Fabrication of biosensor arrays via DPN and detection by surface enhanced resonance Raman scattering

There is a growing need for fast reliable biosensor arrays for disease screening. We have used nanostructured plasmonic gold surfaces for the detection of biological species by surface enhanced resonance Raman scattering (SERRS). Careful, directed placement by Dip-pen Nanolithography (DPN) of the biological species or capture chemistry, within the array facilitates efficient read out via ultra fast Raman line mapping. Further, we can transition the serial placement of biological species / capture chemistry to a massively parallel deposition method, and this flexibility is key to enhancing the throughput of these combined techniques by many orders of magnitude. SERRS is an extremely sensitive spectroscopic technique that offers several advantages over conventional fluorescence detection. For example, the high sensitivity of the method allows detection of DNA capture from single plasmonic array "pixels" ~1 μm2 in area. Additionally, the information rich nature of the SERRS spectrum allows multiple levels of detection to be embedded into each pixel, further increasing the information depth of the array. By moving from micro- to nano-scale features, sensor chips can contain up to 105 times more information, dramatically increasing the capacity for disease screening.