Browsing by Author "Abhishek Rai"

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A benzimidazolyl terpyridine-Fe 2+ system and its recognition driven molecular model of a traffic light
(Royal Society of Chemistry, 2019) Avinash Kumar Sonkar; Abhishek Rai; Kamini Tripathi; Pooja Sharma; H.W. Roesky; Michael G. B. Drew; Lallan Mishra
A new benzimidazolyl terpyridyl ligand (BIT) selectively detects Fe 2+ , F − and CN − ions in acetonitrile. The Fe 2+ complex [Fe(H-BIT) 2 ]·(ClO 4 ) 4 (1) displays the fast and selective detection of 2,4,6-trinitrophenol (TNP) with strong binding (log β = 8.51 ± 0.24) and a low limit of detection (1.4 × 10 −7 M) among several nitroaromatics. The color of complex 1 changes from purple to red, yellow, and green upon the separate addition of 2,4,6-trinitrophenol and tetrabutylammonium salts of fluoride and cyanide, respectively. The overall color changes thus display a model of a traffic light. The structures of BIT, 1 and [Fe(BIT) 2 ]·(TNP) 2 (2) have been well characterized using spectroscopic techniques and single crystal X-ray crystallography. © The Royal Society of Chemistry.
A dual optical probe with larger stokes shift for simultaneous detection of Cu2+ and Zn2+ ions and aggregation induced enhanced emission empowering selective detection of Cu2+ ions
(Elsevier B.V., 2021) Avinash Kumar Sonkar; Abhishek Rai; Kamini Tripathi; Richa Yadav; Manjari Shukla; Brijesh Singh Chauhan; S. Srikrishna; Lallan Mishra
A new aggregation induced enhanced emission (AIEE) active probe (1) has been synthesized via single step condensation reaction of 2-amino-3-benzyloxypyridine with 3-allylsalicylaldehyde in methanol. Probe 1 has been fully characterized by various spectroscopic techniques i.e. IR, NMR (1H and 13C), HRMS and X-ray crystallography. 1 displays a large stokes shift of 190 nm. It recognizes Cu2+ ions colorimetrically and fluorescence intensity enhances on the addition of Zn2+ ions. 1 form nanoaggregates in H2O:CH3OH (80:20, v/v) which detects Cu2+ ions selectively. 1 in the presence of Zn2+ ions and its nanoaggregates n1 show switch on behaviour of green fluorescence comparable to mitochondrial membrane potential indicator, Mitotracker-Red, in larval gut tissues of Drosophila melanogaster. © 2020 Elsevier B.V.
A nanocomposite of ferrocenoyl glutaric acid hydrazone and multiwalled carbon nanotubes as a sensor for azide ions
(Royal Society of Chemistry, 2016) Ida Tiwari; Mandakini Gupta; Abhishek Rai; Lallan Mishra
A nanocomposite containing ferrocenoyl glutaric acid hydrazone and multiwalled carbon nanotubes (MWCNTs) has been synthesized and characterized for its structural, morphological and electrochemical properties. Characterization has been done using scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), infrared (IR), X-ray photoelectron spectroscopy (XPS), and UV-visible studies. The electrochemical behavior and stability of the modified electrode have been investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). A self-standing film of this electroactive and homogeneous composite has been obtained by solution casting method. It is observed that the ferrocenoyl glutaric acid hydrazone (L)/MWCNTs/Nafion composite has better electrochemistry, electrical properties and firm adhesion of the material at the electrode surface. The modified electrode showed an electro-catalytic response to the oxidation of azide ions at the potential of 0.30 V in 0.1 M phosphate buffer solution (pH 7.1). The linear range and detection limit for the azide ion were found to be 0.02 mM to 20 mM and 0.312 μM, respectively. © The Royal Society of Chemistry 2016.
A new rhodamine derivative as a single optical probe for the recognition of Cu2+ and Zn2+ ions
(Royal Society of Chemistry, 2015) Abhishek Rai; Niraj Kumari; Rohini Nair; Kiran Singh; Lallan Mishra
A bifunctional colorimetric and fluorescent chemosensor of type 3,5-dinitro-2-hydroxy benzaldehyde rhodamine hydrazone (RHDN) was synthesized by the condensation of 3,5-dinitro salicylaldehyde and rhodamine B hydrazide. It was characterized using spectroscopic techniques and single crystal studies. The chemosensor RHDN exhibited remarkably enhanced absorbance and colour changes from colourless to pink color on binding with Cu2+ ions. In contrast, Zn2+ ions were identified by their selective binding with RHDN showing OFF-ON type fluorescence, which changes from colorless to orange color in ultra violet-light. The absorbance and emission pattern of RHDN adduct separately with Cu2+ and Zn2+ ions were restored with the addition of an aqueous solution of disodium salt of ethylenediaminetetraacetic acid. Thus, RHDN was found to be very robust and reversible in its binding with Cu2+ and Zn2+ ions separately. © The Royal Society of Chemistry 2015.
A Novel Rhodamine Probe Acting as Chemosensor for Selective Recognition of Cu2+ and Hg2+ Ions: An Experimental and First Principle Studies
(Springer, 2024) Pawan Kumar Sada; Amit Bar; Amanpreet Kaur Jassal; Prabhat Kumar; S. Srikrishna; Alok Kumar Singh; Sumit Kumar; Laxman Singh; Abhishek Rai
Copper and Mercury ions have vital role to play in biological world as their excess or deficiency can cause different type of diseases in human being as well as biological species including plants and animals. Therefore, their detection at trace level becomes very important in term of biological. The current studies embody the fabrication, structural characterization and recognition behavior of a novel rhodamine B hydrazone formed when hydrazide of rhodamine B was condensed with 5-Allyl-3-methoxy salicylaldehyde (RBMA). RBMA was found to be responsive towards the very trace level of Cu2+ and Hg2+ among other tested cations so far. The sensing procedure is based on the classical opening of the spiroatom ring of rhodamine. The limit of detection (LOD) and binding constant is 5.35 ppm, 2.06 × 104 M−1 and 5.16 ppm, 1.26 × 104 M−1 for Cu2+ and Hg2+ ions respectively. The probable mechanism correlates the specific binding of RBMA with Cu2+ and Hg2+ ions. The 1:1 stoichiometry of RBMA with Cu2+ and Hg2+ ions have been supported by HRMS, FT-IR data, Job's plot, and binding constant data. Reversibility is well exhibited by RBMA by the involvement of CO32− ions via demetallation process. The real time application is well demonstrated by the use of paper strip test. The DFT study also carried out which agrees well with the experimental findings. The results displayed the novelty of this current work towards the trace level analysis of the Cu2+ and Hg2+ of the cations which are play the crucial role in industry. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2023.
A quick and selective rhodamine based “smart probe” for “signal-on” optical detection of Cu2+ and Al3+ in water, cell imaging, computational studies and solid state analysis
(Elsevier B.V., 2018) Abhishek Rai; Alok Kumar Singh; Kamini Tripathi; Avinash Kumar Sonkar; Brijesh Singh Chauhan; S. Srikrishna; Tony D. James; Lallan Mishra
A novel rhodamine hydrazone 1 has been synthesized by the condensation of rhodamine B hydrazide with allylsalicylaldehyde and has been fully characterized using various physicochemical techniques including single crystal XRD. Probe 1 can detect Cu2+ and Al3+ ions in aqueous media and displays a turn-on response in absorbance with a high degree of selectivity amongst other common interfering analytes. Al3+ ions lead to fluorescence enhancementby the opening of the spirolactum ring resulting in chelation enhanced fluorescence. DFT and TDDFT calculations support the experimental results. The 1-Al3+ ensemble acts as secondary sensor for pyrophosphate anion due to metal ion induced decomplexation resulting in a low detection limit. Probe 1 can be utilized for bio imaging and displays morphological transformations from crystalline to amorphous state with associated color changes due to mechanical switching. In the solid state, probe 1 displays distinct color changes with emission at different wavelengths in particular Al3+ and Hg2+result in a red shift of the CIE-diagram. While the band gap of probe 1can be tuned from 2.08 eV to 1.60 eV Probe 1 meets many real-world-challenges in that it is prepared using simple synthetic methods, produces fast and distinct response towards multiple-ions, observed by the “naked eye” in solution and on a TLC plate, and can be exploited for binary data storage. © 2018 Elsevier B.V.
A quick look in the recognition and sensing of fluoride anion
(Scientific Publishers, 2014) Abhishek Rai; Niraj Kumari; Lallan Mishra
The fluorine element is the most electronegative and its anion has strong nucleophilic character and behaves as relatively strong Bronsted base. The properties make fluoride ion fond of hydrogen bond interactions. In this manuscript fluoride binding properties in structurally varied molecular structures are exploited. © 2014 Scientific Publishers. All Rights Reserved.
A smart switchable module for the detection of multiple ions: Via turn-on dual-optical readout and their cell imaging studies
(Royal Society of Chemistry, 2016) Abhishek Rai; Alok Kumar Singh; Avinash Kumar Sonkar; Anand Prakash; Jagat Kumar Roy; Rajamani Nagarajan; Lallan Mishra
A module switchable as a function of multi-stimuli response has been designed. The module displays sequential logic gate-based detection of multiple ions (Fe3+, Hg2+, CN- and S2-) at ppm levels via a "turn on" signature which potentially meets real-world-challenges through a simple synthetic route, a fast response, water based-activity, naked-eye visualization, regenerative-action, high selectivity and multiple readout for precise analysis. Living cell imaging of Fe3+ and Hg2+ has also been carried out in HeLa cell lines. © 2016 The Royal Society of Chemistry.
A stable and highly sensitive fluorescent probe for detection of hypochlorite ion in vitro and in living cells
(Chemical Society of Japan, 2019) Richa Yadav; Keiko Odera; Abhishek Rai; Akimi Noguchi; Ryoya Takahashi; Lallan Mishra
We designed and synthesized 2-[(2-amino-5-nitro-phenyl-amino)-methyl]-5-diethylamino-phenol (L1) as a stable and highly sensitive hypochlorite probe. L1 may be used in both colorimetric and fluorometric applications, as well as in paper-strip detection for selective hypochlorite ion sensing. In this study, we successfully applied L1 to the imaging of local hypochlorite generation in the endosomes, including phagosomes, of living cells. Thus, L1 is an appropriate probe for the detection and visualization of hypochlorite ions in vitro and in living cells. © 2019 The Chemical Society of Japan.
A viscochromic, mechanochromic, and unsymmetrical azine for selective detection of Al3+ and Cu2+ ions and its mitotracking studies
(Royal Society of Chemistry, 2019) Richa Yadav; Abhishek Rai; Avinash Kumar Sonkar; Vipin Rai; Subash Chandra Gupta; Lallan Mishra
A hydrazone obtained by the reaction of 2-hydroxynaphthaldehyde with hydrazine hydrate was allowed to react further with 4-diethylamino-2-hdroxybenzaldehyde to provide an unsymmetrical azine derivative (NDEA). The azine has been characterized using spectroscopic techniques and single crystal X-ray crystallography. It selectively detects Al3+ and Cu2+ ions in aqueous methanol (DMSO:H2O:MeOH = 0.1:1.9:8.0, v/v, HEPES buffer, pH 7.4) and exhibits naked eye visible color changes from greenish yellow to bright yellow and brown on the addition of Al3+ and Cu2+ ions, respectively, with concomitant changes in their absorption spectra. The corresponding solutions containing Al3+ and Cu2+ ions also display changes in their emission spectra via "TURN ON" and "TURN OFF" pathways with a detection limit of 1.65 × 10-7 M and 1.52 × 10-7 M, respectively. NDEA works as a reversible probe towards Al3+ ions and Cu2+ ions by the addition of F- ions and EDTA2- ions, respectively. The complexes of NDEA, separately with Al3+ and Cu2+ ions, have been optimized by DFT (density functional theory). It also exhibits viscochromic and mechanochromic properties. Most importantly, NDEA significantly detects these ions in rat C6 glioma cell lines and displays good cell permeability. It also co-localizes with the commercially available Mitotracker Red and exhibits a unique application as a live cell mitochondrial tracker. Practically, NDEA detects Al3+ and Cu2+ ions in real water samples and blood serum with a high accuracy. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
An ensemble of Zn 2+ with a rhodamine B-3-allylsalicylaldehyde hydrazone as novel photosensitive material: Photochromism, photopatterning, photoprinting and molecular logic gates
(Elsevier B.V., 2019) Abhishek Rai; Alok Kumar Singh; Avinash Kumar Sonkar; Kamini Tripathi; Lallan Mishra
An ensemble of Zn 2+ with Rhodamine B-3-allylsalicylaldehyde hydrazone (1-Zn 2+ ), has been synthesized and fully characterized using spectroscopic techniques. A solution of 1-Zn 2+ in THF, displays color changes from light yellow to pink color in the presence UV light (λ, 405 nm). The process is reversible and owes to keto-enol tautomerism which allows the opening of spirolactam ring of rhodamine in the presence of UV light. It is corroborated by the appearance of a new peak at λ max = 554 nm. The ensemble, 1-Zn 2+ embedded in the matrix of silica gel, displays photo patterning phenomena initiated by the conventional light sources including sunlight. It also displays photoprinting property with a laser pen (λ 405 nm) and has been displayed by a videography. The module 1-Zn 2+ meets real challenges through a simple synthetic route, fast response, and as a binary data storage system with non-destructive optical identity. © 2019 Elsevier B.V.
Contemporary progress on multifarious coordination polymers for organocatalytic, sensing, and energy-mimetic applications
(Elsevier Ltd, 2024) Shankab J. Phukan; Suraj Goswami; Neeraj K. Sah; Pranshu K. Gupta; Abhishek Rai; Tapas Ghatak; Chandni Pathak; Manas Roy; Ranjith Krishna Pai; Lallan Mishra; Somenath Garai
Coordination polymers and their subgroup metal–organic frameworks are renowned as the esteemed categories of materials with multifarious properties and possess extensive advantageous applications in the domain of sensing and energy-mimetic applications on account of their expanded surface area, higher charge transfer ability, tunable porous framework, and flexible functionality. This review ruminates on a comprehensive analysis of contemporary outcomes regarding optimized synthetic protocols and structural modulations for various classes of coordination polymers, highlighting their deliberate implications as photoluminescent sensor materials and as energy-mimetic and organoconversion catalysts, along with outlining the significant applicative shortcomings. The additional coordination polymer–assisted exclusive applications have also been discussed, such as the development of ratiometric fluorescent-based probes for specific biological sensing, metal–organic complexes for efficient energy catalysis, and incorporation of bio-inspired photoactive linkers for maximum light harvesting, where the premeditatedly executed frameworks demonstrated augmented results in specialized scientific fields. Finally, a brief overview has been addressed on the effectually applied strategies for assessing electronic mobility, product scalability, and light stability–derived challenges in practical implementations, alongside reviewing the green approaches that expedite sustainable and industrially scalable synthetic pathways consisting potentialities for large-scale outcomes. © 2024 Elsevier Ltd
Correction: Fluorescein hydrazone-based supramolecular architectures, molecular recognition, sequential logic operation and cell imaging (RSC Adv. (2017) 7 (2264-2272) DOI: 10.1039/C6RA26255D)
(Royal Society of Chemistry, 2017) Kamini Tripathi; Abhishek Rai; Amarish Kumar Yadav; Saripella Srikrishna; Niraj Kumari; Lallan Mishra
Correction for ‘Fluorescein hydrazone-based supramolecular architectures, molecular recognition, sequential logic operation and cell imaging’ by Kamini Tripathi et al., RSC Adv., 2017, 7, 2264-2272. © The Royal Society of Chemistry.
Development of a new rhodamine 6G based probe and its application as an optical sensor of Cu2+ and Fe3+ ions: A comprehensive experimental and Theoretical studies
(Elsevier Inc., 2024) Pawan Kumar Sada; Amanpreet Kaur Jassal; Amit Bar; Prabhat Kumar; S. Srikrishna; Sumit Kumar; Alok Kumar Singh; Youngil Lee; Laxman Singh; Abhishek Rai
A new rhodamine appended probe 3-allyl salicylaldehyde rhodamine hydrazone (RGAL) has been synthesized and thoroughly characterized using various spectroscopic techniques, as well as single crystal XRD. The optical properties of RGAL were investigated in 10 mM HEPES buffer in H2O:CH3CN (2:8, v/v, pH=7.2) in the presence of various cations. RGAL showed selectivity and sensitivity towards Cu2+ during absorption process and “turn on” behavior towards Fe3+ during emission study owing to the opening of a spirolactum ring. The detection limits for Cu2+ and Fe3+ ions using RGAL were determined to be 6.15 ppm and 4.75 ppm, respectively. The binding constant of RGAL with Cu2+ and Fe3+ ions was found to be 1.20 × 104 M−1 and 1.71 × 104 M−1, respectively. Hirshfeld surface and fingerprint analysis of RGAL provides the in-depth analysis of pairwise interaction between two atoms. Furthermore, the topological analysis of RGAL is performed using NCI, AIM, ELF and LOL analysis. The analysis provides information about O78-H79…N71 and C40-H41…O77 hydrogen bonding interactions in the monomer of RGAL whereas various inter- and intra- molecular interactions give strength to the dimer pattern of RGAL. © 2024 Elsevier B.V.
Exploring the recognition behavior of a fluorescein-based probe towards the significant detection of Cu2+ and Zn2+ ions: Experimental and computational studies
(Elsevier B.V., 2025) Navneet Kumar; Pawan Kumar Sada; Amit Kumar Kundan; Amit Bar; Amanpreet Kaur Jassal; Surya Prakash Rai; Vipendra Kumar Singh; Neha Garg; Alok Kumar Singh; Ankit Kumar Singh; Sumit Mohan Kumar; Laxman Singh; Abhishek Rai
A new fluorescein hydrazone (FA1) has been synthesized employing fluorescein hydrazide and 3,5-diiodosalicylaldehyde and its complete physiochemical characterization have been carried out. A single crystal XRD studies of FA1 has been performed. Among the tested metal ions FA1 significantly detects Cu2+ and Zn2+ in EtOH/H2O (8:2, v/v)). There is an emergence of a new absorbance peak at λmax 431 nm with Cu2+ ions. A “turn-on” behavior in fluorescence at λem510 nm was observed with Zn2+ ions owing to chelation enhanced fluorescence. This act of spectrophotometric changes and naked eye color variation from colorless to yellow is because of coordination with the metal ions rather than most common opening of spirolactum ring. FA1-Cu2+ and FA1-Zn2+ensembles display reversible behavior with EDTA2− ions. In a study on latent fingerprint detection using powder compounds, it was found that FA1 and FA1–Zn2+ showed excellent adherence to finger ridges and produced clear features without any background stains. The Hirshfeld surface and fingerprint analysis of FA1 offer a detailed examination of pairwise interactions between atoms. Additionally, topological analysis of FA1 has been conducted using NCI, AIM, ELF, and LOL methodologies. Alamar assay of FA1 on HEK-293 cell lines exhibited biocompatibility with minimal cytotoxicity. Hence, they were effectively applied for live cell imaging for intracellular sensing of Cu2+ and Zn2+ in HEK-293 cells. © 2025 Elsevier B.V.
Fluorescein hydrazone-based supramolecular architectures, molecular recognition, sequential logic operation and cell imaging
(Royal Society of Chemistry, 2017) Kamini Tripathi; Abhishek Rai; Amarish Kumar Yadav; Saripella Srikrishna; Niraj Kumari; Lallan Mishra
A fluorescein hydrazone (FDNS) is prepared by the coupling of fluorescein hydrazide with 3,5-dinitrosalicylaldehyde. It is well characterized using spectroscopic (IR, UV-visible, 1H, 13C NMR, ESI-MS) techniques and X-ray crystallography. FDNS is embedded with several H-bonding domains which provide interesting intra and inter molecular H-bonded networks. Its crystal packing along the b crystallographic axis using H-bonding interactions provides a fascinating helical structure. It detects Cu2+ ions selectively over many relevant ions and displays a novel peak at λmax = 495 nm. The significant enhancement in its fluorescence is observed with a peak at λem = 517 nm on addition of Hg2+ ions, which is quenched upon the addition of S2− ions. The sensing of Hg2+ ions by FDNS follow a hydrolysis pathway whereas the binding of Cu2+ ions with FDNS provides a colour change. The addition of a solution of tetrabutylammoniumcyanide in methanol to a corresponding solution of FDNS caused a turn to a green colour immediately. But on keeping the solution at room temperature for 72 h, red coloured crystals are obtained. The crystals were authenticated by X-ray crystallography. It was found to be a new compound FKCN in which a tetrabutylammonium cation is co-crystallized with deprotonated FDNS. Its supramolecular assembly via H-bonding provides an interesting ladder type architecture. FDNS displays chronological logic gate-based detection of several ions (Cu2+, Hg2+, EDTA, and S2−) at ppm levels. The real sample analysis, live cell imaging and portable paper strip based detection of Cu2+ and Hg2+ ions via an obvious colour change endows FDNS with great economic significance in recognition processes. © The Royal Society of Chemistry.
Green single-step hydrothermal synthesis of fluorescent carbon dots from Lantana camara flower for the effective fluorescent detection of Cr(VI) and live cell imaging
(Springer Science and Business Media Deutschland GmbH, 2025) Vikky Kumar Mahto; Vikas Kumar Singh; Vipendra Kumar Singh; Avinash K. Singh; Savita S. Singh; Arjun Kumar Mehara; Naina Rajak; Anurag Mishra; Neha Garg; Akanksha Upadhyay; Abhishek Rai; Ankit Kumar Singh
Chromium is one of the heavy metal ions showing high toxicity and mutagenicity. Owing to this, selective sensing of Cr(VI) from sample metrics is a challenging and tedious process. In the present work, we have synthesized fluorescent carbon dots (FCDs) using the flower of Lantana camara through a one-step hydrothermal method. Various spectroscopic techniques such as transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), EDAX, and Raman analysis well supported the successful synthesis of FCDs. The obtained FCDs revealed a bright blue color under UV-light exposure (@ 365 nm), with excellent optical properties and a fluorescence quantum yield of 29%. Furthermore, FCDs showed excellent fluorescence stability, high ionic strength, good water solubility, low cytotoxicity, and well biocompatibility. Therefore, the proposed FCDs were employed for selective turn-off sensing of toxic Cr(VI) in an aqueous medium with a limit of detection (LOD) of 0.10 µM. Interestingly, the low cytotoxicity and excellent biocompatibility enable the FCDs as a good candidate for cell imaging agents as well as intracellular turn-off sensing of Cr(VI) in HEK-293 cells. Thus, the present work significantly converts biomass of weed plants into a fluorescent probe in a simple and cost-effective way for the detection of Cr(VI) in water samples as well as in living cells. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.
Green single-step hydrothermal synthesis of fluorescent carbon dots from Lantana camara flower for the effective fluorescent detection of Cr(VI) and live cell imaging
(Springer Science and Business Media Deutschland GmbH, 2024) Vikky Kumar Mahto; Vikas Kumar Singh; Vipendra Kumar Singh; Avinash Singh; Savita Singh; Arjun Kumar Mehara; Naina Rajak; Anurag Mishra; Neha Garg; Akanksha Upadhyay; Abhishek Rai; Ankit Kumar Singh
Chromium is one of the heavy metal ions showing high toxicity and mutagenicity. Owing to this, selective sensing of Cr(VI) from sample metrics is a challenging and tedious process. In the present work, we have synthesized fluorescent carbon dots (FCDs) using the flower of Lantana camara through a one-step hydrothermal method. Various spectroscopic techniques such as transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), EDAX, and Raman analysis well supported the successful synthesis of FCDs. The obtained FCDs revealed a bright blue color under UV-light exposure (@ 365 nm), with excellent optical properties and a fluorescence quantum yield of 29%. Furthermore, FCDs showed excellent fluorescence stability, high ionic strength, good water solubility, low cytotoxicity, and well biocompatibility. Therefore, the proposed FCDs were employed for selective turn-off sensing of toxic Cr(VI) in an aqueous medium with a limit of detection (LOD) of 0.10 µM. Interestingly, the low cytotoxicity and excellent biocompatibility enable the FCDs as a good candidate for cell imaging agents as well as intracellular turn-off sensing of Cr(VI) in HEK-293 cells. Thus, the present work significantly converts biomass of weed plants into a fluorescent probe in a simple and cost-effective way for the detection of Cr(VI) in water samples as well as in living cells. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.
Metal Nanocomposites as Optical Sensor for Ions and Molecules of Environmental Concern
(Springer Nature, 2022) Pranshu Kumar Gupta; Pawan Kumar Sada; Vikas Kumar Sonu; Abhishek Rai
Multi phasic metal nanocomposites comprising a zero-dimensional metal nanoparticles phase (0.5–5% w/w) have significantly enhanced the material property and sensing ability of easily recoverable conventional matrices like glass, ceramics, metal, carbon allotropes or polymers. Over the past few years, promising chemical and physical properties of metal nanocomposites, developed via direct in situ chemical, photocatalytic, or thermal reduction of metal salts, over common matrix, or ex situ direct insertion of nanoparticles into the polymer. Colorimetric MNC sensors like metal–metal oxide NPs, quantum dots have depicted a relation between their type, structure, function and sensing performance, via aggregation/decomposition of NPs, fluorescence on/off and ligand-receptor interaction. Functional single/multilayered transition-metal dichalcogenides have been employed both, as a matrix for their decoration exhibiting synergism and quite recently as nanocomposites exhibiting ultra-fast and selective multi-sensor activity over narrow detection limits that are an urgent demand of national, homeland and environment safety. Fabrication of these biosensors endorse their progress in environmental and material aspects. They are employed as bio-analytic sensors against excess of heavy metal ions, nitro-compounds, poly-aromatic hydrocarbons, microbial proteins etc. imparting exclusive photo-chromatic and electronic properties, tuned at grass-root level by adjusting various supramolecular interactions and also the metal-ligands interactions at molecular level. Nanocomposites have several applications mainly in biological arenas, solar cells, communication field, optoelectronic devices etc. In this chapter we would discuss about recently developed nanocomposite-sensors, their synthesis, mechanism for their sensing action and environmental application involving mainly optical sensors. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Neuroprotective Activity of a Novel Synthetic Rhodamine-Based Hydrazone against Cu2+-Induced Alzheimer’s Disease in Drosophila
(American Chemical Society, 2022) Brijesh Singh Chauhan; Abhishek Rai; Avinash Kumar Sonkar; Kamini Tripathi; Sonal Upadhyay; Lallan Mishra; Saripella Srikrishna
A new rhodamine-based probe 3,5-di-tert-butylsali-cylaldehyde rhodamine hydrazone (RHTB) has been synthesized and well characterized using spectroscopic techniques and single-crystal X-ray crystallography. Among several metal ions, it selectively detects Cu2+ ions as monitored by UV−Vis and emission spectral titrations. It displays “turn on” behavior owing to the opening of a spirolactum ring and the presence of 3,5-di-tert-butyl as an electron releasing group. Further, Cu2+ ions play a pivotal role in extracellular aggregation of Aβ42 peptides. So far, we know probably that there are no promising drugs available in this regard. Hence, countering the Cu2+ ions by RHTB chelation against orally administered Cu2+ ion-induced neurotoxicity in the eye tissue of Drosophila expressing human Aβ42 (amyloid-β42) has been tested. The present study involves in vivo and in silico approaches. They reveal the therapeutic potential of RHTB against Cu ion-induced Aβ42 toxicity in Alzheimer’s disease (AD) model of Drosophila. © 2022 American Chemical Society.