The local presence and concentration of metal ions in biological systems has been extensively studied ex vivo using fluorescent dyes. However, the detection of multiple metal ions in vivo remains a major challenge. We present a magnetic resonance imaging (MRI)-based method for noninvasive detection of specific ions that may be coexisting, using the tetrafluorinated derivative of the BAPTA (TF-BAPTA) chelate as a 19F chelate analogue of existing optical dyes. Taking advantage of the difference in the ion-specific 19F nuclear magnetic resonance (NMR) chemical shift offset (δ ω) values between the ion-bound and free TF-BAPTA, we exploited the dynamic exchange between ion-bound and free TF-BAPTA to obtain MRI contrast with multi-ion chemical exchange saturation transfer (miCEST). We demonstrate that TF-BAPTA as a prototype single 19F probe can be used to separately visualize mixed Zn2+ and Fe2+ ions in a specific and simultaneous fashion, without interference from potential competitive ions.
ASJC Scopus subject areas
- Colloid and Surface Chemistry