Browsing by Author "Gargi Mishra"

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A highly efficient nanostructured Au@La2O3 based platform for dopamine detection
(Elsevier B.V., 2022) Ankur Srivastava; Gargi Mishra; Jay Singh; Mrituanjay D. Pandey
In the present work, nanostructured La2O3 and Au doped La2O3 nanocomposites were prepared hydrothermally that were further deposited electrophoretically onto the indium-tin-oxide (ITO) glass surface. The tyrosinase enzyme (Tyr) have been immobilized on the AuNPs modified La2O3/ITO electrode. The fabricated electrode Tyr/Au-La2O3/ITO was utilized for the determination of dopamine. The structural and morphological characterization were done by X-ray diffraction (XRD), Fourier transform infrared (FTIR), Atomic force microscopy (AFM), Transmission electron microscopy (TEM & HR-TEM) and Energy dispersive X-ray analysis (EDX). The results of electrochemical response studies of fabricated electrode Tyr/Au-La2O3/ITO exhibit a linear range of 2–100 µm, sensitivity 2.4806 × 10−7 A/μM and limit of detection of 0.258 μM with response time 30 s and good reproducibility. The fabricated electrode might provide an efficient biointerface for the application of the rare earth metal oxide nanomaterials in biosensors and bioelectronics. © 2021 Elsevier B.V.
A luminescent pyrene-valine conjugates for the detection of copper (II) ions in aqueous media
(Elsevier B.V., 2023) Kamlesh Kumar Nigam; Arpna Tamrakar; Gargi Mishra; Mrituanjay D. Pandey
A novel pyrene-based fluorescent chemosensor (pyren-1-ylmethyl)-L-valine (1) has been synthesized. 1 is a highly selective chemosensor for detecting Cu(II) ions through fluorescence quenching over other competitive metal ions and showing aqueous-organic solvent-based gelation properties. Rod-shaped surface morphology may be attributed to intermolecular Hydrogen bonding between the carboxylic acid group and π-π stacking of pyrene moiety. In addition, 1 can also be utilized for the practical detection of Cu2+ion in natural water samples. © 2023 The Authors
Advancements in the Design and Development of Organic Fluorophores for the Excited State Intramolecular Proton Transfer Phenomenon
(John Wiley and Sons Inc, 2025) Gargi Mishra; Durgesh Singh; Surabhi Asthana; Himanshu Shekhar Tripathi; Rampal Pandey; Mrituanjay D. Pandey
Excited state intramolecular proton transfer (ESIPT) is a process where photoexcited molecules dissipate energy by transferring protons and undergoing tautomerization. With a brief introduction of a new emerging sensing mechanism, viz., C.N isomerization, AIE, etc., this study explores the various aspects of ESIPT based on the current studies. Since Weller discovered ESIPT in salicylic acid and methyl salicylate, extensive research has developed on this topic, attributing to its wide applications. Here, it explores the structural and mechanical aspects of ESIPT and tautomerization. © 2025 The Chemical Society of Japan and Wiley-VCH GmbH.
Advancements in the development of fluorescent chemosensors based on C=N bond isomerization/modulation mechanistic approaches
(Royal Society of Chemistry, 2024) Arpna Tamrakar; Manzoor Ahmad Wani; Gargi Mishra; Ankur Srivastava; Rampal Pandey; Mrituanjay D. Pandey
The C N bond isomerization/modulation as a fluorescence signalling mechanism was explored by studying the photophysical properties of conformationally restricted molecules. From the beginning, the C N bond isomerization method has attracted the attention of researchers owing to its simplicity, high selectivity, and sensitivity in fluorescence evaluation. Continuous developments in the field of sensing using C N bond-containing compounds have been achieved via the customization of the isomerization process around the C N bond in numerous ways, and the results were obtained in the form of specific discrete photophysical changes. C N isomerization causes significant fluorescence enhancement in response to detected metal cations and other reactive species (Cys, Hys, ClO−, etc.) straightforwardly and effectively. This review sheds light on the process of C N bond isomerization/modulation as a signalling mechanism depending on fluorescence changes via conformational restriction. In addition, C N bond isomerization-based fluorescent sensors have yet to be well reviewed, although several fluorescent sensors based on this signalling mechanism have been reported. Therefore, C N-based fluorescent sensors are summarized in this review. © 2024 The Royal Society of Chemistry.
Electronic metal-organic framework sensors
(wiley, 2023) Ankur Srivastava; Rahul Verma; Gargi Mishra; Jay Singh; Mrituanjay D. Pandey
Metal-organic frameworks (MOFs) are well-ordered and managed inorganic and organic molecules or complexes with large surface area and also the porosity. The size and shape is tunnel-like, having host-guest relations causes both physical and chemical sensitivity, such as temperature, pressure, pH, and light. These are active materials in device manufacturing, such as radiation detectors, chemical sensors, photodetectors, and various more. Electronic area and sensor devices are the new generations' research challenges. The hybrid creations in MOFs are also a new working field these days. In the present book chapter, we sum up the basic principle, and current literature on MOFs-based electronic sensors, such as optical, chemiresistive, and electromechanical sensors in terms of work function of MOFs, futures challenges, as well as prospects outlook. © 2024 WILEY-VCH GmbH. Published 2024 by WILEY-VCH GmbH. All rights reserved.
l-Valine Assisted Pyrene Functionalized Gold Nanoparticles Based Interface for Electrochemical Detection of Chloramphenicol Antibiotics
(John Wiley and Sons Inc, 2025) Gargi Mishra; Ankur Srivastava; Roshani Singh; Mrituanjay D. Pandey; Jay Singh
In this study, we have prepared a novel V-Py-functionalized AuNP/ITO electrode platform with excellent selectivity and reproducibility for CAP, even in the presence of a mixture of antibiotics. Here, gold nanoparticles were functionalized by a novel pyrene conjugated valine analogue(V-Py). These V-Py/AuNPs were successfully characterized by standard structural and morphological techniques such as powder XRD, Fourier transform infrared spectroscopy (FT-IR), UV–visible, and fluorescence spectroscopy, and transmission electron microscopy (TEM) techniques. The prepared V-Py/AuNPs were electrophoretically deposited on an indium tin oxide (ITO) glass plate using the electrophoretic deposition (EPD) technique. The electrochemical properties of prepared V-py/AuNPs/ITO were examined by the cyclic voltammetry (C/I/TOV) technique. Electrochemical response studies using the V-Py/AuNPs/ITO electrode for CAP estimation shared a linear progression in the concentration range of 1–150 µM. The limit of detection (LOD) and sensitivity of the electrode were found to be 3.79 × 10−2 µM and 5.08 × 10−3 mA/µM × cm2, respectively, with a response time of 15 s. This study presents a novel V-Py-functionalized AuNP platform with tremendous reusability and selectivity toward CAP, even in the presence of a mixture of antibiotics, which are the key highlights of this work. © 2025 Wiley-VCH GmbH.
Pyrene Appendant Triazole-based Chemosensors for Sensing Applications
(Bentham Science Publishers, 2024) Tarkeshwar Maddeshiya; Manoj K. Jaiswal; Arpna Tamrakar; Gargi Mishra; Chhama Awasthi; Mrituanjay D. Pandey
Over the last two decades, the design and development of fluorescent chemosensors for the targeted detection of Heavy Transition-metal (HTM) ions, anions, and biological ana-lytes, have drawn much interest. Since the introduction of click chemistry in 2001, triazole moieties have become an increasingly prominent theme in chemosensors. Triazoles generated via click reactions are crucial for sensing various ions and biological analytes. Recently, the number of studies in the field of pyrene appendant triazole moieties has risen dramatically, with more sophisticated and reliable triazole-containing chemosensors for various analytes of interest de-scribed. This tutorial review provides a general overview of pyrene appendant-triazole-based chemosensors that can detect a variety of metal cations, anions, and neutral analytes by using modular click-derived triazoles. © 2024 Bentham Science Publishers.
Pyrene-Appended Luminescent Probes for Selective Detection of Toxic Heavy Metals and Live Cell Applications
(John Wiley and Sons Inc, 2024) Ankur Srivastava; Gargi Mishra; Amit Kumar Pathak; Saurabh Pandey; Chhama Awasthi; Mrituanjay D. Pandey; Kamalakanta Behera
Heavy metal contamination has become a global environmental problem and currently drawn much attention from researchers in worldwide. High exposure to heavy metals can lead to problems like kidney, liver and brain damage, skin and lung cancer, etc. Rapid and sensitive detection of heavy metals is of immense importance in environmental monitoring. Over the past few decades, enormous efforts have been made to design various sensors to identify and monitor these harmful metal ions. In Comparison with other methods, fluorescence-based chemosensors have received extensive attention because of the advantages of high sensitivity, low cost, real-time monitoring, simple operation, etc. The pyrene derivatives are significant polycyclic aromatic hydrocarbons (PAHs) with strong fluorescence. They are widely used as fluorescent probes in many applications due to their easy modification, high fluorescence quantum yield, and strong fluorescence emission in live cells, outstanding cell permeability, and very low cytotoxicity. The SDG 6: Clean water and sanitation alarm a strong strategy, and careful identification of the risk connected to environmental pollutants needs urgent attention in this situation. Therefore, we highlight different types of pyrene-based fluorophores and the fluorescence mechanisms for the sensitive and selective detection methodology of Arsenic, Mercury, Cadmium, Lead, and Chromium heavy metals. © 2024 Wiley-VCH GmbH.
Synthesis, characterization, and electrocatalytic behaviour of hydrothermally grown nanostructured La2O3 and La2O3/K-complex
(John Wiley and Sons Ltd, 2023) Ankur Srivastava; Gargi Mishra; Kshitij RB Singh; Jay Singh; Rampal Pandey; Mrituanjay D. Pandey
Rare earth metals play a conspicuous role in magnetic resonance imaging (MRI) for detecting cancerous cells. The alkali metal potassium is a neurotransmitter in the sodium–potassium pump in biomedical sciences. This unique property of rare earth metals and potassium drew our attention to carry forward this study. Therefore, in this work, previously synthesized potassium (K) complexes formed by the reflux of 4-N,N-dimethylaminobenzoic acid (DBA) and potassium hydroxide in methanol, and named [(μ2–4-N,N-dimethylaminobenzoate-κO)(μ2–4-N,N-dimethylaminobenzoic acid-κO)(4-N,N-dimethylaminobenzoic acid-κO) potassium(I) coordination polymer)] were treated hydrothermally with La2O3 nanomaterials to obtain a nanohybrid La2O3/K-complex. After that, the K-complex was analyzed using single-crystal X-ray diffraction and 1H and 13C NMR spectroscopy. In addition, the structural and morphological properties of the as-prepared nanostructured La2O3/K-complex were also characterized, which involved an investigation using X-ray diffraction (XRD)spectroscopy, Fourier transform infrared (FTIR) spectroscopy, atomic force spectroscopy (AFM), transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) analysis. After this, the electrochemical redox behaviour of the synthesized nanohybrid material was studied using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Therefore, the results from these studies revealed that the as-prepared material was a La2O3/K-complex that has a promising future role in sensing various analytes, as it showed effective electrocatalytic behaviour. © 2022 John Wiley & Sons Ltd.