Functionalization of Aqueous-Based Silk Orthopedic Devices
orthopedic hardware is limited in its ability to restore native functionality to a site
of injury. Non-resorbable devices have impressive mechanical properties but they are
associated with long-term complications which often necessitate implant removal via
secondary surgery. Current resorbable orthopedic devices made from synthetic polymers
lack much of the functionality of ... read morenon-resorbable implants (such as ease of implantation
and sterilization) and are also associated with long-term complications. However, since
they are eventually absorbed by the body, the window of opportunity for problems to
arise is smaller. Previous work showed that resorbable fixation devices made from the
natural polymer silk fibroin improve on some aspects of current resorbable options.
However, it was also shown that silk-based orthopedic devices are susceptible to
infection and, if the rate of local bone regeneration cannot match the rate of silk
degradation, a gradual loss in mechanical strength. One method of addressing these
issues is by functionalizing the silk material with drugs that reduce the risk of these
complications occurring. In this work, aqueous-based silk material was functionalized
with bioactive molecules to investigate the bulk silk material's ability to act as a
drug delivery vehicle. A biomimetic process was used to fabricate blocks of the aqueous
silk bulk material which were then machined into screws and pins. Antibiotics
(ciprofloxacin and gentamicin) and osteoinductive peptides (p15 and p24) were used to
functionalize the material. Functionalized devices were then evaluated for bioactivity,
degradation rate, and release profile. Devices functionalized during the fabrication of
the bulk material were further investigated to see if encapsulation had any effect on
their mechanical properties.
Thesis (M.S.)--Tufts University, 2017.
Submitted to the Dept. of Biomedical Engineering.
Advisor: David Kaplan.
Committee: Qiaobing Xu, and Gary Leisk.
Keyword: Biomedical engineering.read less