The lab-chip schematic shows the cell
membrane-bound protein with peptide
(red) tethered by thiol molecules (blue)
to gold electrode (yellow); © JHU
"Studying cell detachment at the subcellular level is critical to understanding the way cancer cells metastasize," says principal investigator Peter Searson, Professor of Materials Science and Engineering at the John Hopkins University. "Development of scientific methods to study cell detachment may guide us to prevent, limit or slow down the deadly spreading of cancer cells."
Tumor cells detach and travel through the bloodstream to settle in other tissues. Scientists have learned much about how cancer cells attach to these surfaces, but they know little about how these insidious cells detach because no one had created a simple way to study the process.
Searson and two other scientists from Johns Hopkins' Whiting School of Engineering have solved this problem with a lab-on-a-chip device that can help researchers study cell detachment. With this device, they hope to discover exactly how cancer cells spread.
The lab-on-a-chip device consists of an array of gold lines on a glass slide. Molecules promoting the formation of cell attachments are tethered to the gold lines like balloons tied to string. A cell is placed on the chip, atop these molecules. The cell spreads across several of the gold lines, forming attachments to the surface of the chip with help from the molecules.
Then, the tethered molecules are released from one of the lines by a chemical reaction, specifically by "electrochemical reduction," Searson explains. Where these molecules are detached, that portion of the cell loses its grip on the surface of the chip. This segment of the cell pauses for a moment and then contracts forcefully toward its other end, which is still attached to the chip. The researchers were able to film this "tail snap" under a microscope.
"In the movies, you can see that the cell doesn't move immediately after the chemical reaction is triggered. We refer to this phenomenon as the induction time of the cell," Bridget Wildt, a materials science and engineering doctoral student, says. "After this induction time, the cell then snaps back and contracts. We analyze the rate of the cell's contraction and then compare this information to separate cells released under different conditions using chemicals called inhibitors. From these results we are beginning to understand the processes that regulate cell detachment at the molecular level."
COMPAMED.de; Source: John Hopkins University