Smartphones may become pregnancy testers

SPR sensorResearchers at Hanover University said they’ve made a fibre optic sensor for smartphones which could be used to detect pregnancy or to monitor diabetes.

The idea is that readings from the sensor could use a smartphone app to give results and the scientists suggest that combined with GPS an app could tell a patient to the way to a hospital or a doctor.

Writing in Optics Express, the scients said that the sensor uses surface plasmon resonance (SPR) to detect what’s in a liquid.

SPR happens when light strikes a metallic film and while most of the light gets reflected, a small band is picked up by surface electrons, making them resonate. By adding recognition elements to the film, an app can use a biological sample to detect its composition.

SPR devices usually need bulky lab equipment using a light detector and light source but a smartphone already has both.

The prototype the scientists made (pictured) uses a 400 micrometre diameter core multimode fibre with a silver coated sensing region.