Ratiometric electrochemiluminescent strategy regulated by electrocatalysis of palladium nanocluster for immunosensing.
This work designed a novel ratiometric electrochemiluminescence (ECL) immunosensing approach based on two different ECL emitters: CdS quantum dots (QDs) as cathodic emitter and luminol as anodic emitter. The ECL immunosensor was constructed by a layer-by-layer modification of CdS QDs, Au nanoparticles and capture antibody on a glassy carbon electrode. With hydrogen peroxide as ECL coreactant, the immunosensor showed a cathodic ECL emission of CdS QDs at -1.5 V (vs Ag/AgCl) in air-saturated pH 8.0 buffer. Upon the formation of sandwich immunoassay, the lumiol/palladium nanoclusters (Pd NCs)@graphene oxide probe was introduced to the electrode. Therefore, the cathodic ECL intensity decreased and luminol anodic ECL emission was appeared at +0.3 V (vs Ag/AgCl) owing to the competition of the coreactant of hydrogen peroxide. Using carcino-embryonic antigen as model, this ratiometric ECL strategy could be used for immunoassay with a linear range of 1.0-100 pg mL(-1) and a detection limit of 0.62 pg mL(-1). The enhanced ratiometric ECL signal resulted from the high density and excellent electrocatalysis of the loaded Pd NCs. The immunosensor exhibited good stability and acceptable fabrication reproducibility and accuracy, showing a great promising for clinical application. This electrocatalysis-regulated ratiometric ECL provides a new concept for ECL measurement, and could be conveniently extended for detection of other protein biomarkers.
State Key Laboratory of Analytical Chemistry for Life Science, Collaborative Innovation Center of Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
Yin
Y
Huang
State Key Laboratory of Analytical Chemistry for Life Science, Collaborative Innovation Center of Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China. Electronic address: jpl@nju.edu.cn.
Jianping
J
Lei
State Key Laboratory of Analytical Chemistry for Life Science, Collaborative Innovation Center of Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
Yan
Y
Cheng
State Key Laboratory of Analytical Chemistry for Life Science, Collaborative Innovation Center of Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
Huangxian
H
Ju
D014408:Biomarkers, Tumor / Q000097:blood; D002272:Carcinoembryonic Antigen / Q000097:blood*; D002384:Catalysis; D003217:Conductometry / Q000295:instrumentation*; D004595:Electroplating / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation*; D008163:Luminescent Measurements / Q000295:instrumentation*; D053768:Metal Nanoparticles / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen; D010165:Palladium
Electrocatalysis; Immunosensor; Palladium nanocluster; Quantum dots; Ratiometric electrochemiluminescence