ABSTRACT
Nanoparticles are used nowadays in increasingly diverse applications i) for fundamental multiscale studies to measure, visualize, and understand how cells, tissues, and organisms function ii) for direct biomedical applications in in vitro diagnostics and nanomedicine. 
We will highlight research on the cell membrane organization using nanoparticles as single-molecule labels and on time- and space-resolved observation of signal transmission activity in cells and inflammation processes in small animals exploiting nanosensors with unique properties. We will furthermore review recent developments in ultrasensitive detection of disease indicators (biomarkers) in blood samples with luminescent nanoprobes, nanocarriers for drug delivery, and nanoparticle-based enhancers of cancer treatment with X-ray radiation