1. We have demonstrated several successful outcomes to date: (1) Chemical protocols can be readily implemented for the production of elastomeric polypeptides equipped with photoactive sidechains (Figure 2); (2) These polypeptides can be readily crosslinked via photochemical methods without loss of polypeptide conformation; and (3) Crosslinked polypeptide-based hydrogels show excellent strain-to-break behavior in oscillatory rheology experiments (Figure 3); (4) Recombinant methods permit production of large quantities of these hydrophilic polypeptides that can be equipped with novel chemistries. PROTEINS CONTAINING NON-NATURAL AMINO ACIDS AS BUILDING BLOCKS FOR NOVEL MATERIALS Kristi L. Kiick, University of Delaware, DMR 0239744 Department of Materials Science and Engineering Figure 1. Schematic of polypeptide material design, with crosslinking via the chemistry of non-natural amino acids. Figure 2. Synthesis of polypeptide-based materials of different molecular weights via chemical methods Figure 3. Rheological characterization of polypeptide- hydrogels, strain-sweep data show high strain-to-break. The production of materials with desired and controlled biological and mechanical properties remains an important goal in producing scaffolds for the genesis of new tissues. In particular, elastomeric materials with appropriate hydrophilicity would offer great advantages in the production of mechanically active materials; however it has remained difficult to produce highly elastomeric materials with excellent hydrophilicity. Polypeptide-based materials offer great promise in this area, and their production via recombinant DNA technology permits the facile, large-scale production of modular, chemically versatile polypeptide-based materials into which multiple biochemical and/or biophysical cues can be engineered with great precision. Elastomeric polypeptide with high elasticity and recovery Stretch (1-1000Hz) Relax In this program, we have developed multiple types of polypeptide-based scaffolds equipped with useful chemistries afforded by non-natural amino acids as a method to control the properties of these materials. In the past year we have demonstrated the ability to produce highly aqueous-soluble, highly elastomeric materials based on the main elastic protein in insects. This protein, which has low stiffness, high extensibility, and efficient energy storage, also shows a remarkable fatigue lifetime, surviving repeated contraction and extension at 200-4000Hz. These materials should therefore offer important opportunities in the synthesis of mechanically active tissues and advanced materials; realization of these benefits requires facile methods for their production and modification, which have lagged the discovery of this protein over 40 years ago. These results offer interesting opportunities in the design and production of advanced elastomeric materials. Multiple chemical and photochemical methods are being explored to permit their patterning and integration into biological constructs. Their utility for tailoring cell adhesion, proliferation, and signaling as a function of mechanical stress, as well as the ability to modify mechanical properties with specific, biologically relevant noncovalent interactions, is underway.

2. In addition to the training and development activities of the PI, this program supports outreach efforts at both the undergraduate and secondary school levels. At the undergraduate level, the PI continues to participate in undergraduate research discussions and poster sessions, and has served as a thesis advisor and reader for several UD undergraduates completing honors theses in the chemical sciences. These students and their work have been included on several published manuscripts and presentations at regional and national meetings, and the students have continued employment in industry as well as in graduate school. An outreach program, “The Science of Art”, developed by Kiick in collaboration with an art teacher (Karen Kiick) at Haddon Township High School in Westmont, New Jersey, has also been continued over the course of this grant program. The outreach activities have included UD graduate students in Materials Science and Engineering and at least 30-40 students, over 90% of whom are female, in the arts and crafts curriculum at Haddon Township (Figure 1 shows participants in one program). Activities have been focused on the science of materials manipulation and have focused on three main areas to date: ceramic glaze formulation (Figure 1), metal surface modification, and titanium anodization (Figure 2). Based on the results of this program, students in this curriculum now create their own glazes and have incorporated a knowledge of metal patinas in their artwork. They have gathered an appreciation for the chemical and materials properties of the materials with which they work, and have hopefully gained increased familiarity and confidence with the manipulation of materials via application of chemical methods. The outreach efforts (Figure 3) are currently directed at the production of a manual describing the glazes, patinas, and outreach activities, so that these can be integrated into curriculum materials for the high school and into outreach efforts of the university in the upcoming years. Figure 2. Anodized titanium pieces (left) and metal surfaces (right, Ni shown) prepared for an outreach module. The image on the right is shown as observed under the optical microscope at a magnification=200x. Figure 1. Examples of the new glaze formulations employed by high school students and teachers at Haddon Township High School in Westmont, New Jersey. Figure 3. Current outreach participants at the University of Delaware. PROTEINS CONTAINING NON-NATURAL AMINO ACIDS AS BUILDING BLOCKS FOR NOVEL MATERIALS Kristi L. Kiick, University of Delaware, DMR 0239744