(656c) Large Amyloid Fibers As Robust Biomaterials

Amyloid structures are found throughout nature and have been shown to be robust biomaterials with a specific modulus comparable to dragline silk.  Amyloids have been self-assembled in vitro into nanometer-sized fibrils from a host of proteins at primarily denaturing conditions.  We have developed a mechanism to grow amyloid fibers 10-20 μm in diameter and several millimeters in length at near physiological conditions.¹  A short, hydrophobic template peptide interacts with an α-helical adder peptide to cooperatively self-assemble into large amyloid fibers.²  By altering the in vitro solution conditions and peptides in the mixture it is possible to engineer a fiber with a tailored morphology (rectangular or cylindrical cross-section) and modulus (0.1-2.5 GPa).³  Here, we show that it is possible to encode micron-sized self-assembled structures at the genetic level.  A template peptide is expressed in Escherichia coli and combined with an adder protein to grow amyloid fibrils (width 200-500 nm) and fibers (width 7-20 μm) in solution.  Beginning at the genetic level, the system could be used to build custom protein fibers, program cells to build their own scaffold for tissue engineering, immobilize cells for bioprocessing, program cell death, or reconstruct or recompartmentalize cells.  

References

1              Ridgley, D. M., Ebanks, K. C. & Barone, J. R. Peptide Mixtures Can Self-Assemble into Large Amyloid Fibers of Varying Size and Morphology. Biomacromolecules 12, 3770-3779, doi:10.1021/bm201005k (2011).

2              Ridgley, D. M. & Barone, J. R. Evolution of the Amyloid Fiber over Multiple Length Scales. ACS nano 7, 1006-1015, doi:10.1021/nn303489a (2012).

3              Ridgley, D. M., Claunch, E. C. & Barone, J. R. The effect of processing on large, self-assembled amyloid fibers. Soft Matter 8, 10298-10306, doi:10.1039/c2sm26496j (2012).