Photoacoustics as a New Modality for Recording Membrane Potential Changes

Voltage sensitive dyes (VSD) are designed to monitor the membrane potential by detecting fluorescence change in response to neuronal or muscle electrical activity. However, fluorescence imaging is limited by depth of penetration and high scattering losses which leads to low sensitivity in vivo systems for external detection. In contrast, photoacoustic (PA) imaging, an emerging modality, is capable of deep tissue, noninvasive imaging by combining near infrared light excitation and ultrasound detection.