M.Sc Thesis

M.Sc StudentRakovsky Artoum
SubjectPolymeric Hydrogels for Biomedical Applications: Structure-
Function Relationship
DepartmentDepartment of Biomedical Engineering
Supervisors PROFESSOR EMERITUS Yoram Lanir
Full Thesis textFull thesis text - English Version


Cartilage substitutes are needed to replace cartilage tissue, damaged in accidents or by pathologies (e.g., osteoarthritis). Treatment by total hip replacement has disadvantages, particularly due to immunological reactions to the implant’s wear debris. A promising alternative is to replace damaged cartilage with substitutes based on hydrogel-type material, designed to mimic the structure and properties of cartilage. In the present study, Poly(ethylene glycol) (PEG)-based hydrogels cross-linked with isophorone diisocyanate and amphiphilic interpenetrating polymer networks (IPNs) of PEG with poly(methyl methacrylate) (PMMA) were prepared and characterized for their mechanical and swelling properties. Twenty seven types of hydrogels were synthesized, differing in their PEG molecular weight, cross-link density and PMMA volume fraction. The properties measured were water content, compression modulus, strength, fatigue durability and poroelastic properties (hydraulic permeability and equilibrium modulus). The obtained results show that low PEG Mw, high cross-link densities and high PMMA fraction, all lead to high modulus and low water content, and that these properties can be controlled independently by proper choice of the ingredients. Introduction of IPN greatly improved the hydrogels’ strength. No reduction in the compression modulus, resulting from fatigue damage, was evident. Poroelastic properties varied non-monotonously with structural characteristics. Seven of the hydrogels prepared were found to resemble cartilage in their water content, modulus and poroelastic properties.