INTELLECTUAL MERIT: Biopolymer-based materials are frequently organized into complex hierarchical structures that span multiple length scales ranging from nanometers to millimeters. The goal of this research is to elucidate pathways by which biopolymers self-assemble into macroscopic materials and relate the structure, mechanical and optical properties of these macroscopic materials to the underlying mesoscopic interactions and microscopic architecture of the constituent biopolymers. The proposal has two specific aims. The first aim is to determine how the continuum mesoscopic properties of individual biopolymers are affected by the mutations of the constituent proteins at the microscopic level. The second aim is focused on understanding the structure and interactions of macroscopic colloidal membranes. Here, attractive depletion interactions are used to assemble thousands of rods into an equilibrium membrane-like structure composed of a monolayer of aligned rods. These two experimental aims are related to each other in several important ways: They both require use of the same biopolymer model systems. They also involve similar experimental techniques and technologies. Finally, they explore the central theme of hierarchical assembly, with each aim focusing on a different level of hierarchy ranging from single filaments to assemblages containing thousands of filaments. Understanding biopolymer assemblages at any one level of hierarchy represents a significant advance in the field. However, only the combined understanding of structure and dynamics at all relevant length scales will result in general design principles required for a ?bottom up? engineering of novel nanostructured materials with predefined structural and mechanical properties. From a techniques perspective special emphasis is being placed on directly visualizing biopolymer assemblages at all levels of hierarchy. Using electron microscopy the PI will determine 3D conformations of biopolymers with nanometer resolution. With optical microscopy he will simultaneously visualize dynamics of individual filaments within an assemblages as well as the structure and dynamics of entire assemblages.
BROADER IMPACTS: The research and education plans are seamlessly joined together through their mutual emphasis on visualization techniques and interdisciplinary approach to science. The proposed educational plan contains four related aims. Specifically, (1) the PI and collaborators will continue development of an interdisciplinary laboratory course focused on optical microscopy. Since microscopy is used in numerous disciplines; they will ensure that the course is accessible to students from all scientific backgrounds. (2) They will integrate students at all levels of education, ranging from high school students to advanced graduate students, into the ongoing vigorous research program. (3) They will develop a virtual online laboratory focused on the quantitative analysis of microscopy images. Students anywhere will be able to remotely download actual experimental data and perform all the subsequent image analysis and data reduction steps using custom written software. (4) Finally, they will develop a permanent exhibit at The Discovery Museum in Acton, Massachusetts, which will use optical microscopy to provide a glimpse into a highly dynamic world at microscopic length scales. Successful implementation of these four aims will result in a new generation of students who are better trained in the fundamentals of microscopy. It will also motivate young minds to pursue science related careers and increases awareness of the importance of scientific research and optical microscopy amongst the general audience.
