Remember the last YouTube video you watched? It was powered by a liquid crystal display: a collection of pixels that produce images when they are rapidly turned on and off. But liquid crystals aren’t just used to show video and text on smartphone screens. In fact, a research team based at the University of Colorado Colorado Springs has found a novel way to leverage them in microscopy: by creating a new fast-switching optical filter for microscopes, the team has created a way to show biological processes in live cells — in just milliseconds.
A great deal of biological research uses high-powered microscopes to examine live cells which have structures that have been stained different colors, so that scientists can distinguish different parts of the cell, said Bob Camley, Director of the UCCS BioFrontiers Center at UCCS and one of the investigators for the research.
“Normally you want to see one color at a time, so you need a filter to block out the other colors,” Camley explained. “But if you want to see all the fast processes within a cell, you have to be able to switch the filter really quickly. We developed a filter that switches from one color to another in about one one-thousandth of a second — ten times faster than a standard mechanical filter wheel — so that we can study the mechanics of complex processes in cells in more detail.”
In order to design and build the fast-switching optical filter, the research team used a special class of liquid crystals known as dual-frequency nematic liquid crystals, which are made up of molecules that can be oriented very quickly with an applied voltage — just like the pixels that display your YouTube video, but faster. When the filter is used with a fluorescence microscope, it can show scientists the processes happening in live cells in real time.
The multidisciplinary project, which combines physics, biology and advanced optics, was “a fantastic combination of theory and experiment,” said Camley.
“First, we understood that there was a strong need in the biological community for a fast-switching filter,” he explained. “This is important for observing specialized structures of a cell as they change over time. Second, we had some background in special, fast-switching, liquid crystals from our earlier microwave related work. It seemed so natural to put this together, but, of course, a good idea is just the starting point for any project.”
That good idea became the team’s new optical filter, which is not just novel — it is patentable. The optical filter doesn’t require any complicated mounting parts, and it can be easily implemented in advanced microscopes. And at ten times the speed of its predecessors, it is poised to change the way scientists observe specialized structures in cells.
The research team included faculty and graduate students from the UCCS BioFrontiers Center, the University of Glasgow and Central Connecticut State University. The graduate students (Olha Melnyk doing the experimental work and Reed Jones doing the theory) were the key researchers. The research, titled “Fast Switching Dual-Frequency Nematic Liquid Crystal Tunable Filters,” was published in ACS Photonics. Read the full study online at https://doi.org/10.1021/acsphotonics.1c00151
About the UCCS BioFrontiers Center
The UCCS BioFrontiers Center is devoted to collaborations between scientists across disciplines to advance biotechnology. Its mission is to do outstanding science focused on interdisciplinary research where the physical, mathematical, engineering and computational sciences collaborate with biological sciences to produce significant new approaches for dealing with fundamental molecular biological questions and related health issues. By bridging the fields of biology and physics, it aims to provide new ways of seeing and manipulating nature. Learn more about the UCCS BioFrontiers Center online.