Department of Biomedical Engineering.
current resorbable fracture fixation devices experience problems with implantation
technique and negative host response, there is a need for new devices that have
multifunctional features. These include immediate fracture stabilization upon
implantation, complete degradation to avoid need for hardware removal, robust mechanical
properties to allow for implantation, and abili... read morety to resterilized and reused to save on
costs. The goal of this study was to prepare and characterize a new family of resorbable
screws and plates from silk protein for craniomaxillofacial (CMF) repair. The screws and
plates were prepared using a solvent-based process, treated with methanol to induce
crystalline, beta sheet structures for stability then machined to the desired
geometries. The silk material was evaluated in dry and in hydrated environments to mimic
implantation as well as in vivo fixation conditions. The silk biomaterials compared
favorably with the mechanical properties of current poly-lactic-co-glycolic acid (PLGA)
resorbable fixation systems, while offering a number of advantages including ease of
implantation, conformal fit to the repair site, easy sterilization by autoclaving and
non-inflammatory response. Assessment of the screws in vivo in a rat femur model showed
they were self-tapping, remained fixed in the bone for a 4 week trial, exhibited
biocompatibility, and showed signs of normal bone remodeling. These silk screws and
plates exhibit potential for resorbable fixation systems due to their mechanical
strength, ease of implantation, ability to degrade, tunable properties with autoclaving,
and potential to be resterilized and reused if opened but not used in the operating
Thesis (M.S.)--Tufts University, 2013.
Submitted to the Dept. of Biomedical Engineering.
Advisor: David Kaplan.
Committee: David Kaplan, Gary Leisk, and Fiorenzo Omenetto.
Keywords: Biomedical engineering, and Mechanical engineering.read less