Chiral Nanostructures from Artificial Helical Polymers: Recent Advances in Synthesis, Regulation, and Functions

Helical structures such as right-handed double helix for DNA and left-handed α-helix for proteins in biological systems are inherently chiral. Importantly, chirality at the nanoscopic level plays a vital role in their macroscopic chiral functionalities. In order to mimic the structures and functions of natural chiral nanoarchitectures, a variety of chiral nanostructures obtained from artificial helical polymers are prepared, which can be directly observed by atomic force microscopy (AFM), scanning tunneling microscopy (STM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). This review mainly focuses on the formation of chiral nanostructures and the morphology regulation triggered by polymer chain length, concentration, solvent, temperature, photoirradiation, and chemical additives. In addition, the distinct chiral functions including chiral recognition, circularly polarized luminescence, drug release, cell imaging, and antibiosis are also discussed.