Table 2.

A few important and relevant parameters for choosing (or to avoid choosing) the appropriate micro- nanofabricated platform for specific stem cell based experiments.

Platform	Techniques	Some Useful Numbers	Notes
Microfluidics	Photolithography	Chamber height1: 10–500μm Minimum feature size2: 5–10μm Length of culture: 2 days 3D culture: difficult Ease of handling: moderate High throughput: yes	1. High chamber height reduces shear.2. Small feature size allow efficient packing of device.
	Stereolithography	Chamber height1: 100–1000μm Minimum feature size2: 25μm Length of culture: 7–10 days 3D culture: easy Ease of handling: easy High throughput: difficult
Microstencils		Ease of handling1: very easy Size of “holes”: 5–500μm Cell types: 2–3 Shape of cell-cell interface: arbitrary Incorporation in microfluidics: difficult	1. Small size of holes present difficulty in introducing cells.
Nanofabrication	Capillary force lithography	Feature size1: >10nm Sample size2: 5cm Shape of features: arbitrary Material compatibility: UV assisted polymerization Length of culture: 1–21 days Ease of handling: very easy Cost: low Microscopy: any Incorporation in microfluidics: easy	1. Possibility to obtain smaller feature size allow a higher flexibility to create a more biomimetic ECM microenvironment.2. Large sample size allow biochemical experiments.
	Electrospinning	Feature size: 10–100nm Sample size1: >1cm3 Shape of features: grooves Material compatibility: limited Length of culture: 1–15 days Ease of handling: moderately easy Cost: moderate Microscopy: confocal	1. Electrospinning allows only 3D samples.
	Nanoimprinting	Feature size: 10–100nm Sample size1: >1cm3 Shape of features: grooves, pillars Material compatibility: UV or thermal curable materials Microscopy: any Cost: moderate Incorporation in microfluidics: easy	Nanoimprinting equipment is required.
Mechanical Gradients in Microfluidics	Polyethylene glycol (PEG) gradients	FDA approved: yes Range of rigidity1,86: 50–500kPa Mode of polymerization: UV/chemical Ease of preparation: moderately difficult Ease of ECM coating: moderately easy	1. Range of rigidity achieved by change in cross-linker concentration.
	Polyacrylamide gradients	FDA approved: no Range of rigidity1,86: 0.01–100kPa Mode of polymerization: UV/chemical Ease of preparation: moderately easy Ease of ECM coating1: difficult	1. ECM coating on PAAM presents complications.
	PDMS gradients	FDA approved: no Range of rigidity86: 10–1000kPa Mode of polymerization: UV/chemical Ease of ECM coating: easy Ease of preparation: moderately difficult Ease of gradients: difficult
	Nanofabrication of polymers	Ease of preparation1: difficult Ease of handling: easy Gradient shape: arbitrary Ease of ECM coating: easy	1. Unlike microfluidics based gradient generation, nanofabricated samples require complex fabrication procedures.