Engineering New Approaches to Cancer Detection and Therapy
published: Feb. 21, 2011, recorded: June 2006, views: 3131
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With his 500-plus patents, Robert Langer, Jr. surely has dibs on the title of MIT’s Mr. Wizard. This talk, which concludes the series on cancer research, deals with Langer’s efforts to design materials for safer and more effective cancer treatment.
Langer describes his groundbreaking work of 30 years ago to inhibit angiogenesis, the growth of blood vessels on which tumors depend. He came up with a way of packaging proteins inside plastic polymers, essentially microspheres of drugs, which could be injected directly into a target site. These tiny beads released an angiogenic inhibitor in a slow and steady way, starving the tumor of nutrients. He notes dryly that it took the FDA 28 years from the time these results were published to approve the first implantable angiogenic inhibitors. Today, this approach is heartily embraced, says Langer, because it “gives you a whole new other avenue of attack” against tumors.
Because many large proteins are effective at combating cancers but can’t be swallowed, taken nasally, injected directly, or put in a patch, they now end up in Langer’s microspheres. One hormone-releasing microsphere attacks advanced prostate cancer. This drug delivery system has even spread to treatments for schizophrenia and alcoholism.
Langer’s recent forays in the lab have yielded dime-sized, gold-covered, degradable microchips conveying multiple, small quantities of a drug. In response to a one-volt zap (“via telemetry like a garage door opener”), these devices release just the right dose. Chips might someday also carry imaging agents. Says Langer, “The beauty of the chip is that information could be transmitted from the body to a computer, your house, doctor’s office, or hospital, so you could have a record of whatever happened.”
In the surgical arena, Langer’s come up with a “shape memory” polymer that can phase from a string at room temperature, to a coil at body temperature -- acting as a self-tying suture in hard-to-reach places.
Langer is now moving into even smaller domains, experimenting with nano-sized drugs for use in the blood stream. Coated with a polymer to prevent attack from the body’s immune system, these nanoparticles show promise in shrinking tumors.
Langer cites his career-long commitment to devise materials for medical treatment that are biologically and chemically compatible with the human body. (Dialysis tubing was based on sausage casing, and the artificial heart from ladies’ girdle material.) His polymers often faced opposition from the research establishment. “When you’re at a place like MIT, you often do speculative work, and when you do speculative work, you’re not always greeted that well in the scientific community,” he says.
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