Nanomedicine is also making an impact on sexually transmitted diseases, including the prevention of HIV, herpes, and bacterial infections in women. “Sexually transmitted infections are a major problem in both developed and developing countries. Women are disproportionately infected with HIV during heterosexual intercourse, for instance, and an easy and discreet female-controlled microbicide could halt millions of infections worldwide,” says Hanes. “But the mucus barrier is a challenge.” The vagina’s surface has numerous folds known as rugae, which are coated by a protective layer of mucus. The mucus layer proves a formidable barrier not only to disease but also to drugs that prolong preventive drug activity. Too few of today’s drugs and antimicrobials can both penetrate the mucus and have a lasting effect on disease, Hanes says.
In a paper published in 2012 in Science Translational Medicine, Hanes and a team of researchers reported creating mucus-penetrating nanoparticles that can make it into crevices of the rugae and remain active for sustained periods of time. The drugs were coated with a slippery polymer that avoids sticking to mucus. These particles provide deep and complete coverage of the rugae in just 10 minutes. “Our mucus-penetrating particles were more effective against herpes infection than existing drugs, even when the existing drugs were used in 10-times higher concentration,” Hanes says. “This bodes well for the future of nanomedicine in safe and effective drug delivery systems for mucosal tissues, like the vagina, lung airways, and gastrointestinal tract.”
Kannan sees a special atmosphere evolving in nanomedicine at Johns Hopkins. It is a place where biomedical engineers like him and Hanes can explore common aspects across many diseases and apply their problem-solving skills while they work with top experts in the specific diseases they are trying to treat. “It’s just a very collaborative place to work on some very big problems,” he says.