COLL 367 |
| This talk will review background chemistry and photophysics of nanocrystal quantum dots that is relevant to their application in biological and biomedical imaging and in opto-electronic device applications. We will discuss control of the hydrodynamic size, valency, and non-specific binding. Valency, or the number of binding sites per quantum dots, is an important parameter to control. Some applications work better with high valency to insure sensitive detection, others require a single binding site per quantum dot, such as for tracking single receptors on the surface of living cells. We will give an example of an in vitro application where one quantum dot is conjugated to a single genetically engineered monomeric streptavidin, to provide a single binding site to biotin for each quantum dot. The issue of overall size of the quantum dot is important for both in vitro and in vivo imaging. For some experiments a hydrodynamic diameter of ~15nm to ~30nm is quite appropriate, but for efficient diffusion into tissue and for renal clearance a smaller hydrodynamic diameter is desired. We will provide specific examples of tuning size and surface characteristic, focusing on lymph node imaging, and showing renal clearance of properly designed quantum dots. We will show that quantum dots can be engineered to be more than passive reporters of their location; that they can also act as sensors of their microenvironment. We will provide an example of a quantum dot based pH sensor that is ratiometric and self-referencing and that is optimized for the biological environment. We will also spend some time discussing the properties of multiexcitons in quantum dots since these are relevant to potential lasing and solar cell applications. |
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Langmuir Lectures
2:00 PM-4:00 PM, Tuesday, August 21, 2007 BCEC -- 151B, Oral
Division of Colloid & Surface Chemistry |