Table 9.

Summary of advantages and disadvantages of each conventional technique commonly used in scaffold fabrication (Chen 2011; Hutmacher 2000; Leong et al. 2003)

Technique	Pore size (μm)	Porosity (%)	Architecture	Advantages	Disadvantages
Solvent casting/particulate leaching	30–300	20–50	Spherical pores	Simple method; controlled porosity and pore size	Possibility of residual of solvent and salt particles; structures generally isotropic; insufficient mechanical integrity for use in load-bearing application
Freeze-drying	15–35	>90	High volume of interconnected micropores	Pore structure with high interconnectivity; good porosity	Insufficient mechanical integrity for use in load-bearing application; small pore sizes
Thermally induced phase separation	5–600	<90	High volume of interconnected micropores	Simple method; high porosities; pore structure with high interconnectivity; controllable structure and pore size by varying preparation conditions	Long time to sublime solvent; possibility of solvent residual; shrinkage issues; small scale production
Gas foaming/supercritical fluid processing	30–700	>85	High volume of non-interconnected micropores	Free of toxic solvents; control of porosity	Insufficient mechanical integrity for use in load-bearing application; inadequate pore interconnectivity; possibility of closed pore structure; formation of an outer skin
Textile technology (electrospinning)	<1–10	90		Simple method; high interconnected porosity; high surface area to volume ratio	Insufficient mechanical integrity for use in load-bearing application; possibility of solvent residual; limitation of thickness
Powder-forming processes (bioglass produced by replication technique)	300–700	>80	High volume of interconnected micropores	Simple method; porous structure similar to sponge bone; highly porous and with open pores; free of toxic chemicals	Insufficient mechanical integrity for use in load-bearing application
Sol–gel techniques (bioactive glasses)	>600	>70		High surface area; microstructure similar to that of dry human trabecular bone	Insufficient mechanical integrity for use in load-bearing application; possibility of solvent residual