Table 2.

Advantages and disadvantages of microsphere sintering methods along with their various process parameters that influence the overall properties of the microsphere-based scaffold

Microsphere sintering method	Process parameters that influence scaffold properties	Advantages	Disadvantages	References
Heat	Temperature Duration	Simple method; does not require complex apparatus Generally utilizes moderate temperatures Offers flexible time constraints Multiple scaffolds can be fabricated at once	May require high temperatures or longer durations May result in loss of bioactivity of encapsulated factors	20, 33, 52, 90
Solvent vapor	Duration Solvent composition Scaffold mass	Can sinter microspheres quickly Allows for inclusion of bioactive factors	Strict time constraints Residual solvent toxicity	69, 70
Weak solvent	Duration Solvent composition	Allows for inclusion of bioactive factors Moderate time constraints Less concern of residual solvent toxicity as a mild solvent is employed	Longer sintering durations compared with solvent vapor method	48, 61, 72, 74
Solvent/nonsolvent	Solution composition Duration	Can be used for a wide range of materials Allows for preloading of bioactive molecules	Requires large amounts of solvent Residual solvent toxicity	44, 80, 81
Subcritical CO2	CO2 pressure Duration Rate of depressurization Temperature (only if necessary)	Straightforward one-step method May be used to create shape-specific scaffolds Allows for simultaneous cell seeding Benign process Does not require extra washing steps Low environmental impact	May not be cytocompatible at high CO2 pressures Shear forces may harm concurrently seeded cells	84–86
Selective laser	Laser power Scan spacing Layer thickness	Fabrication of patient-specific grafts Reproducible method with fast manufacture speed May be utilized for regeneration of complex tissues Free of toxic solvents Excellent controllability over scaffold architecture Macroporous architecture (not limited to stacking)	Large quantities of raw materials are required Logistically challenging Expensive	32, 88