Instead of searching for a needle in a haystack, what if you were able to sweep the entire 

haystack to one side, leaving only the needle behind? That's the strategy researchers in the 

University of Georgia College of Engineering followed in developing a new microfluidic device 

that separates elusive circulating tumor cells (CTCs) from a sample of whole blood.

CTCs break away from cancerous tumors and flow through the bloodstream, potentially 

leading to new metastatic tumors. The isolation of CTCs from the blood provides a minimally 

invasive alternative for basic understanding, diagnosis and prognosis of metastatic cancer. 

But most studies are limited by technical challenges in capturing intact and viable CTCs with 

minimal contamination.

"A typical sample of 7 to 10 milliliters of blood may contain only a few CTCs," said Leidong 

Mao, a professor in UGA's School of Electrical and Computer Engineering and the project's 

principal investigator. "They're hiding in whole blood with millions of white blood cells. It's a 

challenge to get our hands on enough CTCs so scientists can study them and understand 

them."

Circulating tumor cells are also difficult to isolate because within a sample of a few hundred 

CTCs, the individual cells may present many characteristics. Some resemble skin cells while 

others resemble muscle cells. They can also vary greatly in size.

"People often compare finding CTCs to finding a needle in a haystack," said Mao. "But 

sometimes the needle isn't even a needle."

To more quickly and efficiently isolate these rare cells for analysis, Mao and his team have 

created a new microfluidic chip that captures nearly every CTC in a sample of blood—more 

than 99% - a considerably higher percentage than most existing technologies.

The team calls its novel approach to CTC detection "integrated ferrohydrodynamic cell 

separation," or iFCS. They outline their findings in a study published in the Royal Society of 

Chemistry's Lab on a Chip.

The new device could be "transformative" in the treatment of breast cancer, according to 

Melissa Davis, an assistant professor of cell and developmental biology at Weill Cornell 

Medicine and a collaborator on the project.