Abstract:

Periodically sequenced peptides can be confined to interfaces and assembled into patterns that present chemical functionalities with exceptional spatial precision. These rationally designed peptides and polypeptides are rapidly becoming useful components in nanostructured materials for applications ranging from drug delivery to energy storage. This presentation will examine several fundamental aspects of self-assembly and pattern formation of well-defined sheet forming peptides confined at interfaces. Our approach involves three steps. (1) We design and synthesize simple periodic peptide sequences, yielding surface-active β-strands that self-organize into aggregates to form patterns as a function of the peptide sequence. Rational peptide design allows us to systematically explore the role of hydrophobicity, electrostatics and molecular size on materials properties. (2) We use a set of interfacial characterization tools to examine in intermolecular assembly and supramolecular mechanics of the self-assembled structures. (3) We apply two-dimensional equations of state that define both the phase behavior and the critical surface concentrations of nascent aggregates at the interface. Subsequently, we can apply these parameters to predict the dimensions of pattern formation and to determine the potential of the peptide assemblies as biomimetic materials.

Bio:

Raymond Tu received his PhD in chemical engineering from the University of California - Santa Barbara in 2004, studying the design and self-assembly of peptide functionalized molecular architectures.  He completed a post-doctoral fellowship in 2005 at Georgia Institute of Technology investigating rheological properties of biologically functionalized polymer-based materials.  Currently, he is an associate professor at The City College of The City University of New York.  The focus of his research program is the synthesis of surface-active molecular building blocks, which are derived from the combination of elements that direct interfacial assembly with components responsible for selective binding.  This methodology is proving to be an effective tool for engineering complex composite materials that contain structures with multiple length-scales.