Adapting selected nucleic acid ligands (aptamers) to biosensors.
A flexible biosensor has been developed that utilizes immobilized nucleic acid aptamers to specifically detect free nonlabeled non-nucleic acid targets such as proteins. In a model system, an anti-thrombin DNA aptamer was fluorescently labeled and covalently attached to a glass support. Thrombin in solution was selectively detected by following changes in the evanescent-wave-induced fluorescence anisotropy of the immobilized aptamer. The new biosensor can detect as little as 0.7 amol of thrombin in a 140-pL interrogated volume, has a dynamic range of 3 orders of magnitude, has an inter-sensing-element measurement precision of better than 4% RSD over the range 0-200 nM, and requires less than 10 min for sample analysis. The aptamer-sensor format is generalizable and should allow sensitive, selective, and fast determination of a wide range of analytes.
Potyrailo
R A
RA
Laboratory for Spectrochemistry, Indiana University, Bloomington 47405, USA.
Conrad
R C
RC
Ellington
A D
AD
Hieftje
G M
GM
D016880:Anisotropy; D015374:Biosensing Techniques; D004268:DNA-Binding Proteins / Q000737:chemistry*; D005453:Fluorescence; D006801:Humans; D011485:Protein Binding; D013917:Thrombin / Q000737:chemistry
D004268:DNA-Binding Proteins; D013917:Thrombin