Researchers have been able to genetically engineer protein-based materials with novel properties. For instance, silk-elastin-like proteins (SELPs) have been synthesized by fusing polypeptide sequences, derived from native silk of superior mechanical strength, and human elastin, which is remarkably resilient, into single proteins. However, recombinant proteins, like SELPs, still cannot be assembled into robust micro/nanoscale biomedical structures via ?green? processes. In contrast, spiders can spin silk fibers of superior strength at ambient temperatures, low pressures, and with water as the solvent. The objective of this proposal is to understand the assembly mechanism of recombinant proteins under ?green? conditions and to characterize the structure and mechanical properties of assembled protein fibers. In particular, a micro-fluidic device will be used to investigate the influence of protein solution variables (e.g., pH, salt concentrations), fabrication variables (e.g., flow rates), and protein sequences on the controlled assembly and fiber formation of SELPs. The mechanical properties of assembled SELP fibers will be characterized and mathematically modeled. In addition, the secondary structures of SELP fibers will be analyzed using Fourier transform infrared Raman spectroscopy. The proposed research will provide the necessary first step toward the development of ?green? fabrication processes for producing high-performance protein fibers for a variety of biomedical applications. Results from the research will be integrated into the combined undergraduate and graduate course entitled Micro-Biomechanics. Undergraduate and graduate students performing the research, including underrepresented minorities and women, will receive training in the emerging areas of biomechanics, nanotechnology, and biomaterials.
