251. Interspace-controlled biosensing interface with enhanced charge transfer based on tripod DNA probes.
- Author
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Jin, Xin, Lu, Liping, and Wang, Xiayan
- Subjects
- *
DNA probes , *ATOMIC force microscopy , *SPACE probes , *DETECTION limit - Abstract
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. [Display omitted] • A size programmable DNA tripod probe based on triple helix structure was investigated. • Tripod probes with different sizes can control the probes surface density. • Tripod probes exhibited well-behaved charge transport properties. • Tripod probes with appropriate size could obtain excellent sensitivity for protein detection. [ABSTRACT FROM AUTHOR] more...
- Published
- 2021
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