Tissue engineering scaffolds based on photocured dimethacrylate polymers for in vitro optical imaging

Model tissue engineering scaffolds based on photocurable resin mixtures with sodium chloride have been prepared for optical imaging studies of cell attachment. A photoactivated ethoxylated bisphenol A dimethacrylate was mixed with sieved sodium chloride (NaCl) crystals and photocured to form a cross-linked composite. Upon soaking in water, the NaCl dissolved to leave a porous scaffold with desirable optical properties, mechanical integrity, and controlled porosity. Scaffolds were prepared with salt crystals that had been sieved to average diameters of 390, 300, 200, and 100 microm, yielding porosities of approximately 75 vol %. Scanning electron microscopy and X-ray microcomputed tomography confirmed that the pore size distribution of the scaffolds could be controlled using this photocuring technique. Compression tests showed that for scaffolds with 84% (by mass fraction) salt, the larger pore size scaffolds were more rigid, while the smaller pore size scaffolds were softer and more readily compressible. The prepared scaffolds were seeded with osteoblasts, cultured between 3 and 18 d, and examined using confocal microscopy. Because the cross-linked polymer in the scaffolds is an amorphous glass, it was possible to optically image cells that were over 400 microm beneath the surface of the sample.