An ultrasensitive carcinoembryonic antigen electrochemical aptasensor based on 3D DNA nanoprobe and Exo III.

In this study, a highly ordered three dimensional (3D) DNA nanostructure was self-assembled by label-free DNA nanotweezers, which was used as recognized probe to interact with target. Once the target was recognized by the 3D DNA nanoprobe (3D DNT), DNA nanotweezers opened to release target analog (T1). This recognition process was proceeded in homogeneous solution, which can avoid complex electrode modification and improve reaction efficiency. Then these target analogs were captured by the signal DNA probes (E1) modified on the electrode. In the assistance of Exo III, E1 was digested and the T1 was released to participate in the next cycle to realize signal amplification. Finally, an ultrasensitive carcinoembryonic antigen (CEA) electrochemical biosensing with a detection limit of 4.88 fg mL−1 was developed. • Label-free 3D DNA nanoprobe based on DNA tweezers was firstly developed in electrochemical biosensing. • Homogeneous biorecognition strategy simplified experiment procedure and improved reaction efficiency. • Exo III assisted recycling amplification technology improved the sensitivity of biosensor. [ABSTRACT FROM AUTHOR]