Wearable microscope can measure fluorescent dyes through skin

A mobile microscope can detect and monitor fluorescent biomarkers inside the skin with a high level of sensitivity.

Content Dam Bow Online Articles 2016 09 Microscope Web

A team of researchers at the University of California Los Angeles (UCLA) and collaborators has developed a mobile microscope that can detect and monitor fluorescent biomarkers inside the skin with a high level of sensitivity. The device, which is small and light enough for a person to wear, could be an important tool in tracking various biochemical reactions for medical diagnostics and therapy, including continuous patient monitoring at home or at point-of-care settings.

The research was led by Aydogan Ozcan, UCLA's Chancellor's Professor of Electrical Engineering and Bioengineering and associate director of the California NanoSystems Institute, and Vasiliki Demas of Verily Life Sciences (formerly Google Life Sciences; Mountain View, CA).

To test the mobile microscope, researchers first designed a tissue phantom—an artificially created material that mimics human skin optical properties, such as autofluorescence, absorption, and scattering. The target fluorescent dye solution was injected into a micro-well with a volume of about one-hundredth of a microliter and subsequently implanted into the tissue phantom about 0.5–2 mm from the surface, which would be deep enough to reach blood and other tissue fluids in practice.

Flourescence Cinema Web
Researchers can detect spatial frequencies of a fluorescent image, which are then analyzed to sense the target fluorescence signal through the skin. (Image credit: Ozcan Research Group/UCLA)

To measure the fluorescent dye, the wearable microscope created by Ozcan and his team used a laser to hit the skin at an angle. The fluorescent image at the surface of the skin was captured via the wearable microscope. The image was then uploaded to a computer where it was processed using a custom-designed algorithm, digitally separating the target fluorescent signal from the autofluorescence of the skin, at a very sensitive parts-per-billion level of detection.

“We can place various tiny biosensors inside the skin next to each other, and through our imaging system, we can tell them apart,” Ozcan says. “We can monitor all these embedded sensors inside the skin in parallel, even understand potential misalignments of the wearable imager and correct it to continuously quantify a panel of biomarkers.”

Content Dam Bow Online Articles 2016 09 Microscope Web
This microscope can monitor fluorescent biomarkers inside the skin. (Image credit: Ozcan Research Group/UCLA)

This computational imaging framework might also be used in the future to continuously monitor various chronic diseases through the skin using an implantable or injectable fluorescent dye.

Full details of the work appear in the journal ACS Nano; for more information, please visit http://dx.doi.org/10.1021/acsnano.6b05129.

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