, and applied potential on the current response of the biosensors were studied and optimized. The Gr/f-MWCNTs/(Rd-GLD)/GOx biosensor exhibited a rapid response time of less than 5 s, displayed a wide linear range of 0.5 to 28.5 mM, showed a low detection limit of 0.16 μM and revealed a high sensitivity of 15 μA mM−1 cm−2 for glucose. Similarly the Gr/f-MWCNTs/(Rd-GLD)/HRP biosensor showed a fast response time of 3 s, a good linear range of 0.2 to 6.8 mM with a 0.01 μM detection limit and an exceptional sensitivity of 2.1 mA mM−1 cm−2 for hydrogen peroxide. Subsequently, the practical applicability of the glucose biosensor for the analysis of glucose in Eleusine coracana wine and tender coconut water was examined while the Gr/f-MWCNTs/(Rd-GLD)/HRP modified electrode was tested for the determination of H2O2 in herbal bleach. In addition, the biosensors displayed long term stability, anti-interference ability and good reproducibility.
RSC Advances | 2016
Seetharamaiah Nalini; Seetharamaiah Nandini; M. B. Madhusudana Reddy; Gurukar Shivappa Suresh; Jose Savio Melo; Shivayogeeswar Neelagund; Hunasepalya Nagaiah NaveenKumar; Sangaraju Shanmugam
In this work, we report a microbial biosensor fabricated for the preclinical assay of anticancer compounds. Gold nanoribbons were used as a transducer for mounting the microbe. For the synthesis of these unique Au nanostructures, quercetin stabilized gold nanoparticles (Q-AuNPs) were synthesized as a first step using onion peel. Later, dityrosine peptide was used as a sacrificial template for the synthesis of the gold nanoribbons (AuNRs). The structural morphology of the as-synthesized Au nanomaterial was examined using UV spectroscopy, XRD, SEM and TEM. The AuNRs were found to be <10 nm in diameter, which provided a good biocompatible environment and effective protection for the immobilization of Agrobacterium tumefaciens (At), a causative agent of crown gall disease. At is reported to cause tumors in plants through a tumorigenic mechanism similar to that of humans. Inhibition of At indicates that the inhibitory compound being screened exhibits anticancer activity. Clitoria ternatea (Ct) is traditionally used to cure many diseases and is known to possess anticancer activity. Therefore, we have used a Ct flower extract in the preclinical study of its anticancer activity against At by fabricating a simple electrochemical sensor. We have employed electrochemical techniques such as CV and EIS for the characterization of the developed microbial biosensor. Moreover, the as-synthesized AuNRs behave as an ideal transducer and platform, thus improving the electrode surface area and providing good biocompatibility for the immobilization of At. In contrast to other immobilization techniques and biosensors that often require elaborate procedures, cross-linking agents and rigorous chemical reactions, At was directly adsorbed onto the electrode under optimum conditions without any mediators. The results show that the developed biosensor is useful in the pre-clinical analysis of anticancer properties. Indeed the study examines the use of electrochemistry, demonstrating the rapid response and high sensitivity of the proposed sensor in contrast to bioassay procedures. In conclusion, the experimental results indicate that the developed biosensor accentuates the excellent properties of the synthesized AuNRs, which promises to be a novel avenue in designing biosensors.
New Journal of Chemistry | 2018
Shadakshari Sandeep; Arehalli Shivamurthy Santhosh; Ningappa Kumara Swamy; Gurukar Shivappa Suresh; Jose Savio Melo; Nelligeri Arkeswaraiah Chamaraja
The present report demonstrates the development of a highly sensitive and selective electrochemical biosensor for catechol detection by immobilizing crude polyphenol oxidase (PPO) enzyme onto a graphite (Gr) electrode modified using graphene nanoribbons (GNRs) decorated with green synthesized silver nanoparticles (AgNPs). The developed electrochemical sensor, Gr/GNRs/AgNPs/PPO, is characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques at each stage of its fabrication. Under the optimized conditions, the developed sensor showed excellent electrocatalytic activity towards the detection of catechol which is attributed to higher electron transfer rates induced due to incorporation of GNRs and AgNPs in the electrode matrix. The sensor exhibited a wide detection range (2–2300 μM) and low detection limit. The sensor also showed superior selectivity towards catechol detection in the presence of common interferents. Furthermore, the efficiency of the catechol biosensor in real sample analysis is validated by analyzing catechol in different tea samples. The results of electroanalysis in comparison with high performance liquid chromatography (HPLC) results showed good agreement suggesting that the developed GNR composite based catechol sensor is efficient enough to be employed in detection and quantification of catechol in real samples, particularly the analysis of tea samples.
Advanced Materials | 2007
Doron Aurbach; Gurukar Shivappa Suresh; Elena Levi; A. Mitelman; Oren Mizrahi; Orit Chusid; Michela Brunelli
Sensors and Actuators B-chemical | 2010
Revanasiddappa Manjunatha; Gurukar Shivappa Suresh; Jose Savio Melo; S.F. D'Souza; T. V. Venkatesha
Journal of Electroanalytical Chemistry | 2004
P. Ramesh; Gurukar Shivappa Suresh; S. Sampath
Journal of Solid State Electrochemistry | 2011
H. Manjunatha; Gurukar Shivappa Suresh; T. V. Venkatesha