Dual signal amplification of glucose oxidase-functionalized nanocomposites as a trace label for ultrasensitive simultaneous multiplexed electrochemical detection of tumor markers.
A novel tracer, glucose oxidase-functionalized nanocomposite, was designed to label the signal antibodies for ultrasensitive multiplexed measurement of tumor markers using a disposable immunosensor array. The immunosensor array was constructed by coating layer-by-layer colloidal Prussian blue (PB), gold nanoparticles, and capture antibodies on screen-printed carbon electrodes. The preparation of glucose oxidase-functionalized nanocomposites and the labeling of antibody were performed by one-pot assembly of glucose oxidase and antibody on gold nanoparticles attached carbon nanotubes. The PB immobilized on immunosensor surface acted as a mediator to catalyze the reduction of H2O2 produced in the enzymatic cycle. Both the high-content glucose oxidase and carbon nanotubes in the tracer amplified the detectable signal for the sandwich-type immunoassay. Using carcinoembryonic antigen and alpha-fetoprotein as model analytes, the simultaneous multiplexed immunoassay method using the immunosensor array and the designed tracer showed linear ranges of 3 orders of magnitude with the detection limits down to 1.4 and 2.2 pg/mL, respectively. The assay results of serum samples with the proposed method were in an acceptable agreement with the reference values. The dual signal amplification of glucose oxidase-functionalized nanocomposites provided a promising ultrasensitive simultaneous multiplexed immunoassay approach for clinical applications.
Key Laboratory of Analytical Chemistry for Life Science (Ministry of Education of China), Department of Chemistry, Nanjing University, Nanjing 210093, P.R. China.
Guosong
G
Lai
Feng
F
Yan
Huangxian
H
Ju
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000032:analysis* / Q000276:immunology; D002417:Cattle; D003429:Cross Reactions; D004563:Electrochemistry; D004579:Electron Transport; D005295:Ferrocyanides / Q000737:chemistry; D005949:Glucose Oxidase / Q000737:chemistry / Q000378:metabolism*; D006046:Gold / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D051379:Mice; D053761:Nanocomposites / Q000737:chemistry*; D037742:Nanotubes, Carbon / Q000737:chemistry; D013194:Staining and Labeling; D013997:Time Factors
D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D005295:Ferrocyanides; D037742:Nanotubes, Carbon; D006046:Gold; D005949:Glucose Oxidase; C000170:ferric ferrocyanide