Nanoparticles--a historical perspective.

The historical development of nanoparticles starting with Paul Ehrlich and then first attempts by Ursula Scheffel and colleagues and the extensive work by the group of Professor Peter Speiser at the ETH Zürich in the late 1960s and early 1970s are described from a personal point of view. Special attention is given to the years between 1970 and the early 1980s. Further developments resulting from this work are also followed, and focus is placed on especially interesting improvements such as nanoparticles for the delivery of drugs across the blood-brain barrier (BBB) and PEGylated nanoparticles with a prolonged blood circulation time.