title: An electrochemical sensor for single nucleotide polymorphism detection in serum based on a triple-stem DNA probe.
abstract: We report here an electrochemical approach that offers, for the first time, single-step, room-temperature single nucleotide polymorphism (SNP) detection directly in complex samples (such as blood serum) without the need for target modification, postwashing, or the addition of exogenous reagents. This sensor, which is sensitive, stable, and reusable, is comprised of a single, self-complementary, methylene blue-labeled DNA probe possessing a triple-stem structure. This probe takes advantage of the large thermodynamic changes in enthalpy and entropy that result from major conformational rearrangements that occur upon binding a perfectly matched target, resulting in a large-scale change in the faradaic current. As a result, the discrimination capabilities of this sensor greatly exceed those of earlier single- and double-stem electrochemical sensors and support rapid (minutes), single-step, reagentless, room-temperature detection of single nucleotide substitutions. To elucidate the theoretical basis of the sensor's selectivity, we present a comparative thermodynamic analysis among single-, double-, and triple-stem probes.
authors.affiliation: Materials Department, University of California, Santa Barbara, California 93106, USA. yixiao@physics.ucsb.edu
authors.forename: Yi
authors.initials: Y
authors.lastname: Xiao
authors.forename: Xinhui
authors.initials: X
authors.lastname: Lou
authors.forename: Takanori
authors.initials: T
authors.lastname: Uzawa
authors.forename: Kory J I
authors.initials: KJ
authors.lastname: Plakos
authors.forename: Kevin W
authors.initials: KW
authors.lastname: Plaxco
authors.forename: H Tom
authors.initials: HT
authors.lastname: Soh
mesh_terms: D000818:Animals; D015374:Biosensing Techniques; D002417:Cattle; D004247:DNA / Q000097:blood* / Q000235:genetics; D015342:DNA Probes / Q000032:analysis* / Q000235:genetics; D055664:Electrochemical Techniques; D020641:Polymorphism, Single Nucleotide
chemical_list: D015342:DNA Probes; D004247:DNA