Biocompatibility of Low Modulus Porous Titanium Implants Fabricated by Spark Plasma Sintering

Porous Ti compacts were fabricated by spark plasma sintering (SPS) method and their in vitro and in vivo biocompatibilities were investigated. Alkaline phosphatase (ALP) activity representing the activity of osteoblast was increased when osteoblast-like MG-63 cells were cultured on the Ti powder surface. Some genes related to cell growth were over-expressed through microarray analysis. The porous Ti compact with 32.2% of porosity was implanted in the subcutaneous tissue of rats to confirm in vivo cytotoxicity. 12 weeks post operation, outer surface and inside the porous body was fully filled with fibrous tissue and the formation of new blood vessels were observed. No inflammatory response was confirmed. To investigate the osteoinduction, porous Ti compact was implanted in the femur of NZW rabbits for 4 months. Active in-growth of new bone from the surrounded compact bone was observed around the porous body. From the results, The porous Ti compacts fabricated by spark plasma sintering might be available for the application of the stem part of artificial hip joint.