Conformation-Dependent Dynamics of Polymer Capture and Translocation through Solid-State Nanopores

Polymer translocation through solid-state nanopores has attracted widespread attention in many biological processes. However, the dynamics of capture and translocation through nanopores are highly correlated with polymer conformation. Using plasmid pBR322 DNA with supercoiled and linear structures, this work explores the effects of polymer conformation on capture and translocation through nanopores. The polymer translocation dynamics are discussed with the relationship between current blockage characteristics and applied voltages across various pore sizes. Subsequently, linear plasmids are used to clarify the effect of polymer conformation on nanopore capture and translocation. The nonlinear relationships between current blockage amplitudes and voltages demonstrate that the linear conformation affects the plasmid DNA capture process. A decrease in the ratio of supercoiled plasmids improved the frequency of folding translocation and decreased the standard deviation of blockage current amplitudes. As the proportion of supercoiled plasmids rises, the impact of partially folding linear conformation on mixed plasmids translocation is enhanced with increasing applied voltage. Furthermore, the results reveal a polymer conformation-dependent bias in capture and translocation processes, named the "crowding effect". This study provides valuable insights into the dynamics of polymer conformational transitions through solid-state nanopores, that have significant implications for improving sequencing and sensing technologies.