Browsing by Author "Diksha Singh"

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Biogenic synthesis of CuO/ZnO nanocomposite from Bauhinia variegate flower extract for highly sensitive electrochemical detection of vitamin B2
(Elsevier Ltd, 2024) Diksha Singh; Rahul Verma; Kshitij RB Singh; Manish Srivastava; Ravindra Pratap Singh; Jay Singh
In this study, we report the preparation of bio-inspired binary CuO/ZnO nanocomposite (bb-CuO/ZnO nanocomposite) via the biological route using Bauhinia variegata flower extract following hydrothermal treatment. The prepared bb-CuO/ZnO nanocomposite was electrophoretically deposited (EPD) on indium tin oxide (ITO) substrate to develop bb-CuO/ZnO/ITO biosensing electrode which is employed for the determination of vitamin B2 (Riboflavin) through electrochemical techniques. Physicochemical assets of the prepared bb-CuO/ZnO nanocomposite have been extensively evaluated and make use of different characterization techniques including powder XRD, FT-IR, AFM, SEM, TEM, EDX, XPS, Raman, and TGA. Electrochemical characteristics of the bb-CuO/ZnO/ITO biosensing electrode have been studied towards vitamin B2 determination. Furthermore, different biosensing parameters such as response time, reusability, stability, interference, and real sample analysis were also estimated. From the linear plot of scan rate, charge transfer rate constant (Ks), surface concentration of electrode (γ), and diffusion coefficient (D) have been calculated, and these are found to be 6.56 × 10−1 s−1, 1.21 × 10−7 mol cm−2, and 6.99 × 10−3 cm2 s−1, respectively. This biosensor exhibits the linear range of vitamin B2 detection from 1 to 40 μM, including sensitivity and limit of detection (LOD) of 1.37 × 10−3 mA/μM cm2 and 0.254 μM, respectively. For higher concentration range detection linearity is 50–100 μM, with sensitivity and the LOD of 1.26 × 10−3 mA/μM cm2 and 0.145 μM, respectively. The results indicate that the bio-inspired nanomaterials are promising sustainable biosensing platforms for various food and health-based biosensing devices. © 2024 Elsevier B.V.
Cadmium selenide quantum dots and its biomedical applications
(Elsevier B.V., 2023) Diksha Singh; Sushma Thapa; Kshitij RB Singh; Ranjana Verma; Ravindra Pratap Singh; Jay Singh
The focus of the present review is to provide a detailed discussion about the outstanding properties, namely physical, optical (majorly quantum confinement phenomenon), and electrical of cadmium selenide quantum dots (CdSe QDs). CdSe QDs have extensive utility in the biomedical domain owing to their unique properties. Thus, this review illustrates the wide range of applications of CdSe QDs in optical features, such as targeted drug delivery, drug resistance, drug analysis, photo-thermal therapy, antimicrobial activity, and tissue staining. Moreover, this review also highlights by discussing about the optical and optoelectronic application, which includes a good display, lasing, light emitting diode, and bioimaging that requires elevated photoluminescence spectra, quantum yield, and photostability. © 2023 The Author(s)
Chitosan-assisted self-assembly of flower-shaped ε-Fe2O3 nanoparticles on screen-printed carbon electrode for Impedimetric detection of Cd2+, Pb2+, and Hg2+ heavy metal ions in various water samples
(Elsevier B.V., 2024) Diksha Singh; Sarita Shaktawat; Surendra K. Yadav; Ranjana Verma; Kshitij RB Singh; Jay Singh
This study focuses on the fabrication of a novel sensing platform on a screen-printed carbon electrode, modified by a combination of hydrothermally synthesized iron dioxide (ε-Fe2O3) nanoparticles and Chitosan (CS) biopolymer. This unique organic-inorganic hybrid material was developed for Electrochemical Impedance Spectroscopy (EIS) sensing, specifically targeting heavy metal ions that include Hg2+, Cd2+, as well as Pb2+. The investigation encompassed a comprehensive analysis of various aspects of the prepared Fe2O3 and CS/ε-Fe2O3 nanocomposites, including phase identification, determination of crystallite size, assessment of surface morphology, etc. CS/ε-Fe2O3 was drop-casted and deposited on the Screen-Printed Electrode (SPE). The resulting sensor exhibited excellent performance in the precise and selective quantification of Hg2+, Cd2+, and Pb2+ ions, with minimal interference from other substances. The fabricated sensor exhibits excellent performance as the detection range for Hg2+, Cd2+, and Pb2+ ions linearity is 2–20 μM, sensitivity, and LOD are 243 Ω/ μM cm2 and 0.191 μM, 191 Ω/μM cm2, and 0.167 μM, 879 Ω/ μM cm2, and 0.177 μM respectively. The stability of the CS/ε-Fe2O3/SPE electrode is demonstrated by checking its conductivity for up to 60 days for Hg2+, Cd2+, and Pb2+ ions. The reusability of the fabricated electrode is 14 scans, 13 scans, and 12 scans for Hg2+, Cd2+, and Pb2+ ions respectively. The findings indicate the successful development of an innovative CS/ε-Fe2O3 electrode for the EIS sensing platform. This platform demonstrates notable potential for addressing the critical need for efficient and sensitive EIS sensors capable of detecting a range of hazardous heavy metal ions, including Hg2+, Cd2+, and Pb2+. © 2024 Elsevier B.V.
Effects of Indo-Mediterranean style diet and low fat diet on incidence of diabetes in acute coronary syndromes
(Nova Science Publishers, Inc., 2017) R.B. Singh; Banshi Saboo; Anuj Mahashwari; Kshitij Bharatdwaj; Narsingh Verma; Krasimira Hristova; S. Ghosh; M.A. Niaz; Jaipaul Singh; Ernest A. Adeghate; K.A. Bidasee; Mukta Singh; Anubha Mishra; Surbhi Tripathi; Diksha Singh; Smita Pandey; Swarnika Srivastava; Poonam Jaglan
Introduction: Obesity and diabetes are known to increase the risk of mortality due to acute coronary syndromes (ACSs). Effect of ACSs on risk of diabetes is unknown. This study examined the effect of the Mediterranean-style diet compared to a low-fat diet on incidence of obesity, diabetes and prediabetes in patients with ACSs. Subjects and Methods: A randomized, single-blind, controlled trial was carried out on 406 patients with ACSs diagnosed by WHO criteria. The intervention group received a low-energy Indo-Mediterranean diet and the control group received a fat-modified diet, according to the NCEP Step 1 diet. The main outcome measures were compliance with diets and weight loss at one year and frequency of obesity and diabetes and all-cause mortality after two years. Results: The intervention group received significantly greater amounts of Mediterranean-style foods and lower amounts of Western foods compared to the control group at one year of follow-up. The frequency of obesity and known diabetes, as well as prediabetes, was comparable in the two groups at the inception of the study. However, after 2 years, the incidence of obesity, known diabetes, as well as prediabetes (n = 55, 26.9%. vs. 11, 5.4%, P < 0.001) was significantly lower in the intervention group, compared to the reference. In contrast, the incidence of prediabetes was significantly increased in the control group compared to reference (n = 50, 20.2, vs. 58, 28.7%, P < 0.01). The incidence of prediabetes after 2 years was significantly higher in the control group compared to the intervention group (28.7% vs. 5.4%, P < 0.001). These findings were associated with a significantly greater adherence score for the Indo-Mediterranean diet in the intervention group compared to that for the diet of the control group. A greater weight loss of >0.5 kg was associated with significantly (p < 0.001) fewer cardiovascular events and less mortality, more so in the intervention group than in the control group. The total mortality was 14.7% in the intervention group and 25.2% in the control group (p < 0.01) after two years. Conclusions: The Indo-Mediterranean-style diet is effective in decreasing the incidence of known diabetes and prediabetes. However, in the control group, there is no decline in known diabetes but a significant increase in the incidence of prediabetes, compared to the reference indicating that ACSs may have predisposed subjects to prediabetes without any beneficial effect of the low-fat control diet. © 2017 Nova Science Publishers, Inc.
Fabrication of a mesoporous CoFe2O4/rGO nanohybrid and laccase interface biosensor for rapid detection of adrenaline for neurodegenerative disease diagnosis
(Royal Society of Chemistry, 2025) Rahul Verma; Surendra K. Yadav; Diksha Singh; Jay Singh
A hydrothermally synthesized mesoporous CoFe2O4 (CF)/reduced graphene oxide (rGO) nanohybrid (nh) provides the electroactive surfaces and facilitates fast electron transfer between the nanofabricated bioelectrode-electrolyte interfaces, responsible for the high electrocatalytic activity in sensing adrenaline (AD). A promising biosensor for detecting adrenaline and bovine serum albumin (BSA) used as a real sample for diagnosing neurodegenerative diseases is described here. This study focuses on the electrochemical impedance biosensing of AD because of its unique ability to identify various kinds of health issues, including blood pressure, fight-or-flight response, memory loss, multiple sclerosis, Parkinson's disease, and cardiac asthma. A La/CF/rGO/ITO bioelectrode (La: Laccase) is the biosensor component. It is created by electrophoretic deposition (EPD) of a CF/rGO nh and drop-casting immobilization of the La-enzyme. The low charge-transfer resistance (Rct) of the CF/rGO electrode was sensed by electrochemical impedance spectroscopy (EIS), confirming the synergistic impact of CF/rGO on the La/CF/rGO/ITO fabricated bioelectrode in AD detection. This gives the high heterogeneous rate constant (Ks: 2.83 × 10−4) and increases the surface adsorption and diffusion coefficient (D: 5.25 × 10−2 cm2 s−1). The proposed biosensor exhibited high sensitivity (0.214 Ω μM−1 cm−2), long linear range (1 to 500 μM), lower detection limit (LoD: 40.3 μM), high selectivity (RSD 5.8%), and stability with good recovery %, emphasizing its potential implementation in biosensing techniques for monitoring neurotransmitter disorders in real world applications. © 2025 RSC.
Green Synthesis of Carbon Quantum Dots Through Various Strategies
(Springer Science and Business Media Deutschland GmbH, 2024) Sarita Shaktawat; Surendra K. Yadav; Diksha Singh; Jay Singh
Carbon quantum dots (CQDs) are nano-sized particles made of carbon with distinct optical, electronic, and chemical features. These particles can be produced using a range of environmentally friendly techniques, including the hydrothermal process, microwave-assistance, electrochemical methods, laser ablation, and the use of green precursors, solar energy, plant-based extracts, biomass, eco-friendly ligands, and solvents. These sustainable approaches minimize environmental harm while often resulting in CQDs with superior qualities for a wide range of uses. Their unique properties make them highly valuable in diverse sectors, including biomedical imaging, drug delivery systems, sensing technologies, photocatalytic processes, light-emitting devices, energy storage solutions, solar energy conversion, catalysis, optical labelling, and environmental surveillance. Ongoing research efforts are dedicated to finding more eco-conscious ways to manufacture CQDs. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.
Heterostructures Based on 2D Nanomaterials for Biosensing and Imaging Applications
(wiley, 2025) Diksha Singh; Sarita Shaktawat; Ranjana Verma; Kshitij RB Singh; Jay Singh
Here in this study, the center of attention is specified to provide a detailed discussion about the excellent features of heterostructure-based two-dimension (2D) nanomaterials. Heterostructures based on 2D nanomaterials, and their nanocomposite displayed remarkable optical, physical, chemical, and electronic properties and these properties are utilized in encouragement of their wide-spread employment in antibacterial activity, bioimaging, catalysis, drug delivery, chemical & biosensing practices, and therapy. Innumerable 2D layered Black phosphorene and other nanomaterials likewise graphene and its derivatives, tungsten disulfide (WS2), molybdenum disulfide (MoS2), tungsten di-selenide (WSe2), and molybdenum di selenide (MoSe2), designed for the performance of the fiber optic biosensor-based improved surface plasmon resonance (SPR) study also discussed. The fast electron transfer ability of electrochemically reduced MoS2 nanosheets is responsible for its good conductivity, which can be employed for the facile detection of several biological analytes that includes detection of ascorbic acid, dopamine, glucose as well as uric acid. Here we briefly discuss the latest approach for the utilization of 2D based heterostructure nanomaterials and its derivatives for an emerging biosensor that consists of surface-enhanced Raman scattering (SERS) biosensors, surface plasmon resonance (SPR) biosensors, electrochemical biosensors and offered new possibilities intended towards the exploration of sensors and imaging application. © 2025 Scrivener Publishing LLC.
Nanoengineered Mn3O4/rGO electrophotocatalyst with dual functionality for detection of 2,4,6-trichlorophenol and degradation of methylene blue dye in environmental monitoring and cleanup
(Royal Society of Chemistry, 2025) Diksha Singh; Anshu Kumar Singh; Ranjana Verma; Jay Singh
Here, we report the hydrothermal synthesis of Mn3O4 nanomaterial and Mn3O4/rGO nanocomposite (rGO, reduced graphene oxide). The prepared nanocomposite (NC) was electrophoretically deposited (EPD) on indium tin oxide (ITO) to fabricate the Mn3O4/rGO/ITO electrode, which is further utilized for the electrochemical estimation of 2,4,6-trichlorophenol (2,4,6-TCP). The charge transfer rate constant, diffusion coefficient (D), and surface concentration values evaluated for the Mn3O4/rGO/ITO electrode are 0.53 s−1, 0.86 × 10−6 mol cm−2, and 0.358 cm2 s−1, respectively. The electrochemical sensor displays a linear extent of 2,4,6-TCP detection from 1 to 500 μM with a limit of detection (LoD) of 0.038 μM and sensitivity of 2.17 Ω μM−1 cm−2. Here, we demonstrate the 2,4,6-TCP detection via electrochemical impedance spectroscopy (EIS) sensing and photocatalytic degradation, as well as the kinetics of methylene blue (MB) dye, analyzed in parallel with bare Mn3O4 under UV light irradiation. The results indicate that Mn3O4/rGO NCs have preferred MB photodegradation efficacy with a reaction rate constant and low degradation time compared to bare Mn3O4 nanomaterials (NMs). The rate constants for the Mn3O4 and Mn3O4/rGO NCs were found to be 0.00075 and 0.0197, respectively, and the MB dye degradation reached up to 6% with the Mn3O4 catalyst and up to 80% with the Mn3O4/rGO catalyst when exposed to UV light for 80 minutes. This journal is © The Royal Society of Chemistry, 2025
Nanostructured WS2@Chitosan-Modified Screen-Printed Carbon Electrodes for Efficient Amperometric Detection of Histamine
(American Chemical Society, 2025) Diksha Singh; Ankur Srivastava; Vivek K. Chaturvedi; Jay Singh
Histamine, a pivotal chemical within certain cells of the human body, is responsible for eliciting various allergic symptoms, such as sneezing and a runny nose. In cases of allergies, where the immune system misidentifies typically harmless substances, such as certain foods or dust, as harmful, an efficient histamine sensor becomes imperative. This research introduces a novel sensing platform by employing a material comprising hydrothermally synthesized WS2 nanosheets and using this with a chitosan (CS) biopolymer on a screen-printed carbon electrode (SPE). Integrating WS2 and CS components on the SPE via drop-casting synergistically enhances conductivity and various sensor properties. This novel hybrid material combines organic CS and inorganic WS2 components applied for nonenzymatic histamine detection via differential pulse voltammetry. This study also included crystallite size determination and surface morphology assessment through characterization of the synthesized WS2 nanosheets. On the surface of the SPE, WS2 and CS were drop-casted. It is recommended that histamine be electrochemically measured on modified WS2/CS/SPE electrodes. Histamine measurements were conducted within a linear coverage of 1-100 μM, with a limit of detection of 0.0844 μM and sensitivity of 1.44 × 10-4 mA/μM cm2. The developed sensor exhibited notable levels of sensitivity, selectivity, stability, and repeatability, along with an extended linear range. The sensing technique was consequently employed to detect the histamine levels in packed food items like fermented food samples (cheese, tomato sauce, tomato ketchup, and soy sauce) at room temperature (25 °C). The findings recommend the utilization of electrochemical sensing on modified WS2/CS/SPE electrodes for accurate histamine detection. © 2025 The Authors. Published by American Chemical Society.
Potentialities of Starch-Based Sensors and Biosensors for Biomedical Applications: A Comprehensive Review
(Association of Carbohydrate Chemists and Technologists, 2024) Sarita Shaktawat; Diksha Singh; Jay Singh
Recent years have witnessed significant developments in a variety of medical and clinical applications, with researchers continually searching for novel techniques for improving patient care and diagnostics. The creation of starch-based sensors and biosensors is one such subject that has attracted plenty of attention. The polysaccharide starch, which is widely and readily available and biocompatible, has an assortment of beneficial characteristics for sensor applications. Its abundance, low cost, and lack of toxicity make it an attractive option to use in sensors and biosensors-related applications. Furthermore, starch can be easily modified, which makes it feasible to include various groups of functions, to improve its sensing properties. Biosensors and sensors based on starch have shown possibilities in an array of medicinal applications. They have been used for monitoring disease biomarkers, detect pathogens and toxins in clinical samples, and monitor glucose levels in diabetic patients. Owing to its flexibility, starch-based sensors may be employed in point-of-care systems, implanted sensors, and wearable devices. The aim of this comprehensive overview is to investigate the possibilities of starch-based sensors and biosensors for use in clinical and healthcare settings. It provides an overview of materials made of starch, how their properties can be modified, and the principles behind sensor design. In addition, it discusses about this field's recent advances, challenges, and opportunities for the future. This research shall encourage further study into starch-based sensors and biosensors, opening the road for their conversion into usable medical devices and thus improving healthcare outcomes. © (2024), (Association of Carbohydrate Chemists and Technologists). All Rights Reserved.
Various Properties of Green Synthesized Carbon Quantum Dots
(Springer Science and Business Media Deutschland GmbH, 2024) Diksha Singh; Sarita Shaktawat; Ranjana Verma; Jay Singh
Due to their unique features and environmentally benign manufacturing methods, carbon quantum dots (CQDs) produced in this way have focused a lot of interest. The many characteristics of CQDs made using green synthesis methods, such as using natural carbon sources, biocompatible precursors, and sustainable processes, are outlined in this chapter. Green-synthesized carbon quantum dots (G-CQDs) optical characteristics display exceptional photoluminescence with controllable emission wavelength. Due to these characteristics, they are appropriate for assistance in bioimaging as well as in light-emitting diodes, together with other optoelectronic applications. G-CQDs created utilizing environmentally friendly methods frequently exhibit great biocompatibility, making them appropriate for biomedical applications such as drug delivery, imaging, as well as therapy. Green synthesis techniques enable precise control of CQD size and morphology, affecting their characteristics and functionality in a variation of function. The remarkable electrical conductivity of G-CQDs makes it possible to use them as electrocatalysts, supercapacitors, and sensors. The higher photostability of CQDs produced in an environmentally responsible way is well recognized and increases their potential for long-term applications. In keeping with the objectives of sustainable development, the green synthesis of CQDs minimizes the environmental impact by using less energy and hazardous waste. For their continuous advancement and incorporation into environmentally friendly technology, green-synthesized CQDs (G-CQDs) must be fully understood and utilized. This opens a promising path for sustainable nanomaterials with a wide range of uses. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.