Fabrication of three-dimensional polycaprolactone/hydroxyapatite tissue scaffolds and osteoblast-scaffold interactions in vitro.

Computer-aided tissue-engineering approach was used to develop a novel precision extrusion deposition (PED) process to directly fabricate Polycaprolactone (PCL) and composite PCL/hydroxyapatite (PCL-HA) tissue scaffolds. The process optimization was carried out to fabricate both PCL and PCL-HA (25% concentration by weight of HA) with a controlled pore size and internal pore structure of the 0 degrees /90 degrees pattern. Two groups of scaffolds having 60% and 70% porosity and with pore sizes of 450 and 750 microm, respectively, were evaluated for their morphology and compressive properties using scanning electron microscopy (SEM) and mechanical testing. Our results suggested that inclusion of HA significantly increased the compressive modulus from 59 to 84 MPa for 60% porous scaffolds and from 30 to 76 MPa for 70% porous scaffolds. In vitro cell-scaffolds interaction study was carried out using primary fetal bovine osteoblasts to assess the feasibility of scaffolds for bone tissue-engineering application. The cell proliferation and differentiation were calculated by Alamar Blue assay and by determining alkaline phosphatase activity. The osteoblasts were able to migrate and proliferate over the cultured time for both PCL as well as PCL-HA scaffolds. Our study demonstrated the viability of the PED process to the fabricate PCL and PCL-HA composite scaffolds having necessary mechanical property, structural integrity, controlled pore size and pore interconnectivity desired for bone tissue engineering.