Quantitative detection of microRNA-21 using assembled photoacoustic and SERS nanoprobes.

Accurately quantifying microRNA levels is of great importance for cancer staging and prognosis. However, the low abundance of microRNAs and interference from the complex tumor microenvironment usually limit the real-time quantification of microRNAs . Herein, for the first time, we develop an ultrasensitive microRNA (miR)-21 activated ratiometric nanoprobe for quantification of the miR-21 concentration without signal amplification as well as dynamic tracking of its distribution.