TABLE II.

Comparison of static and flow-based microfluidic devices for stem cell differentiation.

Static microfluidics		Flow-based microfluidics
Advantages	Disadvantages	Advantages	Disadvantages
External pumps and tubing not required	Gradient changes with time and stabilizes on a time scale of hours	Gradient constant with time and stabilizes within seconds to minutes	External pumps and tubing required
Commercially available (no operational or fabrication expertise required)	Single option for gradient profile	Tunable control of gradient profile using channel geometry and/or flow rate(s)	Requires operational expertise and access to a fabrication facility
No shear stress on cells	Manual media changes via pipetting required	Media changes on cells are automated	Shear stress can disrupt cell-matrix adhesion
Easily parallelizable			Throughput limited by pump capacity
Preserves autocrine and paracrine signals secreted by cells			Bubbles may arise during flow and disrupt gradient