Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Tiny mirror improves microscope resolution for studying cells

17.06.2016

A tiny mirror could make a huge difference for scientists trying to understand what's happening in the micron-scale structures of living cells.

By growing cells on the mirrors and imaging them using super-resolution microscopy, a group of scientists from universities in the United States, China and Australia have addressed a problem that has long challenged scientists: Seeing the structures of three dimensional cells with comparable resolution in each dimension. Cells are normally grown on transparent glass slides for microscopy examination.


This image shows a Vero cell that was grown on a first surface mirror and fluorescently stained to show the microtubules, which are part of the cell cytoskeleton.

Credit: Eric Alonas, Georgia Tech

The new technique uses the unique properties of light to create interference patterns as light waves pass through a cell on the way to the mirror and then back through the cell after being reflected. The interference patterns provide, at a single plane within the cell, significantly improved resolution in the Z-axis - what scientists see as they look directly into a cell perpendicular to the slide. This improved view could help researchers differentiate between structures that appear close together with existing microscope technology - but are actually relatively far apart within the cells.

Microscope resolution in the X and Y axes is typically superior to resolution in the Z axis, regardless of the microscopy technique. The mirror approach works with super-resolution microscopy as well as with other technologies. Reported in the Nature journal Light: Science & Applications, the technique was developed by scientists at Peking University, the Georgia Institute of Technology, and the University of Technology Sydney (UTS).

"This simple technology is allowing us to see the details of cells that have never been seen before," said Dayong Jin, a professor at UTS and one of the paper's co-authors. "A single cell is about 10 micrometers; inside that is a nuclear core about 5 micrometers, and inside that are tiny holes, called the 'nuclear pore complex,' that as a gate regulates the messenger bio-molecules, but measure between one fiftieth and one twentieth of a micrometer. With this super-resolution microscopy we are able to see the details of those tiny holes."

Being able to see these tiny structures may provide new information about the behavior of cells, how they communicate and how diseases arise in them, said Peng Xi, a professor at Peking University and another of the paper's co-authors.

"Previously, the vision of biologists was blurred by the large axial and lateral resolution," he said. "This was like reading newspapers printed on transparent plastic; many layers were overlapped. By placing a mirror beneath the specimen, we can generate a narrowed focal spot so there is only one layer of the newspaper to read so that every word becomes crystal clear."

The new system, he noted, allows scientists to see the ring structure of the nuclear pore complex for the first time, and the tubular structure of the human respiratory syncytial virus (hRSV). "With this simple, but powerful weapon, biologists can tackle many interesting phenomena that were invisible in the past because of poor resolution," Xi added.

While changing the optical system was relatively simple, growing cells on the custom-made mirrors required adapting existing biological techniques, said Phil Santangelo, another co-author and a professor at Georgia Tech and Emory University. Techniques for growing the cells on the mirrors were largely developed by Eric Alonas, a Georgia Tech graduate student, and Hao Xie, a student in the Ph.D. program of Peking University and Georgia Tech.

"Most people are not growing cells on mirrors, so it required some work to get the cell culture conditions correct," Santangelo said. "We had to make sure the mirror coating didn't affect cell growth, and staining the cells to make them fluoresce also required some adaption. Ultimately, growing cells on the mirrors became a simple process."

The new technique, known as mirror-enhanced, axial narrowing, super-resolution (MEANS) microscopy, begins with growing cells to be studied on a tiny mirrors custom-made by a manufacturer in China. A glass cover slide is placed over the cells, and the mirror placed into a confocal or wide-field microscope in the place of a usual clear slide.

The technique improves axial resolution six-fold and lateral resolution two-fold for Stimulated Emission Depletion (STED) nanoscopy. The ability to increase the resolution and decrease the thickness of an axial section without increasing laser power is of great importance for imaging biological specimens, which cannot tolerate high laser power, the researchers noted.

For scientists attempting to study structures and molecules inside cells, the interference effects can make a dramatic difference in what can be observed.

"The two waves interacting with one another causes a region between the glass surfaces and the cell to be bright, and other parts to be dark," explained Santangelo, who is an associate professor in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University. "They cause light to be removed from some locations so you get darkness, and there is a bright spot in a specific region rather than being all bright."

Santangelo believes the technique could find broad applications for scientists using fluorescence microscopy to examine cells and subcellular structures. Further research could lead to improvements such as the ability to make the mirror's surface movable, allowing more control over how the cells can be imaged.

"There is more to do with this," he said. "We have demonstrated a basic topic that can be applied now in other ways."

The time differences between Australia, China and the United States provided a challenge for the team's collaboration, but the researchers say the work was very worthwhile.

"The development of the mirror-enhanced super-resolution microscopy is a great example of what collaborative, international and multi-disciplinary research can achieve," said Jin, who is the director of the Initiative for Biomedical Materials & Devices at UTS. "It is a significant achievement for the team, and the field, and one that we're proud to have been involved in."

###

CITATION: Xusan Yang, et al., "Mirror-enhanced, axial narrowing, super-resolution microscopy," Light: Science & Applications, 2016).

Media Contact

John Toon
jtoon@gatech.edu
404-894-6986

 @GeorgiaTech

http://www.gatech.edu 

John Toon | EurekAlert!

Further reports about: micrometers mirror super-resolution microscopy

More articles from Life Sciences:

nachricht Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

nachricht The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>