Stimulation of Local Cytosolic Calcium Release by Photothermal Heating for Studying Intra- and Intercellular Calcium Waves.

Abstract

A methodology is described that allows for localized Ca²⁺ release by photoexcitation. For this, cells are loaded with polymer capsules with integrated plasmonic nanoparticles, which reside in endo-lysosomes. The micrometer-sized capsules can be individually excited by near-infrared light from a light pointer, causing photothermal heating, upon which there is a rise in the free cytosolic Ca²⁺ concentration ([Ca²⁺ ]_i ). The [Ca²⁺ ]_i can be analyzed with a Ca²⁺ indicator fluorophore. In this way, it is possible to excite local lysosomal Ca²⁺ release in a desired target cell.