title: Nanomaterial-amplified "signal off/on" electrogenerated chemiluminescence aptasensors for the detection of thrombin.
abstract: Two electrogenerated chemiluminescence (ECL) aptasensors for the detection of thrombin were developed using the thrombin binding aptamer (TBA) taken as a molecular recognition element and nanomaterial as a carrier of the ECL capture/signal probe. In the "signal off" aptasensor, the thiolated capture probe (ss-DNA, 12-mer) was self-assembled on the gold nanoparticles (GNPs) which were self-assembled on the surface of gold electrode, and hybridized with six-base segment of the ss-DNA sequence (Tgt-aptamer, 21-mer) containing TBA-I (ss-DNA, 15-mer) tagged with ruthenium complex, producing a high ECL intensity. Introduction of the analyte thrombin triggered the dissociation of the Tgt-aptamer tagged with ruthenium complex from the aptasensors, led to significantly decrease in ECL intensity. The decreased ECL intensity was in proportion to the concentration of thrombin in a range from 2.7×10(-12) to 2.7×10(-9) M with a detection limit of 8×10(-13) M. In the "signal on" aptasensor, the thiolated TBA-I was self-assembled on the gold electrode for capturing thrombin onto the electrode and then the TBA-II (ss-DNA, 29-mer) labeled with single-walled carbon-nanotubes (SWNT)-ECL tag was bound with epitope of thrombin, producing a high ECL intensity. The increased ECL intensity was linearly with the concentration of thrombin from 1.0×10(-14) M to 1.0×10(-11) M with a detection limit of 3×10(-15) M. The present work demonstrates that using nanomaterial as a carrier for capture probe and signal probe is a promising way to amplify the ECL signal and to improve the sensitivity of the aptasensors.
authors.affiliation: Key Laboratory of Applied Surface and Colloid Chemistry (Shaanxi Normal University), Ministry of Education, School of Chemistry and Materials Science, Shaanxi Normal University, Xi'an 710062, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Honglan
authors.initials: H
authors.lastname: Qi
authors.forename: Qiang
authors.initials: Q
authors.lastname: Gao
authors.forename: Jia
authors.initials: J
authors.lastname: Yang
authors.forename: Chengxiao
authors.initials: C
authors.lastname: Zhang
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry* / Q000528:radiation effects; D015374:Biosensing Techniques / Q000295:instrumentation*; D004574:Electromagnetic Fields; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D008163:Luminescent Measurements / Q000295:instrumentation*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D013917:Thrombin / Q000032:analysis*
chemical_list: D052157:Aptamers, Nucleotide; D013917:Thrombin