Diagnostic detection of human lung cancer-associated antigen using a gold nanoparticle-based electrochemical immunosensor.
The development of rapid and sensitive methods for the detection of immunogenic tumor-associated antigen is important not only for understanding their roles in cancer immunology but also for the development of clinical diagnostics. Alpha-enolase (ENO1), a p48 molecule, is widely distributed in a variety of tissues, whereas gamma-enolase (ENO2) and beta-enolase (ENO3) are found exclusively in neuron/neuroendocrine and muscle tissues, respectively. Because ENO1 has been correlated with small cell lung cancer, nonsmall cell lung cancer, and head and neck cancer, it can be used as a potential diagnostic marker for lung cancer. In this study, we developed a simple, yet novel and sensitive, electrochemical sandwich immunosensor for the detection of ENO1; it operates through physisorption of anti-ENO1 monoclonal antibody on polyethylene glycol-modified disposable screen-printed electrode as the detection platform, with polyclonal secondary anti-ENO1-tagged, gold nanoparticle (AuNP) congregates as electrochemical signal probes. The immunorecognition of the sample ENO1 by the congregated AuNP@antibody occurred on the surface of the electrodes; the electrochemical signal from the bound AuNP congregates was obtained after oxidizing them in 0.1 M HCl at 1.2 V for 120 s, followed by the reduction of AuCl(4-) in square wave voltammetry (SWV) mode. The resulting sigmoidally shaped dose-response curves possessed a linear dynamic working range from 10(-8) to 10(-12) g/mL. This AuNP congregate-based assay provides an amplification approach for detecting ENO1 at trace levels, leading to a detection limit as low as 11.9 fg (equivalent to 5 microL of a 2.38 pg/mL solution).
Ho
Ja-an Annie
JA
BioAnalytical Laboratory, Department of Chemistry, National Tsing Hua University, Hsinchu 300, Taiwan. jaho@mx.nthu.edu.tw
Chang
Heng-Chia
HC
Shih
Neng-Yao
NY
Wu
Li-Chen
LC
Chang
Ying-Feng
YF
Chen
Chii-Chang
CC
Chou
Chien
C
D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology; D000951:Antigens, Neoplasm / Q000032:analysis* / Q000276:immunology; D015374:Biosensing Techniques / Q000379:methods; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D006046:Gold / Q000737:chemistry*; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis*; D053768:Metal Nanoparticles / Q000737:chemistry*; D010751:Phosphopyruvate Hydratase / Q000032:analysis / Q000276:immunology; D011092:Polyethylene Glycols / Q000737:chemistry
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D011092:Polyethylene Glycols; D006046:Gold; D010751:Phosphopyruvate Hydratase