Recently developed cancer-targeting nano-particles promise better cancer therapy, and a different experience at the doctor’s office. Administered to the body in doses of billions, each tiny machine can home in on tumors, inject a growth-stunting drug into one of the offending cells, dispense a speck of oxidized iron for MRIs, and call in its fellow nano-particles for backup.
The particles, developed by the lab of UC San Diego’s Dr. Michael Sailor in collaboration with Dr. Errki Ruoslahti’s Burnham Institute team and Dr. Sanjeeta Bahtia’s lab at MIT, measure just 50 nano-meters in diameter, and cruise through the circulatory system alongside red blood cells 40 times their size. They’re less harmful than the chemicals of chemotherapy, and more keen at spotting small growths than an oncologist.
These microscopic, automated doctors may seem like the stuff of an Asimov novel or a Magic School Bus episode, but making them was much more involved than coming up with a plot device, and their creators hope that their use will be more than episodic.
The core of each particle contains a dose of the cell growth inhibiting antibiotic doxorubicin, and fluorescent quantum dots which allow scientists to track where particles are using scans. Particles also have a fatty outer layer similar in design to the outside of a regular cell. This outer layer is designed to bind to tumor vessels, and allows the particles to stick to and invade cancerous growths. It also allows the particles to specifically seek out cancer, rather than distribute the harmful drug to all cells in the body. This homing ability was one of the major challenges in designing the particles, and one of the greatest advantages that nano-technology has over other cancer therapies.
After the therapy passes through human clinical trials, the particles will likely be used as a means of spotting and eradicating new growths in patients who have malignant tumors. Eventually, once the side effects and risks of the particles’ use are reduced, the particles could be used as a routine cancer screening method.
These particles are not the first nano-technology to hit the biomedical scene. Abraxane, a breast cancer treatment that employs nano-scale structures, went on the market in 2005, and nano-sized bits of oxidized iron are already used in MRIs. But these new nano-particles function as both drug delivery and cancer imaging systems. Their dual function makes them more advanced than earlier nano-scale drug delivery machines, and their sophistication indicates that this technology has a bright future.