INTELLECTUAL MERIT: Spiders manufacture a variety of high performance structural fibers that have outstanding mechanical properties. This project investigates the relationship between the molecular structure and mechanical behavior of spider glue silks, a class of fibers spun from newly discovered glue silk proteins. These spider glue silks differ substantially from the widely studied dragline silks and have unique biochemical properties that make them excellent candidates for large-scale synthetic fiber production. The primary goal of the proposed research is to characterize the molecular and mechanical properties of native and artificially spun glue silk fibers. The central hypothesis is that the molecular sequences of glue silk proteins have evolved specialized features that are well suited for viable biomaterials for design, structural, and other engineering applications. The molecular mechanisms and mechanical behavior of natural and artificially spun glue silk fibers will be studied to help accelerate development of next generation engineering materials. The research should develop new insights into the relationship between the molecular structure of glue silks and its implications on the mechanical behavior of the fibers. Studying the molecular and mechanical properties of glue silks will help delineate how glue silk protein sequences relate to its unique biological function, which will provide insight into how these silk types are capable of being spun into a gelatinous matrix that facilitates spider locomotion and web construction. The nanostructure and mechanical behavior of natural and artificial spider glue silk fibers will be characterized using atomic force and scanning electron microscopy. Emphasis will also be placed on elucidating the secondary and tertiary structure of the glue silk fibroin, PySp1, using circular dichroism, NMR, and mass spectrometry. Spider silk glue proteins will be expressed using a heterologous expression system in yeast, purified and spun into artificial silk fibers. Both natural and synthetic spider glue silk fibers will be characterized at the nanoscale level to reveal the molecular relationship between the protein modules within the PySp1 amino acid sequence and their contributions to the mechanical behavior of glue silks from black widow spiders.
BROADER IMPACTS: The broader impacts of the proposed research include comprehensive mentoring programs and promotion of careers in science, technology, engineering, and mathematics (STEM) fields to underrepresented student groups. Because this work is highly interdisciplinary, integrating engineering, biology, chemistry, and physics, the principal investigators will be able to train students broadly across a wide-range of disciplines. The principal investigators will mentor students at a variety of different educational levels, including at the high school, undergraduate, and graduate student levels. They will also promote engagement from underrepresented groups by encouraging participation by economically disadvantaged and minority students. Additionally, the proposed research will enhance the infrastructure for research and education by fostering collaborations and interdisciplinary research between the Departments of Biology, Chemistry, Physics, and the School of Engineering and Computer Science through the acquisition of an atomic force microscope supported by this proposal. The results of the proposed research will be disseminated broadly to enhance scientific understanding of the bioengineering potentials for spider glue silks. The findings of the proposed studies will be made visible to the community via local news stations, radio stations, community outreach programs, the Science Blast STEM program, scientific research articles, and regional and national scientific meetings. Collectively, these studies have transformative potential and will provide new directions for the utilization of artificial spider glue silks as environmentally friendly, next generation materials.