Table 1.

Design Parameters of Porous Substrate Systems

Type	Substrate Material	Electrode Material	Cell Trapping Mechanism	Pore Diameter (nm)	Pore Length (μm)	Pore Density (cm−2)	Ref.
Membrane	Track-Etched Polycarbonate	Titanium		100	20	2E7	[151]
		ITO-Coated Glass		200	25	5E8	[152, 158]
		U: Silver/Silver Chloride, L: Gold-Coated Glass		600 2000	24 23	4E7 3E6	[153]
	Track-Etched PET	Silver	Vacuum	U: 3000 L: 400			[156]
	U: Track-Etched PET, L: Anodic Alumina			U: 3000 L: 200	U: 10 L: 60	U: 8.5E5 L: 8.0E8	[157]
	Anodic Alumina	Platinum-Coated Glass		20	45	1E11	[154]
		Gold-Coated Upper and Lower Membrane Surfaces	Vacuum	100–200	60		[155]
Array	DRIE and photo-lithographed silicon	U: Copper, L: Gold-Coated Glass	Vacuum	650	20	4E6	[160]
		U: Neon Transfection System Electrode, L: Gold-Coated Glass	Nano-structures	400	10		[161]
		U: ITO-Coated Glass, L: Gold-Coated Glass	*	300	10	4E4	[162]
		U: Platinum, L: Gold-Coated Glass	Magnetic Tweezers or Vacuum	5000 5000	30 30	1E3 4E4	[163]
			Dielectro-phoresis	650			[164]
		U: ITO-Coated Glass, L: Gold-Coated Glass	Dielectro-phoresis	300	10	4E4	[165]
				500	20–25	4E4	[166]
			Vacuum (L)	1000 (U) 2500–3500 (L)	10 (U) 12–13 (L)	1.6E6 (U) 2.5E5 (L)	[167]
		Gold-Coated Glass	Vacuum	2000 5000	1	1.8E4	[168]

U and L denote upper and lower, respectively, in instances where there is a difference between electrodes or when porous substrates are used both above and below.

^*Optical tweezers were used in this study but are only mentioned for positioning cells in the 2D channels, not for positioning on the porous substrates.