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

Ramya H Tunuguntla; Artur Escalada; Vadim A Frolov; Aleksandr Noy

doi:10.1038/nprot.2016.119

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

Nat Protoc. 2016 Oct;11(10):2029-2047. doi: 10.1038/nprot.2016.119. Epub 2016 Sep 22.

Authors

Ramya H Tunuguntla¹, Artur Escalada^{2

3}, Vadim A Frolov^{2

3

4}, Aleksandr Noy^{1

5}

Affiliations

¹ Biosciences and Biotechnology Division, Physics and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, USA.
² Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country, Leioa, Spain.
³ Department of Biochemistry and Molecular Biology, University of the Basque Country, Leioa, Spain.
⁴ Ikerbasque, Basque Foundation for Science, Bilbao, Spain.
⁵ School of Natural Sciences, University of California Merced, Merced, California, USA.

PMID: 27658016
DOI: 10.1038/nprot.2016.119

Abstract

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.