DNA/RNA chimera-templated copper nanoclusters for label-free detection of reverse transcription-associated ribonuclease H

DNA templated fluorescent copper nanoclusters (DNA-CuNCs) have demonstrated enormous potential for biochemical analysis. However, most of them are focused on DNA-related sensing. Here, we designed a hairpin DNA/RNA chimeric chain for the formation of fluorescent CuNCs and further applied it to detect reverse transcription-associated ribonuclease H (RNase H). The DNA/RNA chimera templated copper nanoclusters (DNA/RNA-CuNCs) exhibited similar spectral properties with DNA-CuNCs. In the presence of RNase H, the RNA segment in chimera is hydrolyzed and release short oligonucleotides, which fail to synthsize fluorescent CuNCs. The capabilities for RNase H detection from complex samples and screening of inhibitors were verified. This strategy exhibited high sensitivity for RNase H with a detectable minimum concentration of 5.5 × 10 −4 U mL -1 , which is lower than the developed fluorescent methods. This work will open up new thoughts to design new template for metal nanoclusters and broaden their application in RNA-related sensing.