Synthesis, lipid membrane incorporation, and ion permeability testing of carbon nanotube porins

• Published in: Nature protocols Vol. 11; no. 10; pp. 2029 - 2047
• Main Authors: Tunuguntla, Ramya H, Escalada, Artur, A Frolov, Vadim, Noy, Aleksandr
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.10.2016; Nature Publishing Group
• Subjects: 631/1647/350/1058; 631/45/269; 631/57/2270/1140; 639/301/357/73; Analytical Chemistry; BASIC BIOLOGICAL SCIENCES; Biological membranes; Biological Techniques; Carbon; Channel pores; Computational Biology/Bioinformatics; Conductance; Cutting; Diameters; Fabrication; Fluidics; Geometry; Incorporation; Ion channels; Life Sciences; Lipid bilayers; Lipids; Membrane channels; Membrane permeability; Membranes; Microarrays; Nanofluids; Nanotechnology; Nanotubes; Organic Chemistry; Permeability; Phospholipids; Plasma membranes; Pore size; Porins; Proteins; Protocol; Resistance; Single wall carbon nanotubes; Transport properties; Ultrasound; United States > US; California; Spain
• ISSN: 1754-2189; 1750-2799
• DOI: 10.1038/nprot.2016.119

Incorporation of carbon nanotube porins (CNTPs) into phospholipid membranes allows for the nanofluidic replication of biological ion channels. This protocol describes the fabrication and testing of CNTPs at both bulk and single-pore levels. Carbon nanotube porins (CNTPs) are 10- to 20-nm-long segments of lipid-stabilized single-walled carbon nanotubes (CNTs) that can be inserted into phospholipid membranes to form nanometer-scale-diameter pores that approximate the geometry and many key transport characteristics of biological membrane channels. We describe protocols for CNTP synthesis by ultrasound-assisted cutting of long CNTs in the presence of lipid amphiphiles, and for validation of CNTP incorporation into a lipid membrane using a proton permeability assay. In addition, we describe protocols for measuring conductance of individual CNTPs in planar lipid bilayers and plasma membranes of live cells. The protocol for the preparation and testing of the CNTPs in vesicle systems takes 3 d, and single CNTP conductance measurements take 2–5 h. The CNTPs produced by this cutting protocol remain stable and active for at least 10–12 weeks.