Poster Award "Surface Plasmon Resonance Microscopy of the Cell-Chip Interface"

Abstract

Poster: "Surface Plasmon Resonance Microscopy of the Cell-Chip Interface"Longterm investigation of neuronal networks require non-invasive recordings of the electrical signals. A good coupling between the biological and electronic system is crucial and depends particularly upon the cell-chip distance. The cell-chip distance is an important parameter towards a good sealing, with closer contact leading to a decreased signal dissipation in the cell-electrode cleft. We therefore try to optimize the contact geometry of said interface using protein and lipid coatings. In order to measure the distances between the cell membrane and the chip surface in vitro, we built a surface plasmon resonance microscope (SPRM). With gold coated sapphire chips as the substrate for the cell culture, it is possible to excite plasmons (collective electron oscillations) in the gold layer by illuminating it under a specific angle. The resonance frequency of the plasmons depends strongly upon the dielectric constant of the gold's environment. In turn the angle spectrum of the reflected light depends upon said resonance frequencies. Due to these dependencies it is possible to deduce the cell-substrate distance.Our microscope is capable of imaging the interface in two different modes. The field of view in the live imaging mode is around 65 um x 65 um.This is useful for determining the region of interest for the scanning mode. This mode uses localized surface plasmons to measure the cell-substrate distance. The resolution in z-direction lies in the nanometer range. This allows us to accurately characterize the cell-chip interface.Since SPRM is non-invasive and label free it is suited for longterm investigations.It is therefore possible to observe the development of neuronal networks over several week