Led by electrical and computer engineering professor Gabriel Popescu, the research team developed a new imaging method called spatial light interference microscopy (SLIM) that can measure cell mass using two beams of light.
Described in the Proceedings of the National Academy of Science, the SLIM technique offers new insight into the much-debated problem of whether cells grow at a constant rate or exponentially.
SLIM is extremely sensitive, quantitatively measuring mass with femtogram accuracy. By comparison, a micron-sized droplet of water weighs 1,000 femtograms. It can measure the growth of a single cell, and even mass transport within the cell. Yet, the technique is broadly applicable.
“A significant advantage over existing methods is that we can measure all types of cells – bacteria, mammalian cells, adherent cells, nonadherent cells, single cells and populations,” said Mustafa Mir, a graduate student and a first author of the paper. “And all this while maintaining the sensitivity and the quantitative information that we get.”
Unlike most other cell-imaging techniques, SLIM – a combination of phase-contrast microscopy and holography – does not need staining or any other special preparation. Because it is completely non-invasive, the researchers can study cells as they go about their natural functions. It uses white light and can be combined with more traditional microscopy techniques, such as fluorescence, to monitor cells as they grow.
“We were able to combine more traditional methods with our method because this is just an add-on module to a commercial microscope,” Mir said. “Biologists can use all their old tricks and just add our module on top.”
Because of SLIM’s sensitivity, the researchers could monitor cells’ growth through different phases of the cell cycle. They found that mammalian cells show clear exponential growth only during the G2 phase of the cell cycle, after the DNA replicates and before the cell divides. This information has great implications not only for basic biology, but also for diagnostics, drug development and tissue engineering.
The researchers hope to apply their new knowledge of cell growth to different disease models. For example, they plan to use SLIM to see how growth varies between normal cells and cancer cells, and the effects of treatments on the growth rate.
Popescu, a member of the Beckman Institute for Advanced Science and Technology at the U. of I., is establishing SLIM as a shared resource on the Illinois campus, hoping to harness its flexibility for basic and clinical research in a number of areas.
“It could be used in many applications in both life sciences and materials science,” said Popescu, who also is a professor of physics and of bioengineering. “The interferometric information can translate to the topography of silicon wafers or semiconductors. It’s like an iPad – we have the hardware, and there are a number of different applications dedicated to specific problems of interest to different labs.”
Co-authors on the paper include graduate students Zhuo Wang, Zhen Shen and Michael Bednarz, along with electrical and computer engineering professor Rashid Bashir, physics professor Ido Golding and cell and developmental biology professor Supriya G. Prasanth.The National Science Foundation and the Grainger Foundation supported this work.
The paper, “Optical Measurement of Cycle-Dependent Cell Growth,” is available online.
CONTACT: Liz Ahlberg, Physical Sciences Editor 217-244-1073; email@example.com
Liz Ahlberg | University of Illinois
Energy hybrid: Battery meets super capacitor
01.12.2016 | Technische Universität Graz
Tailor-Made Membranes for the Environment
30.11.2016 | Forschungszentrum Jülich
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy