ATP-Controlled Molecular Transport through Cylindrical Nanochannels Fabricated in Ion Track Etched Polymer Membranes

Nanoscale devices based on solid-state nanochannels have attracted enormous interest owing to the emergence of novel ion transport properties that mimic their biological counterparts. Compared to the fragile and sensitive biological systems, synthetic nanochannels fabricated in solid-state materials have proven a good alternative because of their (a) stability under harsh conditions, (b) easy to tailor surface properties to achieve desired interactions with molecules of interest, and (c) biologically comparable gating mechanisms [1]. To date, molecular transport in synthetic nanochannels mostly focused on selective ionic transport through nanoporous filters based on charge, molecular size as well as bio-/chemical interactions [2,3]. Here, we report the construction of a molecular gate based on nanochannels in which molecular transport can be controlled by the presence of Adenosine-5'triphosphate (ATP) in the external environment. For this purpose, nanochannels were fabricated in heavy-ion irradiated polyethylene terephthalate (PET) foils of 12 μm thickness by symmetric chemical ion-track etching. The etching process leads to carboxyl (–COO) groups on the channel surface that are suitable partners for further chemical modifications performed with branched polyethyleneimine (PEI) by carbodiimide coupling chemistry [4].