title: Broadband activation by white-opsin lowers intensity threshold for cellular stimulation.
abstract: Photoreceptors, which initiate the conversion of ambient light to action potentials via retinal circuitry, degenerate in retinal diseases such as retinitis pigmentosa and age related macular degeneration leading to loss of vision. Current prosthetic devices using arrays consisting of electrodes or LEDs (for optogenetic activation of conventional narrow-band opsins) have limited spatial resolution and can cause damage to retinal circuits by mechanical or photochemical (by absorption of intense narrow band light) means. Here, we describe a broad-band light activatable white-opsin for generating significant photocurrent at white light intensity levels close to ambient daylight conditions. White-opsin produced an order of magnitude higher photocurrent in response to white light as compared to narrow-band opsin channelrhodopsin-2, while maintaining the ms-channel kinetics. High fidelity of peak-photocurrent (both amplitude and latency) of white-opsin in response to repetitive white light stimulation of varying pulse width was observed. The significantly lower intensity stimulation required for activating white-opsin sensitized cells may facilitate ambient white light-based restoration of vision for patients with widespread photoreceptor degeneration.
authors.affiliation: Biophysics and Physiology Lab, The University of Texas at Arlington, TX, USA.
authors.forename: Subrata
authors.initials: S
authors.lastname: Batabyal
authors.affiliation: Biophysics and Physiology Lab, The University of Texas at Arlington, TX, USA.
authors.forename: Gregory
authors.initials: G
authors.lastname: Cervenka
authors.affiliation: Retina Foundation of the Southwest, Dallas, TX, USA.
authors.forename: David
authors.initials: D
authors.lastname: Birch
authors.affiliation: Department of Bioengineering, The University of Texas at Arlington, TX, USA.
authors.forename: Young-tae
authors.initials: YT
authors.lastname: Kim
authors.affiliation: Biophysics and Physiology Lab, The University of Texas at Arlington, TX, USA.
authors.forename: Samarendra
authors.initials: S
authors.lastname: Mohanty
mesh_terms: D000200:Action Potentials; D002460:Cell Line; D015870:Gene Expression; D057809:HEK293 Cells; D006801:Humans; D008027:Light; D009154:Mutation; D055355:Opsins / Q000235:genetics* / Q000378:metabolism*; D015533:Transcriptional Activation / Q000528:radiation effects*
chemical_list: D055355:Opsins