Abstract:
This talk will explore the development and integration of a compact nanosecond electric pulse (nanopulse) generator with a planar microchamber for intracellular detection of individual biological cells. The microchamber is formed between a gold coplanar transmission line fabricated on a standard microscope slide and a poly-dimethyl-siloxane (PDMS) microchannel cap, which approaches the width of a single cell as it crosses the transmission line. The microchannel not only delivers a stream of single cells to the transmission line, but also minimizes the attenuation of nanopulses by cell culture media. The transmission line maintains 50-Ω characteristic impedance when partially covered by PDMS and culture media to minimize the distortion or reflection of nanopulses. Specifically, the gap in the transmission line is adjusted according to the dielectric constants of PDMS and culture media. The
resulting notch in the transmission line also serves to trap a single cell and to concentrate electric field on the cell. The incident, reflected and transmitted nanopulses are monitored by both a sampling oscilloscope in the time domain and a network analyzer in the frequency domain. An equivalent-circuit model is used to complement detailed electromagnetic analysis and to account for real-time evolution of electrically measurable parameters such as cell membrane permittivity and conductivity. The thin and transparent PDMS cap allows simultaneous optical microscopy to determine whether or not a cell is trapped and alive.