Intramolecular enhanced entropy-driven DNA-Au nanodevice for mRNA imaging in living cells

An intramolecular enhanced entropy-driven DNA amplifier-tethered gold nanoparticle (DNA-Au) nanodevice has been designed for highly sensitive in situ imaging of messenger ribonucleic acid (mRNA) in living cells. The DNA amplifier is immobilized on a same AuNP and the initial fluorescence of DNA-Au nanodevice is quenched. Upon internalized into the target cancer cells, the nanodevice can be activated by endogenous TK1 mRNA, and promptly release the fluorophore via the intramolecular enhanced DNA strand displacement reaction. The decreasing distance and increasing local concentration of the probes via intramolecular reaction can significantly improve the reaction kinetics of DNA-Au nanodevice, thus achieving the highly sensitive imaging of TK1 mRNA. The excellent sensitivity and selectivity allow the DNA-Au nanodevice to accurately discriminate different cell lines and monitor the variations in intracellular TK1 mRNA expression levels via fluorescence imaging. Therefore, the proposed intramolecular enhanced entropy-driven DNA-Au nanodevice will afford a reliable approach for accurate determination of mRNA in molecular diagnostic systems.