Issue 41, 2020

Covalent cucurbit[7]uril–dye conjugates for sensing in aqueous saline media and biofluids

Abstract

Non-covalent chemosensing ensembles of cucurbit[n]urils (CBn) have been widely used in proof-of-concept sensing applications, but they are prone to disintegrate in saline media, e.g. biological fluids. We show here that covalent cucurbit[7]uril–indicator dye conjugates are buffer- (10× PBS buffer) and saline-stable (up to 1.4 M NaCl) and allow for selective sensing of Parkinson's drug amantadine in human urine and saliva, where the analogous non-covalent CB7⊃dye complex is dysfunctional. The in-depth analysis of the covalent host–dye conjugates in the gas-phase, and deionized versus saline aqueous media revealed interesting structural, thermodynamic and kinetic effects that are of general interest for the design of CBn-based supramolecular chemosensors and systems. This work also introduces a novel high-affinity indicator dye for CB7 through which fundamental limitations of indicator displacement assays (IDA) were exposed, namely an impractical slow equilibration time. Unlike non-covalent CBn⊃dye reporter pairs, the conjugate chemosensors can also operate through a SN2-type guest–dye exchange mechanism, which shortens assay times and opens new avenues for tailoring analyte-selectivity.

Graphical abstract: Covalent cucurbit[7]uril–dye conjugates for sensing in aqueous saline media and biofluids

Supplementary files

Article information

Article type
Edge Article
Submitted
01 6 2020
Accepted
16 9 2020
First published
22 9 2020
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2020,11, 11142-11153

Covalent cucurbit[7]uril–dye conjugates for sensing in aqueous saline media and biofluids

C. Hu, L. Grimm, A. Prabodh, A. Baksi, A. Siennicka, P. A. Levkin, M. M. Kappes and F. Biedermann, Chem. Sci., 2020, 11, 11142 DOI: 10.1039/D0SC03079A

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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