Interspace-controlled biosensing interface with enhanced charge transfer based on tripod DNA probes.

Binding of a target by a probe for selective detection depends on the state of the probes on the sensing interface. Here, the hanging strand length of triple-helix DNA was used to form tripod probes immobilized via π-π interactions on a reduced graphene-oxide substrate. The spacing between the probes was adjusted by controlling the lengths of the tripod "feet" on the substrate; that is, increased probe spacing occurred when foot size increased over the range of 6-12 bases. The surface coverages and electron-transfer rates mediated the tripod DNA probes were characterized by electrochemical methods and atomic force microscopy. The electron-transfer mediated by the tripod DNA probes was higher than that mediated by doubled-stranded DNA. Then different sizes tripod DNA probes were developed for protein-CEA detection. The DNA probes with 10 bases feet showed the best detection limit of detection of 10-6 ng/mL in the detection linear range (10-6 - 25 ng/mL). The result demonstrated the tripod DNA probes with different sizes could obtain excellent sensitivity when it applied to the target with appropriate size. This interspace-controlled biosensing interface of tripod DNA probes with enhanced charge transfer should find widespread applications in clinical, medical, biological, and environmental areas for precise detection of differently sized targets. Copyright © 2021 Elsevier B.V. All rights reserved.

Citation

Xin Jin, Liping Lu, Xiayan Wang. Interspace-controlled biosensing interface with enhanced charge transfer based on tripod DNA probes. Talanta. 2021 Nov 01;234:122670

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PMID: 34364471

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