My group has been working on the investigation of the interactions between nanowires and living cells for many years. In this presentation, I will review the main results and try to explain why certain cell types enjoy being in contact with nanowires while others not. I will also show that certain nanowire properties (e.g. geometry, photovoltaic properties) can be used to steer cell behavior, opening up for applications in biomedical research as well as clinical applications.