Abstract
Sensitive assay and imaging of multiple low-abundance microRNAs (miRNAs) in living cells remain a grand challenge. Herein, based on polyelectrolyte-induced reduction, a facile approach has been proposed to synthesize novel MnO(2) nanotubes. Owing to the remarkably strong fluorescence quenching ability, low cytotoxicity, and excellent colloid stability, the as-prepared MnO(2) nanotubes showed great potential for simultaneous detection and imaging of multiple miRNAs in vitro and in situ in living cells for the first time. Besides, MnO(2) nanotubes can be reduced to Mn(2+) by intracellular acid pH or glutathione, which may serve as an activatable contrast reagent for MRI. Therefore, the MnO(2) nanotube-based probes, termed "NanoSearchlight", provide a promising, multimodal imaging tool for precise and accurate diagnosis and prognosis of cancers.