Table 1.

Comparative Cytotoxicity of Six Cell Impermeant Nucleic Acid Stains

	PI	7-AAD	SYTOX Green	SYTOX Red	YO-PRO 1	PO-PRO 1
cell lines tested	suspension: U937, HL60, K562, MOLT-4, and Jurkat. adherent: U2OS, Saos2, MDA-MB-231, and 3T3.
ex/em maximum (nm)	536/617	546/647	504/523	640/658	491/509	435/455
guide staining concentration	up to 5 μg/mL	up to 1 μg/mL	up to 1 mM	up to 10 nM	up to 1 mM	up to 1 mM
cytotoxic	-	-	-	-	-	-
phototoxica	-	N/A	-	-	-	-
influence on cell proliferation	-	N/A	-	-	-	-
influence on cell cycleb	-	N/A	-	-	-	-
influence on cell migrationc	-	N/A	-	-	-	-
dynamic viability labeling	+	+	+	+	+	+
photobleaching	slow (1-2 min	slow (1-2 min)	slow (1-2 min)	slow (1-2 min)	slow (1-2 min)	slow (1-2 min)
fluorescence signal	bright	dim	bright	bright	bright	dim
multiplexing	±	±	+	+	+	±

^aPhototoxic effects observed during kinetic cell imaging.

^bU937 and U2OS cell lines incubated with the probe for up to 48 h.

^cDirectional cell motility using the would-closure assay on invasive breast cancer cells MDA-MB-23.