title: Lipid mobility controls the diffusion of small biopolymer adsorbates.
abstract: Recent studies on the diffusion of adsorbed polymers such as DNA on supported lipid bilayers have suggested that such strongly adsorbed polymers can be treated similarly to a polymer "in" a 2D fluid, but this conjecture has not been experimentally verified. To test this hypothesis and also to gain a better understanding of polymer dynamics in two dimensions, we designed an experimental protocol-the lateral transport of a short, single-stranded DNA oligonucleotide adsorbed on a supported cationic lipid bilayer. Fluorescence recovery after photobleaching (FRAP) analysis reveals that the diffusivity of the adsorbed DNA quantitatively tracks that of the underlying lipid, even though the bilayer mobility changes by 2 orders of magnitude with changes in temperature. Interestingly, our results for short, extended, adsorbed biopolymers quantitatively track those for globular proteins in lipid bilayers. We thus conclude that short macromolecules that are strongly adsorbed on lipid bilayers can be treated similarly to macromolecules in the bilayer.
authors.affiliation: Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
authors.forename: Chakradhar
authors.initials: C
authors.lastname: Padala
authors.forename: Richard
authors.initials: R
authors.lastname: Cole
authors.forename: Sanat
authors.initials: S
authors.lastname: Kumar
authors.forename: Ravi S
authors.initials: RS
authors.lastname: Kane
mesh_terms: D000327:Adsorption; D004058:Diffusion; D008051:Lipid Bilayers / Q000737:chemistry*; D009841:Oligonucleotides / Q000737:chemistry*; D038761:Photobleaching; D011506:Proteins / Q000737:chemistry
chemical_list: D008051:Lipid Bilayers; D009841:Oligonucleotides; D011506:Proteins