High-Affinity RNA as a Recognition Element in a Biosensor

A biosensor for l-adenosine employing high-affinity RNA as binder is reported. Real-time measurement is obtained using total internal reflection fluorescence in a fiber-optic format. High-affinity RNA was attached to the core of a multimode fiber via an avidin−biotin bridge. The sensor measures binding of FITC-labeled l-adenosine. The interaction was fully characterized by the determination of association and dissociation rates: k D = 0.0119 s-1; k A = 2200 M-1 s-1. Competitive inhibition with l-adenosine enables this device to detect l-adenosine in the submicromolar range.