. Author manuscript; available in PMC: 2021 Jun 10.

Published in final edited form as: Nat Rev Mater. 2019 Nov 7;5(1):20–43. doi: 10.1038/s41578-019-0148-6

Table 1 |.

Key performance metrics for different techniques for the fabrication of hydrogel microparticles

Production method	Particle size coefficient of variation^* (CV%)	Minimum size range	Production rate	Particle geometry	Compatibility with cells
Batch emulsion	Large variation (>10%)^11,230	1–10 μm¹⁷	High (only limited by vessel size)	Spherical	Average (>80% viability)^11,12
Microfluidic emulsion	Low variation (1–2% possible)²⁶	5–10 μm^14,23,24,51	Average (can be improved with parallel channels)	Spherical	Average (>80% viability)^33,38,47
Lithography	Low variation (1–3% possible)^61,75,231	<1 μm possible^61,62	Low (can be improved when integrated with microfluidics)	Arbitrary 2D and 3D geometries possible	High (>90%); no oil or surfactant required^58,59
Electrohydrodynamic spraying	Average variation >50%^77,79,80	1–10 μm⁷⁸	Average	Spherical	Average (>80%)^76,77
Mechanical fragmentation	Average variation (2–8%)⁸⁶	20–50 μm^85,86	High (only limited by vessel size)	Irregular	Unreported

The coefficient of variation (CV%) is defined as the ratio of the standard deviation of particle size to the mean particle size.