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

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.

Automated summary

The methodology utilizes polymer capsules with integrated plasmonic nanoparticles to enable localized Ca2+ release by photoexcitation. Near-infrared light is used to individually excite micrometer-sized capsules, causing photothermal heating and increasing the free cytosolic Ca2+ concentration. This approach allows for local lysosomal Ca2+ release in a desired target cell.