A new diagnostic tool for detecting cancer

Illustration of a “lab of a chip” for detecting lung-cancer cells. The device is made of a widely used silicone rubber called polydimethylsiloxane and uses a technique called “on-chip immunoisolation.” Credit: University of Kansas/KU News Service

Researchers at the University of Kansas have announced the development of a lab-on-a-chip that can detect early cancer with a non invasive procedure.

All cells expel tiny sacs during their life, called exosomes. To get an idea on how small they are think that they a thousand times smaller than the thickness of a sheet of paper. They represent a sort of signature of the cell and although in the past were considered to be waste by-product of the cell metabolism now they are recognised as sort of communication packets that influence the behaviour of far away cells.

What matters is that exosomes expelled by cancerous cells are different from the one produced by normal cells. The problem is to find them, because they are so small.

The researches at the Kansas University have been able to create a microfluidic chip (where you have tubes into which a liquid can flow) that can detect exosomes and identify the presence of those deriving from cancer cells. The chip can analyse minuscule quantity of liquid, in this case blood, quickly and economically. One trillionth of a litre is sufficient to derive information and check for presence of "suspicious" exosomes. Hence a drop of blood is enough.

The lab-on-a-chip uses polydimethylsiloxane, a sort of silicon rubber as substrata. It uses magnetic beds, 3 micrometer in diameter, to extract exosomes from the plasma. The surface of the beads is chemically prepared as an antibody to bind with a specific target protein present on the exosome membrane. The exosome are thus extracted from the plasma using a magnetic field. The extracted exosomes are then analysed by another part of the chip.

Author - Roberto Saracco

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