By tagging living cells with nanometer-size semiconductor crystals known as quantum dots, researchers recently opened a new way of viewing the cell's machinery (SN: 2/15/03, p. 107: NanoLights! Camera! Action!). With the goal of developing more-sensitive screens for detecting cancer, scientists have now used quantum dots to track down and light up cancer cells in mice.
Typically made with elements such as cadmium, quantum dots are toxic, making them questionable for use in animals. So biomedical engineer Shuming Nie of the Georgia Institute of Technology in Atlanta and his colleagues coated the quantum dots with a protective polymer that lets the nanoparticles' fluorescence shine through. To the coating, the researchers then affixed antibodies that seek out prostate cancer cells. All dressed up, each quantum-dot particle measured 20 nanometers to 30 nm in diameter.
Once injected into the bloodstream of mice bearing prostate tumors, the quantum