In a paper published last week, University of Nebraska professor Ravi Saraf and fellow Chieu Van Nguyen describe a thin-film sensor that can detect breast tumors too small and deep to be felt with the fingers. Using the standard silicone breast model used to train doctors in manual breast exams, the film detected tumors as small as 5 millimeters, up to 20 millimeters deep. The technology could also improve skin cancer detection.

The film, made of nanoparticles and polymers, when pressed against the skin, creates changes in electrical current and light that can be captured by a digital camera. The researchers refer to it as an “electronic skin” able to sense texture and relative stiffness.