An all-glass microfluidic cell for the ABEL trap: fabrication and modeling

The Anti-Brownian Electrophoretic trap (ABEL trap) allows a user to trap and manipulate individual fluorescent molecules in solution. The heart of the ABEL trap is a microfluidic cell. In previous incarnations of the ABEL trap, the microfluidic cell was formed from a polydimethylsiloxane (PDMS) stamp and a glass coverslip. Here we present an improved microfluidic cell, made entirely out of glass. This new design significantly decreases the rate of photobleaching, which previously limited the time that a single molecule could be trapped. Chemical modifications to the surface of the cell prevent adsorption and allow one to control the balance between electroosmotic and electrophoretic forces. The depth of the trapping region in the cell can be adjusted to allow trapping of different-sized objects.