Optical modulation of astrocyte network using ultrashort pulsed laser

Abstract

Astrocyte, the most abundant cell type in the central nervous system, has been one of major topics in neuroscience. Even though many tools have been developed for the analysis of astrocyte function, there has been no adequate tool that can modulates astrocyte network without pharmaceutical or genetic interventions. Here we found that ultrashort pulsed laser stimulation can induce label-free activation of astrocytes as well as apoptotic-like cell death in a dose-dependent manner. Upon irradiation with high intensity pulsed lasers, the irradiated cells with short exposure time showed very rapid mitochondria fragmentation, membrane blebbing and cytoskeletal retraction. We applied this technique to investigate in vivo function of astrocyte network in the CNS: in the aspect of neurovascular coupling and blood-brain barrier. We propose that this noninvasive technique can be widely applied for in vivo study of complex cellular network.

Application of femtosecond‐pulsed lasers for direct optical manipulation of biological functions

“…Laser‐induced ROS resulted in impaired cell division or initiated apoptotic cell death. Scanning with low laser power and relatively long beam dwell time (60–120 µs per pixel) induced a cytotoxic effect; whereas brief exposures of high laser power with a short beam dwell time (∼2 µs per pixel) on a diffraction‐limited volume (∼femtoliter) in cells also evoked damage . This optical stimulation induced whole mitochondrial fragmentation even though the cytosolic laser‐exposed region was less than 1 µm 2 in area, suggesting the involvement of the intermitochondria network.…”