Au Nanoparticle-Based Fluorescent Turn-on Nanoprobes for Real-Time Imaging the Expression of miR-630 during Cell Apoptosis

A simple and fast-responsive fluorescent nanoprobe has been developed for fluorescence imaging of miR-630 during apoptosis in A549 cells. This nanoprobe is composed of gold nanoparticles (AuNPs) modified with thiol-terminated DNA hybridized with a TAMRA labeled DNA, resulting in fluorescence quenching due to the nanometal surface energy transfer (NSET) between the surface of AuNPs and TAMRA. The hybridization of miR-630 and DNA-coupled TAMRA liberates the TAMRA-modified DNA from AuNPs, resulting in the recovery of fluorescence. Based on the specific recognition and fluorescence turn-on phenomenon, the nanoprobe was successfully used for the detection of miR-630 in a wide range of 0.5–120 nM with a detection limit (LOD) of 0.36 nM. Furthermore, this fluorescent nanoprobe with high selectivity, good nuclease stability, and biocompatibility was applied for real-time monitoring the dynamic expression level of miR-630 in the process of apoptosis in A549 cells successfully. Therefore, by monitoring the expression of miR-630 in A549 cells during treatment with different drugs, this proposed method with the superiorities of simplicity, rapidness, and high selectivity might be prospective to understand the cell apoptosis-associated process and evaluating the effect of drug stimulation for further screening of anti-cancer drugs.