A nanoplasmonic biosensor for label-free multiplex detection of cancer biomarkers.

The development of highly sensitive, selective and multiplex sensors has become an important challenge for disease diagnosis. In this study, we describe a multiplex biosensor for the detection of cancer biomarkers based on unique plasmon response of single gold nanoparticles (AuNPs) and antibody-antigen binding activity. To demonstrate the ability of the plasmon biosensor to detect and quantify cancer biomarkers: a panel of biomarkers, including α-fetoprotein (AFP), carcinoembryonic antigen (CEA) and prostate specific antigen (PSA) was used as a model analyte for multiple detection. A novel and sensitive multiplex biosensor was developed by immobilizing plasmonic nanoparticles in a site-specific manner and functionalized with monoclonal antibodies that recognize the target protein on hydrophilic-hydrophobic patterned glass slide. The proposed multi-analyte biosensor exhibited outstanding selectivity and sensitivity. The limit of detection was determined to be 91 fM, 94 fM and 10 fM for AFP, CEA and PSA from patient-mimicked serum, respectively. Finally, using this sensing strategy, this platform presents an excellent approach for versatile molecular diagnostics in both research and clinical medical fields.