It's a popular goal in nanotechnology these days: using tiny particles as containers to ferry drugs to tumors, among other targets. But immune sentries called macrophages quickly spot foreign invaders and gobble them up. Now, a team of Pennsylvania researchers has found a way to give particles a molecular "passport" that gets them past the sentries in mice, where the particles then deliver their lethal cargo to tumors and help destroy them. That success is stoking hope for a new way to improve the delivery of drugs.
In a separate study, Discher and colleagues tested whether their approach could improve the delivery of drugs. They loaded nanoparticles with the anticancer drug paclitaxel and decorated the particle surfaces with their passport peptides as well as with antibodies designed to attach to proteins on the surface of tumor cells. The targeted particles with the passports shrank tumors by 25% in a single day, while nanoparticles with the antibodies but without the peptide passports had no effect on the tumor size.
The paper has "really intriguing results," says Joseph DeSimone, a chemist and nanoparticle and drug delivery expert at the University of North Carolina, Chapel Hill. "It would be great to see this in other tumor models." Discher says his team is already at work on that. What's more, Discher says, unpublished work from his lab suggests that adding the molecular passports to viruses that deliver genes in gene therapy also helps them avoid immune detection. The new molecular passports still must prove their mettle in people, always a daunting hill to climb. If they do, they could potentially make nanomedicines already in clinical trials even more effective.
Robert F. Service, Science Magazine.