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Smartphones could make detecting the presence of bacteria and viruses easier and cheaper, as the development of a new diagnostic system demonstrates.

Your smartphone might feel like an extension of your body — to the point that you might decide to have it surgically implanted into the palm of your hand if you could. You may have used one of the numerous health apps currently available, and might even have read about blood pressure monitors that attach to your iPhone. 

Despite all of that, it probably never occurred to you that you might be able to turn your smartphone into a mobile lab. Yet that's exactly what a scientific team from the University of Houston in Texas is working on at the moment. In the future, a smartphone and a $20 lens attachment may be all that is required to diagnose a variety of medical problems. 

The diagnostic system, based on nanotechnology, is being developed by Jiming Bao, assistant professor of electrical and computer engineering, and Richard Willson, professor of chemical and biomolecular engineering. The team still has some difficulties to overcome, but they are confident that their diagnostic tool will be easy to use and affordable when the final product is ready.

How does it work? What will it be used for? Let's take a closer look. 

How Does The Diagnostic Tool Work?

The smartphone-based diagnostic system will detect the result of a chemical reaction between a virus or bacterium and a molecule that bonds with it — like an antibody combating the disease. Its design is a biosensing device combined with a simple microscope, which would read the results. 

In a paper recently published in the journal ACS Photonics, the team describes how they developed a " high-throughput biosensing technique" using the optical transmission of so-called "nanoholes" with silver staining.

The diagnostic system waits for the chemical reaction, and then picks up the result, ensuring that it cannot be confused with other reactions. 

The biosensing part of the device is actually a glass slide covered with a thin film of gold, which contains thousands of nanoholes (making it look just a little like those tests for color-blindness!). The development of this slide was quite revolutionary in itself, but the next step was to allow the bacteria and viruses to get inside those nanoholes so that the chemical reactions could take place there, and the result could be measured. 


The project didn't finish there, however. There was a problem — the bond created by the chemical reaction between pathogens and antibodies wasn't enough to block out the light. Professor Wilson said: "The thing that binds to the antibody is probably not big and grey enough to darken this hole, so you have to find a way to darken it up somehow."

The team did get there in the end, by using antibodies with enzymes that create silver particles when they are exposed to particular chemicals. When these antibodies attach to the bacteria and viruses in the nanoholes, the entire slide is exposed to chemicals that trigger silver production. The slide is then washed off, and the silver particles stay in the holes to block the light if the required reaction occurred.

Blocked holes indicate a positive result, while clear holes show a negative result. While the process of developing this system was immensely complex, using it will be relatively simple. 

Smartphones Enable A Cheaper Diagnostic Process.

Once the slide is tested, a simple microscope attached to a smartphone is all that is needed to actually read the result. This invention could make the diagnostic process an awful lot cheaper, then! "Some of the more advanced diagnostic systems need $200,000 worth of instrumentation to read the results. With this, you can add $20 to a phone you already have and you're done," Professor Wilson explained. 

The basic idea is now in place. The team still needs to work on finding the best way to get bacteria and viruses into the nanoholes, but when the system is fully developed it will be possible to analyze up to 10 different pathogens all at once. 

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