The design, synthesis and characterization of peptides as synthetic building blocks that possess the ability to self-assemble into functional materials is being pursued. By understanding the rules by which these peptides self-assemble, well-defined materials can be tailored for specific applications such as tissue engineering, therapeutic delivery and biocompatible composites. In general, hierarchical assembly strategies are being developed to prepare micro- and bulk structures from carefully designed assembling peptides. Peptides inherently offer several important features that can be exploited in the self-assembly process; namely, their ability to form well defined secondary structures and specific intermolecular interactions such as hydrogen bonds, salt bridges and hydrophobic contacts. Therefore, one can build novel materials with designed morphologies through single molecule engineering for self-assembly.

In collaboration with Darrin Pochan (Materials Science and Engineering), we are developing responsive materials by preparing peptides that are designed to adopt conformations amenable to self-assembly. Resultant materials are characterized by morphologies and functions that are dictated by the attributes of the individual peptides used for self-assembly. Importantly, responsiveness is imparted to the material by designing peptides that undergo unimolecular conformational changes as a result of external stimuli. This allows active control over the assembled material morphology and/or a "smart" assembly responsive to its environment. For example, Figure 1 shows Laser Scanning Confocal and Cryo-TEM images of a hydrogel material composed of self-assembled b-hairpin peptides. The hydrogel is reponsive to pH changes by virtue of unimolecular peptide unfolding and folding events. Also shown are images of other micro-structures being engineereed in the lab from peptide self-assembly.