title: Label-free genosensor based on immobilized DNA hairpins on gold surface.
abstract: In this report, we demonstrate a label-free genosensor based on DNA hairpins coupled to gold coated sensor surfaces. The hairpin probes were labeled with a thiolated moiety for immobilization at the 5' end and with a fluorophore for signal transduction at the 3' end. In the absence of the complement, the fluorophore is quenched by energy transfer to the gold surface. Addition of the target sequence leads to the hairpin unfolding, and releases the fluorescent signal. This built-in property, using a gold film as both the immobilizing substrate and quenching agent, has the advantage of simplicity in design and ease of further integration. Our results showed that lengths of both the stem and the loop structures have significant effects on the sensor performance. Hybridization kinetics was investigated for various probe/target lengths and concentrations. An optimized hairpin probe gave a fluorescent signal increase of 39 folds after hybridization, which is much higher than the earlier reported results. A limit of detection (LOD) down to 0.3 nM for the complementary target DNA detection has been achieved. The developed sensor was further successfully applied for the detection of single-base mismatch targets, as well as for the direct detection of PCR products.
authors.affiliation: IMEC, Kapeldreef 75, Leuven, Belgium. chengjun.huang@imec.be
authors.forename: Chengjun
authors.initials: C
authors.lastname: Huang
authors.forename: Tim
authors.initials: T
authors.lastname: Stakenborg
authors.forename: Yunan
authors.initials: Y
authors.lastname: Cheng
authors.forename: Frederik
authors.initials: F
authors.lastname: Colle
authors.forename: Tim
authors.initials: T
authors.lastname: Steylaerts
authors.forename: Karolien
authors.initials: K
authors.lastname: Jans
authors.forename: Pol
authors.initials: P
authors.lastname: Van Dorpe
authors.forename: Liesbet
authors.initials: L
authors.lastname: Lagae
mesh_terms: D020137:Base Pair Mismatch; D004247:DNA / Q000032:analysis* / Q000235:genetics; D015342:DNA Probes / Q000737:chemistry*; D004867:Equipment Design; D006046:Gold / Q000737:chemistry*; D057230:Limit of Detection; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods; D009693:Nucleic Acid Hybridization / Q000379:methods*; D016133:Polymerase Chain Reaction; D020349:Surface Plasmon Resonance / Q000295:instrumentation* / Q000379:methods; D013499:Surface Properties
chemical_list: D015342:DNA Probes; D006046:Gold; D004247:DNA