Ratiometric FRET Encoded Hierarchical ZrMOF @ Au Cluster for Ultrasensitive Quantifying MicroRNA In Vivo

Here, Zirconium metal-organic frameworks @ gold (ZrMOF @ Au) cluster architectures have been fabricated and then functionalized with two fluorescent dyes (Quasar [QS] and Cyanine5.5 [Cy5.5]) through deoxyribonucleic acid hybridization, to form a fluorescence resonance energy transfer (FRET) encoded ZrMOF @ Au-QS/Cy5.5 complex. In the presence of the target intracellular microRNA (miR)-21, the fluorescence of Cy5.5 at 705 nm (F705 ) decreases and the fluorescence of QS at 665 nm (F665 ) increases when Cy5.5 is released from the surface of ZrMOF @ Au-QS/Cy5.5. The change in the fluorescence ratio (F705 /F665 ) shows an outstanding linear range of 0.006-67.9 amol/ngRNA , and the limit of detection is 4.51 zmol/ngRNA in living cells. The high ratio loading of nucleic acid on surface of ZrMOF @ Au cluster and two fluorescence encoded signal enables better sensitivity and reliability. Zeptomolar sensitivity and good linearity against target affords distinct imaging-based monitoring of the cancer marker miR-21 both in living cells and in vivo. At the same time, the architecture displays remarkable photothermal conversion efficiency (53.7%) and gives rise to outstanding therapy ability in vivo. This strategy offers new avenues for the intelligent quantification of miRNAs for simultaneous diagnoses and treatments of early-stage cancers.