Highly rigid & transparent supramolecular fibrils of tyrosine

Abstract Various peptides and amino acids can self‐assemble into fibrils in a solution environment both in vivo and in vitro. These fibrils can aggregate as amyloids in the organs of individuals with certain genetic mutations, and can also be assembled in‐vitro for their potential application as bioinspired and biocompatible material. Here, we present our study of the mechanical properties of self‐assembled fibrils of enantiomers of tyrosine, one of the essential amino acids found in living systems. We have observed that Young's modulus of fibrils of L‐tyrosine, the biologically relevant enantiomer, can be as high as 43 GPa with a point stiffness of about 454 N m–1 making these fibrils to be one of the highly rigid bioinspired structures. We have also observed that films of highly rigid L‐tyrosine fibrils also have high optical transmittance of 65% while films of enantiomer D‐tyrosine fibrils and fibrils of an equimolar mixture of D‐ and L‐tyrosine are opaque. This suggests that individual amino acids can self‐assemble into highly rigid fibrils and opens up avenues for using amino acids for constructing mechanically robust structures with varying optical properties.