Optical probing of local membrane potential with fluorescent polystyrene beads

• DOI: 10.1016/j.bpr.2021.100030
• Publication Date: 2021-11-01T17:11:50Z
• Authors: Zehavit Shapira; Nurit Degani-Katzav; Shimon Yudovich; Asaf Grupi; Shimon Weiss
• Keywords: 0301 basic medicine; 570; 0303 health sciences; Biomedical and Clinical Sciences; QH301-705.5; Physics; QC1-999; Neurosciences; Bioengineering; FRET, Polystyrene Beads, voltage sensing, membrane potential; 03 medical and health sciences; Report; Physical Sciences; Biology (General)

AbstractStudying the electrical activity in single cells and in local circuits of excitable cells, like neurons, requires an easy to use and high throughput methodology that enables the measurement of membrane potential. Studying the electrical properties in particular sub-compartments of neurons, or in a specific type of neurons produces additional complexity. An optical voltage-imaging technique that allows high spatial and temporal resolution could be an ideal solution. However, most of the valid voltage imaging techniques are nonspecific; The ones that are more site-directed require much pre-work and specific adaptations in addition to other disadvantages. Here, a new technique for membrane voltage imaging, based on FRET between fluorescent polystyrene (FPS) beads and Dipicrylamine (DPA) is explored. Not only fluorescent intensity is demonstrated to be correlated with membrane potential, but more importantly, single particle voltage detection is demonstrated. Among other advantages, FPS beads can be synthesized with functional surface groups, and be further targeted to specific proteins via conjugation of recognition molecules. Therefore, FPS beads, in the presence of DPA, constitute single-particle detectors for membrane voltage, with a potential to be localized to specific membrane compartments. This new and accessible platform for targeted optical voltage imaging may further elucidate the mechanisms of neuronal electrical activity.