Exploring the interactome: microfluidic isolation of proteins and interacting partners for quantitative analysis by electron microscopy.

Multimolecular protein complexes are important for many cellular processes. However, the stochastic nature of the cellular interactome makes the experimental detection of complex protein assemblies difficult and quantitative analysis at the single molecule level essential. Here, we present a fast and simple microfluidic method for (i) the quantitative isolation of endogenous levels of untagged protein complexes from minute volumes of cell lysates under close to physiological conditions and (ii) the labeling of specific components constituting these complexes.

Connecting μ-fluidics to electron microscopy.

A versatile methodology for electron microscopy (EM) grid preparation enabling total content sample analysis is presented. A microfluidic-dialysis conditioning module to desalt or mix samples with negative stain solution is used, combined with a robotic writing table to micro-pattern the EM grids. The method allows heterogeneous samples of minute volumes to be processed at physiological pH for structure and mass analysis, and allows the preparation characteristics to be finely tuned.