Multiphoton imaging and control of opsins in living neural systems by spectral-temporal modulation of a supercontinuum source
Abstract: Our body’s internal clocks, known as circadian rhythms, dictate a myriad of biological functions in living organisms. This includes sleep patterns, thermoregulation, and other daily biological rhythms. Intrinsically photosensitive retinal ganglion cells (ipRGCs) are cells in our eye responsible for signaling light levels to our brains to facilitate regulation. Melanopsin is the chromophore activated in ipRGCs that begins this regulation. Despite increased knowledge of the spectroscopic and biomolecular properties of melanopsin, the effects of multiphoton absorption and tailored ultrafast light on its functionality remain unexplored. Here, illumination with supercontinuum-generated 900-1160 nm, ~20 femtosecond laser pulses caused consistent increases in calcium signals in vitro with single cell-precision via two-photon activation of melanopsin. Tailoring of the supercontinuum’s spectral phase also caused modulation in the activation kinetics of melanopsin-expressing cells. These results demonstrate the ability to carefully activate calcium signaling using melanopsin with single-cell precision using two-photon absorption by tailoring ultrafast laser pulses.
Bio: Carlos Renteria is a PhD candidate at the University of Illinois at Urbana-Champaign, working in the biophotonics imaging lab of Professor Stephen A. Boppart. His research merges biophotonics and nonlinear optics to interrogate biophysical phenomena, developing unprecedented imaging techniques to investigate the effects of chemical agents and radiation on cellular function. Additionally, he tailors light sources for directed visualization and control of living cellular systems.