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IPhone and porous silicon at the nanoscale equals simple and cheap home diagnostics

IPhone and porous silicon at the nanoscale equals simple and cheap home diagnostics

Silicon chips similar to those that would be used in the detection process. Credit: Vanderbilt University / Heidi Hall

The simplest medical tests at home may look like a pack of various silicon chips coated in special film, one that can detect drugs in the blood, another for proteins in the urine indicating infection, another for bacteria in the water and the like. Add the body fluid you want to test, take a picture with your smartphone, and a special application lets you know if there is a problem or not.

That's what electrical engineer Sharon Weiss, an engineering professor at Vanderbilt University, and her students have developed in their lab, combining their research into low-cost nanostructured thin films with a device that most American adults already own. "The novelty lies in the simplicity of the basic idea, and the only expensive component is the smart phone," Weiss said.

"Most people are familiar with silicon as the material inside their computer, but it has infinite uses," she said. "With our porous silicon at the nanoscale, we create these nanoscale holes that are a thousand times smaller than their hair. They capture molecules selectively when they are pretreated with the appropriate surface coating, darkening the silicon, which the application detects."

The similar technology being developed depends on the expensive hardware that complements the smartphone. The Weiss system uses the phone's flash as a light source, and the team plans to develop an application that can handle all the data processing necessary to confirm that the film simply darkened with the addition of fluid. In addition, in the future, this phone could replace a mass spectrometry system that costs thousands of dollars. The Transportation Security Administration has hundreds of people at airports across the country, where they are used to detect gunpowder on hand swabs.

Other home tests depend on a color change, which is a separate chemical reaction that introduces more room for errors, Weiss said.

Weiss, Ph.D. The student Tengfei Cao and his team used a biotin-streptavidin protein assay and an iPhone SE, model A1662, to test their silicon films and found that accuracy is similar to that of benchtop measuring systems. They also used a 3-D hard case to stabilize the phone and obtain standardized measurements for the paper, but Weiss said that this would not be necessary if further research and development led to a commercialized version.

Your results will appear in a future edition of Analyst, one in the Royal Society of Chemistry journal family.

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More information:
Tengfei Cao et al, A smartphone biosensor based on the structural color analysis of porous silicon, The analyst (2019) DOI: 10.1039 / C9AN00022D

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University of Vanderbilt

iPhone and porous silicon at nanoscale equate to simple and cheap home diagnostics (2019, June 11)
recovered on June 11, 2019

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