Biomedical Engineering Challenges Addressed in Report

Prof. Robert Langer, from the Massachusetts Institute of Technology (MIT; Cambridge, MA, USA), reported about the great challenges facing biomedical engineering in the next century, at the annual meeting of the American Association for the Advancement of Science (AAAS) in Boston, MA, USA, on February 15, 2008. The report, titled "Grand Challenges for Engineering,” described the areas of research that are seen as most likely to produce results that could considerably improve life on Earth.

In addition to Prof. Langer, two other MIT scientists were members of the panel and participated in the press conference: Wesley L. Harris, a professor of aeronautics and astronautics at MIT, and MIT president emeritus Charles Vest, a professor in the department of mechanical engineering.

One of Prof. Langer's specialties is growing the vital tissues of the human body--including skin, blood vessels, bone, and parts of organs such as the liver and intestines--in a laboratory dish instead of in the body. For example, based on Prof. Langer's research scientists can grow patches of skin that can be used as grafts for burn victims.

Among the great challenges in the area of biomedical engineering, according to Prof. Langer, is finding new ways of delivering drugs and other large molecules to targeted sites inside the human body. As part of that research, Prof. Langer, who already has more than 600 patents granted or pending, has been working on the development of innovative ways to introduce DNA strands into human cells, a necessary step in gene therapy to correct genetic abnormalities or predispositions to disease.

Conventionally, such DNA insertions have been done using viruses that have a natural ability to penetrate the cell and insert segments of DNA into the nucleus. However, these viruses can sometimes have hazardous side effects, and have been responsible for deaths in some early gene-therapy trials. "We're working on polymers that could deliver DNA as efficiently as viruses, that could put a DNA strand wherever you want, without the safety problems of viruses,” Prof. Langer said. Moreover, they could be less expensive and easier to manufacture.

So far, the problem has been that such "synthetic vectors” have been far less effective in carrying out the delivery. However, in early studies conducted by the MIT researchers, some polymers have been as efficient at delivering the DNA strands to their target as the viruses, but with 100 times less toxicity.

Such new polymers, according to Prof. Langer, might ultimately lead to new treatments for some types of cancer. Furthermore, they may also enable the delivery of small interfering RNA segments (siRNAs), whose discovery led to a Nobel Prize in 2006. These may be used to fight a range of diseases.

Professors Anderson, Langer, and graduate student Michael Goldberg have also been working on the design of chemicals similar to lipids in the body, called lapidaries, that could be used to deliver drugs including siRNA to specific tissues in the body and release them in a controlled way. Already more than 50 promising compounds have been found and all are undergoing tests. "That work is going quite well,” Langer stated.

Tissue engineering is another important area of ongoing research, according to Prof. Langer. One major project is growing replacements for damaged tissues such as the neurons damaged by spinal cord injuries that lead to paralysis. Using a neuronal scaffold, Prof. Langer and his colleagues have succeeded in growing new tissue from neuronal stem cells, and have succeeded in helping paralyzed mice to walk again.


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