Multiply Guaranteed and Successively Amplified Activation of a Catalytic DNA Machine for Highly Efficient Intracellular Imaging of MicroRNA

DNA amplification machines show great promise for intracellular imaging, yet are always constrained by off-site machinery activation or signal leakage, originating from the inherent thermodynamically driven hybridization between machinery substrates. Herein, an entropy-driven catalytic DNA amplification machine is integrated with the on-site amplified substrate exposure procedure to realize the high-contrast in vivo imaging of microRNA (miRNA). The key machinery substrate (fuel strands) is initially split into substrate subunits that are respectively grafted into an auxiliary DNA polymerization amplification accessory for eliminating the undesired signal leakage. Meanwhile, in target cells, the auxiliary polymerization accessory can be motivated by cell-specific mRNA for successively restoring their intact machine-propelling functions for guaranteeing the on-site amplified imaging of miRNA with high specificity. This intelligent on-site multiply guaranteed machinery can improve the specificity of catalytic DNA machines for discriminating different cell types and, thus, can provide a remarkable prospect in biomedical diagnosis.

Automated summary

In this study, a high-contrast in vivo imaging of microRNA (miRNA) was achieved by integrating an entropy-driven catalytic DNA amplification machine with on-site amplified substrate exposure procedure. The undesired signal leakage was eliminated by grafting substrate subunits into an auxiliary DNA polymerization amplification accessory. The intact machine-propelling functions were restored by cell-specific mRNA, ensuring the high specificity of on-site amplified miRNA imaging. This intelligent machinery shows great potential in biomedical diagnosis.