title: Electrochemiluminescence immunosensor using poly(l-histidine)-protected glucose dehydrogenase on Pt/Au bimetallic nanoparticles to generate an in situ co-reactant.
abstract: In this work, Pt/Au bimetallic nanoparticles (Pt/Au NPs) were used as nanocarriers to develop an electrochemiluminescence (ECL) immunosensor for sensitive cardiac troponin I (cTnI) detection, coupling with enzyme-based signal amplification. First, gold nanoparticles modified Ru(phen)3(2+)-doped silica nanoparticles (Au@RuSiO2 NPs) with numerous luminophores were used as a platform, potentially increasing the signal intensity. Second, Pt/Au NPs with large surface area and rich surface atoms were a superior matrix for the immobilization of numerous antibodies (Ab2), poly(l-histidine) (PLH) and glucose dehydrogenase (GDH). More importantly, the PLH-protected GDH exhibited excellent enzymatic activity for the oxidation of glucose accompanied by the reduction of NAD(+) to NADH. The in situ generated NADH acted as a co-reactant of Ru(phen)3(2+), significantly enhancing the ECL signal. In this manner, the designed immunosensor displayed high sensitivity for the detection of cTnI in the range of 0.010 ng mL(-1) to 10 ng mL(-1) with a detection limit of 3.3 pg mL(-1) (S/N = 3). The proposed strategy holds a new promise for highly sensitive bioassays for application in clinical analyses.
authors.affiliation: Education Ministry Key Laboratory on Luminescence and Real-Time Analytical Chemistry, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, People's Republic of China. yqchai@swu.edu.cn.
authors.forename: Lijuan
authors.initials: L
authors.lastname: Xiao
authors.forename: Yaqin
authors.initials: Y
authors.lastname: Chai
authors.forename: Haijun
authors.initials: H
authors.lastname: Wang
authors.forename: Ruo
authors.initials: R
authors.lastname: Yuan
mesh_terms: D055910:Antibodies, Immobilized / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods*; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism; D042843:Glucose 1-Dehydrogenase / Q000737:chemistry* / Q000378:metabolism; D006046:Gold / Q000737:chemistry; D006639:Histidine / Q000737:chemistry*; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods; D057230:Limit of Detection; D008163:Luminescent Measurements / Q000379:methods; D053768:Metal Nanoparticles / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry; D019210:Troponin I / Q000097:blood*
chemical_list: D055910:Antibodies, Immobilized; D004800:Enzymes, Immobilized; D019210:Troponin I; C033223:polyhistidine; D010984:Platinum; D006639:Histidine; D006046:Gold; D042843:Glucose 1-Dehydrogenase