Full-field interferometric imaging of propagating action potentials

• DOI: 10.1038/s41377-018-0107-9
• Publication Date: 2018-12-10T14:17:31Z
• Authors: Tong Ling; Kevin C. Boyle; Georges Goetz; Peng Zhou; Yi Quan; Felix S. Alfonso; Tiffany W. Huang; Daniel Palanker
• Keywords: Optical recording; Photobleaching; Temporal resolution

Currently, cellular action potentials are detected using either electrical recordings or exogenous fluorescent probes that sense the calcium concentration transmembrane voltage. Ca imaging has a low temporal resolution, while voltage indicators vulnerable to phototoxicity, photobleaching, and heating. Here, we report full-field interferometric of individual by detecting movement across entire cell membrane. Using spike-triggered averaging movies synchronized with recordings, demonstrate deformations up 3 nm (0.9 mrad) during potential in spiking HEK-293 cells, rise time 4 ms. The course optically recorded spikes matches waveforms. Since shot noise limit camera (~2 mrad/pix) precludes detection single frame, for all-optical spike detection, images acquired at 50 kHz, frames binned into 1 ms steps achieve sensitivity 0.3 mrad pixel. self-reinforcing enhancement algorithm based on iteratively expanding region interest spatial averaging, can be matching previously extracted template optical recording. This allows propagating without exogeneous labels electrodes.