Browsing by Author "Raksha Singh"

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5-Amino uracil activated silver nano resonators for highly selective visual detection of dopamine and as an agonist towards BAP: Promoting shoot growth in Bacopa monnieri L.
(Elsevier B.V., 2024) Saumya Singh; Raksha Singh; Anurag Kumar Singh; Minu Yadav; S.K. Mishra; Jyoti Dixit; Pooja Verma; K.N. Tiwari; K.K. Upadhyay
Silver nanoparticles (AgNPs) with an average size of about 17.5 nm have been synthesized using 5-amino uracil as a reducing and capping agent. The concentration of these AgNPs was worked out to be 48 nM. These AgNPs served as a highly selective optical sensor against an important neurotransmitter like dopamine (DA) at its nano molar level (94 nM) with the linearity range of 1–5 µM. The quantification of DA in one of its injection sample was also achieved with a recovery of 91 %. Studies like FTIR, UV–Vis, XPS, SEM, TEM, EDX, DLS and Zeta potential measurements have supported our findings. Significant amplification in the Raman signal of DA was also observed upon its addition into as prepared AgNPs solution. Moreover, these AgNPs seemed to augment the activity of cytokinin (BAP) in synergistic fashion and enhanced in vitro high frequency shoots regeneration in B. monnieri L. and also led to increment in its antioxidant metabolite contents like phenol and flavonoid. © 2023 Elsevier B.V.
A low cost yet highly sensitive silver nanoprobe for naked eye detection and determination of bisulphate (HSO4-) in a few real samples
(Elsevier B.V., 2022) Raksha Singh; Minu Yadav; Anurag Kumar Singh; S.K. Mishra; K.K. Upadhyay
Herein, we report a simple and economical yet highly sensitive and efficient silver nanoresonators based protocol for naked eye detection of a janus-faced ion like bisulphate from its two real samples in real time. The SEM-TEM, DLS, AFM and EDAX alongwith spectroscopic studies have further substantiated our observation in the same context. The quantification of bisulphate in one of its real sample through UV–Vis spectroscopy using these nanoprobes as indicator has also been carried out successfully. The Raman measurements have clearly indicated the rich SERS potential of these silver nanoresonators. © 2022 Elsevier B.V.
A rapid and sensitive colorimetric discrimination and detection of cysteine, homocysteine and glutathione by phloroglucinol-functionalized silver nanoresonators with real applications
(Royal Society of Chemistry, 2023) Anurag Kumar Singh; Raksha Singh; Minu Yadav; Manish Sharma; Ida Tiwari; K.K. Upadhyay
This study describes the preparation and application of simple yet effective silver nanoprobes for the facile colorimetric discrimination and detection of cysteine, homocysteine and glutathione in real time at the micro molar levels with three distinct colors. These nanoprobes were further exploited to detect and determine cysteine and glutathione from their respective commercial samples, with recoveries exceeding 80%. FT-IR spectroscopy, UV-Vis spectroscopy, SEM, TEM, EDAX, AFM and DLS studies have supported our findings. © 2023 The Royal Society of Chemistry.
Colorimetric and SERS detection of H2S by D (±) galactose functionalized truncated hexagonal bipyramidal silver nanoresonators
(Elsevier B.V., 2023) Minu Yadav; Raksha Singh; Anurag Kumar Singh; Manish Sharma; Ida Tiwari; Kaushal Kumar Upadhyay
We report hereby, a simple and easy to perform experimental protocol for highly selective and real time dual mode (Colorimetric and SERS) detection of hydrogen sulfide (H2S) in aqueous medium through galactose activated silver nanoresonators. The truncated hexagonal bipyramids were clearly seen in TEM images of as prepared silver nanoparticles. The interaction of H2S with these AgNPs induced their etching followed by agglomeration and led optical (greenish yellow to brown) as well as SERS changes. The optical changes were further exploited to determine the H2S from its two spiked samples of human saliva and blood serum each with their percent recovery rates of 91, 82 and 67, 72 respectively. These determinations were totally free from any visual interference from any biothiols like cysteine, homocysteine and glutathione. The optimized silver nanosensor exhibited an excellent linear response in the concentration range of 50–130 nM along with its limit of detection (LOD) as 2.83 nM. Moreover, consecutive additions of different aliquots of H2S to a fixed volume of these silver colloids exhibited stepwise decrease in intensity of their absorption bands in the Raman silent (10–500 cm−1) and Raman finger print regions (500–1800 cm−1) upon their excitation at 532 nm. Our findings are well supported by spectroscopic (FTIR, UV–Vis and Raman) and microscopic (SEM, TEM, DLS and zeta potential). © 2023 Elsevier B.V.
Glucosamine functionalized gold nanoparticles for the specific detection and colorimetric assay of glutathione in real samples
(Royal Society of Chemistry, 2024) Anurag Kumar Singh; Saumya Singh; Raksha Singh; Manish Sharma; Ida Tiwari; K.K. Upadhyay
In this study, we report an experimental protocol based on gold nanoparticles (GNPs) for the selective and efficient chromogenic detection and determination of glutathione in two pharmaceutical samples, viz. Maxiliv and Glutaderm, in real time. The glucosamine hydrochloride driven hydrothermal (40 °C) wet chemical reduction of gold(iii) chloride trihydrate resulted in gold sol with a ruby red color exhibiting a surface plasmon resonance (SPR) at 521 nm. The most frequent average size of these GNPs was found to be 23 nm and their concentration was evaluated to be 8.4 nM. The zeta potential measurements and interaction of these GNPs against NaCl of varying molarities indicated their long-term stability. According to SEM analysis, these GNPs exhibited a nanowire morphology and produced a categorical color change from ruby red to blue selectively with GSH in the presence of a wide range of similar analytes in real time. UV-vis, FT-IR, XPS, SEM, TEM, AFM, EDAX, DLS, zeta potential, and other techniques were used to characterize the as-synthesized GNPs and to study their interaction with glutathione. © 2024 The Royal Society of Chemistry.
Naked-eye detection of cysteine/homocysteine through silver nano-resonators and specific identification of homocysteine through nanoresonator-thiosulphate conjugate
(Royal Society of Chemistry, 2022) Raksha Singh; Anurag Kumar Singh; Minu Yadav; Manish Sharma; Ida Tiwari; K.K. Upadhyay
This study presents simultaneous colorimetric detection of two very similar amino thiols viz. cysteine and homocysteine at their micro and sub-micromolar levels, respectively, through the aggregation of citrate capped silver nanoparticles. A rare kind of categorical naked-eye detection of homocysteine over cysteine was accomplished through the conjugation of these AgNPs with thiosulphate. The UV-Vis and SERS characteristics of these AgNPs were also more prominent with homocysteine compared to cysteine. The quantification of cysteine was performed in a pharmaceutic sample with an accuracy of 89 ± 5%. © 2022 The Royal Society of Chemistry.
Plant proteomics in India and Nepal: Current status and challenges ahead
(2013) Renu Deswal; Ravi Gupta; Vivek Dogra; Raksha Singh; Jasmeet Kaur Abat; Abhijit Sarkar; Yogesh Mishra; Vandana Rai; Yelam Sreenivasulu; Ramesh Sundar Amalraj; Manish Raorane; Ram Prasad Chaudhary; Ajay Kohli; Ashok Prabhakar Giri; Niranjan Chakraborty; Sajad Majeed Zargar; Vishwanath Prasad Agrawal; Ganesh Kumar Agrawal; Dominique Job; Jenny Renaut; Randeep Rakwal
Plant proteomics has made tremendous contributions in understanding the complex processes of plant biology. Here, its current status in India and Nepal is discussed. Gel-based proteomics is predominantly utilized on crops and non-crops to analyze majorly abiotic (49 %) and biotic (18 %) stress, development (11 %) and post-translational modifications (7 %). Rice is the most explored system (36 %) with major focus on abiotic mainly dehydration (36 %) stress. In spite of expensive proteomics setup and scarcity of trained workforce, output in form of publications is encouraging. To boost plant proteomics in India and Nepal, researchers have discussed ground level issues among themselves and with the International Plant Proteomics Organization (INPPO) to act in priority on concerns like food security. Active collaboration may help in translating this knowledge to fruitful applications. © 2013 Prof. H.S. Srivastava Foundation for Science and Society.
Salicylazine activated plasmonic silver nanoprisms for identification of Fe(ii) and Fe(iii) from aqueous solutions
(Royal Society of Chemistry, 2021) Deovrat Singh; Raksha Singh; Abhay Kumar; Anurag Kumar Singh; Minu Yadav; K.K. Upadhyay
Herein, we report the synthesis and characterization, along with the successful application, of silver nanoprisms for the identification of Fe(ii)/Fe(iii) at the nanomolar level. A few real samples have also been analyzed successfully. The scanning electron microscopy (SEM)-transmission electron microscopy (TEM) imaging of the sensing events indicate analyte induced changes in the morphology and geometrical pattern of the silver nanoparticles. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2021.
Sunlight-powered total green synthesis of silver nanoresonators from aqueous extract of soybean (Glycine max) chunks: A highly specific colorimetric probe for H2S
(Elsevier B.V., 2024) Raksha Singh; Minu Yadav; Manish Sharma; Ida Tiwari; K.K. Upadhyay
We report herein a total green synthesis of silver nano resonators having 43.77 nM concentration with their most frequent average size of ∼ 17 nm. The reaction mixture comprising of aqueous extract of soybean (Glycine max) chunks (15 mL) and AgNO3 (1 mL, 0.1 M) in a 100 mL round bottom flask was irradiated with sunlight for 3 hrs to bring out this synthesis. The as prepared AgNPs were fully characterized through various spectroscopic (FTIR & UV–Vis) and microscopic (SEM, TEM, SAED, EDX, AFM and DLS) studies. The same AgNPs were further exploited for highly selective detection and determination of a janus faced analyte like H2S from its aqueous solution at submicromolar level (LOD 7.39×10-7 M). The H2S is known for its role as one of the gaso-neurotransmitters in humans beside playing dubious role towards our environment. Two spiked real samples of water from pond and sewage were subjected for determination of their H2S content against these AgNPs, showed recoveries of 99 % and 106 % respectively. © 2023 Elsevier B.V.