Controlled Assembly of Sequence-Defined Peptoids into Hierarchical Materials

As one of the most common and well-developed peptidomimetics, peptoids have recently received increasing attention for the design and synthesis of functional materials 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 team recently reported their self-assembly into highly crystalline membrane-mimetic 2D nanosheets^{2, 6} and 1D nanotubes,⁷ we demonstrated that these peptoid materials 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 our recent discovery of designing short peptoid oligomers 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, the number of hydrophobic side chains, and the solution pH 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.