Hierarchical Self-Assembly Pathways of Peptoid Helices and Sheets

January 12, 2022

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Molecular dynamics simulations predict a hierarchical self-assembly pathway of peptoid sheets in evaporation-induced assembly: monomers first assemble disordered aggregates, then 1D helical rods, and finally 2D crystalline sheets. Predictions are supported by experimental observations using x-ray diffraction and atomic force microscopy. 

Scientific Achievement

We use coarse-grained molecular dynamics simulations and experimental validation to establish a new mechanistic and thermodynamic understanding of the evaporation-induced assembly of peptoids into 2D nanosheets, and to identify conditions that stabilize previously unknown 1D helical rod intermediates.

Significance and Impact

The results define new principles and guidance for the predictive design of peptoid-based nanomaterials.

Research Details

  • MD simulations predict a hierarchical assembly pathway in which peptoid oligomers first assemble into disordered aggregates that next self-order into 1D chiral helical rods, which then assemble into 2D achiral crystalline nanosheets.

  • Experimental observation of 1D rods in mixed solvent by SAXS and CD, and of 2D crystalline sheets in pure water by XRD and AFM, support computational predictions.

Zhao, M., K.J. Lachowski, S. Zhang, S. Alamdari, J. Sampath, P. Mu, C.J. Mundy, J. Pfaendtner, J.J. De Yoreo, C-L Chen, L.D. Pozzo, and A.L. Ferguson. (2022). Hierarchical self-assembly pathways of peptoid helices and sheets. Biomacromolecules 23: 992-1008. DOI: 10.1021/acs.biomac.1c01385

Work performed at the University of Chicago, University of Washington and Pacific Northwest National Laboratory