Polymer-based cancer nanotheranostics: retrospectives of multi-functionalities and pharmacokinetics

The pressing need for targeting, detecting, monitoring, and treating diseased cells concomitantly gives rise to multi-functional nanomedicines, especially those that can combine diagnostic and therapeutic abilities, which are referred to as nanotheranostics. Recently, nanotheranostics are of significant clinical interest as these nanomedicines offer new opportunities to directly visualize drug blood circulation and biodistribution, thus facilitating the development of more personalized treatment regimens. To date, much research has shown the exciting potential of nanotheranostics in cancer therapy and imaging. In particular, the advancements of polymeric nanomaterials in the past decades have paved the way for the development of cancer nanotheranostics that are primarily comprised of polymers or conjugates of polymer and other types of nanomaterials such as gold nanoparticles, quantum dots, carbon nanotubes, and magnetic iron oxide nanoparticles. Additionally, to improve the therapeutic and diagnostic efficiency of cancer nanotheranostics, various strategies have been utilized to provide targeted-delivery across biological barriers and environmental-responsive delivery, leading to the alteration of pharmacokinetics such as drug distribution, cellular partition, and elimination routes. In this review, we will summarize recent development of polymer-based cancer nanotheranostics and some novel strategies to improve their pharmacokinetics, especially biodistribution, followed by a brief discussion of their applications in cancer therapies as well as their toxicity and safety.