Calcium-stimulus-responsive cucurbit[7]uril–thioflavin T supramolecular nanocapsule for fluoride sensing and logic operation

• We performed a novel assay of fluoride in 100% water solution.
• Ca(II)–cucurbit[7]uril–thioflavin T supramolecular nanocapsule was used as probe.
• The detection limit was 68 times lower than the maximum contaminant level defined by EPA.
• This nanocapsule was reusable.
• The system was employed to design sequential memory unit.

The supramolecular nanocapsule was fabricated by addition a suitable amount of Ca2+ into the stoichiometrically mixed cucurbit[7]uril (CB7) and thioflavin T (ThT) (CB7:ThT = 2:1). This capsule exhibited excellent selectivity toward fluoride anions in absolute water solution. Especially, the signaling responses can be switched back and forth by successively adding F− and Ca2+ along with the fluorescent state of “on” and “off”. Based on such a reversible and reproducible sensing system, we designed a molecular-scale sequential memory unit displaying “Writing–Reading–Erasing–Reading” functions in the form of binary logic.

A simple assay for the determination of fluoride ion in 100% water solution based on calcium-stimulus-responsive cucurbit[7]uril–thioflavin T supramolecular nanocapsule was performed. The assay allows quantitation of fluoride in low micromolar levels with high selectivity. This sensing system has huge potentiality to develop logic devices.Figure optionsDownload as PowerPoint slide