Qdots are tiny fluorescent particles, smaller than a virus, and over 1000 times smaller than a cell, which can be linked to biological molecules, such as antibodies. Once linked, the fluorescence would make it easy to find which cells contain the protein the antibody recognizes, and where in the cell this protein is located. However there have been problems getting the Qdots into cells without them clumping, or being packaged in to endosomes, and excreted from the cells as waste.
Researchers from the City College of New York have overcome this problem by coating the Qdots in lipid and protein coats based on Sendai virus. Prof Maribel Vazquez explained, "While cells have complex defense mechanisms to protect themselves against attack, viruses have evolved ways to fool the cell into letting them in. We were able to exploit these mechanisms by fusing inactivated mouse parainfluenza virus with liposomes containing Qdots. The Qdots were in turn attached to an antibody against EGFR. So, once inside the cell, the Qdot-antibody complexes were able to bind to the receptor and the amount of bound complex could be monitored by measuring Qdot fluorescence."
This study looked at the level of EGFR as a marker for cancer but the Qdots could be attached to any antibody. Antibody-Qdot sets would allow rapid identification of different cancer types, determine potential chemotherapy resistance, and lead a more individualized treatment plan.
Source: Eurekalert
