Time-Resolved Fluorescence Spectroscopy is a powerful tool for biochemistry; it can provide unique insights into the structure and assembly of macromolecular complexes. We are wrapping up a decade of studying the dynamics of water near proteins using the picosecond response of Tryptophan(Trp), an amino acid found in most proteins, to the electric field caused by water dipole motions. The overall subject of upconversion (sub-ps) studies of Trp was separately published by us in book chapters. All Trp studies have now moved to East China Normal University in Shanghai. We continued collaborative studies into the status of a primary fuel of heart muscle mitochondria- NADH. Our efforts distinguish free and bound populations of NADH by their different fluorescence lifetimes, and in collaboration with Light Microscopy Core and LCE, we are continually refining 'Decay-Associated Images' software to more rapidly extract profiles of NADH binding within isolated tissue and/or tumor cells. This year we updated DAI software for large images. We continue to develop coupled lifetime and translational diffusion capabilities in time-resolved FCS for this and other projects. We used our spectroscopic tools to help prototype a new imaging molecule for cellular(tissue) oxygen concentration detection- we modified myoglobin to contain a red fluorescent dye (e.g. Alexa594) or a red fluorescent protein tail (e.g. mCherry). They respond to the oxygen-binding of myoglobin by changing lifetime and brightness.

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Support Year
35
Fiscal Year
2018
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U.S. National Heart Lung and Blood Inst
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Ardeshirpour, Yasaman; Sackett, Dan L; Knutson, Jay R et al. (2018) Using in vivo fluorescence lifetime imaging to detect HER2-positive tumors. EJNMMI Res 8:26
Trachman 3rd, Robert J; Abdolahzadeh, Amir; Andreoni, Alessio et al. (2018) Crystal Structures of the Mango-II RNA Aptamer Reveal Heterogeneous Fluorophore Binding and Guide Engineering of Variants with Improved Selectivity and Brightness. Biochemistry 57:3544-3548
Lucotte, Bertrand M; Powell, Chloe; Knutson, Jay R et al. (2017) Direct visualization of the arterial wall water permeability barrier using CARS microscopy. Proc Natl Acad Sci U S A 114:4805-4810
Rosales, Tilman; Sackett, Dan L; Xu, Jianhua et al. (2015) STAQ: A route toward low power, multicolor nanoscopy. Microsc Res Tech 78:343-55
Xu, Jianhua; Chen, Binbin; Callis, Patrik et al. (2015) Picosecond fluorescence dynamics of tryptophan and 5-fluorotryptophan in monellin: slow water-protein relaxation unmasked. J Phys Chem B 119:4230-9
Biesso, Arianna; Xu, Jianhua; Muíño, Pedro L et al. (2014) Charge invariant protein-water relaxation in GB1 via ultrafast tryptophan fluorescence. J Am Chem Soc 136:2739-47
Dasgeb, Bahar; Smirnov, Aleksandr V; Ardeshirpour, Yasaman et al. (2014) Multiscale BerEp4 molecular imaging of microtumor phantoms: toward theranostics for basal cell carcinoma. Mol Imaging 13:
Biesso, Arianna; Xu, Jianhua; Knutson, Jay R (2014) Upconversion spectrophotofluorometry. Methods Mol Biol 1076:303-19
Combs, Christian A; Smirnov, Aleksandr; Glancy, Brian et al. (2014) Compact non-contact total emission detection for in vivo multiphoton excitation microscopy. J Microsc 253:83-92
Rosales, Tilman; Nie, Zuqin; Kapoor, Varun et al. (2013) Partition of Myc into Immobile vs. Mobile Complexes within Nuclei. Sci Rep 3:1953

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