Phase-based cell imaging techniques for microbeam irradiations

Abstract

The microbeam facility at Columbia University is expanding current protocols for single-particle, single-cell irradiations, so experimenters can locate and irradiate nuclei and cytoplasm of unstained cells. The ion beamline is located directly under the dish, therefore, any new techniques must use reflection microscopy. Two approaches are being integrated and neither require the removal of the cell growth medium prior to irradiation.(1)A novel immersion-based Mirau interferometry lens which uses low-coherence light sources to inhibit unwanted fringing is under design. The process requires tens of nanometers or better precision of vertical stage motion, which will be accomplished with our custom high-precision z-stage.(2)Quantitative Phase microscopy is under testing, also using the z-stage. Future plans include optimization of software routines to decrease time between irradiations.Both methods will be compared further with the automated location routines which use nuclear and cytoplasm stains.