Applying microfluidic techniques for biomaterial and mechanical regulation of mesenchymal stem cells

Table 2 Microfluidic techniques for mechanical stimulation of mesenchymal stem cells

Category	Microfluidic implementation	Key effects on MSCs	Ref.
Fluid shear stress	Passive (constant flow) or active (externally modulated) systems	(1) Low shear stress (10-5-10-2 dyn/cm2): Osteogenesis; (2) Medium shear stress (7.8-13.7 dyn/cm2): Endothelial differentiation; and (3) High shear stress (15 dyn/cm2): Adipogenesis	[85,87-90,99]
Cyclic stretch	Elastic membrane deformation	(1) Directs alignment; (2) Promotes proliferation, osteogenesis, and angiogenesis; and (3) High stretch (RMD > 3.5%) suppresses adipogenesis	[84,91,92]
Compressive stress	Fluidic pressure, confined microchannels, or mechanoactive hydrogels	(1) Promotes osteogenesis; and (2) Elevates vesicle secretion	[17,93-96,100]

MSCs: Mesenchymal stem cells; RMD: Relative membrane deformation.