Cellular lasers *IMAGES*
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NATURE PHOTONICS
Optics and photonics
Embargo
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London: Monday 27 July 2015 16:00 (BST)
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New York: Monday 27 July 2015 11:00 (EDT)
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Tokyo: Tuesday 28 July 2015 00:00 (JST)
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Sydney: Tuesday 28 July 2015 01:00 (AEST)
The creation of self-contained cellular lasers is reported online this week in Nature Photonics. The
approach offers a new way of labelling biological cells and monitoring their health.
Luminescent probes, such as fluorescent dyes and proteins, are useful tools for biochemical sensing
applications. However, these probes have relatively broad emission spectra, which makes them
difficult to distinguish from the broad background emission of molecules in biological tissue.
Seok Yun and Matjaž Humar demonstrate that ordinary cells can be transformed into miniature lasers
by injecting small droplets of oil or natural lipids mixed with a fluorescent dye into the cell. The droplet
acts as a tiny spherical laser cavity that confines light, and when the cell is excited by short pulses of
light, it lases. Importantly, the exact wavelength of the laser light depends on the level of mechanical
stress within the cell, offering a very sensitive means for detecting internal cytoplasmic stress. In
addition, by using fluorescent polystyrene beads of varying sizes instead of droplets, the authors
found that it is possible to vary the colour of the lasing and thus uniquely identify or label a cell. In
principle, the approach can be scaled to individually tag thousands of cells.
Article and author details
1. Intracellular microlasers
Corresponding Author
Seok Yun
Harvard Medical School Massachusetts General
Hospital, Cambridge, Massachusetts, United States
Email: syun@hms.harvard.edu, Tel: +1 617 768 8704
DOI
10.1038/nphoton.2015.129
Online paper*
http://nature.com/articles/doi:10.1038/nphoton.2015.129
* Please link to the article in online versions of your report (the URL will go live after the embargo ends).
Image caption credits:
Image 1
Caption: Confocal image of a single fat cell containing large lipid droplet (orange) and
small cell nucleus (blue). The lipid droplet within the cell can be used as a natural laser.
Credit: Matjaž Humar and Seok Hyun Yun
Image 2
Caption: Lipid cells within subcutaneous fat tissue, which can be used as natural lasers.
Yellow are lipid droplets, blue dots are cell nuclei and blue filaments are collagen fibres
making up the connective tissue.
Credit: Matjaž Humar and Seok Hyun Yun
Image 3
Caption: An optical fibre is inserted in a piece of pig’s skin to excite and extract the laser
light generated by the subcutaneous fat cells.
Credit: Matjaž Humar and Seok Hyun Yun
Image 4
Caption: Confocal image of cells (green), their nuclei (blue) and the injected oil droplets
(red). The droplets are used as deformable lasers, which can very precisely measure
mechanical forces within the cells.
Credit: Matjaž Humar and Seok Hyun Yun
Image 5
Caption: A fluorescent polystyrene microbead (green) engulfed by a cell, which can be
used as a laser for cell tagging and intracellular sensing. The cell nucleus (blue) is giving
space to the bead, forming a kidney shape.
Credit: Matjaž Humar and Seok Hyun Yun
Image 6
Caption: A number of cells containing lasers (green). The lasers can be used to uniquely
tag thousands of cells.
Credit: Matjaž Humar and Seok Hyun Yun
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