Confinement of single macromolecules in free solution using a hydrodynamic trap

Abstract

We demonstrate the feasibility of trapping and manipulating individual macromolecules such as globular proteins (~ 5 nm in diameter) in free solution using a flow-based, microfluidic confinement method. This new method enables confinement of small nanoscale objects in free solution by utilizing a planar extensional flow created at a microchannel junction. The fluid flow based confinement method described in this work expands the micro/nanomanipulation toolbox by offering a powerful and versatile platform for non-perturbative observation and analysis of single macromolecules in free solution without force fields (electrical, magnetic, optical and acoustic) and surface immobilization.