Simultaneous Detection of SERS and Fluorescence Using a Single Excitation for Microbead-Based Analysis

We demonstrate simultaneous detection of surface-enhanced Raman scattering (SERS) and fluorescence signals from a silver microbead. For the dual signal generation, silver microbeads with a diameter of 15 mu m were functionalized with benzenethiol (BT) as a Raman tag and a cardiac troponin I (cTnI) antibody on their surface. SERS and fluorescence signals were obtained using a single argon laser source with 488 nm wavelength. The SERS signals from Raman tag can be used as identification indices for decoding a particular microbead, while the fluorescence signals provide the information about molecular interactions with a specific biomarker. With simultaneous detection of SERS and fluorescence signals using single excitation on the functionalized microbeads, we successfully showed the possibility of a simple barcoding strategy for multiplex analysis using suspension arrays.