Partition and optical response of a voltage sensitive dye in polarized lipid membranes: a computational approach.

SOSA, MICAELA; GALASSI, VANESA V.; MARIO G DEL POPOLO

Buenos Aires

Jornada; Primeras jornadas virtuales de la Sociedad Argentina de Biofísica; 2020

Sociedad Argentina de Biofísica

Therequirement of higher spatio-temporal resolution in measurements ofmembrane potential is a growing fieldof research. There is emerging evidence that the pathogenesis ofneurodegenerative diseases is related to widespread and progressivemissfunction in brain network connectivity. 1 Thus, there is a needfor a method that makes possible to monitor the electrical activityof neuronal populations. Optical imaging is a promising technique totackle this challenge. This technique uses optically active moleculesas voltage sensitive dyes (VSD) to measure changes in membranepotential of excitable cells. Indocyanine Green (ICG) is a VSD withthe highly convenient characteristicof being approved by the Food and Drug Administration for clinicaluse. In addition, its absorption and emission in the Near Infraredspectrum allows transdermal optical penetration for excitation andemission. 2,3 These characteristics make ICG appealing in thedevelopment of VSD with putative application in diagnostic imaging.In this work we present a computational study of ICG in membranes ofpalmitoyloleoylphosphatidilcholine (POPC) with differentpolarization states. We have assessed the energetics andcharacterized the configurationfor the partition of ICG into these bilayers. We have computed theoptical differentialresponse of the dye to changes in the polarization state. Our aim isto develop a methodological background to evaluate the molecularbasis underlying voltage sensitivity of the response. A long termgoal is to enhance the optical response of the dye by screeningmolecular derivatives from currently available VSD. Contact:smicaelajanet@gmail.com References[1]Roisin McMackin, Muthuraman Muthuraman, [...], and Orla Hardiman. JNeurol Neurosurg Psychiatry. 2019 Sep; 90(9): 1011?1020. [2]Jeremy S Treger, Michael F Priest, Raymond Iezzi, and FranciscoBezanilla. Real-time imaging of electrical signals with an infraredfda-approved dye. Biophysical journal, 107(6):L09?L12, 2014. [3]Akorn, Inc. 2012. IC-GREEN [package insert]. Akorn, Lake Forest, IL. AcknowldegmentsWewant to acknowledge CIN fellowship, CONICET and ANPCyT for funding.p { margin-bottom: 0.1in; line-height: 115% }a:link { so-language: zxx }