Controlled Assembly of Sequence-Defined Peptoids into Hierarchical Materials

Peptoid (N-substituted glycines), as one of the unique sequence-defined synthetic “foldamers that mimic proteins and peptides for functions, - have recently received increasing attention for the design and synthesis of biomimetic nanomaterials with hierarchical structures.¹ Due to the unique proteinase-resistance, chemical and thermal stabilities of peptoids, peptoid-based nanomaterials are promising candidates for applications in photonics,^{2, 3} flexible electronics,⁴ and biological systems.^{2, 3, 5} Recently, by designing amphiphilic peptoids that contain aromatic hydrophobic domains, our group recently reported their self-assembly into highly crystalline membrane-mimetic 2D nanosheets^{2, 6} and 1D nanotubes,⁷ we demonstrated that these peptoid-based nanomaterials are highly stable and a wide range of functional groups can be precisely placed within these materials to achieve programmable functions. To gain a better understanding of their formation mechanisms of these biomimetic materials, herein, I will report my group’s recent discovery of designing short peptoid oligomers, including tetramers, for controlled assembly into twisted nanoribbons, helices, along with nanosheets and nanotubes. Mechanistic studies using X-ray diffraction, AFM, TEM combined with computational simulations indicate the asymmetric packing of amphiphilic peptoids is the main driving force that leads to the formation of twisted nanoribbons and nanohelices. Tuning hydrophilic side chain chemistry and the number of hydrophobic side chains can significantly influence the peptoid assembly pathways and dynamics for the formation of hierarchical materials with designed morphologies.<br/><br/>References:<br/>(1) Li et al., <i>Chem. Rev. </i><b>2021</b>, 14031. Cai et al., <i>Acc. Chem. Res. </i><b>2021</b>, 81. Yang et al., <i>Chem. Mater. </i><b>2021</b>, 3047.<br/>(2) Song et al., <i>ACS Mater. Lett.</i><b>2021</b>, 420.<br/>(3) Wang et al., <i>ACS Applied Bio Materials </i><b>2020</b>, 6039.<br/>(4) Li et al., <i>Macromol. Rapid Commun. </i><b>2022</b>, 2100639.<br/>(5) Cai et al., <i>Research </i><b>2021</b>, 9861384. Song et al., <i>Small </i><b>2018</b>, 1803544.<br/>(6) Jin et al., <i>Nat. Commun. </i><b>2016</b>, 12252.<br/>(7) Jian et al., <i>Nat. Commun. </i><b>2022</b>, 3025. Jin et al., <i>Nat. Commun. </i><b>2018</b>, 270.