Single-chain polymer nanoparticles.

The synthesis of polymer nanoparticles (NPs) with controlled characteristics has become an appealing research topic lately. Nanomedicine, and especially drug delivery and imaging, are fields that require particles of a controlled size and with a tailored arrangement of functional groups. Intramolecular cross-linking or collapse of single polymer chains has emerged as an efficient alternative for the synthesis of well-defined polymer NPs. This technique allows the generation of 1.5-20 nm particles with a wide variety of chemical compositions and functionalities. This review begins by gathering synthetic strategies described in the literature and groups them into four main synthetic methods: homo-functional collapse, hetero-functional collapse, crosslinker-mediated collapse, and one-block collapse of diblock or triblock copolymers. Afterwards, the main characterization techniques and physical properties of single-chain polymer NPs (SCPNs) are exposed. Finally, several applications in nanomedicine are mentioned followed by some future perspectives.