On target: We have developed two cascade amplification strategies that combine duplex specific nuclease (DSN) amplicon with either G-quadruplex-based DNA peroxidase or 8-17 DNAzyme amplicon for miRNA detection. In this way, sensitive and convenient detection of miRNAs was achieved. In the DNA peroxidase-based system, a visual color change could be observed in the presence of target miRNAs (see scheme).

The analysis of DNA methylation and MTase (methyltransferase) activity is important in epigenetic study. We have developed a novel strategy for sensitive analysis of MTase activity based on a hairpin shaped DNAzyme; 8-17 DNAzyme amplicon has been adopted and found to be very effective in such analysis.

We reported an efficient strategy based on a strand displacement amplification for serum miRNA detection. In such a system, a multiplexed, sensitive and quick detection of miRNAs could be achieved through a combination of fluorescence labeled probes, a common primer and a polymerase. This could be potentially used in the clinical field to achieve early disease diagnosis and prognosis.

The present study demonstrated a highly sensitive strategy for measuring telomerase activity in cell extracts. Furthermore, we applied the new strategy for in situ detection of telomerase at the cellular level in cancer cells, together with a normal cell as the negative control.

The G-quadruplex is one of the most important DNA secondary structures and has elicited widespread interest in this field of scientific research. As G-quadruplex studies have progressed, its significant roles in a variety of biological process have been revealed, including telomerase activity, genome stability, DNA replication, and oncogene expression. In addition to its biological functions, as a special DNA quadruplex structure, it also has potential for other important applications like asymmetric catalysis, probing for important biomarkers, acting as a vehicle for drug delivery, or as a structural regulator for some nanostructure designs. Here, we discuss its application to aspects of biological target detection and drug delivery. Its utility in biological target detection mainly results from its special DNAzyme activity. We would summarize some typical systems, utilizing G-quadruplex as signal readout unit, for various target detection, such as SNP, miRNAs, ions, transcription factors and so on. On the other hand, its use in drug delivery always relies on probes' structural change, as the switch of drug release. Here, we would also exhibit some typical drug delivery designs.