Nanoparticles precisely engineered at the nanoscale have emerged as novel therapeutic and diagnostic agents due to their unique physicochemical properties (e.g. optical, magnetic, electronic, etc.) that are dictated by their size, shape, composition, surface; and can be customized for the desired biological targets and functions. With applications ranging from imaging and detection probes to nanocarriers for (bio)therapeutics delivery, engineered nanoparticles can give unprecedented information on the chemical and physical processes that take place in biological systems, and enable targeted therapeutic interventions. In the group of BioInterfaces, we aim to address currently unmet biomedical needs in the diagnosis, monitoring, and treatment of disease with engineered nanoparticles tailored for the desired biological targets and functions. We utilize an interdisciplinary approach at the interface between materials chemistry, nanotechnology, and biology for bench-to-bedside development of optical and magnetic detection probes, (pre-)clinical imaging agents, and drug delivery systems based on inorganic and polymeric nanoparticles. We study the diagnostic and therapeutic performance of these nanoparticles in vitro and in vivo using advanced imaging and cell culture techniques and disease models.