Nano Archive

Photoacoustic probing of fluorophore excited state lifetime with application to oxygen sensing

Ashkenazi, Shai and Huang, Shen-Wen and Horvath, Thomas and Koo, Yong-Eun L. and Kopelman, Raoul (2008) Photoacoustic probing of fluorophore excited state lifetime with application to oxygen sensing. JOURNAL OF BIOMEDICAL OPTICS, 13 (3).

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Official URL: http://dx.doi.org/10.1117/1.2927466

Abstract

A new method is developed to perform local measurements of fluorophore excited state lifetimes in turbid media without collecting the fluorescence emission. The method is based on a pump-probe approach where a first laser pulse excites the dye and then a second laser pulse is used for photoacoustic probing of the transient absorption. The photoacoustic response generated by the probe pulse is recorded by an ultrasound receiver. Repeating the measurement for increasing pump-probe time delays yields a series of photoacoustic signals that are used to extract the lifetime of the excited state. The method is validated by measuring the lifetime of an oxygen sensitive dye solution at different concentrations of dissolved oxygen. The dye is pumped with a 532-nm pulsed laser and the transient absorption at 740 nm is probed using a second pulsed laser system. The photoacoustic-based results are in close agreement with those obtained from time-dependent fluorescent measurements. The method can be extended to photoacoustic lifetime imaging by using a receiver array instead of a single receiver. Potential applications of this method include tissue oxygen imaging for cancer diagnostics and mapping molecular events such as resonant energy transfer and ion collisions in a biological environment. (c) 2008 Society of Photo-Optical Instrumentation Engineers.

Item Type:Article
Uncontrolled Keywords:fluorescence lifetime imaging; photoacoustic imaging; transient absorption; oxygen sensing; molecular imaging
Subjects:Analytical Science > Microscopy and probe methods
Analytical Science > Nanotechnology for sensing and actuating
Analytical Science > Beam methods
ID Code:1167
Deposited By:Anuj Seth
Deposited On:16 Dec 2008 16:52
Last Modified:19 Jan 2009 13:32

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