@article {42499, title = {Interrupted PET coupled TBET process for the design of a specific receptor for Hg2+ and its intracellular detection in MCF7 cells}, journal = {Chemical Communications}, volume = {48}, year = {2012}, month = {JUL}, pages = {9293-9295}, abstract = {

A new coumarin{\textendash}rhodamine conjugate constitutes a unique example of the interrupted PET coupled TBET response for developing an imaging reagent for determining the intracellular distribution of Hg2+ in MCF7 cells exposed to [Hg2+] as low as 2 ppb.

}, doi = {10.1039/C2CC34490D}, author = {Saha, Sukdeb and Mahato, Prasenjit and Baidya, Mithu and Ghosh, Sudip K. and Das, Amitava} } @article {42496, title = {New chemodosimetric reagents as ratiometric probes for cysteine and homocysteine and possible detection in living cells and in blood plasma}, journal = {Chemistry a European Journal}, volume = {18}, year = {2012}, month = {NOV}, pages = {15382{\textendash}15393}, abstract = {

In this work, we have rationally designed and synthesized two new reagents (L1 and L2), each bearing a pendant aldehyde functionality. This aldehyde group can take part in cyclization reactions with β- or γ-amino thiols to yield the corresponding thiazolidine and thiazinane derivatives, respectively. The intramolecular charge-transfer (ICT) bands of these thiazolidine and thiazinane derivatives are distinctly different from those of the molecular probes (L1 and L2). Such changes could serve as a potential platform for using L1 and L2 as new colorimetric/fluorogenic as well as ratiometric sensors for cysteine (Cys) and homocysteine (Hcy) under physiological conditions. Both reagents proved to be specific towards Cys and Hcy even in the presence of various amino acids, glucose, and DNA. Importantly, these two chemodosimetric reagents could be used for the quantitative detection of Cys present in blood plasma by using a pre-column HPLC technique. Such examples are not common in contemporary literature. MTT assay studies have revealed that these probes have low cytotoxicity. Confocal laser scanning micrographs of cells demonstrated that these probes could penetrate cell membranes and could be used to detect intracellular Cys/Hcy present within living cells. Thus, the results presented in this article not only demonstrate the efficiency and specificity of two ratiometric chemodosimeter molecules for the quantitative detection of Cys and Hcy, but also provide a strategy for developing reagents for analysis of these vital amino acids in biological samples.

}, keywords = {charge transfer; chemodosimetric detection; cysteine/ homocysteine sensors; fluorescent probes; imaging agents; ratiometric probes}, doi = {10.1002/chem.201201621}, author = {Das, Priyadip and Mandal, Amal Kumar and Chandar, Nellore Bhanu and Baidya, Mithu and Bhatt, Harshad B. and Ganguly, Bishwajit and Ghosh, Sudip K. and Das, Amitava} } @article {42501, title = {Recognition of Hg 2+ and Cr 3+ in physiological conditions by a rhodamine derivative and its application as a reagent for cell-imaging studies}, journal = {Inorganic Chemistry}, volume = {51}, year = {2012}, month = {DEC}, pages = {336{\textendash}345}, abstract = {

A new rhodamine-based receptor, derivatized with an additional fluorophore (quinoline), was synthesized for selective recognition of Hg2+ and Cr3+ in an acetonitrile/HEPES buffer medium of pH 7.3. This reagent could be used as a dual probe and allowed detection of these two ions by monitoring changes in absorption and the fluorescence spectral pattern. In both instances, the extent of the changes was significant enough to allow visual detection. More importantly, the receptor molecule could be used as an imaging reagent for detection of Hg2+ and Cr3+ uptake in live human cancer cells (MCF7) using laser confocal microscopic studies. Unlike Hg(ClO4)2 or Hg(NO3)2 salts, HgCl2 or HgI2 failed to induce any visually detectable change in color or fluorescence upon interaction with L1 under identical experimental conditions. Presumably, the higher covalent nature of HgII in HgCl2 or HgI2 accounts for its lower acidity and its inability to open up the spirolactam ring of the reagent L1. The issue has been addressed on the basis of the single-crystal X-ray structures of L1{\textperiodcentered}HgX2 (X{\textendash} = Cl{\textendash} or I{\textendash}) and results from other spectral studies.

}, doi = {10.1021/ic2017243}, author = {Saha, Sukdeb and Mahato, Prasenjit and Reddy, Upendar G. and Suresh, E. and Chakrabarty, Arindam and Baidya, Mithu and Ghosh, Sudip K. and Das, Amitava} } @article {42500, title = {Recognition of Hg2+ion through restricted imine isomerization: crystallographic evidence and imaging in live cells}, journal = {Organic Letters}, volume = {14}, year = {2012}, month = {JUN}, pages = {2980{\textendash}2983}, abstract = {

A newly synthesized imine-based receptor (L) showed remarkable specificity toward the Hg2+ ion in aqueous media over other metal ions. Coordination of L to Hg2+ induces a turn-on fluorescence response. This was explained based on the restricted imine isomerization along with PET on coordination to Hg2+. X-ray structural evidence tends to favor a C{\textendash}C bond rotation rather than C=N isomerization for adopting a favorable conformation in L for coordination to Hg2+. This reagent could be used for imaging the accumulation of Hg2+ ions in HeLa cells.

}, doi = {10.1021/ol3009733}, author = {Mandal, Amal Kumar and Suresh, Moorthy and Das, Priyadip and Suresh, E. and Baidya, Mithu and Ghosh, Sudip K. and Das, Amitava} } @article {42494, title = {CN? specific turn-on phosphorescent probe with probable application for enzymatic assay and as an imaging reagent}, journal = {Chemical Communications}, volume = {49}, year = {2013}, month = {OCT}, pages = {255-257}, abstract = {

A new {\textquotedblleft}turn-on{\textquotedblright} luminescence probe for imaging the uptake of 0.2 ppm inorganic CN- in live HeLa cells as well as for probing the CN- generation through an enzymatic process in a virtual aqueous medium at appropriate pH.

}, doi = {10.1039/C2CC37243F}, author = {Reddy, Upendar G. and Das, Priyadip and Saha, Sukdeb and Baidya, Mithu and Ghosh, Sudip K. and Das, Amitava} } @article { ISI:000325194900021, title = {Designing a thiol specific fluorescent probe for possible use as a reagent for intracellular detection and estimation in blood serum: kinetic analysis to probe the role of intramolecular hydrogen bonding}, journal = {Organic \& Biomolecular Chemistry}, volume = {11}, number = {38}, year = {2013}, month = {OCT}, pages = {6604-6614}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

A new and simple chemodosimetric probe L-1 is utilized for the selective detection of biothiols in the presence of other relevant amino acids under physiological conditions (pH = 7.4). This eventually led to a turn-off luminescence response due to an effective photoinduced electron transfer based signaling mechanism. A comparison of the results of the fluorescence kinetic analysis and H-1 NMR studies of the reaction between thiol and L-1 or the analogous compound L-2 revealed the role of intramolecular hydrogen bonding in activating the imine functionality towards nucleophilic addition. Such an example is not common in contemporary literature. Conventional MTT assay studies revealed that this probe (L-1) has low cytotoxicity. Results of the cell imaging studies revealed that this probe was cell membrane permeable and could detect the intracellular distribution of biothiols within living HeLa cells. Furthermore, our studies with human blood plasma demonstrated the possibility of using this reagent for the quantitative optical detection of total biothiols in biological fluid. Such an example for the detection of biothiols in real biological samples is rare in the contemporary literature. These results clearly demonstrate the possibility of using this reagent in medicinal biology and diagnostic applications.

}, issn = {1477-0520}, doi = {10.1039/c3ob41284a}, author = {Das, Priyadip and Mandal, Amal Kumar and Reddy, Upendar G. and Baidya, Mithu and Ghosh, Sudip K. and Das, Amitava} } @article { ISI:000325552900018, title = {New chemodosimetric probe for the specific detection of Hg2+ in physiological condition and its utilisation for cell imaging studies}, journal = {Dalton Transactions}, volume = {42}, number = {42}, year = {2013}, month = {JUL}, pages = {15097-15105}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

A dithiane derivative of BODIPY is synthesized. This new reagent could be used for the specific and instantaneous detection of Hg2+ in physiological condition. This dithiane reagent reacts specifically with Hg2+ to regenerate the parent BODIPY-aldehyde with consequential change in visually detectable optical responses and this provides the possibility of using this reagent as a colorimetric probe or as a fluorescent biomarker/imaging reagent. Further, non-covalent interactions could be utilized for formation of an inclusion complex with biologically benign beta-cyclodextrin for enhancing its solubility in aqueous environment and this included adduct could be used as a fluorescent marker and imaging reagent for Hg2+. Uptake of Hg2+ ions in live HeLa cells, exposed to a solution having Hg2+ ion concentration as low as 2 ppb, could also be detected by confocal laser microscopic studies.

}, issn = {1477-9226}, doi = {10.1039/c3dt51744f}, author = {Saha, Sukdeb and Agarwalla, Hridesh and Gupta, Hariom and Baidya, Mithu and Suresh, E. and Ghosh, Sudip K. and Das, Amitava} } @article {43330, title = {Proteomic analysis of human plasma in chronic rheumatic mitral stenosis reveals proteins involved in the complement and coagulation cascade}, journal = {Clinical Proteomics}, volume = {11}, year = {2014}, month = {SEP}, pages = {Article Number: 35}, abstract = {Background: Rheumatic fever in childhood is the most common cause of Mitral Stenosis in developing countries. The disease is characterized by damaged and deformed mitral valves predisposing them to scarring and narrowing (stenosis) that results in left atrial hypertrophy followed by heart failure. Presently, echocardiography is the main imaging technique used to diagnose Mitral Stenosis. Despite the high prevalence and increased morbidity, no biochemical indicators are available for prediction, diagnosis and management of the disease. Adopting a proteomic approach to study Rheumatic Mitral Stenosis may therefore throw some light in this direction. In our study, we undertook plasma proteomics of human subjects suffering from Rheumatic Mitral Stenosis (n = 6) and Control subjects (n = 6). Six plasma samples, three each from the control and patient groups were pooled and subjected to low abundance protein enrichment. Pooled plasma samples (crude and equalized) were then subjected to in-solution trypsin digestion separately. Digests were analyzed using nano LC-MSE. Data was acquired with the Protein Lynx Global Server v2.5.2 software and searches made against reviewed Homo sapiens database (UniProtKB) for protein identification. Label-free protein quantification was performed in crude plasma only. }, doi = {10.1186/1559-0275-11-35}, author = {Mukherjee, Somaditya and Jagadeeshaprasad, Mashanipalya G. and Banerjee, Tanima and Ghosh, Sudip K. and Biswas, Monodeep and Dutta, Santanu and Kulkarni, Mahesh J. and Pattari, Sanjib and Bandyopadhyay, Arun} }