(561c) Self Assembly of Beta Sheet Forming Peptides at the Air-Water Interface
AIChE Annual Meeting
Wednesday, November 19, 2008 - 3:55pm to 4:15pm
Naturally occurring biological interfaces present nano-scale patterns of chemical functionality with exceptional precision. This precision is applied in a variety of processes, such as biomineralization, where control over the spatial distribution of chemical functionality is often templated by ?bottom-up? construction of 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 well defined chemical patterns at 2D interfaces. In doing so, we attempt to decouple the self-assembly from the nucleation and growth in an effort to verify if controlling the peptide self-assembly defines the hierarchical mineral structure formed. The peptide molecules are designed using algorithms that promote a β-strand secondary structure. Some of the molecules designed have differing charge distributions and the same overall charge to highlight the role that electrostatic effects play on self-assembly and nucleation. In addition molecules with different overall charges have been designed. The behavior of the peptides at the air-water interface has been characterized using circular dichroism, langmuir blodgett, and Brewster angle microscopy methods. The results obtained by the CD spectra and pressure-area isotherms confirm the overall design hypothesis, establishing the presence of sheet like assemblies at the interface. Preliminary Brewster angle microscopy results indicate that the supramolecular assembly of these peptides is in the form of fibrous aggregates. Transferring the peptide monolayers from the air-water interface to solid substrates will enable the use of atomic force microscopy and Fourier transform infrared spectroscopy to provide more detailed look at these 2D assemblies.