Akademik Veri Yönetim Sistemi
Journal of Physical Chemistry C, cilt.111, sa.7, ss.2965-2973, 2007 (SCI-Expanded)
The transport of the amino acids tyrosine and phenylalanine through Au-nanotubule membranes with self-assembled monolayers of alkanethiols is theoretically and experimentally studied. The membranes are prepared by electroless deposition of gold on porous polycarbonate track-etched membranes with control of the inner pore size, followed by self-assembly of acid-functionalized thiols (final mean average pore radius: 7 nm). The capability of switchable ion-transport selectivity by external control (e.g., by changing the pH, ionic strength, and amino acid concentration) is discussed. The flux changes with the pH and the ionic strength of the solution clearly show that electrical charges play a key role in the amino acid transport through the nanopores. Remarkably, an uphill transport of the amino acid is observed when a pH difference is imposed in the external solutions. The theoretical approach based on the Nernst-Planck flux equations considers all of the charged species present in the system (the cationic, anionic, and zwitterionic forms of the amino acid, the hydrogen and hydroxide ions, and the two salt ions) and allows a qualitative understanding of the transport phenomena in the charged nanopores. © 2007 American Chemical Society.