A delicate oily sheath encloses cells' watery innards.© exam.net

Researchers are building polka dot cell coats by borrowing silicon technology. They could help understand what triggers allergies.

On a chip, the team from New York's Cornell University makes tiny patterns simulating the delicate oily sheath that encloses cells watery innards.

The artificial membranes - as small as one thousandth of a millimetre wide - could help researchers figure out what stimulates immune cells, explained team member Adam Hammond at the American Society for Cell Biology meeting this week in San Francisco.

Often researchers bathe allergy-stimulating mast cells in substances that mimic pollen or dust, called antigens. Now they can watch the mast cells respond to a single spot of antigen by inserting it in the artificial membrane. "It allows spatial resolution," says Hammond.

The team has already shown that antigens in the membranes activate mast cells. "The cells like to cosy up to them," says Hammond.

The artificial membranes could also help resolve which molecules a protein reacts with, suggests Wendy Boss who studies cell signalling at North Carolina State University in Raleigh.

The protein could be washed over a grid of membrane spots, each made of different fats or proteins, to see which one sticks. "It would be really neat," says Boss.

Light work

Many groups are trying to build artificial membranes. Harold Craighead and his colleagues have developed a way to print them into any pattern they choose.

They cover silicon chips with plastic, then use light to engrave a template of squares in it. They fill these holes with fatty lipids, before ripping off the template to leave the membranes.