Enhancing the Hyperpolarized Xenon NMR Signal through Multivariate Metal-organic Framework

Motivation: The nuclear magnetic resonance (NMR) signal of entrapped 129Xe in the molecular cages currently suffers too weak, posing a challenge to further applications in vivo. Goal(s): To improve the entrapped 129Xe NMR signal intensity in aqueous solution. Approach: Introduce the nickel into the ZIF-8 to construct multivariate ZIF-8, which can increase the affinity of the framework for the xenon atoms and prolong the resident time of xenon in the MOF pores to enhance the 129Xe NMR signal intensity. Results: The hyperpolarized 129Xe NMR signal intensity of the xenon atoms entrapped in multivariate ZIF-8 is approximately 33% stronger than that in pristine ZIF-8. Impact: We develop a MOF for efficiently entrapping xenon atoms and provide a general method for enhancing the 129Xe NMR signal and facilitating the application of hyperpolarized 129Xe molecular imaging in vivo.