Electrogenerated chemiluminescence resonance energy transfer between luminol and MnO2 nanosheets decorated with Cu2O nanoparticles for sensitive detection of RNase H

In the present work, a novel approach was developed for the preparation of Cu2O nanoparticle decorated MnO2 nanosheets (Cu2O@MnO2). Uniformly dispersed Cu2O nanocrystals were produced on the surface of MnO2 nanosheets by in situ reduction under refluxing conditions. The unique structure of the used MnO2 nanosheet support played a vital role in the preparation of such Cu2O@MnO2 nanocomposites. The electrogenerated chemiluminescence (ECL) resonance energy transfer can occur between the luminol/H2O2 system and Cu2O@MnO2 nanocomposites, resulting in a decrease of the ECL intensity, which can be used to fabricate an ECL sensor. Cu2O@MnO2 nanocomposite modified heterologous DNA/RNA duplexes were modified on the GCE to construct an ECL-RET system, leading to the decrease of ECL intensity. As a highly conserved damage repair protein, RNase H can specifically hydrolyze RNA in DNA/RNA strands to release Cu2O@MnO2 nanocomposites and recover the ECL signal. As a result, an "off-on" mode ECL sensor for sensitive RNase H assay was fabricated. Under the optimal conditions, the detection limit of RNase H is 0.0005 U mL-1, which is superior to other approaches. The proposed method provides a universal platform for monitoring RNase H, and exhibits great potential in bioanalysis.