Effect of terminal modification on the molecular assembly and mechanical properties of protein-based block copolymersa

• Published in: Macromolecular bioscience 2017-06, Vol.17 (9)
• Main Authors: Jacobsen, Matthew M., Tokareva, Olena S., Ebrahimi, Davoud, Huang, Wenwen, Ling, Shengjie, Dinjaski, Nina, Li, David, Simon, Marc, Staii, Cristian, Buehler, Markus J., Kaplan, David L., Wong, Joyce Y.
• Format: Article
• Language: English
• ISSN: 1616-5187; 1616-5195
• DOI: 10.1002/mabi.201700095

Accurate prediction and validation of the assembly of bioinspired peptide sequences into fibers with defined mechanical characteristics would aid significantly in designing and creating materials with desired properties. This process may also be utilized to provide insight into how the molecular architecture of many natural protein fibers is assembled. In this work, computational modeling and experimentation are used in tandem to determine how peptide terminal modification affects a fiber-forming core domain. Modeling shows that increased terminal molecular weight and hydrophilicity improve peptide chain alignment under shearing conditions and promotes consolidation of semicrystalline domains. Mechanical analysis shows acute improvements to strength and elasticity, but significantly reduced extensibility and overall toughness. These results highlight an important entropic function that terminal domains of fiber-forming peptides exhibit as chain alignment promoters, which ultimately has notable consequences on the mechanical behavior of the final fiber products. Protein fibers are important physiological structures that assemble from monomers in various ways. In this work, simulation and experimental results are presented that describe a general means by which fiber assembly is facilitated by terminal domains and how resulting fiber mechanical properties are affected. This design process shows promise as a means to investigate and develop materials with desired properties.