Macromolecules in diverse phases can adsorb onto natural systems, composite materials, and thin-film devices. In a new report now published in Science Advances, Yuma Morimitsu and a research team in applied chemistry and polymer interfaces and molecular adhesion used atomic force microscopy (AFM) to visualize well-defined double-stranded DNAs and conducted molecular dynamics simulations to identify the adsorption mechanisms of polymer chains to solid surfaces.
Effect of chain length on adsorption. (A) AFM-based single-molecule imaging for DNA12kbp, DNA24kbp, and DNA48kbp on mica substrates observed in 10Ni. Images were acquired after incubating the mica substrates with 3.1 pM dsDNA solution in 5Ni for 2 min. (B) Relationship between Lc and Lex. Dashed line indicates a match between Lc and Lex. (C) Plots show the relationship between Nbp and Rg,2D. The blue line corresponds to the best fit of the experimental data assuming Lp,2D of 48 ± 7 nm. For comparison, dashed line superimposes Rg in 5Ni. (D) [Ni2+] dependence of Rg,2D for DNA48kbp. For comparison, the dotted line superimposes Rg in 5Ni. (E) AFM images for DNA12kbp and DNA48kbp acquired under the same condition as those for (A), except the incubation time was increased to 30 min. Credit: Science Advances (2022). DOI: 10.1126/sciadv.abn6349 The study outcomes can contribute to the development of light and durable polymer composites and films across a variety of industrial, biomedical and environmental applications. The adsorption behavior of string-like molecules Homeostasis of life involves natural systems of biomolecules such as proteins or nucleic acids that can adsorb onto a solid interface. This has been a topic of interest in polymer engineering fields for the past several decades. For instance, the polymer layer adjacent to a solid surface has a distinct structure from that of the bulk, where their aggregation states and thermal molecular motion can completely differ, compared to those in the bulk, and are therefore critical for the performance of polymer composites and thin-film devices. Dip and spin-coating methods are classic examples of the physisorption of polymer chains from a solution system to adsorb macromolecules on to a surface. In this work, Morimitsu and colleagues directly viewed three double-stranded DNAs with different lengths via atomic force microscopy (AFM) to provide information on the adsorption behavior of string-like molecules from…