A Schematic illustration with self-sustained intracellular laser lasing from live cells containing intracellular optical resonators. B Confocal laser scanning microscopy image of NIH 3T3 fibroblasts, Human Embryonic Kidney 293, and primary mouse microglia internalized with polystyrene divinylbenzene (PS-DVB) microsphere resonators (green fluorescence). Adapted with permission from 101, Copyright 2015 AMERICAN CHEMICAL SOCIETY. C Schematic Illustration of a semiconductor nanodisk laser internalized into a cell, which is optically pumped through a microscope objective (blue) with laser emission (red) collected by the same objective. D Laser scanning confocal fluorescence microscopy image of fixed macrophage with internalized nanodisks (red fluorescence). Adapted with permission from 100, Copyright 2018 NATURE.