title: Ultrasensitive electrochemical strategy for trace detection of APE-1 via triple signal amplification strategy.
abstract: A novel ultrasensitive electrochemical immunoassay for the determination of apurinic/apyrimidinic endonuclease (APE-1) using a three-step signal amplification process was reported in this work. The first-step signal amplification process was based on the labeled biotinylated alkaline phosphatase (bio-AP) on the nickel hexacyanoferrates nanoparticle-decorated Au nanochains (Ni-AuNCs) toward the biocatalysis of ascorbic acid 2-phosphate (AA-P) to in-situ produce ascorbic acid (AA). Then the signal was further amplified by electrochemical oxidation of the in-situ-produced AA because of the catalysis of Ni-AuNCs. Finally, with the nanochain-modified streptavidin (SA), the stoichiometry of bio-AP could be increased through the specific and high affinity interaction of streptavidin-biotin. On the other hand, a kind of organic material (PTC-NH(2)), owing the amino-functionalized interface and unique electrochemical properties, as matrix for primary antibodies (Ab(1)) immobilization could lower the background current signal and enhance the amount of immobilized Ab(1). With a sandwich-type immunoreaction, the triple signal amplification greatly enhanced the sensitivity for the detection of APE-1. Under optimal conditions, the electrochemical immunosensor exhibited a linear range of 0.01-100 pg/mL with an extremely low detection limit of 3.9 fg/mL (signal/noise=3).
authors.affiliation: Education Ministry Key Laboratory on Luminescence and Real-Time Analysis, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Han
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhuo
authors.forename: Yaqin
authors.initials: Y
authors.lastname: Chai
authors.forename: Yu
authors.initials: Y
authors.lastname: Xiang
authors.forename: Ruo
authors.initials: R
authors.lastname: Yuan
authors.forename: Yali
authors.initials: Y
authors.lastname: Yuan
authors.forename: Ni
authors.initials: N
authors.lastname: Liao
mesh_terms: D000669:Amplifiers, Electronic; D015374:Biosensing Techniques / Q000295:instrumentation*; D003217:Conductometry / Q000295:instrumentation*; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000032:analysis* / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007118:Immunoassay / Q000295:instrumentation*; D008832:Microchemistry / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: C085108:APEX1 protein, human; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase