title: Free-floating ultrathin two-dimensional crystals from sequence-specific peptoid polymers.
abstract: The design and synthesis of protein-like polymers is a fundamental challenge in materials science. A biomimetic approach is to explore the impact of monomer sequence on non-natural polymer structure and function. We present the aqueous self-assembly of two peptoid polymers into extremely thin two-dimensional (2D) crystalline sheets directed by periodic amphiphilicity, electrostatic recognition and aromatic interactions. Peptoids are sequence-specific, oligo-N-substituted glycine polymers designed to mimic the structure and functionality of proteins. Mixing a 1:1 ratio of two oppositely charged peptoid 36mers of a specific sequence in aqueous solution results in the formation of giant, free-floating sheets with only 2.7 nm thickness. Direct visualization of aligned individual peptoid chains in the sheet structure was achieved using aberration-corrected transmission electron microscopy. Specific binding of a protein to ligand-functionalized sheets was also demonstrated. The synthetic flexibility and biocompatibility of peptoids provide a flexible and robust platform for integrating functionality into defined 2D nanostructures.
authors.affiliation: Molecular Foundry; National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Ki Tae
authors.initials: KT
authors.lastname: Nam
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Shelby
authors.forename: Philip H
authors.initials: PH
authors.lastname: Choi
authors.forename: Amanda B
authors.initials: AB
authors.lastname: Marciel
authors.forename: Ritchie
authors.initials: R
authors.lastname: Chen
authors.forename: Li
authors.initials: L
authors.lastname: Tan
authors.forename: Tammy K
authors.initials: TK
authors.lastname: Chu
authors.forename: Ryan A
authors.initials: RA
authors.lastname: Mesch
authors.forename: Byoung-Chul
authors.initials: BC
authors.lastname: Lee
authors.forename: Michael D
authors.initials: MD
authors.lastname: Connolly
authors.forename: Christian
authors.initials: C
authors.lastname: Kisielowski
authors.forename: Ronald N
authors.initials: RN
authors.lastname: Zuckermann
mesh_terms: D000595:Amino Acid Sequence; D032701:Biomimetics; D002021:Buffers; D003460:Crystallization; D005583:Fourier Analysis; D005998:Glycine / Q000031:analogs & derivatives*; D008024:Ligands; D008956:Models, Chemical; D049329:Nanostructures / Q000737:chemistry / Q000648:ultrastructure; D034444:Peptoids / Q000737:chemistry*; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017386:Sequence Homology, Amino Acid; D055672:Static Electricity; D014867:Water / Q000737:chemistry
chemical_list: D002021:Buffers; D008024:Ligands; D034444:Peptoids; D011108:Polymers; D014867:Water; D005998:Glycine
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