A Microfluidic Device to Study Translocation Across Lipid Membranes

Abstract

The regulation of protein trafficking across cellular membranes, done by transmembrane proteins, is a vital process known as translocation. However, protein translocation is not completely understood and traditional electrophysiology techniques cannot give an insight into the mechanical properties of translocation. On the other hand, optical tweezers has been shown to be a suitable candidate to study the translocation of soluble proteins but becomes a challenge with transmembrane proteins. Hence there is a need to develop a biophysical tool that allows the study of transmembrane proteins into their membrane environment with optical tweezers.There is an increasing effort to miniaturize black lipid membranes (BLM), and several approaches have now been developed to study the translocation of proteins in miniaturized systems. In this work, we develop a microfluidic system suitable for the study of transmembrane proteins into artificial membranes. The advantages of our approach include: real-time control over the charge gradient across the membrane, dynamic exchange of buffers, and capability to combine with force-spectroscopy techniques.We demonstrate the formation of a free-standing BLM on a glass micro-device by measures of capacitance and electron flux detection through toxin pores. This microfluidic device is combined with a high-resolution optical tweezers for the study of protein translocation across membranes and the evaluation of current translocation models.