Taking a pregnancy test using a smartphone to be possible

LONDON: Women could soon be able to use their smartphone as a mobile pregnancy testing kit.

 

And smartphones may also be able to monitor diabetes thanks to a sensor that can measure body fluids such as blood, urine, saliva, sweat or breath.

The readings can run through an application which provide real-time results. They can even be combined with the GPS signal of a smartphone so users are guided to the next drug store, hospital or ambulance.

The sensor uses an optical phenomenon known as surface plasmon resonance (SPR), which occurs when light causes electrons on the surface of a thin film to jostle. This detects the composition of a liquid or the presence of particular biomolecules or trace gases.

Surface plasmon resonance occurs when a fixed beam of light strikes a metallic film. Most of the light is reflected, but a small band is absorbed by the film’s surface electrons, causing them to resonate.

Dr Kort Bremer, of the University of Hanover in Germany, said: “We have the potential to develop small and robust lab-on-a-chip devices for smartphones. So, surface plasmon resonance sensors could become ubiquitous now.”

The study, published in the journal Optics Express, said small add-on devices could turn a smartphone’s built-in optical components into biosensing technology to monitor diabetes, test for pregnancy and monitor hazardous gases, among other applications.

The idea is doctors can determine important information about a biological sample’s composition based on which light is reflected and which is absorbed.

Surface plasmon resonance is a phenomenon commonly used for biosensing, but typically requires bulky lab equipment involving both a light detector and light source.

Fortunately, smartphones already have both of these, allowing the minimalist, U-shaped device the researchers designed to consist solely of a 400-micrometer diameter core multimode fiber with a silver-coated sensing region.

In a proof-of-concept version of the sensor, Dr Bremer carefully excised the polymer coating from a 10-millimeter segment of the optics cable to expose the bare 400-micrometer diameter glass fiber core.

He then cleaned the segment, subjected it to a silver-coating process, added a small well in which to pour the solutions being observed, and polished both ends of the fiber to 45 angled faces.

In subsequent experiments, the device’s sensitivity was tested using various concentrations of glycerol, and the team confirmed it was on par with current equipment, at a fraction of the cost and size.