Selective laser sintered poly-ε-caprolactone scaffold hybridized with collagen hydrogel for cartilage tissue engineering

Selective laser sintering (SLS), an additive manufacturing (AM) technology, can be used to produce tissue engineering scaffolds with pre-designed macro and micro features based on computer-aided design models. An in-house SLS machine was built and 3D poly-epsilon-caprolactone (PCL) scaffolds were manufactured using a layer-by-layer design of scaffold struts with varying orientations (0 degrees/45 degrees/0 degrees/45 degrees, 0 degrees/90 degrees/0 degrees/90 degrees, 0 degrees/45 degrees/90 degrees/135 degrees), producing scaffolds with pores of different shapes and distribution. To better enhance the scaffold properties, chondrocytes were seeded in collagen gel and loaded in scaffolds for cartilage tissue engineering. Gel uptake and dynamic mechanical analysis demonstrated the better suitability of the 0 degrees/90 degrees/0 degrees/90 degrees scaffolds for reconstructive cartilage tissue engineering purposes. Chondrocytes were then seeded onto the 0 degrees/90 degrees/0 degrees/90 degrees scaffolds in collagen I hydrogel (PCL/COL1) and compared to medium-suspended cells in terms of their cartilage-like tissue engineering parameters. PCL/COL1 allowed better cell proliferation when compared to PCL or two-dimensional tissue culture polystyrene. Scanning electron microscopy and confocal microscopy observations demonstrated a similar trend for extracellular matrix production and cell survival. Glycosaminoglycan and collagen II quantification also demonstrated the superior matrix secretion properties of PCL/COL1 hybrid scaffolds. Collagen-gel-suspended chondrocytes loaded in SLS-manufactured PCL scaffolds may provide a means of producing tissue-engineered cartilage with customized shapes and designs via AM technology.