Richard D. Berlin Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, CT 06030.
European Laboratory for Non-Linear Spectroscopy, University of Florence, Sesto Fiorentino 50019, Italy.
Proc Natl Acad Sci U S A. 2023 Aug 22;120(34):e2305093120. doi: 10.1073/pnas.2305093120. Epub 2023 Aug 14.
Voltage-sensitive dyes (VSDs) are used to image electrical activity in cells and tissues with submillisecond time resolution. Most of these fast sensors are constructed from push-pull chromophores whose fluorescence spectra are modulated by the electric field across the cell membrane. It was found that the substitution of naphthalene with chromene produces a 60 to 80 nm red-shift in absorption and emission spectra while maintaining fluorescence quantum efficiency and voltage sensitivity. One dye was applied to ex vivo murine heart with excitation at 730 nm, by far the longest wavelength reported in voltage imaging. This VSD resolves cardiac action potentials in single trials with 12% ΔF/F per action potential. The well-separated excitation spectra between these long-wavelength VSDs and channelrhodopsin (ChR2) enabled monitoring of action potential propagation in ChR2 hearts without any perturbation of electrical dynamics. Importantly, by employing spatially localized optogenetic manipulation, action potential dynamics can be assessed in an all-optical fashion with no artifact related to optical cross-talk between the reporter and actuator. These new environmentally sensitive chromene-based chromophores are also likely to have applications outside voltage imaging.
电压敏感染料（VSDs）用于以亚毫秒时间分辨率对细胞和组织中的电活动进行成像。这些快速传感器大多由推拉发色团构建而成，其荧光光谱受细胞膜两侧电场的调制。研究发现，用色烯取代萘会使吸收和发射光谱发生 60 到 80nm 的红移，同时保持荧光量子效率和电压敏感性。一种染料在离体鼠心脏上以 730nm 的波长激发，这是迄今为止在电压成像中报道的最长波长。这种 VSD 在单个试验中每个动作电位可分辨 12%的 ΔF/F，分辨率很高。这些长波长 VSD 与通道视紫红质（ChR2）之间良好分离的激发光谱，使我们能够在不干扰电动力学的情况下监测 ChR2 心脏中的动作电位传播。重要的是，通过采用空间局域光遗传学操作，可以以全光学方式评估动作电位动力学，而不会出现与报告器和执行器之间光学串扰相关的伪影。这些新型环境敏感的基于色烯的发色团也可能在电压成像之外有应用。
