Imaging oxygen in vivo presents a challenging and important problem in modern physiology and medicine. A number of methods for mapping oxygenation in biological objects have been proposed in the past, but none of them provides means for microscopic imaging with three-dimensional capability. We propose to develop a technique for microscopic imaging of oxygen in biological systems by coupling the phosphorescence quenching method with two-photon laser scanning microscopy (2P LSM). The work plan has three main objectives: 1) synthetic development of two-photon excitable phosphorescent probes and their photophysical characterization;2) construction of two-photon imaging system for phosphorescence (long radiative lifetimes of phosphorescent probes make standard systems for two-photon imaging non- suitable for this application);3) testing the technique using biological systems for which information about the distribution of oxygen at microscopic (sub-cellular) level is of high significance. These systems are: oxygen gradients formed-during phagocytic endocytosis (S. Muro, Penn Pharmacology);oxygen gradient between the choroid and the retina of the eye (E. Pugh, Penn Ophthalmology);oxygen distribution in the brain (D. Boas, Harvard/MGH). Development of two-photon phosphorescent oxygen nanosensors is the key to the proposal, and the corresponding part of the work plan (Specific Aims 1 and 2) is a continuation of the pilot project funded by the NIH grant R21 EB-003663-01. The design of the sensor combines principles and approaches currently under scrutiny in several nanotechnology applications: two-photon absorption (2PA) by an antenna-array, consisting of multiple chromophores, coupled to the same functional core;intramolecular energy transfer (ET) from the antenna to the core;dendritic encapsulation of the core to achieve its protection and to control its local environment. The feasibility of the design has been demonstrated and the ways of optimization of probes for in vivo applications have been identified. Furthermore, the results obtained reveal changes that will have to be made to two-photon standard imaging setup to permit imaging of phosphorescence. The biological systems are selected to evaluate the performance of the technique and to simultaneously obtain valuable information for the related bio-medical problems.

Agency
National Institute of Health (NIH)
Institute
National Institute of Biomedical Imaging and Bioengineering (NIBIB)
Type
Research Project (R01)
Project #
5R01EB007279-03
Application #
7568976
Study Section
Enabling Bioanalytical and Biophysical Technologies Study Section (EBT)
Program Officer
Zhang, Yantian
Project Start
2007-04-01
Project End
2011-01-31
Budget Start
2009-02-01
Budget End
2010-01-31
Support Year
3
Fiscal Year
2009
Total Cost
$240,764
Indirect Cost
Name
University of Pennsylvania
Department
Biochemistry
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Chen, Ping; Finikova, Olga S; Ou, Zhongping et al. (2012) Electrochemistry of platinum(II) porphyrins: effect of substituents and ýý-extension on redox potentials and site of electron transfer. Inorg Chem 51:6200-10
Mani, Tomoyasu; Niedzwiedzki, Dariusz M; Vinogradov, Sergei A (2012) Generation of phosphorescent triplet states via photoinduced electron transfer: energy and electron transfer dynamics in Pt porphyrin-Rhodamine B dyads. J Phys Chem A 116:3598-610
Devor, Anna; Sakadzic, Sava; Srinivasan, Vivek J et al. (2012) Frontiers in optical imaging of cerebral blood flow and metabolism. J Cereb Blood Flow Metab 32:1259-76
Esipova, Tatiana V; Karagodov, Alexander; Miller, Joann et al. (2011) Two new ""protected"" oxyphors for biological oximetry: properties and application in tumor imaging. Anal Chem 83:8756-65
Lecoq, Jerome; Parpaleix, Alexandre; Roussakis, Emmanuel et al. (2011) Simultaneous two-photon imaging of oxygen and blood flow in deep cerebral vessels. Nat Med 17:893-8
Ceroni, Paola; Lebedev, Artem Y; Marchi, Enrico et al. (2011) Evaluation of phototoxicity of dendritic porphyrin-based phosphorescent oxygen probes: an in vitro study. Photochem Photobiol Sci 10:1056-65
Sakadži?, Sava; Roussakis, Emmanuel; Yaseen, Mohammad A et al. (2011) Cerebral blood oxygenation measurement based on oxygen-dependent quenching of phosphorescence. J Vis Exp :
Devor, Anna; Sakadzic, Sava; Saisan, Payam A et al. (2011) ""Overshoot"" of O? is required to maintain baseline tissue oxygenation at locations distal to blood vessels. J Neurosci 31:13676-81
Pedersen, Brian W; Sinks, Louise E; Breitenbach, Thomas et al. (2011) Single cell responses to spatially controlled photosensitized production of extracellular singlet oxygen. Photochem Photobiol 87:1077-91
Filatov, Mikhail A; Lebedev, Artem Y; Mukhin, Sergei N et al. (2010) Pi-extended dipyrrins capable of highly fluorogenic complexation with metal ions. J Am Chem Soc 132:9552-4

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