Enzyme-free aptamer/AuNPs-based fluorometric and colorimetric dual-mode detection for ATP

Abstract

An enzyme-free fluorometric and colorimetric dual-mode assay for the determination of adenosine triphosphate (ATP) was designed based on the specific recognition ability of fluorescent labeled aptamer (FAM-Apt) for target (ATP) and cDNAs modified gold nanoparticles (cDNAs-AuNPs). The fluorescence of FAM-Apt could be quenched by cDNAs-AuNPs because of the fluorescence resonance energy transfer (FRET) between the FAM and AuNPs. Herein, cDNAs-AuNPs served as the FAM-Apt capturers and fluorescence quenchers by narrowing the distance between FAM and AuNPs surface via the complementary base pairing of cDNAs with Apt. The existence of ATP will compete with cDNAs-AuNPs to capture FAM-Apt, and release FAM-Apt from the cDNAs-AuNPs surface, inducing fluorescence enhancement. What’s more, the separated cDNAs (single stranded DNA) in the presence of ATP showed better AuNPs protection performance than FAM-Apt-cDNAs complex (double stranded DNA) formed without ATP. Corresponding, the presence of ATP could be evidently confirmed by either fluorometric or colorimetric “light-on”. The detection limits and linear ranges could compare with other ATP detection platforms that needed expensive equipment or complex operations favorably. More important is that our design may provide a general method to detect various other biologically small molecules, metal ions and proteins based on their suitable aptamer.