Lab-on-a-chip identifies how cancer cells detach

Johns Hopkins engineers have invented a lab-on-a-chip that could be used to help discern how cancer cells break free from neighbouring tissue and spread to other parts of the body.

Principal investigator Professor Peter Searson and his colleagues at the US Johns Hopkins’ Whiting School of Engineering have developed a lab-on-a-chip device that can help researchers study cell detachment. They hope to use the device to discover exactly how cancer cells spread.

“Studying cell detachment at the subcellular level is critical to understanding the way cancer cells metastasize,” said Searson.

“Development of scientific methods to study cell detachment may guide us to prevent, limit or slow down the deadly spreading of cancer cells.”

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. When a cell is placed on top of these molecules on the chip, the cell spreads across several of the gold lines and forms attachments to the surface of the chip with help from the molecules.

The scientists then release the tethered molecules from one of the lines by a chemical reaction — specifically by “electrochemical reduction”, Searson said. When 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, then reacts by forcefully contracting towards the end of the cell still attached to the chip.

The researchers were able to film this 'tail snap' under a microscope. “It’s very dramatic,” said Professor Denis Wirtz, a co-author of the paper.

“The cell stretches way, way out across the chip and then, on command, the tail snaps towards the body of the cell.”

The researchers hypothesise that the tail snap reaction time for cancer cells, as compared to noncancerous cells, would be shorter since cancer cells are more pliable. If their ongoing tests prove this, it may give them a tool to differentiate between cancerous and noncancerous cells.

The study, Programmed subcellular release for studying the dynamics of cell detachment, was published in the March issue of the journal Nature Methods.