Emerging chemistry in improving the metabolism or degradability of organic/polymeric conjugated materials for biomedical applications

Organic/polymeric conjugated materials are playing an increasingly important role in biomedical field. Their special properties such as fluorescence, photosensitization, and photothermal conversion make them promising candidates for disease diagnosis and phototherapy. However, these conjugated materials are usually extremely hydrophobic, so they tend to take a relatively long time to be excreted or metabolized after theranostics, leading to unpredictable side effects, which has made their clinical implementation a daunting task. In this review, we will focus on the safety of organic/polymeric conjugated materials for biomedical applications and discuss in detail the general strategies to improve their metabolism or degradability by rational molecular design, based on representative examples. Finally, the challenges and opportunities are also presented by considering further perspectives.