M.Sc Thesis

M.Sc StudentLevi Liora
SubjectBiosynthetic Hydrogel Scaffolds for Tissue Engineering Made
from Fibrinogen and Polythylene Glycol
DepartmentDepartment of Biomedical Engineering
Supervisor ASSOCIATE PROF. Dror Seliktar


We developed a novel biosynthetic hybrid scaffold for tissue engineering. The scaffold is comprised of a fibrinogen backbone and crosslinked with difunctional polyethylene glycol (PEG) side-chains.  This unique hydrogel material provides a distinct advantage over other scaffold materials because its mechanical properties are highly malleable while the biological functionality is maintained by the backbone of the polymeric network. In the current study we describe the fabrication and characterization of this novel scaffold material, as well as report on its biofunctionality using an in vitro cell culture model. The hydrogel material is made from denatured fibrinogen fragments, functionaliozed with PEG-diacrylates (PEG-DA), and exposed to UV light in the presence of a photoinitiator. Six types of hydrogels are made from three different PEG molecular weights and two types of fibrinogen fragments (whole and cleaved) are characterized in the present study.  An in vitro cell cultures assay is used to examine the biofunctionality of the hydrogels in the presence of smooth muscle cells (SMCs). Our results demonstrate that the elastic modulus of the PEG-fibrinogen hydrogel is dependent on the molecular weight of the PEG constituent and proportional to the percent polymeric composition. The biological domains in the fibrinogen backbone provide attachment motifs for smooth muscle cell (SMC) adhesion as well as proteolytic sensitivity for biodegradation. SMCs demonstrate the ability to proteolytically penetrate through the hydrogel material and form interconnecting networks of cells. In conclusion, we present a unique biomaterial with biofunctionality, malleable mechanical properties, and biodegradability for 3-D cell culture and other tissue engineering applications.