Fishing for one bad cell out of trillions of good ones

Cancer cells can break away from a tumor and circulate through the blood. There are few of the cancer cells compared to the trillions of blood cells. Current methods to find and extract these circulating tumor cells (CTC) are expensive and may be out of reach for medical facilities in rural areas.

Wei Li, an assistant professor in the Texas Tech Department of Chemical Engineering, is developing a new technology that could make it possible to pluck circulating cancer cells out of a few milliliters of blood taken from a patient.

"Cancer cells can break off from a tumor site and travel through the blood to a find a new host, creating yet another tumor," said Li. "Detecting these cells early can aid physicians in devising treatment much earlier. And early detection of cancer is key in survival rates."

Good Guys vs Bad Guys

Li, who came to Texas Tech in 2014, is working with hollow glass bubbles that are coated with a special nanofilm that attracts cancer cells, but not blood cells. A mixture of cancer cells in blood is put into a plastic tube containing the bubble and it is shaken for a few minutes. Cancer cells attached on the bubbles will float to the surface while normal blood cells will sink to the bottom.

"The goal is to capture only the bad guys, the cancer cells," he says. "By using a special polymer coating on the top of the hollow bubble we can prevent the capture of the good guys, the regular blood cells."

Li's technology, coupled with new microscope lenses that can be attached to a smart phone could give physicians, especially in rural and under-funded areas, new, faster diagnosis options.

"This technology could give doctors an early hint that cancer has spread," he said. "Or it can be possible to have an early way to know if a patient's symptoms might be cancer and treatment needs to be determined right away."

Currently, magnetic particles are used to hunt down the CTCs and a magnet pulls them out of the blood. That technology is expensive and usually found in big city medical facilities. Another drawback Li says is that this method can produce false positive results since the regular blood cells also attached to the magnetic particles. His use of specific polymer coatings that capture only cancer cells reduces the number of false positives.

The next step in Li's research is to collaborate with researchers in the Texas Tech University Health Sciences Center Southwest Cancer Center to apply this technology to blood drawn from current cancer patients.

Preservation of Cells in Blood Sample

Li also believes his technology has other applications beyond cancer detection. The same system could preserve cells of interest from patient blood that must be sent to distant medical facilities for testing.

"Big cities have testing facilities," he said. "But rural areas most often do not. It's easy to draw blood anywhere, but getting some tests done is another matter. Some tests must be done within four hours of drawing the blood."

Cells in blood degrades rapidly, making it difficult to retain over several hours. If Li's microbubble system can preserve cells of interest from blood for longer periods of time, the blood can be drawn in remote areas and the cell samples can be sent to larger testing facilities, saving patients time and travel expense.

"We think our microbubble system could preserve the cells for a long enough time to get them to a facility," he said. "We don't know yet, but it's the next phase of our research."

Nano Architecture

Li became interested in cancer research while he was a post-doctoral researcher at Massachusetts Institute of Technology (MIT). He is trained as a polymer chemist. A polymer is a large synthetic or natural molecule made up of many small repeating molecules that form the basis for such things as plastic.

"I worked in a lab at MIT that was looking a developing new biomedical uses, especially for cancer treatment," he said. "I became interested in seeing if we could use nano-scale materials for drug delivery to cancers."

Li began looking at drug resistance of cancer cells and whether nanoparticles could be used as drug carriers to cells that reject cancer drugs. Li has expended his research focus recently to look at using nanomaterials to detect cancer.

While Li's work is solidly in the realm of biomedicine, he is first and foremost an engineer. He calls his work nano architecture.

"Behind my work is the ability to engineer nanofilms," he said. "The most important part of this work is the nanofilm that coats the hollow glass microbubbles. I am building layer-by-layer, a film of multi-functional ingredients that will capture the bad guys and reject the good guys."

Li's research is detailed in a recent online version of the American Chemical Society journal Applied Materials and Interfaces