Preparation and characterization of cartilage mimicked structures

Abstract

In this thesis, micro-environment of cartilage tissue was mimicked by adjusting the surface topography, sti ness and chemistry of polydimethylsiloxane (PDMS) which is a biocompatible synthetic elastomeric polymer. PDMS substrates were synthesized with di erent sti ness between 2.13 0.150 MPa and 0.56 0.06 MPa which were in the range of healthy human articular cartilage's sti ness (0.45-0.80 MPa) and measured by nanoindendation. A template mimicking the collagen type II bundle alignment, geometry and size of healthy human cartilage tissue were prepared (A= 100, 150, 200 m; B= 30, 40, 50 m; C= 30, 40, 50 m) by photolithography. PDMS substrates with desired patterns were prepared by soft lithography. In order to mimic the chemistry of the cartilage tissue micro-environment, PDMS substrates were modi ed with amino acid conjugated self-assembled molecules (Histidine, Leucine and Tryptophan) and also with type II collagen. Sti ness of PDMS substrates were analyzed with nanoindentation measurements and chemical modi cations of substrates were con rmed by using X-ray Photoelectron Spectroscopy and contact angle measurements. According to the characterization results, prepared substrates with cartilage like sti ness, chemistry and topography are possible cell substrates for cartilage tissue engineering.|Keywords : Cartilage-mimicked structures, Polydimethylsiloxane (PDMS), Sti ness, Amino acids, Self-assembled Molecules (SAMs)