Faculty Publications
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Item Plant root nodule like nickel-oxide-multi-walled carbon nanotube composites for non-enzymatic glucose sensors(Royal Society of Chemistry, 2015) Prasad, R.; Gorjizadeh, N.; Rajarao, R.; Sahajwalla, V.; Badekai Ramachandra, B.R.Herein, in this work we synthesized plant root nodule like NiO-MWCNT nanocomposites by a simple, rapid and solvent-free method using nickel formate as a precursor. Using a first-principle simulation study the interactions and charge transfer behaviour of the NiO and MWCNT composite is investigated. The as-prepared NiO-MWCNT composite is employed to fabricate a modified non-enzymatic carbon paste electrode (CPE) for glucose sensing. From the electrochemical investigation, the fabricated sensor shows an excellent sensitivity of 6527 ?A mM-1 cm-2 with a detection limit of 19 ?M and a linear response over a range from 0.001 mM to 14 mM of glucose concentrations, at an applied potential of 0.5 V. Importantly the sensor also exhibits greater stability, selectivity and reproducibility. A first principle simulation study shows the differences in charge density and charge transfer behaviour from nanotubes to NiO nanoparticles, which in turn enhances the electro catalytic property of the NiO-MWCNT composite. Hence, these results indicate that the NiO-MWCNT composite is a potential material for non-enzymatic electrochemical glucose sensors. This journal is © The Royal Society of Chemistry.Item Multi-wall carbon nanotube-NiO nanoparticle composite as enzyme-free electrochemical glucose sensor(Elsevier, 2015) Prasad, R.; Badekai Ramachandra, B.R.We report a simple, solvent-free method to decorate multi-walled carbon nanotubes (MWCNTs) with nickel oxide nanoparticles (NiO-NPs). The as prepared NiO-MWCNT composite were characterised by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy. The enzyme-free modified carbon paste electrode (CPE) was fabricated using as-synthesised composite material and investigated for glucose sensing. The 10% NiO-MWCNTs composites sensor showed excellent electro-catalytic activity towards direct glucose oxidation. The sensitivity of this sensor is found to be 1696 ?A mM-1 cm-2 and 122.1 ?A mM-1 cm-2 and the limit of detection (LOD) was found to be 11.04 nM and 31 ?M for the linear response over glucose concentration ranging from 1-200 ?M to 0.5-9.0 mM, respectively. Furthermore, the 10% NiO-MWCNTs sensor also showed excellent anti-interference ability, high stability and good reproducibility. Hence, due to simple method of material preparation, easy sensor fabrication and excellent electro catalytic activity towards glucose oxidation, the 10% NiO-MWCNT/CPE is a potential material for the development of enzyme-free sensor for reliable glucose determination. © 2015 Elsevier B.V. All rights reserved.Item Nickel-oxide multiwall carbon-nanotube/reduced graphene oxide a ternary composite for enzyme-free glucose sensing(Royal Society of Chemistry, 2016) Prasad, R.; Ganesh, V.; Badekai Ramachandra, B.R.We report a solvent-free method of preparation for a NiO-carbon nanotube/graphene ternary composite using nickel formate as a green precursor via a thermal decomposition method. In this ternary composite, NiO with an average particle size of 7 nm is regularly decorated on the surfaces of conductive carbon matrix networks such as MWCNTs and reduced graphene oxide (rGO). Here rGO serves as an ideal support for the uniform distribution of NiO nanoparticles and also functions as an efficient transducer material, whereas, MWCNTs act as a spacer between rGO, which enhances the electrical conductivity and accessibility of the active reaction sites for direct glucose oxidation. The electrochemical performances were evaluated by cyclic voltammetry and amperometric techniques. Under the optimal conditions, the 20 wt% NiO-MWCNT/rGO/GCE exhibits a sensitivity of 4223.3 ?A cm-2 mM-1 and a detection limit of 0.92 ?M over a linear glucose concentration range up to 19 mM. Furthermore, the constructed sensor is effectively employed to detect glucose in real human blood serum samples with adequate results. The modified 20 wt% NiO-MWCNT/rGO/GCE also shows a high sensitivity, greater selectivity, excellent reproducibility and long-term stability. © 2016 The Royal Society of Chemistry.Item Nickel oxide—multi walled carbon nanotube composite as non-enzymatic electrochemical glucose sensor(American Scientific Publishers, 2016) Raghavendra Prasad, J.; Badekai Ramachandra, B.R.In this scientific letter, we report a simple, scalable, economical and solvent-free method for the synthesis of uniformly decorated nickel-oxide (NiO) multi-walled carbon nanotube (MWCNT) composites. These materials were characterized by using scanning electron microscopy (SEM), X-ray diffractometer (XRD) and then were used to prepare modified electrode for glucose sensing application. The electrochemical investigations like cyclic voltammetry (CV) and chronoamperometry were carried out in 0.2 M NaOH. The electrochemical results show excellent sensitivity of 323 mA mM?1cm?2and detection limit of 10? M. Therefore, proposed sensor may serve as a potential candidate for non-enzymatic glucose sensing application. © 2016 American Scientific Publishers All rights reserved.Item Aggregative ways of graphene quantum dots with nitrogen-rich edges for direct emission spectrophotometric estimation of glucose(Elsevier B.V., 2019) Mishra, P.; Badekai Ramachandra, B.R.We report a facile one step in-situ synthesis of amino-functionalized graphene dots. These quantum dots were employed for the detection of glucose in both standard aqueous solutions and commercially available fruit juice to assess its practicability. The characterization of the quantum dots revealed that they were decorated with amine functionality. Additionally, the interaction between glucose and amine functionalized graphene quantum dots gave enhancement in the UV–vis absorption and photoluminescence (PL) due to aggregation of quantum dots via glucose link. Therefore, the quantum dots were able to detect the concentration of glucose in solution exhibiting linearity from 0.1 to 10 mM and 50–500 mM with a sensitivity transition from 10 mM to 50 mM. The limit of detection for the determination of glucose was found to be 10 ?M. This determination was agreed from both UV–Vis absorption and PL spectroscopy. However, the PL emission method of determination was most suited with its very high accuracy of 98.04 ± 1.96% and 97.33 ± 2.67% for the linear range of glucose concentration within 0.1–10 mM and 50–500 mM, respectively. The PL enhancement was highly selective towards glucose in mixture of other form of sugars making it suitable for determining glucose in food samples. © 2019Item Enhancing glucose detection: Vanadium-doped TiO2 (V0.07Ti0.93O2) as non-enzymatic biosensor(Springer, 2024) Rao, L.; Badekai Ramachandra, B.R.Humans need glucose as a source of energy, but abnormal glucose levels can have a negative influence on health. Elevated blood glucose levels are a common symptom of conditions like diabetes, which can cause problems with the kidneys, nerves, and cardiovascular system. For precise glucose monitoring and control, reliable glucose biosensors are essential. In a recent study, we synthesized Vanadium-doped TiO2 (V0.07Ti0.93O2) using the solvothermal method. This material underwent thorough SEM and XRD investigations to characterize it before being coated over nickel foam (NF) to fabricate a non-enzymatic glucose biosensor. Notably, our research shows that this biosensor outperforms the Ag/AgCl electrode at 0.6 V with improved cyclic electrochemical stability and more effective glucose oxidation using the electrochemical workstation. The material has a sensitivity of 1482.8 μA.mM−1 cm−2 and has a broad linear range spanning 0.2 mM to 2 mM. The biosensor has extraordinary sensitivity, providing accurate glucose detection even at lower concentrations, with a limit of detection (LOD) at 0.488 mM and a limit of quantification (LOQ) at 1.629 mM. These results highlight the biosensor’s potential for reliable and precise glucose sensing, a crucial benefit for continuous glucose monitoring, especially for individuals with diabetes. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.Item Elucidating mechanisms and DFT analysis of monometallic Vanadium incorporated nanoporous TiO2 as advanced material for enzyme-free electrochemical blood glucose biosensors with exceptional performance tailored for point-of-care applications(Elsevier Inc., 2024) Rao, L.; Rodney, J.D.; Naik, S.; Udayakumar, U.; Udayashankar, N.K.; Kim, B.C.; Badekai Ramachandra, B.R.Diabetes is a chronic condition that can last a lifetime and has claimed a great number of lives in recent years. This motivated scientists to design a glucose biosensor to monitor and control blood glucose levels in diabetic patients. Herein, hydrothermal derived Vanadium (V), Nickel (Ni), and Cobalt (Co)-doped TiO2 (MxTi1-xO2 (x = 0.01, 0.02, and 0.03)) was synthesized to achieve the best material to answer the pertaining problem. Of all the materials synthesized, V0.03Ti0.97O2@NF demonstrated the highest level of sensitivity, and selectivity, and has higher electrochemical cycling stability in 0.1 M KOH. It exhibits a very high sensitivity of 1129.31 μAmM-1cm-2 and Limits of Detection (LOD) and Limits of Quantification (LOQ) of 1.8 μM (S/N = 3) and 6.2 μM, respectively, with a broad linear range from 20 μM to 2 mM. The DFT approach was employed computationally to analyze the adsorption of glucose on surfaces of pure TiO2 and TiO2 doped with V, Ni, and Co respectively. The research findings highlight that when it comes to its interaction with glucose, pure TiO2 exhibits significantly less reactivity compared to transition metal-doped TiO2. Experimentally it shows that the V0.03Ti0.97O2@NF surface has the most sensitive glucose detection capability and it also exhibited significant selectivity towards glucose in the presence of additional interference. It demonstrated 100% retention after cycling stability and had a shelf life of ≃30 days. The V0.03Ti0.97O2@NF-based sensor exhibits accurate glucose sensing, even for human serum samples. © 2024 Elsevier B.V.