A selective supramolecular photochemical sensor for dopamine

<div><p>Dopamine (DA) is an important biomarker for diseases and biological disorders. Existing techniques for DA detection suffer from drawbacks including low sensitivity and selectivity as well as interfering signals from non-target molecules. A simple and selective photochemical sensor for the determination of DA in a supramolecular manner is presented. This approach utilises the complexation properties of a highly fluorescent water-soluble complex of perylene bis(diimide) dye with the macrocyclic host cucurbit[8]uril. The method can be used for the determination of DA in aqueous media, with detection limits below 2 × 10^− 5 M, even in the presence of known interferents including ascorbic acid and the catecholamines epinephrine and norepinepherine.</p></div

Quantitative SERS Using the Sequestration of Small Molecules Inside Precise Plasmonic Nanoconstructs

We show how the macrocyclic host, cucurbit[8]­uril (CB[8]), creates precise subnanometer junctions between gold nanoparticles while its cavity simultaneously traps small molecules; this enables their reproducible surface-enhanced Raman spectroscopy (SERS) detection. Explicit shifts in the SERS frequencies of CB[8] on complexation with guest molecules provides a direct strategy for absolute quantification of a range of molecules down to 10^–11 M levels. This provides a new analytical paradigm for quantitative SERS of small molecules