Really Cool Stuff: Colored Beads Stepped Up
By Caroline Crocker
I first came across quantum dots when working in cancer research for the Department of Defense. We used them to label different structures on our cells–and they were so new that I actually saw them demonstrated at an educational seminar at the National Institutes of Health. Now the plan is for them to eventually be everywhere–even in our camera-phones!
So, what is a quantum dot? The technical answer is “a semi-conducting particle just a few nanometers across” (reference is below). Basically, these nanocrystals “absorb photons of light, then re-emit photons at a different wavelength” (reference above). All the dots absorb UV light, but the color of the emitted light is related to the size of the crystal, with the largest crystals releasing light of a lower wavelength than the smaller.
In the case of cell research, the quantum dots are attached to antibodies (proteins that stick to other proteins) that recognize antibodies that are specific for a certain cell structure. In the case of the cell phone cameras, the quantum dot photodetector would be placed on the surface of a chip and the dots would change size because of the wavelength of incoming light. Amazing! Makes my head spin what people can do when allowed the freedom to invent.