For many years, Escherichia coli has served as a useful host for the production of heterologous proteins. E. coli has long been the model system for bacterial study, and its well-understood host-vector systems, experimental methods, and genetics has made it the most commonly used system for producing recombinant proteins (a classic example of this is production of insulin via expression of proinsulin in E. coli). Promoters are typically used to induce the bacterial system to over-express the recombinant protein and thereby maximize the output of the system. Unfortunately, over-expression of recombinant proteins usually leads to the formation of (insoluble) inclusion bodies, since the bacterial host system often cannot properly fold the protein or induce post-translational modifications such as methylation and glycosylation. Thus the protein is left in a non-functional agglomerated state.

The process of developing refolding protocols to convert the protein from non-functional to functional form is often the costliest and most time-consuming portion of the protein production process. Unfortunately, to date, no technique has been shown universally successful, nor are there techniques for reliably predicting the solution conditions required to refold the protein properly; thus protein refolding has historically been empirical. We are developing microscale devices to allow for rapid exploration of protein refolding protocols, both at low and high pressure.