Significant progress has been made in the application of optogenetic stimulation as a means to modulate and control cellular functions within chemically-identical groups of cells. High resolution imaging can detect subtle morphological (shape/refractive index) changes in cells subsequent to optogenetic stimulation. Invasive topographical measurement methods such as mainstream AFM and other scanning probe techniques suffer from low temporal resolution and restricted field of view, resulting in reduced throughput, even though these methods exhibit high sensitivity to morphological changes. QPM, integrated with optogenetic stimulation incorporates a wide-field, label-free, non-invasive optical imaging technique for all optical stimulation and detection with high spatial and temporal resolution. We dynamically monitored phase of cells, sensitized with and without ChR2, using quantitative phase microscopy with and without light stimulation. The variation of phase in optogenetically stimulated cells (expressing ChR2) was found to be higher than that of the control cells. We report that our method could potentially evaluate effectiveness of various opsins and stimulation parameters including cellular function under different physiological surroundings via spatiallymodulated optogenetic stimulation and wide-field quantitative phase imaging.

Date Published: 8 March 2013
PDF: 6 pages
Proc. SPIE 8586, Optogenetics: Optical Methods for Cellular Control, 85860Y (8 March 2013); doi: 10.1117/12.2020308

Published in SPIE Proceedings Vol. 8586:
Optogenetics: Optical Methods for Cellular Control
Samarendra K. Mohanty; Nitish V. Thakor, Editor(s)