Shara C. Williams

Biological applications of colloidal nanocrystals

Due to their interesting properties, research on colloidal nanocrystals has moved in the last few years from fundamental research to first applications in materials science and life sciences. In this review some recent biological applications of colloidal nanocrystals are discussed, without going into biological or chemical details. First, the properties of colloidal nanocrystals and how they can be synthesized are described. Second, the conjugation of nanocrystals with biological molecules is discussed. And third, three different biological applications are introduced: (i) the arrangement of nanocrystal–oligonucleotide conjugates using molecular scaffolds such as single-stranded DNA, (ii) the use of nanocrystal–protein conjugates as fluorescent probes for cellular imaging, and (iii) a motility assay based on the uptake of nanocrystals by living cells.

Cell motility and metastatic potential studies based on quantum dot imaging of phagokinetic tracks

A wide variety of eukaryotic cells are shown to engulf colloidal semiconductor nanocrystals, or quantum dots, when they migrate. Here we show that the uptake of the nanocrystals is directly correlated with the cell motility, by comparing in detail the motions of both cancerous and healthy human breast cancer cells, as well as several other cell types. The nanocrystals are more photochemically robust than organic dyes (which fade quickly) and do not perturb the cells. The ability to examine these behaviors in live cells over extended time periods, and to quantify changes in response to various molecular manipulations, provides a powerful tool for studying the processes of cell motility and migration – behaviors that are responsible for metastases of primary cancers.