Au纳米颗粒作用下的仿生纳米通道

A Bio-inspired Nanochannel with Au Nanoparticles

在自然界的生物体系中,各种各样的离子通道对物质交换、能量输运等生理过程起着重要作用.用人工制备的仿生纳米器件模仿生物孔道的离子输运性质是一项非常具有挑战性的课题.通过在对称柱形聚对苯二甲酸乙二醇酯(PET)聚合物孔道中引入非对称结构,获得了一种具有高整流比的人工纳米孔道体系.通过带正电荷的2-十一烷基-1-二硫脲乙基咪唑啉季铵盐(SUDEI)在柱形纳米孔道的单面吸附,使体系具有了非对称的电荷分布和几何结构,从而具有非线性的离子输运性质,表现出较好的门控性能.Au纳米颗粒可以与SUDEI以Au—S键稳定结合,有效地减小柱孔一端的孔径,进一步提高体系的门控比,且该纳米通道体系非对称响应离子输运有很好的稳定性.

Ion channels that exist in the living systems play important roles in maintaining normal physiological processes, and they have attracted great attentions of scientists because of their unique property in many biological activities. Learning from nature become an important source of new materials development. Inspired by natural biological ion channels, artificial polyethylene terephthalate （PET） nanochannel was built by track-etched method and served as one kind of the biomimetic ion channels in this paper. By introducing the idea of asymmetric modification in the PET cylindrical nanochannels, we designed and fabricated an artificial nanochannel system with high and controllable rectification, which ion transport properties can be regulated by Au nanoparticles. PET cylindrical nanochannels are modified with 2-undecyl-1-disulfide ureidoethyl quaternary imidazolinium salt （SUDEI） by electrostatic adsorption, resulting in positively charged on one side of PET cylindrical na- nochannels. Since the other side of nanochannels are negatively charged, this membrane exhibits rectified properties with asymmetric charge distribution and geometric structure. The movement of cation presents a priority direction, which is from SUDEI side to the other side, and the opposite direction is suppressed. The ion transportation properties of the nanochannels can be investigated by measuring the current-voltage characteristics, and the diode-like behavior is quantified by the current rectification ratios. By introducing the SUDEI, PET nanochannels have a non-linear ion transport properties, showing better gating performance. In addition, the rectification ratios of this system can be regulated by SUDEI modification time and Au nanoparticles. SUDEI contains active sulfitr element, resulting in Au nanoparticles stably bounding to SUDEI with Au--S bond. Therefore, the addition ofAu nanoparticles can further increase the nanogating ratio because it can reduce the effective diameter of the cylindrical nanochannels, making the system more asymmetrical. And the ion transport in this system exhibits excellent stability. This system provides a new design idea for further research on more complicated functionalization and smart nanochannel systems.