Abstract:
:We report a signal-on, electronic DNA (E-DNA) sensor that is label-free and achieves a subpicomolar detection limit. The sensor, which is based on a target-induced strand displacement mechanism, is composed of a "capture probe" attached by its 5' terminus to a gold electrode and a 5' methylene blue-modified "signaling probe" that is complementary at both its 3' and 5' termini to the capture probe. In the absence of target, hybridization between the capture and signaling probes minimizes contact between the methylene blue and electrode surface, limiting the observed redox current. Target hybridization displaces the 5' end of the signaling probe, generating a short, flexible single-stranded DNA element and producing up to a 7-fold increase in redox current. The observed signal gain is sufficient to achieve a demonstrated (not extrapolated) detection limit of 400 fM, which is among the best reported for single-step electronic DNA detection. Moreover, because sensor fabrication is straightforward, the approach appears to provide a ready alternative to the more cumbersome femtomolar electrochemical assays described to date.
journal_name
Proc Natl Acad Sci U S Aauthors
Xiao Y,Lubin AA,Baker BR,Plaxco KW,Heeger AJdoi
10.1073/pnas.0607693103subject
Has Abstractpub_date
2006-11-07 00:00:00pages
16677-80issue
45eissn
0027-8424issn
1091-6490pii
0607693103journal_volume
103pub_type
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