Antibiotics play a life-saving role in the treatment of critically ill patients in intensive care units (ICUs), who are frequently fighting against severe infections. We are developing a miniature Raman spectroscopic sensor for therapeutic drug monitoring (TDM), especially for personalized antibiotics therapy. With this project, we want to advance our on-chip Raman sensor to achieve 1 mg/L concentration measurements of the free-fraction of β-lactam antibiotics in plasma. This innovation enables routine clinical use of TDM for β-lactam antibiotics, as well as TDM of multiple other drugs in later stages. This project supports the incubation of the spin-off Antares who wants to commercialize this medical device for TDM.