Nanoscale ionic diodes with tunable and switchable rectifying behavior.
Nanoscale ionic diodes have attracted interest as circuit elements for development of nanofluidic devices for a variety of applications, including biosensing, constructing artificial cells, and engineering biological batteries. This paper presents a bottom-up, self-assembly approach for constructing nanopores with rectified conductance behavior in a membrane using semisynthetic derivatives of the ion-channel-forming peptide gramicidin A. The capability to individually access each half of a dimeric gramicidin channel makes it possible to generate asymmetric channels in a membrane that exhibit diodelike conductance properties. The modular nature of these self-assembled channels affords the possibility of tuning their rectifying conductance properties by simple replacement of one peptide derivative with another in the membrane. Additionally, introduction of an external stimulus (here, an enzyme) to change the functional group attached to one side of the gramicidin pore induces diodelike conductance behavior in previously nonrectified channels, demonstrating the possibility of switching the conductance properties of these nanopores in situ in a controlled manner.
Macrae
Michael X
MX
Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, MC 0358, La Jolla, California 92093-0358, USA.
Blake
Steven
S
Mayer
Michael
M
Yang
Jerry
J
D000595:Amino Acid Sequence; D004553:Electric Conductivity; D004566:Electrodes; D006096:Gramicidin / Q000737:chemistry / Q000378:metabolism; D007473:Ion Channels / Q000737:chemistry / Q000378:metabolism; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D049329:Nanostructures / Q000737:chemistry*; D016062:Porosity; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary
D007473:Ion Channels; D008051:Lipid Bilayers; D006096:Gramicidin