Peptide-coated Quantum Dots: Applications to Biological Imaging of Single Molecules in Live Cells and Organisms

There is little doubt that recent advances in material sciences and nanotechnology will contribute to the development of new therapeutics and permit new discoveries in medical and biological sciences. Already, nanomaterials such as semiconductor nanocrystals, also known as quantum dots, have revolutionized cell and animal imaging techniques. The stringent conditions imposed by complex biological milieus demand that these nanomaterials be stable and biocompatible. Toward this aim, this thesis introduces an original surface chemistry that employs custom-designed peptides as an organic/inorganic interface on the surface of quantum dots. This peptide coating strategy was successfully tested on quantum dots emitting from the visible to the near-infrared spectrum range. Using the versatile physico-chemical properties of peptides, a ¿toolkit¿ was developed to functionalize quantum dots and control their biochemical activity at the nanometer scale. Peptide-coated quantum dots were engineered for in vivo animal imaging and employed to study the diffusion and the compartmentalization of lipid raft-associated membrane proteins, one at a time, in live cells.