Flexible and Zwitterionic Fluorinated Hydrogel Scaffold with High Fluorine Content for Noninvasive ¹⁹ F Magnetic Resonance Imaging under Ultrahigh Scanning Resolution.

Abstract

The imaging of hydrogel scaffolds by ¹⁹ F magnetic resonance imaging (MRI) represents an attractive tool for straightforward and noninvasive monitoring of their morphology and in vivo fate. However, their further applications are significantly limited by a dilemma of insufficient signal resolution with low ¹⁹ F content, and/or hydrophobic aggregation of fluorine moieties-induced signal attenuation with high ¹⁹ F content. Herein, a novel label-free fluorinated hydrogel (PFCB) is fabricated with high fluorine content to realize noninvasive monitoring through ¹⁹ F MRI under ultrahigh scanning resolution (1 mm of scanning thickness). The integration of a zwitterionic unit into each fluorine moiety completely overcame the hydrophobic aggregation-induced signal attenuation, manifesting as high ¹⁹ F content and imaging performance. Importantly, 3D reconstruction of the PFCB hydrogel in vivo can be facilely and accurately performed with background free signals, providing detailed biological information of the implanted hydrogel. Additionally, PFCB hydrogel showed adjustable and high mechanical performance, and exhibited minimum foreign body reaction after implantation. As a proof of concept, PFCB hydrogel could be further applied as gel electrodes and wireless flexible sensors for healthcare monitoring. Overall, such label-free fluorinated PFCB hydrogel is an ideal flexible scaffold for eventual clinical applications integrating ¹⁹ F MRI-guided unequivocally 3D reconstruction and healthcare monitoring.