Monday, May 16, 2011

Engineering Solutions to the Problems of Cancer

From MIT World

Engineers “bring a new set of tools and a new way of looking at problems posed by biologists,” says Paula T. Hammond, and are proving integral to advances in cancer diagnostics and therapies. Hammond cites evidence of bioengineering breakthroughs against the disease: the design of micron-sized posts that can identify and capture metastatic cancer cells on their passage through blood vessels; and particles manufactured to act as “smart bombs” for destroying tumors. In this symposium, panelists discuss promising discoveries from labs that are merging engineering and life sciences in the war against cancer.

As the developing world increasingly becomes the source of new cancer cases, “we have to change how we think about diagnosing and treating” the disease, says Sangeeta Bhatia. Researchers find one road map for transforming diagnostics in the computer industry, where miniaturization makes technology both more cost effective and portable. Bhatia describes a small microscope that may bring screening tests for cervical cancer to the patient, and the possibility of a postage stamp-sized piece of paper that can test urine for the biological markers of cancer, working along the lines of a pregnancy test.

Changing cancer treatment proves more difficult, defined as it is currently by surgery, chemotherapy and radiation. But Bhatia is developing nano-scale tools to deal direct blows to tumors with fewer side effects. Partnering with chemists, she is designing magnetic “nanoworms” that respond to heat and release precise drug payloads to diseased cells at designated times, as well as gold “nanorods” that land in tumor sites and act as beacons to attract drug molecules in large concentrations. These methods show promising suppression of tumor growth in mice.

Joseph DeSimone comes list in hand of “unmet needs in cancer,” including focal delivery to poorly vascularized tumors, cancer vaccines and cancer prevention. He describes how engineering is opening up avenues for addressing these challenges. Building on the model of drug-laden stents used in heart disease, DeSimone discusses efforts to use catheters to drive drugs -- from small molecules to nanoparticles -- into cancerous tissues that have been difficult to dose directly.

He has also borrowed a page from the microelectronics industry, using the kind of lithography normally found in silicon wafer manufacturing, to fabricate nano-scale, flexible molds for medicines intended to be taken up by cells. This new nano-manufacturing platform, loaded with chemotherapeutic or biological agents, permits exquisitely precise and optimal dosing of tumors. DeSimone also describes the possibility of sending drug-carrying particles that mimic red blood cells through blood vessels to obstruct the spread of cancer in different sites throughout the body.

From a deep immersion in biological sciences, a new kind of engineering has emerged, says Douglas Lauffenburger. It is “not rooted specifically in mathematics, physics and chemistry,” but in the revolutions of molecular biology and genomics. This convergence means engineers can “look under the hood and see what one can do inside the biology,” thinking about cancer “in terms of biomolecular machines and circuits.”

Lauffenburger offers several examples of biological systems thinking. There are cancers where drugs “work splendidly but only in a fraction of patients.” An engineering approach looks at the signaling biochemistry and cell biology in tumor cells, models the machinery, and attempts to “characterize behavior of tumor cells that are sensitive to drugs, and those resistant.” Quantitative analysis helps determine when the drug works, and how to make it better, he says. Systems analysis proves useful in isolating other potential genetic targets for some cancer drugs, and circuit diagrams come in handy when analyzing the receptors and signaling circuitry that antibody drugs take aim at. “Straightforward biochemistry” needs quantitative and systems analysis to reveal the multilayered mystery of tumor growth and regulation, suggests Lauffenburger.

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