The Experts below are selected from a list of 78912 Experts worldwide ranked by ideXlab platform
Luke P Lee - One of the best experts on this subject based on the ideXlab platform.
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selective and sensitive detection of metal ions by plasmonic Resonance Energy transfer based nanospectroscopy
Nature Nanotechnology, 2009Co-Authors: Yeonho Choi, Taewook Kang, Younggeun Park, Luke P LeeAbstract:Highly selective and sensitive optical methods for the detection of metal ions have had a substantial impact on molecular biology1,2,3, environmental monitoring4,5,6,7,8,9,10 and other areas of research. Here we demonstrate a new method for detecting metal ions that is based on selective plasmonic Resonance Energy transfer (PRET) between conjugated metal–ligand complexes and a single gold nanoplasmonic probe. In addition to offering high spatial resolution due to the small size of the probe, our method is 100 to 1,000 times more sensitive than organic reporter-based methods3,4,5,6,7,8. Moreover, it can achieve high selectivity owing to the selective formation of Cu2+ complexes and selective resonant quenching of the gold nanoplasmonic probe by the conjugated complexes. We expect that PRET-based metal ion sensing could have applications in cellular imaging, systems biology and environmental monitoring. Metal-ion detection on the basis of plasmonic Resonance Energy transfer is proposed and demonstrated in a proof-of-concept experiment by detecting copper ions down to one nanomole with high selectively.
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quantized plasmon quenching dips nanospectroscopy via plasmon Resonance Energy transfer
Nature Methods, 2007Co-Authors: Gang Logan Liu, Yitao Long, Yeonho Choi, Taewook Kang, Luke P LeeAbstract:We observed quantized plasmon quenching dips in resonant Rayleigh scattering spectra by plasmon Resonance Energy transfer (PRET) from a single nanoplasmonic particle to adsorbed biomolecules. This label-free biomolecular absorption nanospectroscopic method has ultrahigh molecular sensitivity.
Graeme Milligan - One of the best experts on this subject based on the ideXlab platform.
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monitoring receptor oligomerization using time resolved fluorescence Resonance Energy transfer and bioluminescence Resonance Energy transfer the human δ opioid receptor displays constitutive oligomerization at the cell surface which is not regulated
Journal of Biological Chemistry, 2001Co-Authors: Mary Mcvey, Douglas Ramsay, Elaine Kellett, Stephen Rees, Shelagh Wilson, Andrew J Pope, Graeme MilliganAbstract:Abstract Oligomerization of the human δ-opioid receptor and its regulation by ligand occupancy were explored following expression in HEK293 cells using each of co-immunoprecipitation of differentially epitope-tagged forms of the receptor, bioluminescence Resonance Energy transfer and time-resolved fluorescence Resonance Energy transfer. All of the approaches identified constitutively formed receptor oligomers, and the time-resolved fluorescence studies confirmed the presence of such homo-oligomers at the cell surface. Neither the agonist ligand [d-Ala2,d-Leu5]enkephalin nor the inverse agonist ligand ICI174864 were able to modulate the oligomerization status of this receptor. Interactions between co-expressed δ-opioid receptors and β2-adrenoreceptors were observed in co-immunoprecipitation studies. Such hetero-oligomers could also be detected using bioluminescence Resonance Energy transfer although the signal obtained was substantially smaller than for homo-oligomers of either receptor type. Signal corresponding to the δ-opioid receptor-β2-adrenoreceptor hetero-oligomer was increased in the presence of agonist for either receptor. However, substantial levels of this hetero-oligomer were not detected at the cell surface using time-resolved fluorescence Resonance Energy transfer. These studies demonstrate that, following transient transfection of HEK293 cells, constitutively formed oligomers of the human δ-opioid receptor can be detected by a variety of approaches. However, these are not regulated by ligand occupancy. They also indicate that time-resolved fluorescence Resonance Energy transfer represents a means to detect such oligomers at the cell surface in populations of intact cells.
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monitoring receptor oligomerization using time resolved fluorescence Resonance Energy transfer and bioluminescence Resonance Energy transfer the human δ opioid receptor displays constitutive oligomerization at the cell surface which is not regulated
Journal of Biological Chemistry, 2001Co-Authors: Mary Mcvey, Douglas Ramsay, Elaine Kellett, Stephen Rees, Shelagh Wilson, Andrew J Pope, Graeme MilliganAbstract:Oligomerization of the human delta-opioid receptor and its regulation by ligand occupancy were explored following expression in HEK293 cells using each of co-immunoprecipitation of differentially epitope-tagged forms of the receptor, bioluminescence Resonance Energy transfer and time-resolved fluorescence Resonance Energy transfer. All of the approaches identified constitutively formed receptor oligomers, and the time-resolved fluorescence studies confirmed the presence of such homo-oligomers at the cell surface. Neither the agonist ligand [d-Ala(2),d-Leu(5)]enkephalin nor the inverse agonist ligand ICI174864 were able to modulate the oligomerization status of this receptor. Interactions between co-expressed delta-opioid receptors and beta(2)-adrenoreceptors were observed in co-immunoprecipitation studies. Such hetero-oligomers could also be detected using bioluminescence Resonance Energy transfer although the signal obtained was substantially smaller than for homo-oligomers of either receptor type. Signal corresponding to the delta-opioid receptor-beta(2)-adrenoreceptor hetero-oligomer was increased in the presence of agonist for either receptor. However, substantial levels of this hetero-oligomer were not detected at the cell surface using time-resolved fluorescence Resonance Energy transfer. These studies demonstrate that, following transient transfection of HEK293 cells, constitutively formed oligomers of the human delta-opioid receptor can be detected by a variety of approaches. However, these are not regulated by ligand occupancy. They also indicate that time-resolved fluorescence Resonance Energy transfer represents a means to detect such oligomers at the cell surface in populations of intact cells.
Mary Mcvey - One of the best experts on this subject based on the ideXlab platform.
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monitoring receptor oligomerization using time resolved fluorescence Resonance Energy transfer and bioluminescence Resonance Energy transfer the human δ opioid receptor displays constitutive oligomerization at the cell surface which is not regulated
Journal of Biological Chemistry, 2001Co-Authors: Mary Mcvey, Douglas Ramsay, Elaine Kellett, Stephen Rees, Shelagh Wilson, Andrew J Pope, Graeme MilliganAbstract:Abstract Oligomerization of the human δ-opioid receptor and its regulation by ligand occupancy were explored following expression in HEK293 cells using each of co-immunoprecipitation of differentially epitope-tagged forms of the receptor, bioluminescence Resonance Energy transfer and time-resolved fluorescence Resonance Energy transfer. All of the approaches identified constitutively formed receptor oligomers, and the time-resolved fluorescence studies confirmed the presence of such homo-oligomers at the cell surface. Neither the agonist ligand [d-Ala2,d-Leu5]enkephalin nor the inverse agonist ligand ICI174864 were able to modulate the oligomerization status of this receptor. Interactions between co-expressed δ-opioid receptors and β2-adrenoreceptors were observed in co-immunoprecipitation studies. Such hetero-oligomers could also be detected using bioluminescence Resonance Energy transfer although the signal obtained was substantially smaller than for homo-oligomers of either receptor type. Signal corresponding to the δ-opioid receptor-β2-adrenoreceptor hetero-oligomer was increased in the presence of agonist for either receptor. However, substantial levels of this hetero-oligomer were not detected at the cell surface using time-resolved fluorescence Resonance Energy transfer. These studies demonstrate that, following transient transfection of HEK293 cells, constitutively formed oligomers of the human δ-opioid receptor can be detected by a variety of approaches. However, these are not regulated by ligand occupancy. They also indicate that time-resolved fluorescence Resonance Energy transfer represents a means to detect such oligomers at the cell surface in populations of intact cells.
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monitoring receptor oligomerization using time resolved fluorescence Resonance Energy transfer and bioluminescence Resonance Energy transfer the human δ opioid receptor displays constitutive oligomerization at the cell surface which is not regulated
Journal of Biological Chemistry, 2001Co-Authors: Mary Mcvey, Douglas Ramsay, Elaine Kellett, Stephen Rees, Shelagh Wilson, Andrew J Pope, Graeme MilliganAbstract:Oligomerization of the human delta-opioid receptor and its regulation by ligand occupancy were explored following expression in HEK293 cells using each of co-immunoprecipitation of differentially epitope-tagged forms of the receptor, bioluminescence Resonance Energy transfer and time-resolved fluorescence Resonance Energy transfer. All of the approaches identified constitutively formed receptor oligomers, and the time-resolved fluorescence studies confirmed the presence of such homo-oligomers at the cell surface. Neither the agonist ligand [d-Ala(2),d-Leu(5)]enkephalin nor the inverse agonist ligand ICI174864 were able to modulate the oligomerization status of this receptor. Interactions between co-expressed delta-opioid receptors and beta(2)-adrenoreceptors were observed in co-immunoprecipitation studies. Such hetero-oligomers could also be detected using bioluminescence Resonance Energy transfer although the signal obtained was substantially smaller than for homo-oligomers of either receptor type. Signal corresponding to the delta-opioid receptor-beta(2)-adrenoreceptor hetero-oligomer was increased in the presence of agonist for either receptor. However, substantial levels of this hetero-oligomer were not detected at the cell surface using time-resolved fluorescence Resonance Energy transfer. These studies demonstrate that, following transient transfection of HEK293 cells, constitutively formed oligomers of the human delta-opioid receptor can be detected by a variety of approaches. However, these are not regulated by ligand occupancy. They also indicate that time-resolved fluorescence Resonance Energy transfer represents a means to detect such oligomers at the cell surface in populations of intact cells.
Karin A Eidne - One of the best experts on this subject based on the ideXlab platform.
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bioluminescence Resonance Energy transfer bret for the real time detection of protein protein interactions
Nature Protocols, 2006Co-Authors: Kevin D G Pfleger, Ruth M Seeber, Karin A EidneAbstract:Bioluminescence Resonance Energy transfer (BRET) for the real-time detection of protein-protein interactions
Hedi Mattoussi - One of the best experts on this subject based on the ideXlab platform.
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quantum dot based Resonance Energy transfer and its growing application in biology
Physical Chemistry Chemical Physics, 2009Co-Authors: Igor L Medintz, Hedi MattoussiAbstract:We provide an overview of the progress made in the past few years in investigating fluorescence Resonance Energy transfer (FRET) using semiconductor quantum dots (QDs) and the application of QD-based FRET to probe specific biological processes. We start by providing some of the pertinent conceptual elements involved in Resonance Energy transfer, and then discuss why the Forster dipole–dipole mechanism applies to QD fluorophores. We then describe the unique QD photophysical properties of direct relevance to FRET and summarize the main advantages offered, along with some of the limitations encountered by QDs as exciton donors and/or acceptors. Next we describe the overall progress made and discuss a few representative examples where QD-based FRET sensing of specific biological processes has been demonstrated. We also detail some of the advances of single molecule FRET using QD-conjugates and highlight the unique information that can be extracted. We conclude by providing an assessment of where QD-based FRET investigations may be evolving in the near future.
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proteolytic activity monitored by fluorescence Resonance Energy transfer through quantum dot peptide conjugates
Nature Materials, 2006Co-Authors: Igor L Medintz, Aaron R Clapp, Florence M Brunel, Theresa Tiefenbrunn, Tetsuo H Uyeda, Eddie L Chang, Jeffrey R Deschamps, Philip E Dawson, Hedi MattoussiAbstract:Proteases are enzymes that catalyse the breaking of specific peptide bonds in proteins and polypeptides. They are heavily involved in many normal biological processes as well as in diseases, including cancer, stroke and infection. In fact, proteolytic activity is sometimes used as a marker for some cancer types. Here we present luminescent quantum dot (QD) bioconjugates designed to detect proteolytic activity by fluorescence Resonance Energy transfer. To achieve this, we developed a modular peptide structure which allowed us to attach dye-labelled substrates for the proteases caspase-1, thrombin, collagenase and chymotrypsin to the QD surface. The fluorescence Resonance Energy transfer efficiency within these nanoassemblies is easily controlled, and proteolytic assays were carried out under both excess enzyme and excess substrate conditions. These assays provide quantitative data including enzymatic velocity, Michaelis-Menten kinetic parameters, and mechanisms of enzymatic inhibition. We also screened a number of inhibitory compounds against the QD-thrombin conjugate. This technology is not limited to sensing proteases, but may be amenable to monitoring other enzymatic modifications.