Enzyme-free and protein-assisted dual-amplified fluorescence anisotropy for sensitive miRNA detection in tumor cells

Abstract We here report a double amplification strategy to construct a fluorescence anisotropy sensor for microRNA analysis in practical biological samples. In this strategy, one target can trigger cyclic catalyzed hairpin assembly (CHA), with streptavidin incorporated as an amplifier of molar mass to enhance the signal intensity. The proposed strategy has a good linearity in the range of 5 pM - 0.5 nM with a detection limit down to 2.3 pM. More importantly, by using fluorescence anisotropy as the signal output, the strategy can be used directly for detection of miRNA in practical samples without any tedious sample pretreatment, holding the practical value in real biological systems.