Biominerizaiton occurs in nature in a wide variety of organisms, ranging from the formation of the shell of a mollusk to that of human bone. This phenomenon requires an exceptional degree of control over the spatial distribution of chemical functionality, and, in nature, this process is often governed by “bottom-up” construction of supramolecular amino-acid based assemblies. The work presented here is based on the design, synthesis and characterization of peptides that assemble at the air-water interface. The aim of this research is to mimic the biomineralization pathways found in nature by designing peptides to template the growth of inorganic crystals, particularly, investigating the influence of charge distribution on templated nucleation.

The peptide that has been designed is a Beta hairpin (two beta strand “legs” connected by a beta turn). The design incorporates:

• Alternating periodicity, where hydrophobic and hydrophilic residues are presented on either face of the Beta-strand. • One of the legs is predominately negatively charged and the other is predominately positively charged. • Beta-turn constructed from the inclusion of residues D-Pro and Gly. • Cysteine residues are included for cross-linking. • Optically active residues Tryptophan and Tyrosine are included for quantification.

The supramolecular behavior of this peptide is investigated at the air/water interface using Langmuir-Blodgett techniques. Preliminary results show a large degree of hysterisis, which is characteristic of an interfacial crystal. Additionally, the behavior of the peptide monolayers are being investigated as a function of electrolyte concentration in the subphase in order to obtain information on the influence of charge on the self-assembled structure. The supramolecular organization of this peptide at the air/water interface is visualized using a Brewster angle microscope. The analysis of this behavior should provide insight as to how the peptide will control the nucleation of inorganic crystals.