From Velcro to solar cells, many technological innovations have been inspired by nature. In medical diagnostics, researchers also draw inspiration from biological principles. A research team from the University of Freiburg and the INM – Leibniz Institute for New Materials in Saarbrücken has developed testing methods in which simple LEDs could replace complex mechanical pumps. These OptoAssays not only mimic the behaviour of biological cells but also use their genetic programming.