Table 1.

Taxonomy of Sensors for Monitoring Microphysiological Systems (MPSs)

	target	sensor	sampling rate	operating time	physiological relevance	ref.
development	cellular organization	TEER	daily	62 days	epithelial barrier formation, function	56
	cellular organization	TEER	daily	10 days	barrier integrity	58
	contractile stress	strain gauge	seconds	28 days	cardiomyocyte maturation	38
	DNA	impedance	10 min	2 days	cell mitotic division	95
	glycerol	phosphorescence	90 s	2+ hrs	adipocyte secretion	43
	oxygen	optical	440 ns	5 h	culture environment	96
	oxygen	phosphorescence	2s	24 h	culture environment	97
	oxygen, pH, cell adhesion	electrochemical	20 min	11 days	control of culture conditions; cell proliferation	94
	scaffold stiffness	strain gauge	daily	20 days	matrix remodeling; tissue maturation	68
	strain	Wheatstone bridge	daily	20 days	endothelial barrier forming to create perfusable lumen	68
function	acidic metabolites	electrochemical	seconds	400 s	cellular metabolism; dose-response	17
	albumin, GSTα, CK-MB	electrochemical	seconds	120 days	nephrotoxicity; cardiotoxicity	88
	albumin, GSTα	electrochemical	4 h	7 days	metabolite monitoring	98
	cell growth	impedance	2s	24 h	cardiotoxicity; drug efficacy	99
	cell migration	impedance	real-time	200 min	cancer cell migration; metastasis	100
	cell viability	impedance	6 h	2 days	chemosensitivity	55
	differentiation	impedance	180 s	17 days	stem cell differentiation	101
	γ-glutamyl transpeptidase	smartphone-based fluorescence microscopy	n/a		drug-induced nephrotoxicity	102
	glucose, lactate, oxygen	optical	1h	24 h	glucose metabolism; mitochondrial function/dysfunction	45
	glucose, lactate, oxygen	optical, electrochemical	real-time	21 days	metabolite monitoring	103
	glucose, lactate	electrochemical	real-time	16 h	cellular metabolism; toxicity	104
	HGF, TGF-β1	optical	daily	7 days	cell secreting growth factors	75
	lactate, oxygen	electrochemical	10 min	3 days	metabolite monitoring	105
	TGF-β	electrochemical	near realtime	10+ hrs	cellular response to alcohol injury	86