title: Amplified electrochemiluminescent aptasensor using mimicking bi-enzyme nanocomplexes as signal enhancement.
abstract: In this work, a sandwich-type electrochemiluminescence (ECL) aptasensor for ultrasensitive detection of thrombin (TB) was designed based on mimicking bi-enzyme cascade catalysis to in situ generate coreactant of dissolved oxygen (O2) for signal amplification. We utilized hollow Au nanoparticles (HAuNPs) as carriers to immobilize glucose oxidase nanoparticles (GOxNPs) and Pt nanoparticles (PtNPs) by electrostatic adsorption. Then, the detection aptamer of thrombin (TBA 2) was immobilized on the PtNPs/GOxNPs/HAuNPs nanocomplexes. Finally, hemin was intercalated into the TBA 2 to obtain the hemin/G-quadruplex structure. The hemin/G-quadruplex was an interesting DNAzyme that commonly mimiced horseradish peroxidase (HRP). Herein, GOxNPs, hemin/G-quadruplex and PtNPs could form mimicking bi-enzyme cascade catalysis system to in situ generate dissolved O2 as coreactant in peroxydisulfate solution when the testing buffer contained proper amounts of glucose. This method had successfully overcome the disadvantage of difficulty to label the dissolved O2 and realized the ECL signal amplification. The experiment proved that the aptasensor had good linear relationship on low concentration of TB. The linear range was 1×10(-6)-10 nM, with a detection limit of 0.3 fM.
authors.affiliation: Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China. Electronic address: yingzhuo@swu.edu.cn.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhuo
authors.affiliation: Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China.
authors.forename: Meng-nan
authors.initials: MN
authors.lastname: Ma
authors.affiliation: Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China.
authors.forename: Ya-qin
authors.initials: YQ
authors.lastname: Chai
authors.affiliation: Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhao
authors.affiliation: Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China. Electronic address: yingzhuo@swu.edu.cn.
authors.forename: Ruo
authors.initials: R
authors.lastname: Yuan
mesh_terms: D000327:Adsorption; D052157:Aptamers, Nucleotide / Q000032:analysis* / Q000378:metabolism; D055162:Biocatalysis; D015374:Biosensing Techniques / Q000379:methods*; D021881:DNA, Catalytic / Q000737:chemistry / Q000378:metabolism*; D055664:Electrochemical Techniques; D005949:Glucose Oxidase / Q000737:chemistry / Q000378:metabolism*; D006046:Gold / Q000737:chemistry / Q000378:metabolism; D006735:Horseradish Peroxidase / Q000737:chemistry / Q000378:metabolism*; D049449:Luminescence; D018716:Molecular Mimicry; D053758:Nanoparticles / Q000737:chemistry / Q000378:metabolism*; D010100:Oxygen / Q000737:chemistry / Q000378:metabolism; D010984:Platinum / Q000737:chemistry / Q000378:metabolism; D055672:Static Electricity; D013499:Surface Properties; D013917:Thrombin / Q000032:analysis* / Q000378:metabolism
chemical_list: D052157:Aptamers, Nucleotide; D021881:DNA, Catalytic; D010984:Platinum; D006046:Gold; D005949:Glucose Oxidase; D006735:Horseradish Peroxidase; D013917:Thrombin; D010100:Oxygen
keywords: Electrochemiluminescence aptasensor; Glucose oxidase nanoparticles; Hemin; Mimicking bi-enzyme; Pt nanoparticles