Stimuli-Responsive Polymers for Advanced 19F Magnetic Resonance Imaging: From Chemical Design to Biomedical Applications.

Fluorine magnetic resonance imaging (¹⁹F MRI) is a rapidly evolving research area with a high potential to advance the field of clinical diagnostics. In this review, we provide an overview of the recent progress in the field of fluorinated stimuli-responsive polymers applied as ¹⁹F MRI tracers. These polymers respond to internal or external stimuli (e.g., temperature, pH, oxidative stress, and specific molecules) by altering their physicochemical properties, such as self-assembly, drug release, and polymer degradation. Incorporating noninvasive ¹⁹F labels enables us to track the biodistribution of such polymers. Furthermore, by triggering polymer transformation, we can induce changes in ¹⁹F MRI signals, including attenuation, amplification, and chemical shift changes, to monitor alterations in the environment of the tracer. Ultimately, this review highlights the emerging potential of stimuli-responsive fluoropolymer ¹⁹F MRI tracers in the current context of polymer diagnostics research.