Imaging Small Cancer Tumors with Silicon Quantum Dots
Nanotechnology researchers believe that using quantum dot–based nanoparticles in the body can help them identify smaller cancer tumors and provide better images of cancer tumors. In addition, during surgery, the glowing nanoparticles can help a surgeon identify and remove an entire tumor.
Quantum dots glow a particular color after you shine light on them and some of the electrons receive enough energy to break free from the atoms. Researchers are developing silicon nanoparticles to be used for fluorescent imaging of diseased tissue in the body, such as tumors.
Because silicon is a semiconductor, silicon nanoparticles are part of the class of nanoparticles called quantum dots. Quantum dots containing some substances, such as cadmium, may be toxic. Researchers believe that quantum dots made of silicon have less chance of producing toxic effects than other types of quantum dots.
Just as they’re using cadmium selenide quantum dots for the diagnostic testing of blood samples, researchers are surrounding silicon quantum dots with other layers for the same purpose.
The first layer is made up of silicon dioxide, which is used to prevent the oxidation of the outer layer of silicon atoms. The second layer is a hydrophilic layer, which allows nanoparticles to mix with water solutions, like blood. Attached to this polymer layer are the antibodies that attach the quantum dot to diseased cells. Another type of molecule, polyethylene glycol (PEG), is also attached to the polymer layer.
As this nanoparticle travels through the bloodstream, white blood cells in the body’s immune system might attack the nanoparticle. However, polyethylene glycol molecules shield the nanoparticle from the immune system.