DNA Aptamers as Radically New Recognition Elements for Biosensors

V. A. Spiridonova^1* and A. M. Kopylov^1,2

¹Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992 Russia; fax: (095) 939-3181; E-mail: spiridon@genebee.msu.su

²School of Chemistry, Lomonosov Moscow State University, Moscow, 119899 Russia

^* To whom correspondence should be addressed.

Received November 1, 2001

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A fiber-optic biosensor based on DNA aptamers used as receptors was developed for the measurement of thrombin concentration. Anti-thrombin DNA aptamers were immobilized on silica microspheres, placed inside microwells on the distal tip on an imaging optical fiber, coupled to a modified epifluorescence microscope through its proximal tip. Thrombin concentration is determined by a competitive binding assay using a fluorescein-labeled competitor. The biosensor is selective and can be reused without any sensitivity change. The thrombin limit of detection is 1 nM, sample volume is 10 µl, and assay time per sample is 15 min including the regeneration step.

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KEY WORDS: DNA aptamers, thrombin, glass fiber, biosensor, SELEX

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