Table 2.
The procedures used to manufacture porous calcium orthophosphate scaffolds for tissue engineering [374].
| Year | Who and where | Process | Calcium orthophosphate | Sintering | Compressive strength | Pore sizes | Porosity |
|---|---|---|---|---|---|---|---|
| 2006 | Deville et al. Berkeley, CA | HA + ammonium methacrylate in PTFE mold, freeze dried and sintered. | HA | Yes: 1300 °C | 16 MPa, 65 MPa, 145 MPa | open unidirectional 50–150 μm | >60%, 56%, 47% |
| 2006 | Saiz et al. Berkeley, CA | Polymer foams coated, compressed after infiltration, then calcined. | HA powder | Yes: 700–1300 °C | – | 100–200 μm | – |
| 2006 | Murugan et al. Singapore + USA | Bovine bone cleaned, calcined. | Bovine bone | Yes: 500 °C | – | retention of nanopores | – |
| 2006 | Xu et al. Gaithersburg, MD | Directly injectable calcium orthophosphate cement, self hardens, mannitol as porogen. | Nanocrystalline HA | No | 2.2–4.2 MPa (flexural) | 0–50% macroporous | 65–82% |
| 2004 | Landi et al. Italy + Indonesia | Sponge impregnation, isotactic pressing, sintering of HA in simulated body fluid. | Calcium hydroxide + orthophosphoric acid | Yes: 1250 °C for 1 hr | 23 ± 3.8 MPa | closed 6%, open 60% | 66% |
| 2003 | Charriere et al. EPFL, Switzerland | Thermoplastic negative porosity by ink jet printing, slip casting process for HA | DCPD + Calcite | No: 90 °C for 1 day | 12.5 ± 4.6 MPa | – | 44% |
| 2003 | Almirall et al. Barcelona, Spain | α-TCP foamed with hydrogen peroxide at different conc., liq. ratios, poured in PTFE molds. | α-TCP + (10% and 20% peroxide) | No: 60 °C for 2 hr | 1.41 ± 0.27 MPa 2.69 ± 0.91 MPa |
35.7% macro 29.7% micro 26.8% macro 33.8% micro | 65.5% 60.7% |
| 2003 | Ramay et al. Seattle, WA | Slurries of HA prepared: gel-casting + polymer sponge technique. Sintered. | HA powder | Yes: 600 °C for 1 hr, 1350 °C for 2 hr | 0.5–5 MPa | 200–400 μm | 70–77% |
| 2003 | Miao et al. Singapore | TTCP to calcium orthophosphate cement. Slurry cast on polymer foam, sintered. | TTCP | Yes: 1200 °C for 2 hr | – | 1 mm macro, 5 μm micro | ~70% |
| 2003 | Uemura et al. China + Japan | Slurry of HA with polyoxyethylenelaurylether (crosslinked) and sintered. | HA powders | Yes: 1200 °C for 3 hr | 2.25 MPa (0 wk) 4.92 MPa (12 wks) 11.2 MPa (24 wks) | 500 micron 200 μm interconnects | ~77% |
| 2003 | Ma et al. Singapore + USA | Electrophoretic deposition of HA, sintering. | HA powders | Yes: 1200 °C for 2 hr | 860 MPa | 0.5 μm, 130 μm | ~20% |
| 2002 | Barralet et al. Birmingham, London | Calcium orthophosphate cement + sodium orthophosphate ice: evaporated. | Calcium carbonate + DCDP | 1st step: 1400 °C for 1 day | 0.6 ± 0.27 MPa | 2 μm | 62 ± 9% |