00937nas a2200181 4500008004100000245013400041210006900175260000800244300001400252490000700266520026000273100001700533700002200550700001800572700002100590700001700611856012700628 2012 eng d00aInterrupted PET coupled TBET process for the design of a specific receptor for Hg2+ and its intracellular detection in MCF7 cells0 aInterrupted PET coupled TBET process for the design of a specifi cJUL a9293-92950 v483 a

A new coumarin–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.

1 aSaha, Sukdeb1 aMahato, Prasenjit1 aBaidya, Mithu1 aGhosh, Sudip, K.1 aDas, Amitava uhttps://library.ncl.res.in/content/interrupted-pet-coupled-tbet-process-design-specific-receptor-hg2-and-its-intracellular02539nas a2200229 4500008004100000245014400041210006900185260000800254300001800262490000700280520158900287653013501876100001802011700002402029700002802053700001802081700002302099700002302122700002102145700001702166856012602183 2012 eng d00aNew chemodosimetric reagents as ratiometric probes for cysteine and homocysteine and possible detection in living cells and in blood plasma0 aNew chemodosimetric reagents as ratiometric probes for cysteine  cNOV a15382–153930 v183 a

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.

10acharge transfer; chemodosimetric detection; cysteine/ homocysteine sensors; fluorescent probes; imaging agents; ratiometric probes1 aDas, Priyadip1 aMandal, Amal, Kumar1 aChandar, Nellore, Bhanu1 aBaidya, Mithu1 aBhatt, Harshad, B.1 aGanguly, Bishwajit1 aGhosh, Sudip, K.1 aDas, Amitava uhttps://library.ncl.res.in/content/new-chemodosimetric-reagents-ratiometric-probes-cysteine-and-homocysteine-and-possible01954nas a2200217 4500008004100000245014700041210006900188260000800257300001400265490000700279520116100286100001701447700002201464700002301486700001501509700002501524700001801549700002101567700001701588856013101605 2012 eng d00aRecognition of Hg 2+ and Cr 3+ in physiological conditions by a rhodamine derivative and its application as a reagent for cell-imaging studies0 aRecognition of Hg 2 and Cr 3 in physiological conditions by a rh cDEC a336–3450 v513 a

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·HgX2 (X– = Cl– or I–) and results from other spectral studies.

1 aSaha, Sukdeb1 aMahato, Prasenjit1 aReddy, Upendar, G.1 aSuresh, E.1 aChakrabarty, Arindam1 aBaidya, Mithu1 aGhosh, Sudip, K.1 aDas, Amitava uhttps://library.ncl.res.in/content/recognition-hg-2-and-cr-3-physiological-conditions-rhodamine-derivative-and-its-application01290nas a2200205 4500008004100000245011900041210006900160260000800229300001600237490000700253520056400260100002400824700002000848700001800868700001500886700001800901700002100919700001700940856012700957 2012 eng d00aRecognition of Hg2+ion through restricted imine isomerization: crystallographic evidence and imaging in live cells0 aRecognition of Hg2ion through restricted imine isomerization cry cJUN a2980–29830 v143 a

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–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.

1 aMandal, Amal, Kumar1 aSuresh, Moorthy1 aDas, Priyadip1 aSuresh, E.1 aBaidya, Mithu1 aGhosh, Sudip, K.1 aDas, Amitava uhttps://library.ncl.res.in/content/recognition-hg2ion-through-restricted-imine-isomerization-crystallographic-evidence-and00928nas a2200193 4500008004100000245011800041210006900159260000800228300001200236490000700248520023900255100002300494700001800517700001700535700001800552700002100570700001700591856012600608 2013 eng d00aCN? specific turn-on phosphorescent probe with probable application for enzymatic assay and as an imaging reagent0 aCN specific turnon phosphorescent probe with probable applicatio cOCT a255-2570 v493 a

A new “turn-on” 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.

1 aReddy, Upendar, G.1 aDas, Priyadip1 aSaha, Sukdeb1 aBaidya, Mithu1 aGhosh, Sudip, K.1 aDas, Amitava uhttps://library.ncl.res.in/content/cn-specific-turn-phosphorescent-probe-probable-application-enzymatic-assay-and-imaging02257nas a2200205 4500008004100000022001400041245020800055210006900263260011000332300001400442490000700456520133800463100001801801700002401819700002301843700001801866700002101884700001701905856012901922 2013 eng d a1477-052000aDesigning 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 bonding0 aDesigning a thiol specific fluorescent probe for possible use as aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcOCT a6604-66140 v113 a

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.

1 aDas, Priyadip1 aMandal, Amal, Kumar1 aReddy, Upendar, G.1 aBaidya, Mithu1 aGhosh, Sudip, K.1 aDas, Amitava uhttps://library.ncl.res.in/content/designing-thiol-specific-fluorescent-probe-possible-use-reagent-intracellular-detection-001771nas a2200217 4500008004100000022001400041245013700055210006900192260011000261300001600371490000700387520090800394100001701302700002301319700001801342700001801360700001501378700002101393700001701414856012201431 2013 eng d a1477-922600aNew chemodosimetric probe for the specific detection of Hg2+ in physiological condition and its utilisation for cell imaging studies0 aNew chemodosimetric probe for the specific detection of Hg2 in p aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcJUL a15097-151050 v423 a

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.

1 aSaha, Sukdeb1 aAgarwalla, Hridesh1 aGupta, Hariom1 aBaidya, Mithu1 aSuresh, E.1 aGhosh, Sudip, K.1 aDas, Amitava uhttps://library.ncl.res.in/content/new-chemodosimetric-probe-specific-detection-hg2-physiological-condition-and-its-0