INTELLECTUAL MERIT: The goal of this proposal is to measure secondary structure and inter-atomic distances within designer protein nanofiber matrices with sufficient accuracy using solid state NMR methods to establish definitive structural models. Subjects of study will be the peptides RADA16-I (Zhang et al.), MAX1 and MAX8 (Schneider et al.), and SAF-p1/SAF-p2a (Woolfson et al.), each with a specifically designed self-assembly pattern. The PI will evaluate molecular level details of nanofiber self-assembly and self-healing processes. The motivation for this work is to establish a molecular level basis for engineering structure and properties of self-assembled protein matrices. Among potentially desired properties are those possessed by naturally derived protein matrices, such as strength and toughness, broad diversity of chemical and physical functionalities, and ability to self-assemble and self-heal in response to stimuli. Specifically, the following tasks will be completed during the grant period: (1) Measure secondary structure and inter-atomic distances with sufficient accuracy to formulate a structural model for RADA16-I nanofibers. (2) Formulate structural models for MAX1 and MAX8 nanofiber scaffolds. (3) Characterize the surface interactions between alpha-helices in SAF-p1/SAF-p2a nanofibers. (4) Test a recently proposed mechanism of self-healing of RADA16-I nanofibers. (5) Track self-assembled peptide particle sizes for short self-assembly times. (6) Quantify the nanofiber formation kinetics by varying soluble species concentrations. In the long term, this work will establish detailed structural understanding necessary to more effectively use self-assembling peptides as building blocks for scaffolds that support tissue growth and cell differentiation, hydrogels for drug delivery, and molecular templates for organization of other nanostructures (e.g., nanotubes and nanowires). On the nano-scale, material properties would ideally be determined by modular elements and simple design rules, so that a designed protein matrix could contain different domains optimized for specific mechanical properties, interactions that mediate cellular signaling, chemical functionality, or electrical conductivity.
BROADER IMPACTS: The broader impact of this work lies in establishing a biomimetic bottom-up approach to nanomaterial construction with applications in regenerative medicine and nanotechnology. Biological nanotechnology will benefit from systematic methods to integrate structural protein domains with chemically and biologically active molecules and further interface with biological and non-biological components at multiple lengths scales. Principles established by this work will lead to design of versatile nanomaterials with a level of sophistication that rivals natural systems and surpasses present lithography-based micropatterning technologies. Furthermore, since proteins self-assemble primarily through noncovalent interactions, guided protein self-assembly is a promising route to producing self-healing and environment-responsive materials. This work includes several avenues for positive broader societal impacts. The FAMU-FSU College of Engineering is home to a diverse student body where 42% of the undergraduate student population belongs to traditionally under-represented groups; these students will be encouraged to participate in undergraduate research and pursue graduate study. The current and future research findings will be integrated into new coursework for a wide range of student age groups. Mentoring in research activities of Ph.D. candidates, undergraduates, and schoolteachers will provide a stimulating environment for learning and discovery. Outreach activities will stimulate enthusiasm for science and technology among children and families and middle through high school students. The target audience includes students from underrepresented groups in a nearby rural county.
