Being able to monitor drug concentration in the blood of a patient is an important aspect of any pharmaceutical treatment. However, this requires equipment and facilities that are often missing from field healthcare in developing countries, but also inhibits the quality of life for patients elsewhere. EPFL scientists, working through their startup LUCENTIX, have now developed an antibody-linked biosensor that can track drug concentration in the blood by changing its color. The biosensor is incorporated into a full system that can be used in the field or by patients at home. The science behind it is published in Angewandte Chemie.