Vertical Nanopillars For Highly-Localized Fluorescence Imaging in Live Cells

The rapidly evolving field of nanotechnology creates new frontiers for biological sciences such as quantum dots for fluorescence imaging and nanotransistor-based biosensors. Recently, vertical nanopillars protruding from a flat surface has been shown to support cell survival and deliver large molecules into the attached cells. Here we demonstrate (1) the use of vertically aligned SiO2 nanopillars to achieve below-the-diffraction limit observation volume in vitro and inside live cells and (2) the use of vertical Pt nanopillars to enhance electrical coupling between neuron cells and the recording electrodes. Transparent SiO2 nanopillars embedded in a nontransparent substrate restricts the propagation of light and affords evanescence wave excitation along its vertical surface. This effect creates high-localized illumination that can be used for single molecule detection with high fluorescence background. We also fabricate vertically aligned Pt nanopillars to enhance the electrical coupling between cultured neurons and the measuring microelectrode arrays. Pt nanopillars were found to serve as geometrically better focal adhesion points for cell attachment and thus enable high-quality signal recording. Therefore, vertical nanopillars can serve as a versatile platform to optically, electrically and chemically probe biological activities in live cells.