biomedical

New optical technique could transform brain imaging in animals

Charles Ferrer — Thu, 04 Sep 2025 14:10:32 +0000

New optical technique could transform brain imaging in animals Charles Ferrer Thu, 09/04/2025 - 08:10

Charles Ferrer

Catherine Saladrigas

�� postdoc Catherine Saladrigas is helping bring high-resolution imaging into miniature microscopes for neuroscience research.

In a promising leap forward for imaging, Saladrigas and a team of researchers have developed an optical method that could one day allow scientists to observe brain activity in animals with more clarity, which could provide insights for the human brain. Their research, published in Applied Physics Letters, tackles one of the key challenges in brain imaging: how to miniaturize complex optical systems without sacrificing resolution or contrast.

Saladrigas has been exploring ways to translate benchtop imaging techniques into tiny, head-mounted microscopes working alongside Professors Juliet Gopinath in the Department of Electrical, Computer and Energy Engineering and the Department of Physics and Victor Bright in the Paul M. Rady Department of Mechanical Engineering. These devices could enable real-time, in vivo studies of neural activity in animals yielding payoffs in the areas of neuroscience.

“Our goal was to come up with a strategy for high-resolution, high-contrast imaging that would work well in a miniaturized system,” Saladrigas said.

Traditional pixel-shifting technologies like those used in digital projectors and cameras enhance image resolution by making tiny sub-pixel movements. But in imaging systems, achieving this effect typically requires bulky optics or mechanically stabilized components. Both would be difficult for compact systems like wearable microscopes.

To overcome these design limitations, the team turned to a lesser-used technology: the tunable electrowetting prism, an electrically tunable liquid prism. This optical component uses fluid dynamics and electric fields to adjust the angles of a prism and shift an image laterally without any mechanical parts.

“We showed that an electrowetting prism could perform the image-shifting normally done with much bulkier components,” Saladrigas said. “That makes it a great opportunity for miniature imaging systems.”

The inspiration came from an unlikely place: projector technology. Saladrigas adapted a technique called wobulation, originally developed to make digital projectors appear higher resolution.

In wobulation, a display flickers between slightly offset images to create the perception of finer detail. Her team applied a similar concept to structured illumination microscopy, an imaging method that enhances contrast by shining patterned light on a sample.

“No one has applied a wobulation-like method to structured light microscopy before,” Saladrigas said, “and certainly not with a tunable electrowetting device.”

Though the project is still in its early stages, initial results are encouraging. The team successfully demonstrated the method on a benchtop system using test patterns.

“We compared our experimental results to theoretical predictions and were really happy with how close the results were,” she said.

The project drew on expertise from across the university and beyond. Saladrigas credited Bright’s background in fabrication and electrowetting devices, Gopinath’s optics experience and the contributions of colleagues like Eduardo Miscles, a former PhD student in mechanical engineering, who fabricated the device. The team also collaborated with researchers from Columbia University, Vikrant Kumar and Professor John Kymissis, who developed the custom LED light source used in the project.

The next phase? Miniaturization. Saladrigas is setting sights to integrate the technique into an actual head-mounted microscope, ideally one that can be tested on freely moving mice or voles in collaboration with �� and CU Anschutz neuroscientists.

“There’s so much happening in the brain during behavior with motion and visual cues,” Saladrigas said, “and we want to give neuroscientists a clearer window into all of it.”

�� postdoc Catherine Saladrigas is helping bring high-resolution imaging into miniature microscopes for neuroscience research.

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New bioimaging device holds potential for eye and heart condition detection

Charles Ferrer — Wed, 13 Aug 2025 16:21:08 +0000

New bioimaging device holds potential for eye and heart condition detection Charles Ferrer Wed, 08/13/2025 - 10:21

Charles Ferrer

If you’ve been to a routine eye exam at the optometrist’s office, chances are you’ve had to place your chin and forehead up close to a bioimaging device.

It’s known as optical coherence tomography (OCT) and widely used in eye clinics around the world. OCT uses light waves to take high-resolution, cross-sectional images of the retina in a non-invasive manner.

Samuel Gilinsky

These images can be essential for diagnosing and monitoring eye conditions.

In any bioimaging — either retinal or in-vivo, imaging that takes place inside the human body — devices require them to be quite small, compact that can produce high-quality images.

However, mechanical aspects of OCT devices, like spinning mirrors can increase the chance of device failure.

Researchers at �� have developed a new bioimaging device that can operate with significantly lower power and in an entirely non-mechanical way. It could one day improve detecting eye and even heart conditions.

In a recent study published in Optics Express, the team of engineers created a device that uses a process called electrowetting to change the surface shape of a liquid to perform optical functions.

“We are really excited about using one of our devices, in particular for retinal imaging,” said lead author Samuel Gilinsky, a recent PhD graduate in electrical engineering. “This could be a critical technique for in-vivo imaging for inside our bodies.”

By creating a device that doesn’t use scanning mirrors, the technique requires less electrical power than other devices used for OCT and bioimaging.

“The benefits of non-mechanical scanning is that you eliminate the need to physically move objects in your device, which reduces any sources of mechanical failure and increases the overall longevity of the device itself,” Gilinsky said.

Gilinsky noted the need for these OCT systems to be compact, lightweight and, most importantly, safe for use for the human body.

Other members of the research team included Juliet Gopinath, professor of electrical engineering; Shu-Wei Huang, associate professor of electrical engineering; Victor Bright, professor of mechanical engineering; PhD graduates Jan Bartos and Eduardo Miscles; and PhD student Jonathan Musgrave.

“Our work presents an opportunity where we can hopefully detect health conditions earlier and improve the lives of people,” said Gopinath.

Where zebrafish meets the eye

A cross-section image of the cornea and iris of a zebrafish eye. These images allowed CU researchers to verify that their OCT device can resolve structure in biological samples.

To test the device’s ability to perform biomedical imaging, the researchers turned to a surprising aquatic animal: zebrafish.

Zebrafish have been used in OCT research because the structure of their eyes is fairly similar to the structure of the human eye. For the study, the researchers focused on identifying where the cornea, iris and retina was from the zebrafish.

To conduct in-vivo or other bioimaginging, scientists need to be able to identify the structure of the samples of interest, such as the eye or organs inside the body. The two benchmarks that the group hoped to achieve were 10 micron in axial resolution and then around 5 microns in lateral resolution, all smaller than the width of a human hair.

“The interesting result was that we were able to actually delineate the cornea and iris in our images,” said Gilinsky. “We were able to meet the resolution targets we aimed for, which was exciting.”

Being able to test this bioimaging device can open new doors for mapping aspects of the retina that can be essential for diagnosing potential eye conditions like age-related macular degeneration and glaucoma.

Additionally, Gilinsky said, the new bioimagining technique could help in delineating actual human coronary features that would be important in diagnosing heart disease — the leading cause of death in the United States.

With the research team’s expertise in microscopy systems, they are hopeful to create endoscopes that could revolutionize bioimaging technology.

“There is a growing push to make endoscopes as small in diameter and flexible as possible to cause as little discomfort as possible,” he said. “By using our components, we can maintain a very small scale optical system compared to a mechanical scanner that can help OCT technologies.”

The project was funded by the Office of Naval Research, National Institutes of Health and the National Science Foundation.

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Two from ECEE earn AB Nexus grants for collaborations with CU Anschutz

Anonymous — Wed, 16 Nov 2022 16:52:54 +0000

Two from ECEE earn AB Nexus grants for collaborations with CU Anschutz Anonymous (not verified) Wed, 11/16/2022 - 09:52

Juliet Gopinath will tackle novel neurophotonics methods to access deep brain structures for decision making, while Zoya Popovic will advance technique for noninvasive brain temperature monitoring during cardiac surgery.

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Researchers make strides in commercializing simplified dual-comb spectroscopy

Anonymous — Tue, 30 Aug 2022 13:57:25 +0000

Researchers make strides in commercializing simplified dual-comb spectroscopy Anonymous (not verified) Tue, 08/30/2022 - 07:57

Emily Adams

Huang (left) and a graduate student discuss a project in their lab.

It is sometimes said that science is about truth, while engineering is about compromise.

With one laser project in his lab in the Department of Electrical, Computer and Energy Engineering, Shu-Wei Huang and his team are working on a compromise in order to find new applications for a powerful new technology and make it easier to commercialize.

As they looked at the innovative and extremely precise dual-comb spectroscopy being honed by mechanical engineering Associate Professor Greg Rieker and others, Huang’s team saw an opportunity to expand its applications.

“We've been trying to see whether we can compromise the performance a little bit to greatly simplify the architecture,” Huang said. “The application that we are especially interested in is the biomedical application because in biomedical applications, you don't need the same resolution you need to do something like methane detection.”

The result is the counter-propagating all-normal dispersion (CANDi) fiber laser, which won Bowen Li, a postdoctoral researcher in Huang’s lab, a prestigious award from Optica in 2021.

The key has been a redesigned laser cavity that allows for light to travel both clockwise and counterclockwise, which essentially makes two lasers out of one laser cavity. That, in turn, decreases the number of complex electronics needed to configure two lasers in dual-comb devices, Huang explained.

“We reduce the complexity in the laser design, and we have to compromise the precision a little bit, but it's still much better than the state of art tools used in biomedical applications,” Huang said.

In the team’s most recent Optica paper, they introduced new techniques to reduce the CANDi laser’s relative timing jitter, further proving that the laser will be a good option for a host of applications. That work won PhD student Neeraj Prakash a best poster award at Optica’s 2021 Laser Congress.

Huang said they’ve been working with a startup company in Taiwan that is interested in using CANDi for terahertz imaging – often used in screening for security and drugs. A lab at Colorado State University is also experimenting with the laser for Raman spectroscopy, which has applications in pharmaceuticals and water-quality monitoring.

“CANDi is a new fiber laser architecture and right now, we are working on several projects to unveil its full potential for dual-comb applications,” Huang said.

Read the Optica paper

Shu-Wei Huang and his team are working on a compromise in order to find new applications for a powerful new technology.

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Research collaboration explores multiple methods for brain imaging

Anonymous — Wed, 13 Apr 2022 20:31:33 +0000

Research collaboration explores multiple methods for brain imaging Anonymous (not verified) Wed, 04/13/2022 - 14:31

Researchers at the �� and Anschutz Medical Campus are exploring several imaging techniques aimed at creating lightweight miniature microscopes.

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Detailed time-lapse images of brain cells could lead to new insights for neurological disorders

Anonymous — Wed, 30 Mar 2022 13:52:56 +0000

Detailed time-lapse images of brain cells could lead to new insights for neurological disorders Anonymous (not verified) Wed, 03/30/2022 - 07:52

In the journal Biomedical Optics Express, CU researchers describe their new SIMscope3D, a miniature microscope designed for high-resolution 3D images.

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