Earlier this week, Google unveiled its next moonshot project: to use nanoparticles to detect cancer. Though the search giant’s experimental wing, Google X, loves tackling the seemingly impossible, the development of nanoparticles that attach to cells and pass through the body–as innovative as it is–has already been done.
Scientists were able to safely deploy ultrabright nanoparticles, which bind to and light up cancer cells, in five patients with metastatic melanoma at the Memorial Sloan Kettering Cancer Center in New York City. The silica-organic hybrid particles–called Cornell dots, or C dots for short–measure 7 nanometers (a nanometer is a billionth of a meter) and can contain peptides that bind to receptors on tumors. Under near-infrared light, the particles light up, serving as a beacon during surgery. The nanoparticles could also be used to deliver highly targeted drugs by adhering to specific cells.
Michelle Bradbury, senior author and clinician on the study, said more than 40 people at the Memorial Sloan Kettering Cancer Center were involved in the trial. “There are a lot of decisions that have to happen before you get it into a person,” she told Fast Company. “It’s a thousand times smaller than the width of a human hair, and you’re asking for it to bind to cells and deliver cargo. Lots of sophisticated things have to happen, and it has to be done at the site you want without toxic effects to the body. That’s something that takes a career to do right.”
In contrast, Google’s vision for cancer detection involves magnetized nanoparticles, likely delivered via pill, that attach to cells. The company is also developing a wearable device to attract, monitor, and count particles using a magnet.
For the melanoma trial, scientists injected patients with nanoparticles containing radioactive iodine so they can be tracked under a PET scan. The study, published in the journal Science Translational Medicine, was administered under the Federal Drug Administration’s investigational new drug guidelines. The trial found that the nanoparticles, which exited the body via patients’ urine, are safe for humans.
“This has been very encouraging,” Uli Wiesner, a professor at Cornell who invented C dots more than a decade ago, said in a statement. “It’s the first case we’re aware of in which the FDA has approved an inorganic optical nanoparticle as an [investigation new drug] for a clinical trial. While this was just a safety and pharmacokinetics [a branch of pharmacology] study, this opens the door to using these particles in real applications.”
The trial began in 2010, but there’s still more studying to be done. The researchers are currently recruiting patients with brain tumors for the study. A separate trial will look at the effectiveness of C dots as a cancer diagnostic tool.
Read more about Google’s work with medical nanoparticles here.