Polymer Translocation

The translocation of a polymer through a pore that is much smaller than its size is a fundamental and actively researched topic in polymer physics. An understanding of the principles governing polymer translocation provides important guidance for various practical applications, such as the separation and purification of polymers, nanopore-based single-molecule deoxyribonucleic acid/ribonucleic acid(DNA/RNA) sequencing, transmembrane transport of DNA or RNA, and infection of bacterial cells by bacteriophages. The past several decades have seen great progresses on the study of polymer translocation. Here we present an overview of theoretical, experimental, and simulational stduies on polymer translocation, focusing on the roles played by several important factors, including initial polymer conformations, external fields, polymer topology and architectures, and confinement degree. We highlight the physical mechanisms of different types of polymer translocations, and the main controversies about the basic rules of translocation dynamics. We compare and contrast the behaviors of force-induced versus flow-induced translocations and the effects of unknotted versus knotted polymers. Finally, we mention several opportunities and challenges in the study of polymer translocation.