Nanotube “forest” in a microfluidic channel may help detect rare proteins and viruses

Engineers at MIT have devised a new technique for trapping hard-to-detect molecules, using forests of carbon nanotubes.

The team modified a simple microfluidic channel with an array of vertically aligned carbon nanotubes — rolled lattices of carbon atoms that resemble tiny tubes of chicken wire. The researchers had previously devised a method for standing carbon nanotubes on their ends, like trees in a forest. With this method, they created a three-dimensional array of permeable carbon nanotubes within a microfluidic device, through which fluid can flow.

Now, in a study published this week in the Journal of Microsystems and Nanoengineering, the researchers have given the nanotube array the ability to trap certain particles. To do this, the team coated the array, layer by layer, with polymers of alternating electric charge.

“You can think of each nanotube in the forest as being concentrically coated with different layers of polymer,” says Brian Wardle, professor of aeronautics and astronautics at MIT. “If you drew it in cross-section, it would be like rings on a tree.”

A patterned and cylindrical structure made up of carbon nanotubes. Courtesy of the researchers