Magnetic SERS-based immunoassay for cancer biomarker detection

• Main Author: Liang, Weikang
• Other Authors: Duan Hongwei
• Format: Final Year Project
• Language: English
• Published: 2017
• Subjects: DRNTU::Engineering::Bioengineering
• Online Access: http://hdl.handle.net/10356/71964
• Institution: Nanyang Technological University

Cancer is the world's second leading cause of death despite exponential growth in the knowledge of cancer and technological advancement in the area of cancer research over the last two decades. This is commonly attributed by dietary risks, lifestyle factor, late-stage presentation and late detection. Early detection of cancer at early stage is essential for preventing the development of cancer into advance stage and it increase the patient‟s chance for successful treatment. Herein, we developed a magnetic SERS-based immunoassay for fast and sensitive liquid biopsy of common human cancer biomarkers present in biofluids, e.g. prostate specific antigen (PSA), carcinoembryonic antigen (CEA) and Alpha-fetoprotein (AFP). The quantitative analysis was conducted by integrating the use of multifunctional magnetic nanochains and surface-enhanced Raman spectroscopy (SERS) technique. In the experiment, we made use of the self-polymerization property of musselinspired polydopamine (PDA) to fabricate functionalized chains of magnetic Fe3O4 nanoparticles as a straight forward and effective approach to capture and isolate target biomarkers. Gold nanorod (AuNR) based SERS probes were encoded with a unique Raman reporter molecule and is functionalized with highly-specific monoclonal antibody to detect the target cancer biomarkers. Consequently, in the presence of target biomarkers it will lead to the formation of magnetic chain/biomarker/SERS probe sandwich immunocomplexes that underwent SERS characterization. The quantitative analysis had revealed a consistent increase of SERS intensity with increasing concentration of cancer biomarkers and calibration curves had shown a substantial linearity (coefficient of determination, R2 > 0.966) throughout tested cancer biomarkers. Results suggest that this SERS-based immunoassay of liquid biopsy platform for detecting biomarkers has high potential for biosensing applications in medical diagnostics.