title: Intracellular microlasers.
abstract: Optical microresonators1which confine light within a small cavity are widely exploited for various applications ranging from the realization of lasers2and nonlinear devices3, 4, 5to biochemical and optomechanical sensing6, 7, 8, 9, 10, 11. Here we employ microresonators and suitable optical gain materials inside biological cells to demonstrate various optical functionsin vitroincluding lasing. We explored two distinct types of microresonators: soft and hard, that support whispering-gallery modes (WGM). Soft droplets formed by injecting oil or using natural lipid droplets support intracellular laser action. The laser spectra from oil-droplet microlasers can chart cytoplasmic internal stress (~500 pN/μm2) and its dynamic fluctuations at a sensitivity of 20 pN/μm2(20 Pa). In a second form, WGMs within phagocytized polystyrene beads of different sizes enable individual tagging of thousands of cells easily and, in principle, a much larger number by multiplexing with different dyes.
authors.affiliation: Wellman Center for Photomedicine, Harvard Medical School, Massachusetts General Hospital, 65 Landsdowne St. UP-5, Cambridge, Massachusetts 02139, USA ; Condensed Matter Department, J. Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia.
authors.forename: Matjaž
authors.initials: M
authors.lastname: Humar
authors.affiliation: Wellman Center for Photomedicine, Harvard Medical School, Massachusetts General Hospital, 65 Landsdowne St. UP-5, Cambridge, Massachusetts 02139, USA ; Harvard-MIT Health Sciences and Technology, Cambridge, 77 Massachusetts Avenue Cambridge, Massachusetts 02139, USA.
authors.forename: Seok Hyun
authors.initials: SH
authors.lastname: Yun