Maintaining Hyper-CEST Performance of a Dye-Labelled Cryptophane Cage

Federica Rossella¹, Christopher Witte¹, Leif Schrder¹

Xenon biosensors are currently under development as a new type of contrast agent. They contain a molecular cage to temporarily trap the detected hyperpolarized 129Xe. To improve our understanding of their interaction with cells, fluorophore-labelled cages have been proposed. However, attachment of functional units like dyes may influence exchange dynamics and accessibility of the noble gas to its host, thereby potentially hampering the Hyper-CEST signal amplification technique that has been successfully applied to biosensor detection. Here, we present proof that a flexible linker between the cage and the dye ensures full Hyper-CEST performance as a prerequisite for future NMR studies.