Jonas presented our new high-speed tracking system at the SPIE Optical Metrology 2021 and published in SPIE Proceedings. The article explains the working principle and shows the application of our technology to observe the drug response of a single cell. By continuous high-speed tracking of tracer particles with highest positional accuracy and sub-pixel resolution the impact of blebbistatin on the mechanical properties of 3T3 mouse fibroblasts is shown. Frequency analysis of the response of the tracer particles that are incorporated in the cell shows that active transport processes in the cell are inhibited by the drug.