title: Ultrasensitive electrochemiluminescent detection of cardiac troponin I based on a self-enhanced Ru(II) complex.
abstract: To promote the luminous efficiency of luminophore, traditional electrochemiluminescence (ECL) immunoassay usually adopts the adding of coreactant into testing solution. However, many adverse micro-environmental factors in the solution are a limiting factor in ECL analytical techniques and received extensive attention. In our work, a self-enhanced ECL luminophore was synthesized by combining the coreactant (l-cysteine) and the luminophor (tris (4,4'-dicarboxylicacid-2,2'-bipyridyl) ruthenium(II) dichloride (Ru(dcbpy)3(2+))) to form one Ru(II) complex and was applied to fabricate a reagentless immunosensor for the detection of cardiac troponin I (cTnI) for the first time. Herein gold nanorods (AuNRs), due to their high specific surface area and good electrocatalytic ability, were used as carriers for the immobilization of Ru(II) complex and cTnI antibody to obtain the Ab2 bioconjugates as signal labels. The application of the self-enhanced Ru(II) complex not only avoided the addition of any coreactant into testing solution for simplifying the operation, but also achieved the intramolecular reaction for improving the ECL signal due to shorter electron transfer path and less energy loss. In view of these advantages, the proposed immunosensor achieved a wide linear range from 0.25 pg/mL to 0.1 ng/mL with an impressive detection limit of 0.083 pg/mL for cTnI (S/N=3).
authors.affiliation: Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhuo
authors.affiliation: Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Ni
authors.initials: N
authors.lastname: Liao
authors.affiliation: Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China. Electronic address: yqchai@swu.edu.cn.
authors.forename: Yaqin
authors.initials: Y
authors.lastname: Chai
authors.affiliation: Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China. Electronic address: yuanruo@swu.edu.cn.
authors.forename: Ruo
authors.initials: R
authors.lastname: Yuan
mesh_terms: D015374:Biosensing Techniques; D004563:Electrochemistry / Q000379:methods*; D004579:Electron Transport; D004583:Electrons; D006046:Gold / Q000737:chemistry; D006801:Humans; D007118:Immunoassay / Q000379:methods; D049449:Luminescence; D053768:Metal Nanoparticles / Q000737:chemistry; D009206:Myocardium / Q000378:metabolism; D036103:Nanotechnology / Q000379:methods; D015203:Reproducibility of Results; D012428:Ruthenium / Q000737:chemistry*; D019210:Troponin I / Q000032:analysis*
chemical_list: D019210:Troponin I; D006046:Gold; D012428:Ruthenium
keywords: Electrochemiluminescence; Immunosensor; Reagentless; Ru(dcbpy)(3)(2+); Self-enhanced; cTnI; l-Cysteine