Emerging Platforms for Imaging, Sensing and Diagnostics

At 2020 Photonics West, researchers discuss compact prototypes and efficient techniques to improve a range of biomedical and environmental applications, including imaging and disease diagnosis.
03 February 2020
By Sophia Chen
2020 Photonics West attendees

Could you use a smartphone camera to test for pollutants in drinking water? Or to test your eye for glaucoma? Researchers say yes, as they reported in a Sunday session called "Emerging Platforms for Imaging, Sensing, and Diagnostics." In the presentations, they discussed compact prototypes and efficient techniques to improve a range of biomedical and environmental applications, including imaging and disease diagnosis.

Hatice Ceylan Koydemir of the University of California, Los Angeles, developed a compact accessory for a smartphone that evaluates the turbidity, or cloudiness, of water. Their system costs about $50 to make, compared to turbidity-measuring instruments that are currently available, which are over $1000, said Koydemir. Cheap, portable tools for measuring turbidity could help people in developing countries characterize their water quality.

Koydemir's invention exploits a phone camera to characterize water turbidity. The process works like this: first, they shine a white LED through the sample. Then, they collect the light transmitted through the water with an optical fiber, and redirect that light to the smartphone camera, which records it as a photograph. Then, they analyze the photo via an app they developed, which runs calculations on the cloud and reports the turbidity to the phone in about a minute.

Hironori Miyauchi of QD Lasers in Japan, presented on a smartphone-based prototype that allows people to self-test their visual field. They built the device by adding extra optics to a Blackview Max 1 phone, which includes its own laser projector. Together, this hardware scans the retina and can detect irregularities in its visual field. Testing the device on the retinas of a 45-year-old man, they could find his blind spot, as well as an area of abnormal visual field.

This technology is to help diagnose people who suffer from or are at risk of glaucoma and macular degeneration, eye conditions that cause the loss of visual field. In Japan, only 10 percent of people over the age of 40 treat their glaucoma, said Miyauchi.

Not all the inventions were based on smartphones. Riley McKeough, an undergraduate at the University of North Carolina, Charlotte, presented a technique that could potentially be used to keep vaccines and other biologic drugs fresh without refrigeration. "They have problems with long shelf life," says Susan Trammell, McKeough's principal investigator, who led the invention of the technique. The method, known as light-assisted drying (LAD), involves placing biologics such as proteins inside a sugar solution, and dehydrating the sample using infrared laser light. McKeough explained that they used Raman spectroscopy to determine that LAD dries samples uniformly.

The technique offers several advantages, says Trammell. Unlike freeze-drying, the current method of drying biologics, which tends to be a one-size-fits-all technique, LAD can be customized based on the sample. They can turn up the laser power to speed up drying in heat-tolerant biologics, for example. LAD also works much more quickly compared to freeze-drying. Their technique could dry 40 microliters of a model protein, lysozyme, in about an hour. Freeze-drying the same sample would have taken on the order of a day, says Trammell. To rehydrate the biologic, you simply add water.

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