Charge-selective transport of organic and protein analytes through synthetic nanochannels.

We present an experimental demonstration of a synthetic nanoporous membrane suitable for charge-selective transport of ionic species. The surfaces and walls of synthetic nanochannels, fabricated in heavy ion-tracked polyethylene terephthalate membranes are negatively charged due to the presence of carboxylate moieties. These nanofilters discriminate and gate the transport of cations while inhibiting the passage of anions.

Fabrication and functionalization of single asymmetric nanochannels for electrostatic/hydrophobic association of protein molecules.

We have developed a facile and reproducible method for surfactant-controlled track-etching and chemical functionalization of single asymmetric nanochannels in PET (polyethylene terephthalate) membranes. Carboxyl groups present on the channel surface were converted into pentafluorophenyl esters using EDC/PFP (N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride/pentafluorophenol) coupling chemistry. The resulting amine-reactive esters were further covalently coupled with ethylenediamine or propylamine in order to manipulate the charge polarity and hydrophilicity of the nanochannels, respectively.