Microfluidic-based Metal Enhanced Fluorescence For Capillary Electrophoresis By Ag Nanorod Arrays

ABSTRACT:As metal nanorods show much higher metal enhanced fluorescence (MEF) enhancement than metal nanospheres, microfluidic-based MEF is first explored with Ag nanorods (NDs) arrays made by oblique angle deposition.1. First, Ag NDs with varying length were deposited by oblique angle deposition (OAD) technique. The features of the Ag NDs measured directly on the SEM images.2. By measuring the fluorescein isothiocyanate (FITC) solution sandwiched between the Ag NDs and a piece of cover slip, the enhancement factors (EFs) are found as3.70±0.64and6.74±2.04, for a solution thickness at20.8μm and10μm, respectively.3. Owing to the strong plasmonic coupling between the adjacent Ag NDs, only the emission of the fluorophores present in the three-dimensional NDs array gets enhanced. Thus, the corresponding effective enhancement factors (EEFs) are revealed to be relatively close,259±92and340±102, respectively.4. To demonstrate the application of MEF in microfluidic systems, a multilayer of SiO2NDs/Ag NDs is integrated with a capillary electrophoresis device. At a microchannel depth of10μm, an enhancement of6.5fold is obtained for amino acids separation detection. These results are very encouraging and open the possibility of MEF applications for the Ag ND arrays decorated microchannels.5. With the miniaturization of microfluidic devices, size of capillary electrophoresis device reduces to a few microns. In this study, Ag NDs also is integrated with a miniaturization of capillary electrophoresis device, an enhancement of6fold is obtained.