Table 3.

Zinc ion cytotoxicity.

Concentration of Zn (μM)	Medium	Cell	Exposition time (h)	Test	Result	Ref
20–80	serum-free medium	Rat retinal cells	24	LDH	20-40 μM: little cell death; 50 μM: 30%–40% cell death; 60-80 μM: almost 100% death	[187]
1–100	serum-free medium	Human proximal tubular cells	24–96	MTT	1-10 μM: ≥ 80% viability at 24–96 h; 50 μM: ≥ 80% viability until 48 h while then 30%–40% cell death; 100 μM: significant cell reduction at 24–96 h	[188]
2–300	DMEM/MEM +5%FBS	U–2OS (human cell line derived from osteosarcoma)	24	WST-1	2-120 μM: > 70% viability, 180–300 μM: nearly 100% cell death	[189]
2–300	DMEM/MEM +5% FBS	L929	24	WST-1	2-80 μM: > 70% viability, 120-300 μM: nearly 100% cell death	[189]

Note: a) MEM: minimum essential medium, b) DMEM: Dulbecco's modified Eagle's medium, c) FBS: fetal bovine serum.