The most basic home medical tests might seem like a pack of different silicon chips applied with a special film, one for detecting drugs in the blood, another for proteins in the urine signifying infection, another for bacteria in water, and many more.
One just needs to add the bodily fluid to be tested and take a picture of it with a smartphone; the special app will show whether or not there is a problem.
This is precisely what electrical engineer Sharon Weiss, Cornelius Vanderbilt Professor of Engineering at Vanderbilt University, and her students developed in her lab, by integrating their research on low-cost, nanostructured thin films with a device that is already possessed by most American adults.
The novelty lies in the simplicity of the basic idea, and the only costly component is the smartphone. Most people are familiar with silicon as being the material inside your computer, but it has endless uses. With our nanoscale porous silicon, we’ve created these nanoscale holes that are a thousand times smaller than your hair. Those selectively capture molecules when pre-treated with the appropriate surface coating, darkening the silicon, which the app detects.
Sharon Weiss, Cornelius Vanderbilt Professor of Engineering, Vanderbilt University
A comparable technology that is being created is based on costly hardware that compliments the smartphone. Weiss’ system employs the phone’s flash as a light source, and the group intends to create an app that could manage all data processing needed to substantiate that the film simply darkened with the addition of fluid.
Moreover, someday, such a phone could substitute a mass spectrometry system that costs thousands of dollars. The Transportation Security Administration possesses hundreds of those at airports across the country, where they are employed to find out gunpowder on hand swabs.
Other home tests are based on a color variation, which is a separate chemical reaction that creates more chances for error, Weiss stated.
Weiss, PhD student Tengfei Cao, and their group tested their silicon films using a biotin-streptavidin protein assay and an iPhone SE, model A1662, and determined that the accuracy was equivalent to that of benchtop measurement systems. They also employed a 3D-printed box to stabilize the phone and obtain standardized measurements for the paper; however, Weiss stated that it would not be essential if further research and development resulted in a commercialized version.
The study outcomes will be reported in a future edition of Analyst, one among the Royal Society of Chemistry family of journals.
This research was funded by Army Research Office grant W911NF-15-1-0176 and National Science Foundation grant DMR-1263182.
(Video credit: Vanderbilt University)