“You can watch the biology of the cancer change,” he said. The device “gives you clues as to why a treatment may no longer be working.”
The scientists took short strands of DNA that bind with the targeted cancer cell surface and copied them hundreds of times. By connecting these DNA strands, they produced wispy material much longer than the cell itself. One end of the strand is connected to the microchip; the other floats free in the bloodstream. As cancer cells drift by, the strands bind to them, just as a jellyfish grabs food, Karp explained. The team is about to begin testing on patient tumor samples.
Russell Stewart, a professor of bioengineering at the University of Utah, is inspired by another marine creature: the sandcastle worm. This worm, named for its ability to assemble underwater reefs that resemble sand castles, is coveted by researchers trying to figure out how to create adhesive substances that work inside the water-heavy human body.
Making it stick
Ever tried putting on a plastic bandage in the shower? Common glues and tapes don’t stick to wet surfaces because the water prevents the glue from adhering. Super Glue and similar products are water-insoluble if you create the bond while the glue is dry, but they don’t adhere to wet surfaces.
Another problem in developing bio-inspired medical devices is the body’s immune system, which usually rejects foreign objects. “Our bodies are extremely good at recognizing materials that don’t belong there and attacking them,” Stewart explained.
The worm’s glue bonds, in part, by using oppositely charged proteins to form a fluid that is denser than water. The worm-inspired adhesive is a fluid that can be separated from water but still adheres to wet surfaces.
Stewart and co-workers created chemical analogs that mimic the worm’s adhesive proteins and properties.
Stewart and collaborators Ramesha Papanna and Kenneth Moise at the University of Texas Medical School in Houston are testing the new adhesives for sealing holes in fetal membranes. If it works, the glue would allow surgeons to perform advanced surgeries to treat conditions in the uterus, such as spina bifida, Stewart said.
The project is in preclinical trials and years from being used in hospitals.
Still, Stewart said, “If we could solve this problem, there are lots of other fetal surgeries that could be done in the womb.”
Researchers working in bio-
inspired engineering have benefited from better technology to dissect organisms at the atomic level, according to David J. Mooney, a research scientist at Harvard University’s Wyss Institute for Biologically Inspired Engineering.