Expert observers are impressed, not only by the ability of the nano drugs to shrink tumors but also by its potential to seek out early-stage tumors. “This could have an impact in the overall treatment of cancer patients, not just for therapy but for diagnosis too,” says Kattesh Katti, a researcher at the University of Missouri-Columbia who works with nanoparticles in cancer therapy.
But others are skeptical of pH as a viable marker for cancer cells. Denis Wirtz, associate director of the Institute for Nanobiotechnology at Johns Hopkins University, warns that sites of infection are also highly acidic, and could potentially throw pH-sensitive cancer drugs off their course. “It’s not always the most specific way to do it,” Wirtz says. “For viral infections, you can have drastic pH changes that have nothing to do with cancer.”
Wirtz suggests another approach: map the molecules on a tumor’s surface, design peptides that can recognize those tumor molecules, then coat a drug-carrying nanoparticle with the tumor-targeted peptides.
That kind of research may be down the line, suggests Amiji, adding that an advantage in working with a polymer-based nanoparticle is that its surface can be easily modified.
Meanwhile, Amiji’s lab is also tackling the problem of drug resistance. Over 50 percent of women with ovarian cancer relapse after any given treatment. It’s a statistic that spurred the team to experiment with multiple drugs, encapsulating several drugs into a single nanoparticle, and controlling when each drug is released.“If you think about it, we have luggage,” says Amiji. “So the contents inside that package really are up to the creativity of the scientist.”