UC Berkeley

The development of sensitive and chemically selective MRI contrast agents is imperative for the early detection and diagnosis of many diseases. Conventional responsive contrast agents used in ¹ H MRI are impaired by the high abundance of protons in the body. ¹²⁹ Xe hyperCEST NMR/MRI comprises a highly sensitive complement to traditional ¹ H MRI because of its ability to report specific chemical environments. To date, the scope of responsive ¹²⁹ Xe NMR contrast agents lacks breadth in the specific detection of small molecules, which are often important markers of disease. Herein, we report the synthesis and characterization of a rotaxane-based ¹²⁹ Xe hyperCEST NMR contrast agent that can be turned on in response to H₂ O₂ , which is upregulated in several disease states. Added H₂ O₂ was detected by ¹²⁹ Xe hyperCEST NMR spectroscopy in the low micromolar range, as well as H₂ O₂ produced by HEK 293T cells activated with tumor necrosis factor.