Higher Resolution for Fluorescence Microscopes

HeLa cells were imaged using the light-sheet illumination technique. (Source: UNM)

HeLa cells were imaged using the light-sheet illumination technique. (Source: UNM)

For scientists developing life-saving medi­cines, knowing how cells interact and commu­nicate with one another is an important part of the puzzle. The problem is, being able to see those inter­actions through a micro­scope hasn’t always been possible. But now, thanks to Uni­versity of New Mexico Keith Lidke, a new technique has opened the door to allow researchers a better view of cellular interactions. The technique is called single objective light-sheet micro­scopy and improves on an existing method of fluores­cence micro­scopy.

According to Lidke, who works in UNM’s Department of Physics & Astronomy, traditional fluores­cence microscopy tech­niques can only provide researchers a very limited view of the cells they’re looking at and exposes the sample to an abundance of light that degrades the image quality and leads to cell damage through photo-toxicity. “What light-sheet micro­scopy does is allow us create a sheet of light that is matched exactly to the focal plane that we’re imaging,” he explained. “We reduce light exposure and we reduce background noise in the system, so in living cells that allows us to see fluores­cent proteins with enough signal to look at the dynamics of those proteins.”

A new approach to this technique, developed by Lidke, his research group and collaborators at Sandia National Labo­ratories, overcomes these prominent issues and allows light-sheet micro­scopy to be performed using common microscopes found in most cell biology labo­ratories. While Lidke’s technique is still in its early stages, he has already received a lot of interest from researchers at UNM and across the country because of the unique view the equipment can provide. According to Lidke, cells function through sig­naling pathways which are a series of protein-protein inter­actions. But, exactly how those inter­actions work isn’t clear due to a lack of techno­logy available to see those events happen in living cells.

“What we’re trying to do is to develop this light-sheet technology to see these interactions in living cells,” said Lidke. “And, if we can understand how that’s working then somebody may be able to target a therapy to a dys­regulated signaling pathway.” Essentially, the technique has the ability to help answer questions about how cells commu­nicate and work inter­nally, making it possible for researchers to develop medicine or therapies that utilize these inter­actions. “Knowing that our work has a poten­tially valuable appli­cation really makes what we’re doing everyday feel extremely important,” Lidke said.

Microfluidic chip that contains an integrated mirror to allow their light-sheet technique to work. (Source: UNM)

Microfluidic chip that contains an integrated mirror to allow their light-sheet technique to work. (Source: UNM)

The new technique is made possible through two different components; a specialized optics attachment that creates the light-sheet and a highly engineered micro­fluidics chip that holds the sample. Lidke’s group is responsible for creating the optics component which was developed as an attachment to most epi-fluorescent micro­scopes as a way to make the technique usable for a large audience. Colla­borators at Sandia National Labs worked with the group to develop the micro­fluidics chip which has an integrated mirror in it that allows them to create the light-sheet using a single objective lens. Together, these two pieces give researchers the oppor­tunity to see cellular inter­action on an entirely new level.

Right now, Lidke says he’s working with the team at Sandia to develop an improved, next-generation chip that he expects to be made commer­cially available to researchers. As a physicist, Lidke and his research group don’t neces­sarily use the micro­scopes they develop to study a particular biological system. Instead, they create these techniques to allow other biological researchers the chance to apply them to their work. Naturally, this leads to inter­disciplinary colla­borations with scientists in a variety of fields to determine their needs and come up with methods to meet them. (Source: UNM)

Reference: M. B. M. Meddens et al.: Single objective light-sheet microscopy for high-speed whole-cell 3D super-resolution, Biom. Opt. Ex. 7, 2219 (2016); DOI: 10.1364/BOE.7.002219

Link: Dept. of Physics and Astronomy, University of New Mexico, Albuquerque, USA

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