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

SOSA, MICAELA; GALASSI, VANESA; DEL PÓPOLO, MARIO

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

The requirement of higher spatio-temporal resolution in measurements of membrane potential is a growing field of research. There is emerging evidence that the pathogenesis of neurodegenerative diseases is related to widespread and progressive missfunction in brain network connectivity.Thus, there is a need for a method that makes possible to monitor the electrical activity of neuronal populations. Optical imaging is a promisingtechnique to tackle this challenge. This technique uses optically active molecules as voltage sensitive dyes (VSD) to measure changes in membrane potential of excitable cells. Indocyanine Green (ICG) is a VSD with the highly convenient characteristic of being approved by Food and Drug Administration  for clinical use. In addition, its absorption and emission in the Near Infrared spectrum allows transdermal optical penetration for excitation and emission. These characteristicsmake ICG appealing in the development of VSD with putative application in diagnostic imaging.In this work we present a computational study of ICG in membranes ofpalmitoyloleoylphosphatidilcholine (POPC) with different polarization states. We have assessed the energetics and characterized the configuration for the partition of ICG in these bilayers. We have computed the optical differential response of the dye to changes in the polarization. Our aim is to develop a methodological background to evaluate the molecular basis underlying voltage sensitivity of the response. A long term goal is to enhance the optical response by screening molecular derivatives from currently available VSD.