“…In the chemical design of imaging agents, organic materials provide greater biocompatibility and synthetic versatility in comparison to inorganic materials. Also, to overcome the low electron density of these materials, a variety of iodinated small-molecule agents have been explored because the innermost electron of iodine strongly absorbs diagnostic X-rays. , As a result, most of the iodinated agents include ionic (e.g., Diatrizoate and Ioxaglate) or nonionic (e.g., Iohexol and Iodixanol) aromatic small-molecule forms and can be injected through intravenous routes or loaded into carriers, such as emulsions, liposomes, hydrogels, or particles. − Although these agents have achieved the desired properties under physiological conditions and have been commercialized, they still suffer from a rapid excretion rate and nonspecificity, limiting their potential in other biorelated fields. − As an alternative, polymeric materials have been investigated by taking advantage of their structural diversification, tunable functionality, and intrinsically high molecular weight. In general, iodinated motifs are conjugated on predesigned backbones or directly polymerized, which provides a platform for the development of multifunctional nanoparticles and implantable devices that require X-ray visibility for in situ monitoring. − However, the stable covalent backbone generally reduces the biodegradability of polymeric materials when they reach the end of their usefulness.…”