Engulfment of Nanocrystals Reveals Migratory Paths of Breast Tumor Cells.A wide variety of mammalian cells engulf quantum dots when migrating. This migration is correlated to the cell’s metastatic potential. After 24 hours, dark clearings in the nanocrystal layer are observed around motile tumor cells.

APPLICATIONS OF TECHNOLOGY:

• Rapid method for assaying metastatic potential in biopsies
  
• Cancer drug development
  
• Research on cell motility

ADVANTAGES:

• More photochemically robust than organic dyes
  
• Less labor intensive than the Boyden Chamber invasion assay
  
• Can be used with live cells – no fixation/processing required
  
• Allows for real time variation of external conditions
  
• Nanocrystals don’t perturb cell viability
  
• Good film homogeneity, cellular resolution

ABSTRACT:

Carolyn Larabell, Paul Alivisatos, and colleagues have discovered a powerful tool for studying cell motility and migration - behaviors that are responsible for metastases of primary cancers. The Berkeley Lab researchers compared the motions of cancerous and healthy human breast cells, as well as several other cell types, as they migrated across a layer of colloidal semiconductor nanocrystals. As they move, they engulf the quantum dots and leave behind a phagokinetic track which yields information about the health of the cells. Migration of cells and their metastatic potential are well known to be correlated.

Colloidal quantum dots are robust and efficient light emitters that have been used for static biological labeling. They are superior to organic dyes, which fade quickly and perturb the assayed cells. Larabell’s lab has shown that these nanocrystals are spontaneously ingested by a wide variety of cells while remaining fully luminescent, enabling researchers to examine live cells over extended time periods and to quantify changes in response to various molecular manipulations.

The Berkeley Lab technique is less labor intensive than the Boyden Chamber invasion assay method, it does not require killing the cells, and it enables real-time variation of external conditions and analyses of cellular responses. It also overcomes the marker problems encountered in the original phagokinetic tracking methods. The method can be coupled to information about chemical signals and allows a wide variety of tissue culture substrates to be used, including growth on all extracellular matrix substances.

The improved cell motility studies and rapid assaying of metastatic potential enabled by this quantum dot method will provide improved diagnostics and enhanced information for cancer drug development.

STATUS:

• Published Patent Application. Available for licensing

REFERENCE NUMBER: IB-1755

PUBLICATIONS:
"Cell motility and metastatic potential studies based on quantum dot imaging of phagokinetic tracks," W. J. Parak, R. Boudreau, M. Le Gros, D. Gerion, D. Zanchet, C. M. Micheel, S.C.Williams, A. P. Alivisatos, C. Larabell, Advanced Materials 14 (12): 882-885 (June 18 2002)