New technology that could allow non-invasive testing for glucose via contact lens has been developed by Scientists. Contact lens that samples its levels in tears. Blood testing is the standard option for checking glucose levels, researchers said.
"There's no noninvasive method to do this. It always requires a blood draw. This is unfortunately the state of the art," said Wei-Chuan Shih, from the University of Houston (UH) in the US. However, glucose is a good target for optical sensing, and especially for what is known as surface-enhanced Raman scattering spectroscopy, said Shih, who worked with colleagues at UH and in Korea to develop the project.
This is an alternative approach, in contrast to a Raman spectroscopy-based noninvasive glucose sensor Shih developed as a PhD student at the Massachusetts Institute of Technology. Researchers developed a tiny device, built from multiple layers of gold nanowires stacked on top of a gold film and produced using solvent-assisted nanotransfer printing, which optimised the use of surface-enhanced Raman scattering to take advantage of the technique's ability to detect small molecular samples.
The device enhances the sensing properties of the technique by creating "hot spots," or narrow gaps within the nanostructure which intensified the Raman signal, the researchers said. Researchers created the glucose sensing contact lens to demonstrate the versatility of the technology.
The contact lens concept is not unheard of - Google has submitted a patent for a multi-sensor contact lens, which the company says can also detect glucose levels in tears - but the researchers say this technology would also have a number of other applications.
"It should be noted that glucose is present not only in the blood but also in tears, and thus accurate monitoring of the glucose level in human tears by employing a contact-lens-type sensor can be an alternative approach for noninvasive glucose monitoring," the researchers said. The research was published in the journal Advanced Materials.