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8 May 1995 Energy-transfer-based fiber optic metal ion biosensor
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Recently, we have demonstrated a fluorescence-based fiber optic biosensor for zinc in aqueous solutions. Binding of zinc to the active site of human apocarbonic anhydrase II is transduced by subsequent binding of a fluorescent inhibitor, dansylamide, to the zinc in situ, resulting in large changes in the wavelength, quantum yield and lifetime of the danslamide emission. These fluorescence changes can be readily measured through optical fiber, and yield subnanometer detection limits and 50 dB dynamic range with excellent selectivity. However, the dansylamide is only excitable in the ultraviolet, a spectral regime where fiber optic attenuation is very high; longer wavelength fluorescent inhibitors akin to dansylamide are not yet available. Thus we chose a different transduction scheme wherein the enzyme is labeled with a suitable fluorescent tag and the inhibitor is colored, absorbing in the visible region. When zinc is bound the inhibitor can then bind, bringing it in close proximity to the fluorescent tag and allowing energy transfer to occur; the energy transfer can be followed by changes in intensity or, preferably, lifetime. Recent results using gas laser and laser diode excitation will be shown.
© (1995) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Richard B. Thompson, Zhengfang Ge, Marcia W. Patchan, and Carol A. Fierke "Energy-transfer-based fiber optic metal ion biosensor", Proc. SPIE 2388, Advances in Fluorescence Sensing Technology II, (8 May 1995);

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