Microfluidic approaches for the analysis of protein-protein interactions in solution.

Abstract

Elucidation and characterisation of the human proteome has massive implications for a heightened understanding of biological function and pharmaceutical design; new and improved experimental approaches are required to meet this challenge. Here, we present a thorough review of recently developed microfluidic techniques for the study and quantification of protein–protein interactions. We focus on methodologies that utilise the inherent strength of microfluidics for the control of mass transport on the micron scale, to facilitate surface and membrane-free interrogation and quantification of interacting proteins. Thus, the microfluidic tools described here provide insights on protein–protein interactions under physical conditions more similar to biological reality than conventional biochemical and biophysical approaches. We begin by describing the defining principles of microfluidics, and methods for the analysis of protein–protein interactions that utilise the diffusion-controlled mixing characteristic of fluids at the microscale. We then discuss techniques that employ electrophoretic forces to manipulate and fractionate interacting protein systems for their biophysical characterisation, before summarising strategies that use micro-droplet compartmentalisation for the analysis of protein interactions. We conclude by discussing future directions for the field, such as the integration of microfluidic experiments into high-throughput workflows for the investigation of protein interaction networks.