Abstract: Spider silks exist in Nature as block copolymers, where hydrophobic and hydrophilic regions are linked forming natural biopolymers that organize into functional materials with exceptional properties. The resemblance of silk to synthetic polymer systems allowed the design and synthesis of silk-inspired block copolymers. The main goal was to provide fundamental insight into relationships b... read moreetween peptide primary sequence, block composition, and block length and observe morphological and structural features, as a route to understand structure-property relationships with bioengineered spider silk block copolymers. Assembly was studied at the air-water interface using the Langmuir Blodgett technique. 2D film assembly was further used to determine assembled morphologies with varying lengths of hydrophobic blocks. To more fully understand the role of specific chemical domains responsible for the material features, selective regions were utilized in peptide formats. The self-assembly features of a spider-silk variant, in combination with environmental factors was utilized to gain insight into how to tune the protein designs to direct the process towards specific types of material morphologies. Tailored materials with tunable functional properties are desirable for many applications ranging from biomaterials design and drug delivery to high performance structures for use in engineering. To improve predictability of materials function, multiple parameters in polymer design need to be considered, along with appropriate models to engineer tailored material solutions. In collaboration with other labs, a trinity approach was employed where the combination of controlled synthesis (genetically programmed), tailorable processing (via microfluidic focusing and film assembly) and molecular modeling were used to enable prediction of material properties. This approach offers a robust discovery path when looking towards next generation approaches to targeted functional materials outcomes. In the second part of the studies, new modes were explored, building off of block copolymer silk designs above, to target the recovery of heavy metals, with a goal towards needs in the field of remediation. A chimeric spider silk protein fused with uranium recognition motifs, was designed, cloned and expressed to generate new proteins that exploit the benefits of each component, but in a versatile materials-related format. These new proteins may find utility in chelation therapies to treat exposures to heavy metals, for environmental recovery operations including monitoring, nuclear waste management, developmental biology and clinical toxicology.
Thesis (Ph.D.)--Tufts University, 2012.
Submitted to the Dept. of Chemistry.
Advisor: David Kaplan.
Committee: Krishna Kumar, Elena Rybak-Akimova, and Markus Buehler.
Keywords: Chemistry, Biomedical engineering, and Physical chemistry.read less