Thermodynamics of Xenon Binding to Cryptophane in Water and Human Plasma

摘要

We synthesized a water-soluble cryptophane 1 that exhibited better Xe binding, K_A ≈ 3.0 x 10~4 M~(-1) at 310 K, than any previously described compound. Fluorescence and ITC methods offered distinct advantages in sensitivity, speed, and accuracy for measuring Xe binding parameters at micromolar cryptophane and xenon concentrations. This study illustrates the important role of entropy for the encapsulation of a hydrophobic guest (xenon) by an organic host molecule (cryptophane) in water. The demonstration of xenon binding to cryptophane 1 in human plasma strongly supports the development of ~(129)Xe biosensors for in vivo studies.