Microfluidic chip with pillar array for controlled production and observation of lipid membrane nanotubes

Abstract

Lipid membrane nanotubes (NTs) are a widespread template for in vitro studies of cellular processes happening at high membrane curvature. Traditionally NTs are manufactured one by one, using sophisticated membrane micromanipulations, while simplified methods for controlled batch production of NTs are in growing demand. Here we propose a lab-on-a-chip (LOC) approach to the simultaneous formation of multiple NTs with length and radius controlled by the chip design. The NTs form upon rolling silica micro-beads covered by lipid lamellas over the pillars of a polymer micro-pillars array. The array´s design and surface chemistry set the geometry of the resulting free-standing NTs. The integration of the array inside a microfluidic chamber further enables fast and turbulence-free addition of components, such as proteins, to multiple preformed NTs. This LOC approach to NTs production is compatible with the use of high power objectives of a fluorescence microscope, making possible real-time quantification of the different modes of the protein activity in a single experiment.