UV-Activated Zwitterionic Fluorine-Containing Hybrid Probe for Dual-Modal 19F/1H MRI

Dual-modal 19F/1H MRI probes often suffer from hydrophobic aggregation caused by high fluorine content, limiting their solubility and imaging performance. Herein, a water-soluble dual-modal probe (PFCP-Gd) was developed by grafting fluorinated phosphocholine zwitterions and Gd3+ chelates onto a UV-responsive polymer via RAFT polymerization and ring-opening reactions. The design enables UV-triggered paramagnetic relaxation enhancement (PRE) modulation, allowing for activatable 19F/1H MRI contrast. Upon UV irradiation, PFCP-Gd exhibited a significantly enhanced 19F signal with a T2 relaxation time of 23 ms and a signal-to-noise ratio of 11.34 at 12 mM 19F. The probe also showed good biocompatibility and an efficient cellular uptake. This work provides a strategy for constructing water-soluble, activatable fluorinated MRI probes for dual-mode imaging.