Functionalized Iron Oxide Nanoparticles as Disease Detectors
Nanotechnology materials, including nanowires, quantum dots, and iron oxide, are being functionalized and tested for the purpose of disease diagnostics. The paramagnetic properties of functionalized iron oxide have interesting properties for this diagnostic application.
One way to identify disease indicators in a blood sample is to tag them with magnetic or paramagnetic nanoparticles. The first step in this process is to simply attach antibodies to the magnetic material, for example, iron oxide nanoparticles.
Like iron, iron oxide has magnetic properties. Iron has four unpaired electrons, but in iron oxide, two of those electrons are paired with oxygen, leaving two unpaired electrons. Iron oxide is therefore less magnetic than iron. Because of this lesser magnetic quality, iron oxide is referred to as a paramagnetic material.
The paramagnetic properties of iron oxide nanoparticles are not changed from the bulk material except that these tiny particles can go where larger particles never could. These functionalized nanoparticles can attach themselves to a protein or virus, forming a cluster that indicates a particular disease. These clusters of iron oxide nanoparticles can be detected by magnetic resonance imaging (MRI) technology, the same technique used to image organs in your body.
Another approach that is currently being developed to use magnetic nanoparticles to analyze a blood sample is to attach several different antibodies to magnetic sensor tips built on a computer chip. When the chip is placed in a blood sample, any viruses or proteins that match one of the antibodies on the chip would attach to the corresponding antibody.
Next, a solution containing magnetic nanoparticles that have been functionalized with antibodies is introduced into the chamber. Those magnetic nanoparticles attach to the virus or protein that attached itself to the antibody on the sensor tip. A signal associated with a particular disease is then sent for that particular virus or protein.