(2c) Designing Scaffolds with Optimal Chemical and Physical Properties for Tissue Engineering

The design of scaffolds that resemble natural organs is becoming increasingly important for tissue engineering. Cells ability to proliferate and function depends strongly on the mechanical and chemical properties of the scaffold. In this experiment we studied the effects of surface chemistry on cell morphology and proliferation. Polydimethylsiloxane (PDMS) was utilized as a scaffold due to its wide range of medical applications and the results were compared with those of cells cultured on tissue culture plates. The mechanical properties of the PDMS substrate were varied by adding different amount of a cross-linking agent. For each cross linking ratio, sets of samples containing 0, 0.5, 1.0, and 2.0 percent of Na clay were prepared. We observed the mechanical characteristics of the polymer samples using Instron tensile tester and Nicolet Spectra FTIR instrument. We measured the tensile modulus and extension at yield and break as a function of the degree of cross-linking. Cross-linked spherical plug molds were then made of each sample and placed in a 24 well plate where fibroblast-like cells (CF-29) were cultured. Cell counts were obtained after 24 hours and three days. The cells were also stained and imaged under a confocal microscope (Leica-SP). The results indicate that cell proliferation is hindered on PDMS substrates relative to tissue culture plastic (TCP) substrates. Addition of clays in the PDMS susbstrates increased the cell counts to values that were comparable to those obtained on TCP.