The transport of ionic species through nanochannels plays an important role in the basic research and practical application of nanofluidic devices. Here, a visualized CdSe@ZIF-8/PAA nanochannel membrane was created by employing in situ growth of zeolite imidazole skeleton (ZIF-8) and CdSe quantum dots (CdSe QDs) on a porous anodized aluminum oxide (PAA) membrane surface using CdSe QDs, 2-methylimidazole, and zinc nitrate as the precursor solvents. ZIF-8 is a kind of metal-organic framework, a microporous material that possesses strong metal adsorption capacity. In addition, CdSe quantum dots have fluorescent properties. The nanochannel membrane detects copper ions (Cu2+) by quenching the fluorescence intensity by the interaction between Cu2+ and Se and S atoms. The direct potential of 5 V was applied to achieve Cu2+ enrichment at the nanochannel interface, and the fluorescence change was observed. The CdSe@ZIF-8/PAA nanochannel membrane has a good linear range of concentration (0.01 pM-1 μM) for Cu2+ detection. With the help of nanochannel enrichment, its detection limit reaches 4 fM. In addition, this nanochannel membrane has good selectivity for Cu2+.

中文翻译：

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电场富集下用于超灵敏铜离子检测的原位生长可视化纳米通道膜。

离子物质通过纳米通道的运输在纳米流体装置的基础研究和实际应用中起着重要作用。在这里，通过使用CdSe在多孔阳极氧化铝（PAA）膜表面上原位生长沸石咪唑骨架（ZIF-8）和CdSe量子点（CdSe QDs），创建了可视化CdSe @ ZIF-8 / PAA纳米通道膜QD，2-甲基咪唑和硝酸锌作为前体溶剂。ZIF-8是一种金属有机骨架，是一种微孔材料，具有很强的金属吸附能力。另外，CdSe量子点具有荧光特性。纳米通道膜通过Cu2 +与Se和S原子之间的相互作用猝灭荧光强度来检测铜离子（Cu2 +）。施加5 V的直流电势以实现纳米通道界面处的Cu2 +富集，并观察到荧光变化。CdSe @ ZIF-8 / PAA纳米通道膜具有良好的线性浓度范围（0.01 pM-1μM），用于检测Cu2 +。借助纳米通道富集，其检测极限达到4 fM。另外，该纳米通道膜对Cu 2+具有良好的选择性。