On-chip extrusion of lipid vesicles and tubes through microsized apertures

Abstract

In this work we present the formation of micrometre-sized lipid vesicles and tubes with perfectly homogeneous diameter and extraordinary length. The method is a novel approach for unconventional fabrication of soft-matter microstructured devices based on the combination of top-down and bottom-up fabrication processes. Photolithography techniques are applied to fabricate microsized apertures that provide the requirements to form lipid structures with predictable size and to align and guide the vesicles and tubes in microstructured channels. The formation is facilitated by self-assembly of polar lipids to a lipid membrane that is afterwards forced to undergo a shape transformation by extrusion through a microsized aperture. Both the geometrical restriction by the small aperture and the pressure difference between the top and bottom sides of the aperture determine the form and length of the vesicles and tubes. A strong pressure difference favors the formation of lipid tubes, while a low pressure difference results in the formation of vesicle bunches with spherical and cylindrical shapes. Potential applications for the formed lipid structures could be as microreactors and transport channels as well as in the construction of flexible microfluidic networks.

Entrapment of water by subunit c of ATP synthase

“…2004). We note that the tight twists of the tubes (figure 1, top left inset) are a more extreme property of very narrow tubes of proteolipid, but this phenomenon can also be induced when lipid is extruded from nanoholes, and there, rather than twisting like a rope, it coils into helices (Dittrich et al . 2006).…”

A Microfluidic Approach for the Formation of Conductive Nanowires and Hollow Hybrid Structures

“…In particular, the formation of crystals and nanoparticles was achieved in microchannels in superior quality due to the excellent handling of small fluid volumes of nano‐ and even picolitres 6, 7. Several studies report the formation of polymer fibers, metal wires, and tubular structures in simple planar microfluidic networks 8–10. One important difference of microfluidic systems compared to conventional large‐scale manufacturing processes is the reproducible, well‐controlled supply of reagents due to the laminar flow regime present in microfluidic channels.…”

Fabrication and functionalization of lipid tubular microstructures

“…The formed tubes at different stages are shown in Figure 1b. Dittrich et al 15 applied photolithography techniques to fabricate micro-sized apertures that provide a way to form lipid structures with predictable sizes. When a vacuum pump was connected to the outlet, lipid tubes with a perfectly homogeneous diameter and extraordinary length were generated.…”