The intrinsic ability of polypeptides to adopt higher-ordered structures such as β-sheet provides opportunity to fabricate nanoscale materials with unique properties that are not easily accessible by typical organic molecules and/or polymers. However, since β-sheet forming polypeptides are typically hydrophobic and non-ionic, the synthesis of such peptides is often hampered by aggregation and premature termination. These aggregates tend to be insoluble in most organic solvents, which limits their application as building block for more complex materials. To avoid these synthetic challenges and processability issues, studies thus far has typically relied on the formation of block copolymers composed of short β-sheet forming motifs (dp &lt;20) and long hydrophilic polymer/polypeptide blocks.1,2 Herein, we report the application of surface-initiated ring-opening polymerization (ROP) of α-amino acid N-carboxyanhydrides (NCA) (‘grafting-from’) as a simple bottom-up strategy for the preparation of currently-inaccessible polypeptide architectures3 stabilized by β-sheets (Scheme 1). Since NCA monomers have excellent solubility in organic solvents and the growing polymer chains are anchored to a template, this grafting-from approach does not suffer from aggregation issues associated with solution state polymerization. H-bonding between the surface-anchored peptide grafts also allow for the in situ formation of β-sheet secondary structures. As such, the resulting films adopt the 3D shape of the template, providing access to stable and well-defined free-standing H-bonded polypeptide architectures following template dissolution. Given the versatility of this synthetic approach and broad range of potential templates, this strategy enables the fabrication of currently-inaccessible peptide β-sheet-stabilized architectures with tailored shapes and dimensions. Such architectures are of great interest in the areas of solid-supported catalysis, (bio)diagnostics devices and therapeutic delivery vectors. 1. J. Zou, et al., Soft Matter, 2013, 9, 5951. 2. A. Sinaga, T. A. Hatton and K. C. Tam, Biomacromol., 2007, 8, 2801. 3. S. H. Wibowo, et al., Adv. Mater., 2013, 25, 4619.

Formation of β-sheet hollow microspheres by NCA-ROP and surface-anchored peptide assembly

249th National Meeting (2015)

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