Biological sodium channels ferry sodium ions across the lipid membrane while rejecting potassium ions and other metal ions. Realizing such ion selectivity in an artificial solid-state ionic device will enable new separation technologies but remains highly challenging. In this work, we report an artificial sodium-selective ionic device, built on synthesized porous crown-ether crystals which consist of densely packed 0.26-nm-wide pores. The Na+ selectivity of the artificial sodium-selective ionic device reached 15 against K + , which is comparable to the biological counterpart, 523 against Ca2 + , which is nearly two orders of magnitude higher than the biological one, and 1128 against Mg2 + . The selectivity may arise from the size effect and molecular recognition effect. This work may contribute to the understanding of the structure-performance relationship of ion selective nanopores.
Glass micropipette has characteristics of easy fabrication, excellent flexibility and stable properties. The HKUST-1 and MIL-68(In) in-situ grow into the tip of micropipette to construct the porous nanochannel. After absorbing...
Pore
structure-based analytical techniques have great potential
applications for the detection of biological molecules. However, the
sophistication of traditional pore sensors is restricted in their
applicability of analytical chemistry due to a lack of effective carrier
probes. Here, we used porous coordination network-224 (PCN-224) composite
probes in conjunction with a glass nanopipette (GN) as a sensing platform.
The sensor exhibits a good fluorescence signal and a change in GN’s
ionic current at the same time. Due to the volume exclusion mechanism
coming from PCN-224, the detection limit of target DNA reaches 10
fM in a GN with a diameter of up to ca. 260 nm, outperforming a simple
probe. The structure of the composite probe is optimized by the probe’s
pairing efficiency. Furthermore, the sensor can also discriminate
between 1-, 3-, and 5-mismatch DNA sequences and capture the target
DNA from a complex mixture. Based on the GN platform, a series of
techniques for detecting biomolecules are expected to emerge because
of its simplicity, robustness, and universality by incorporating advanced
nanoprobes.
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