Department of Chemistry
Quantification of Cancer Biomarkers in Serum Using Scattering-Based Quantitative Single Particle Intensity Measurement with a Dark-Field Microscope
In this work, we developed a simple yet robust single particle scattering intensity measurement method for the quantification of cancer-related biomarkers. The design is based on the plasmonic coupling effect between noble metal nanoparticles. First, the primary and secondary antibodies were conjugated onto the surface of 60 nm gold nanoparticles (AuNPs, act as capture probes) and 50 nm silver nanoparticles (AgNPs, act as signal amplification probes) respectively. In the presence of corresponding antigen, a sandwiched immunocomplex was formed, resulting a significantly enhanced scattering intensity in contrast to that of individual probes. By measuring the intensity change of the particles with a dark-field microscope (DFM), the amount of target protein could be accurately quantified. As a proof of concept experiment, quantification of three types of antigens, including carcinoembryonic antigen (CEA), prostate-specific antigen (PSA) and alpha fetoprotein (AFP) by this platform was demonstrated with limit of detection (LOD) of 1.7, 3.3, and 5.9 pM, respectively, with a linear dynamic range of 0 to 300 pM. Furthermore, to elucidate the potential in clinical application, the content of antigens in a serum sample was also quantified directly without additional sample pretreatment. In order to validate the reliability of this method, the measured result was also compared with that obtained by regular enzyme-linked immunosorbent assay (ELISA) kit, showing good consistency between these two data sets. Therefore, owing to the simplicity and accuracy of this method, it could be potentially applied for massive disease screening in clinical assay in the future.
Source Publication Title
American Chemical Society
Financial support from the University Grants Council of Hong Kong Special Administrative Region, China (Grant GRF/HKBU201612) and Faculty Research Grant of Hong Kong Baptist University (Grants FRG2/14-15/057 and FRG2/15-16/028). This work was also supported by NSFC (Grants 21405045 and 21522502), Program for New Century Excellent Talents in University (China, Grant NCET-13-0789), and Hunan Natural Science Funds for Distinguished Young Scholar (Grant 14JJ1017).
Link to Publisher's Edition
Poon, C., Wei, L., Xu, Y., Chen, B., Xiao, L., & Li, H. (2016). Quantification of Cancer Biomarkers in Serum Using Scattering-Based Quantitative Single Particle Intensity Measurement with a Dark-Field Microscope. Analytical Chemistry, 17 (88), 8849-8856. https://doi.org/10.1021/acs.analchem.6b02429