High-Efficient Electrochemiluminescence of DNA-Au Ag Nanoclusters with Au NPs@Ti<sub>3</sub>C<sub>2</sub> as a Novel Coreaction Accelerator for Ultrasensitive Biosensing
Huiling Wu, Xiaochun Zhu, Xiaoyu Shi, Yaqin Chai, Ying Zhou, Ruo Yuan
Abstract
In this work, an ultrasensitive electrochemiluminescence (ECL) biosensor was constructed based on DNA-stabilized Au Ag nanoclusters (DNA-Au Ag NCs) as the efficient luminophore and Au NPs@Ti 3 C 2 as a new coreaction accelerator for determining microRNA-221 (miRNA-221) related to liver cancer. Impressively, DNA-Au Ag NCs were stabilized by the high affinity of the periodic 3C sequence, exhibiting an excellent ECL efficiency of 27% compared with classical BSA-Au Ag NCs (16%). Moreover, the Au NPs@Ti 3 C 2 nanocomposites, as a new coreaction accelerator, were first introduced to accelerate the production of abundant sulfate free radicals (SO 4 •– ) for promoting the ECL efficiency of DNA-Au Ag NCs in the DNA-Au Ag NCs/Au NPs@Ti 3 C 2 /S 2 O 8 2– ternary system due to the energy band of Au NPs@Ti 3 C 2 being well-matched with the frontier orbital of S 2 O 8 2– . Furthermore, the trace target (miRNA-221) could drive the rolling circle amplification to generate an amount of output DNA with periodic 3C and 10A sequences. Through covalent bonds on the surface of poly A and Au NPs, the distance between the luminophor and the coreaction accelerator could be narrowed to further enhance the detection sensitivity. As a result, the constructed sensor has been applied for the ultrasensitive detection of miRNA-221 with a low detection limit of 50 aM and successfully monitored miRNA-221 in MHCC-97L and HeLa cell lysates. This strategy could be utilized for guiding the synthesis of light-emitting DNA-metal NCs, which has great potential in the construction of ultrasensitive biosensors for the early diagnosis of diseases.