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Proceedings Paper

Oxygen concentration measurement with a phosphorescence lifetime based micro-sensor array using a digital light modulation microscope
Author(s): Shih-hui Chao; Mark R. Holl; Sarah C. McQuaide; Deirdre R. Meldrum
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Paper Abstract

A digital light modulation microscope (DLMM) using a digital micro-mirror device (DMD, Texas Instruments) has been developed to enable detection of O2 concentration in micro-bioreactors using O2-quenching porphyrin phosphorescent dyes. The emission intensity and phosphorescence lifetime of such dyes are both a function of O2 concentration. While emission intensity can vary in these dye systems as a function of concentration and illumination intensity, phosphorescence lifetime is primarily sensitive to only O2 concentration. In contrast to conventional phosphorescence lifetime imaging, the DLMM eliminates the need for a pulsed light source, scanning mirrors, or a high-speed camera for time-gated imaging. This technique can selectively address structured light illumination to each sensor location, which is a beneficial feature for analysis of large micro-sensor arrays within lab-on-a-chip devices. The mirrors on the DMD perform as electronically addressable optical switches, each having a ~15 μs switching time, shorter than the phosphorescence lifetimes of potential O2 sensing dyes (~25-100 μs). The structured light pattern of the DMD and the switching rate of the mirrors are controlled by a PC. An arc lamp illuminates the DMD uniformly and then projects to the specimen through a filter cube for the selected phosphorescent sensor compound. The emitted light returns to the filter cube and is detected by a photo multiplier tube (PMT). An oscilloscope is used to record the emission signal waveform from the PMT. To demonstrate O2 sensing with lab-on-a-chip devices, an array of 150-μm-diameter micro-wells coated with phosphorescent porphyrin were observed using the DLMM. The goal of this platform is to measure the O2 consumption of individual cells trapped in the microwells.

Paper Details

Date Published: 21 February 2006
PDF: 8 pages
Proc. SPIE 6088, Imaging, Manipulation, and Analysis of Biomolecules, Cells, and Tissues IV, 60880S (21 February 2006); doi: 10.1117/12.644939
Show Author Affiliations
Shih-hui Chao, Univ. of Washington (United States)
Mark R. Holl, Univ. of Washington (United States)
Sarah C. McQuaide, Univ. of Washington (United States)
Deirdre R. Meldrum, Univ. of Washington (United States)

Published in SPIE Proceedings Vol. 6088:
Imaging, Manipulation, and Analysis of Biomolecules, Cells, and Tissues IV
Daniel L. Farkas; Dan V. Nicolau; Robert C. Leif, Editor(s)

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