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

Abstract

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. The permselectivity of these membranes is reversed by converting the carboxylic moieties into terminated amino groups. The positively charged (aminated) membranes facilitate the transport of anions. Based on the same principle, charged biomolecules (bovine serum albumin and lysozyme) are successfully filtered through these membranes. These membranes also exhibit the phenomenon of ion concentration polarization.

Two‐Way Nanopore Sensing of Sequence‐Specific Oligonucleotides and Small‐Molecule Targets in Complex Matrices Using Integrated DNA Supersandwich Structures

“…Cylindrical nanopores were fabricated through a previously published method. [14] Briefly, the PET films were pre-treated with UV light (approximately 4.2 mW cm À2 ) for 1 h on each side before etching with NaOH (2 m) at 50 8C for 8 min (Supporting Information). After that, the films were thoroughly washed with and restored in distilled water.…”

“…[14] The mean diameter of the nanopores for the sensor was 79 AE 7 nm and the pore density was approximately 5 10 8 cm À2 (Supporting Information, Figure S2). [14] The mean diameter of the nanopores for the sensor was 79 AE 7 nm and the pore density was approximately 5 10 8 cm À2 (Supporting Information, Figure S2).…”

“…A cylindrical nanopore array was prepared through UV treatment and chemical etching of irradiated poly(ethylene terephthalate) (PET) membranes. [14] The mean diameter of the nanopores for the sensor was 79 AE 7 nm and the pore density was approximately 5 10 8 cm À2 (Supporting Information, Figure S2). The nanopore membranes were chemically modified with capture DNA (20-mer) through a two-step chemical reaction (see the Supporting Information).…”

Optical Gating of Photosensitive Synthetic Ion Channels

“…Preparation of Cylindrical Nanochannel Array : For this purpose, PET membranes irradiated with 5 × 10 8 ions cm −2 were used. The fabrication of cylindrical nanochannels was achieved by the symmetric track‐etching technique 60. Polymer membranes fixed in a sample holder were immersed in the pre‐heated etching solution.…”

A single glass conical nanopore channel modified with 6-carboxymethyl-chitosan to study the binding of bovine serum albumin due to hydrophobic and hydrophilic interactions

“…Studying how molecules interact with the single nanopore at the nanoscale level is the foundation of constructing nanopore-based biosensing platform. Nowadays, a number of interaction patterns between the functional nanopore surface and the target analytes such as the hydrophobic interaction [8], electrostatic interaction [24], bio-specific interaction [10,20,25] and metal-chelating interaction [11,12] have been investigated inside the synthetic nanopore channels, thus suggesting the construction of promising platforms for sensing the protein molecules. Previously, Ali et al [8] has reported covalently modifying single asymmetric nanochannels in polyethylene terephthalate (PET) membranes with ethylenediamine or propylamine to manipulate the charge polarity and hydrophobicity of the nanochannel, respectively.…”