Analytical Sciences

A Novel DNAzyme Signal Amplification-based Colorimetric Method for RNase H Assays

Ye XIE,* Sina ZHANG,* Ting DENG,* Ke ZHANG,* Jiali REN,* and Jishan LI**

*Institute of Applied Chemistry, School of Science, Hunan Province Key Laboratory of Edible Forestry Resources Safety and Processing Utilization, Central South University of Forestry and Technology, Changsha, 410004, China
**State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China

A simple visual strategy was developed for the RNase H colorimetric measurement using DNAzyme-mediated signal amplification. When RNase H was presented, the RNA strand of the duplex formed by the G-rich DNA sequence (G-Rich) and its complementary RNA sequence (cp-RNA) was digested, releasing G-Rich to form HRP-mimicking DNAzymes of the G-quadruplex/hemin complexes in the presence of hemin. These DNAzymes catalyze the oxidation reaction of the substrate of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) to produce green-color products of ABTS^•−, allowing for the detection of RNase H. A horseradish peroxidase (HRP)-mimicking DNAzyme of the G-quadruplex/hemin complex was used to mediate the signal amplification in the sensing strategy, resulting in high selectivity and sensitivity. This proposed colorimetric method shows a low detection limit of 0.04 U/mL, with a detection range of 0.1 to 3 U/mL. Moreover, this colorimetric method has been successfully used for RNase H assays in complicated biosamples, such as cell lysates. These results indicate that our colorimetric method not only detects RNase H in an ideal system, but also in real samples.

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