Microfluidic Machines

Microfluidic machines, self-assembled and yet reconfigurable, have been created by a collaboration of Northwestern, ProChimia Poland and Harvard scientists.

The machines consist largely of patterns of rotors which perform a variety of tasks in a liquid environment---manipulation or sorting of floating particles and microreactors in which mixing of reagents, and microcrystallization can be performed.

The rotors are made in tiny molds and then loosed onto a liquid-air interface, where they are guided into place and set spinning by electromagnets positioned beneath the interface. By changing the magnet activity, the overlying rotors can be put into new arrangements for carrying out new a new job (see figure). The rotors are at the millimeter scale but can be made much smaller.

Unlike conventional machines the rotor arrays have no fixed axles and are virtually friction free. (Grzybowski et al., Applied Physics Letters, 8 March 2004, contact Bartosz Grzybowski, grzybor@northwestern.edu or George Whitesides, gwhitesides@gmwgroup.harvard.edu.)