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A Simple Fluorescent Biosensor for Theophylline Based on its RNA Aptamer

2006; Taylor & Francis; Volume: 25; Issue: 12 Linguagem: Inglês

10.1080/15257770600919084

1532-2335

Connie Rankin, Esther Fuller, K. H. Hamor, S. A. Gabarra, Thomas P. Shields,

Molecular Junctions and Nanostructures

Abstract Theophylline is a potent bronchodilator with a narrow therapeutic index. A simple fluorescent biosensor that detects clinically relevant theophylline concentrations has been developed using the well-characterized theophylline binding RNA aptamer. Hybridization of the RNA aptamer to a fluorescently labeled DNA strand (FL-DNA) yields a fluorescent RNA:DNA hybrid that is sensitive to theophylline. The biosensor retains the remarkable selectivity of the RNA aptamer for theophylline over caffeine and is sensitive to 0–2 μM theophylline, well below the clinically relevant concentration (5–20 mg/L or ∼10–50 μM). Adding a dabcyl quenching dye to the 3′-terminus of the fluorescently labeled DNA strand yielded a dual-labeled DNA strand (FL-DNA-Q) and increased the dynamic range of this simple biosensor from 1.5-fold to 4-fold. Keywords: RNA aptamerFluorescent biosensorTheophylline Acknowledgments This research was supported in part by the Research Corporation (CC5796), and the University of San Diego SURE and Faculty Research Grant programs. The authors would also like to thank Sweetie Kaycee for assistance in purifying oligonucleotides and Dr. Christy Chow (Wayne State University, Detroit, MI) for careful reading and discussion of the manuscript.