title: Supersandwich-type electrochemiluminescenct aptasensor based on Ru(phen)3(2+) functionalized hollow gold nanoparticles as signal-amplifying tags.
abstract: An electrochemiluminescent (ECL) aptasensor was fabricated and used for the amplified detection of thrombin (TB) based on DNA supersandwich structure. Herein, hollow gold nanospheres (HGNPs) were firstly employed as effective tag-carriers for the immobilization of detection aptamer (TBA 2) to form the HGNPs labeled TBA 2 (HGNPs-TBA 2). Subsequently, streptavidin (SA) was used to block the non-specific binding sites of HGNPs-TBA 2 as well as to supply binding sites, which could further introduce numerous initiator DNA strands (bio-S1) via biotin-streptavidin specific interaction. Next, bio-S1 could in situ trigger hybridization chain reaction (HCR) to create a long nicked double helices analogous (dsDNA) in the present of ssDNA S2 and ssDNA S3 (S3 is partially complementary to the S2) to obtain the DNA supersandwich structure. Furthermore, Ru(phen)3(2+), a well-known ECL luminophore, could be intercalated into the grooves of dsDNA (Ru-dsDNA) to form the Ru-dsDNA-SA-HGNPs-TBA 2 bioconjugate. As a result, the target of TB was sandwiched between Ru-dsDNA-SA-HGNPs-TBA 2 and TBA 1. In this strategy, numerous Ru(phen)3(2+) could be immobilized on the electrode based on the supersandwich structure, resulting in an increased ECL signal output. A supersandwich ECL assay for TB detection was developed with excellent sensitivity of a large concentration variation from 5fM to 50pM and a detection limit of 1.6fM.
authors: Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China.
authors: Guofeng
authors: G
authors: Gui
authors: Ying
authors: Y
authors: Zhuo
authors: Ya-Qin
authors: YQ
authors: Chai
authors: Ni
authors: N
authors: Liao
authors: Min
authors: M
authors: Zhao
authors: Jing
authors: J
authors: Han
authors: Qiang
authors: Q
authors: Zhu
authors: Ruo
authors: R
authors: Yuan
authors: Yun
authors: Y
authors: Xiang
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D001665:Binding Sites; D015374:Biosensing Techniques / Q000379:methods*; D004247:DNA / Q000737:chemistry; D055664:Electrochemical Techniques / Q000379:methods; D006046:Gold / Q000737:chemistry; D006801:Humans; D017403:In Situ Hybridization; D057230:Limit of Detection; D008163:Luminescent Measurements; D053768:Metal Nanoparticles / Q000737:chemistry*; D013917:Thrombin / Q000302:isolation & purification*
chemical_list: D052157:Aptamers, Nucleotide; C081676:thrombin aptamer; D006046:Gold; D004247:DNA; D013917:Thrombin