Various types of nanoprobes have recently been utilized to monitor living organisms by detecting and imaging intracellular biomarkers, such as microRNAs (miRs). We here present a simple one-pot method to prepare stellate gold nanoparticles functionalized with miR-detecting molecular beacons (SGNP-MBs); low pH conditions permitted the rapid-high loading of MBs on the surface of SGNPs. Compared to the conventional gold nanoparticle-based MBs, SGNPs carried a 4.5-fold higher load of MBs and exhibited a 6.4-fold higher cellular uptake. We demonstrated that SGNP-MBs were successfully internalized in human gastric cancer cell lines and could be used to accurately detect and image intracellular miRs in an miR-specific manner. Furthermore, the relative levels of intracellular miRs in three different cell lines expressing miR-10b (high, moderate, and low levels) could be monitored using SGNP-MBs. Consequently, these results indicated that SGNP-MBs could have applications as highly potent, efficient nanoprobes to assess intracellular miR levels in living cells.
Keywords: branched gold nanoparticles; cancer imaging; miRNA sensing; molecular beacon; nanobiosensor.