Massachusetts General Hospital (MGH) investigators have induced structures incorporated within individual cells to produce laser light. The wavelengths of light emitted by these intracellular microlasers differ based on factors such as the size, shape and composition of each microlaser, allowing precise labeling of individual cells. The researchers' report has received Advance Online Publication in Nature Photonics.
"The fluorescent dyes currently used for research and for medical diagnosis are limited because they emit a very broad spectrum of light," explains Seok Hyun Yun, PhD, of the Wellman Center for Photomedicine at MGH, corresponding author of the report. "As a result, only a handful of dyes can be used at a time, since their spectral signatures would overlap."
Massachusetts General Hospital investigators have induced subcutaneous fat cells in a piece of skin from a pig to emit laser light in response to energy delivered through an optical fiber.
Credit: Matja Humar, Ph.D., and Seok Hyun Yun, Ph.D., Wellman Center for Photomedicine, Massachusetts General Hospital
Lead author Matja Humar, PhD, also of the Wellman Center, adds, "The narrow-band spectrum of light emitted by these intracellular lasers would allow us to label thousands - in principal up to a trillion - of cells individually, and the very specific wavelengths emitted by these microlasers also would allow us to measure small changes happening within a cell with much greater sensitivity than is possible with broadband fluorescence."
Previous studies by Yun's lab demonstrated the first laser based on a living cell, which used fluorescent proteins as the gain medium to amplify the light signal. But this first-generation cellular laser required a laser cavity consisting of a pair of mirrors placed outside the cell to generate laser light. For the current study, Yun and Humar used tiny spherical objects capable of confining light by reflection from their inner surfaces as microcavities for the amplification of laser light within the cavity.
The first versions used droplets of oil - either injected into individual cells or naturally occurring within the fat cells called adipocytes - and showed that either could be induced to emit specific wavelengths of laser light by pumping energy from an external laser into fluorescent dyes diffused into the droplet, a process that produced minimal heating of the cells.
Changes in the shape of the droplet induced by miniscule pressure alterations within the cell altered the spectra of light emitted, and those alterations could be readily measured. Along with showing lasing with a variety of cells - such as cancer cells, fibroblasts, macrophages and adipocytes extracted from the skin of pigs - the researchers also induced adipocytes residing within a piece of porcine skin to emit clearly visible laser light.
Production of laser light within solid plastic fluorescent microbeads, which are readily taken up into cells, resulted in unique signature spectra based on the size and number of beads within a cell and the fluorescent dye used. The investigators calculated that it would be possible to tag individual cells with more than a trillion different laser signatures, a number that matches the estimated number of cells in the human body.
"One immediate application of these intracellular lasers could be basic studies, such as understanding how cells move and respond to external forces," says Yun, an associate professor of Dermatology at Harvard Medical School. "Another challenging step will be figuring out how to use biologically generated energy from mechanical movement or a biochemical reaction to pump a cellular laser in a living body. Cells are smart machines, and we are interested in exploiting their amazing capabilities by developing smart-cell lasers that might be able to find diseases and fire light at them on their own. We can envision lasers completely made out of materials that are safe for use within the human body, which could enable remote sensing within the body or be used in laser-light therapies."
Support for the study includes National Science Foundation grants ECCS-14 1101947, EEC-1358296 and ECCS-1505569, National Institutes of Health grant P41 15 EB015903, and Marie Curie International Outgoing Fellowship grant 627274.
Massachusetts General Hospital, founded in 1811, is the original and largest teaching hospital of Harvard Medical School. The MGH conducts the largest hospital-based research program in the United States, with an annual research budget of more than $760 million and major research centers in AIDS, cardiovascular research, cancer, computational and integrative biology, cutaneous biology, human genetics, medical imaging, neurodegenerative disorders, regenerative medicine, reproductive biology, systems biology, transplantation biology and photomedicine. In July 2015, MGH returned into the number one spot on the 2015-16 U.S. News & World Report list of "America's Best Hospitals."
Cassandra Aviles | EurekAlert!
Scientists decipher key principle behind reaction of metalloenzymes
15.01.2018 | Rheinisch-Westfälische Technische Hochschule Aachen
New method to map miniature brain circuits
15.01.2018 | The Francis Crick Institute
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.
Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...
The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...
Scientists at Helmholtz Zentrum München have discovered a mechanism that amplifies the autoimmune reaction in an early stage of pancreatic islet autoimmunity prior to the progression to clinical type 1 diabetes. If the researchers blocked the corresponding molecules, the immune system was significantly less active. The study was conducted under the auspices of the German Center for Diabetes Research (DZD) and was published in the journal ‘Science Translational Medicine’.
Type 1 diabetes is the most common metabolic disease in childhood and adolescence. In this disease, the body's own immune system attacks and destroys the...
15.01.2018 | Event News
08.01.2018 | Event News
11.12.2017 | Event News
15.01.2018 | Physics and Astronomy
15.01.2018 | Life Sciences
15.01.2018 | Life Sciences