Yale Bulletin and Calendar

April 26, 2002Volume 30, Number 27


Robert Langer

With the eye of an engineer, scientist
tackles problems of medicine

It's not every day that an engineering researcher gets to see the systems he developed written into a top-rated TV show, but that's just what happened to Robert Langer, a renowned biomedical engineer from the Massachusetts Institute of Technology (MIT) and the third lecturer in Yale Engineering's Sesquicentennial Distinguished Lecture Series.

Speaking to an audience at Davies Auditorium on April 16, Langer recalled how his concept of local chemotherapy to reduce side-effects to brain cancer patients not only resulted in the first new FDA-approved treatment for brain cancer in 20 years, but also made it into the script of the TV show "ER." On that show, the main character Mark Green develops brain cancer and his only hope for survival is this new surgical technique, which in real life was developed by Langer.

"This concept of local chemotherapy involves lining the surgical cavity with discs containing a drug that delivers high concentrations in the brain where you want to focus the treatment, and less concentrations in other areas of the body, reducing chances of side effects," said Langer, who is the Kenneth J. Germeshausen Professor of Chemical and Biomedical Engineering at MIT.

Langer, who is always thinking about new ways to address different medical problems, has for the past 28 years studied ways of delivering drugs across complex barriers such as the skin and lungs. He is also creating new approaches to using materials to do different things in the human body, such as engineering new tissues.

Langer's interest in creating new drug delivery and tissue engineering systems was piqued in 1974 when he began studying how blood vessels grow. He spent several years in the laboratory devising ways to distribute drugs to prevent the blood vessels from re-closing.

One of the problems with conventional drug delivery systems is that there is no regulation of the drug, Langer explained. When someone takes a drug, the levels start out low, reaches a peak and then goes down. For some drugs, the peaks can cause terrible side effects, and in the valleys the drug is not effective. Langer cited an article in the Journal of the American Medical Association stating that over 100,000 deaths each year are caused by people taking prescription drugs exactly as they were supposed to.

"We'd like to be able to target drugs to specific parts of the body," Langer said. "This is what the very young field of drug delivery is all about. In a short time, it has made a considerable economic and clinical impact. From an economic standpoint, in 1980 the sales of advanced drug delivery systems were zero dollars. But last year they exceeded $20 billion. Over 10 million people in the United States use these."

One of the earliest drug-delivery systems was a nitroglycerin patch used for angina. It caused fewer side effects and had a higher rate of patient compliance. Langer said the Norplant five-year delivery system is now used in over 50 countries around the world for birth control.

"As I started doing research in this field, the conventional wisdom was that this could not work. If you have a large molecule going though a conventional polymer, it's kind of like going through a brick wall. On the other hand, you could make something very porous and then it might go through too quickly. The challenge is to get it to go through, but slowly, and to do so in a polymer that was safe in the human body."

Langer added: "Many times in medicine, the materials we use in the human body are far from perfect. When I first started my career, the driving force for bringing materials into medicine were the clinicians, not engineers. They wanted to solve a problem as quickly as possible, and they would use objects, usually from their houses, to solve medical problems. For example, in 1967 clinicians from the National Institutes of Health used the materials from ladies' girdles to craft an artificial heart, and that same material is still used in 2002. Once you get started, you don't change."

The problem with using girdle material, Langer explained, is that the material forms a clot so the patient can get a stroke and die. Other common materials used in medicine include sausage casing for dialysis tubing and mattress stuffing and lubricant (silicone) for breast implants, he noted.

Langer began studying materials from an engineering and chemistry standpoint.

"When we first started, there was only one FDA-approved polymer for drug delivery, and this polymer posed many problems such as surface erosion, like the way a bar of soap dissolves." Langer studied the erosion and release rates of different polymers until he was able to create the perfect material.

In the area of tissue engineering, Langer is doing research that forces a cell type, such as the bone, cartilage or liver, to differentiate. By using the appropriate engineering techniques, he said, you can make cells in any shape, such as a nose or an ear. He and his team have licensed their technologies to companies, and many of them have been able to make new skin for burn victims or patients with skin ulcers from diabetes.

"Scaffolds" of polymers are also being used with neuronal stem cells to make new spinal cords, said Langer. In fact, he and his team were able to use the technology to help a child with no chest covering his heart; the researchers were able to make a new chest out of a polymer scaffold.

"The fields of drug delivery and tissue engineering are in an embryonic stage," said Langer. "The possibilities are endless and it's up to the imaginations of the engineers and clinicians to see what they can do."

Langer said he thinks he and his colleagues in these fields have raised more questions than they've answered. "It is my hope that as we go forward that scientists and engineers and clinicians working together will be able to develop new principles and use principles like these to try to create new entities and technologies that will relieve suffering and prolong life."

-- By Karen Peart

T H I SW E E K ' SS T O R I E S

Emerging leaders from 18 nations coming to Yale as first World Fellows

World Fellows diverse in nationality and experience

Alumnus' gift funds visiting chair in economics

Yale opens center for student groups

Wanted: Your views about the YB&C

Journalists decry globalization's effect on Latin America

HUD Secretary hails spirit of volunteerism in the U.S.

Streets is reappointed as chaplain and is named acting master of Trumbull College


ALUMNI NEWS

Research on genes upholds Darwin's theories, says Moore

With the eye of an engineer, scientist tackles problems of medicine

Exhibit explores transformations in American life

Communiversity Day 2002

Nobel laureate to present Farr Lecture at event showcasing student research


SCHOOL OF NURSING NEWS

In this year's 'showdown,' robots will demolish and build

Divinity School partners with Lutheran seminaries

Threats to nation's computer systems to be examined

Conference to explore relationship between 'apocalypse and violence'

Texas Rangers are subject of historian's talk

Juniors honored for their college spirit, contributions and talent

Ten scientists win NARSAD research grants

Edwin D. Mullen, long-time manager of purchasing, dies

Center marks retirement of noted child psychologist

Student musicians will perform works by Brahms in two May concerts

May Day concert to feature program of German music

Celebrating Earth Day


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