A low-molecular-weight ditopic MRI probe for ratiometric sensing of zwitterionic amino acid neurotransmitters

Abstract

We report a novel ditopic Gd(III)-based probe selective to zwitterionic amino acid neurotransmitters (ZNTs) crafted for ratiometric MRI imaging. The probe displayed increased binding affinity to ZNTs and non-synchronized concentration-dependent changes of the r₁- and r₂-relaxivity. Through the application of a T₂/T₁ weighted MRI strategy, we demonstrated signal enhancement for cooperatively bound glutamate and γ-aminobutyric acid ZNTs over competitive hydrogencarbonate, which remained MR silent.