Synthesis Approaches of Zinc Oxide Nanoparticles: The Dilemma of Ecotoxicity

Table 2

Frequently employed capping agents and stabilizers.

Capping agents/stabilizers	Inherent toxicity	Toxicity reported by	Reference of utility in ZnO NP synthesis
Triethyl amine	Reversible; ocular effects including corneal swelling and halo vision in humans	[119]	[120]; [121]; [122]
Oleic acid	Promote apoptosis and necrosis, mitochondrial depolarization, lipid accumulation, and overexpression of C-MYC and P53	[123]	[124]; [125]; [126]
Thioglycerol	Irritant for skin, eye and inhalation; Hazardous in case of ingestion	[127]	[128]; [129]; [130]
EDTA	Cytotoxic and genotoxic	[131]; [132]	[133]; [134]; [135]
Tetraethyl ammoniumbromide	Tremors, incoordination, flaccid prostration, and death from respiratory failure in animals	[136]	[137]; [138]; [139]
Tetraethyl orthosilicate	Highly damaging to eyes	[140]	[141]; [142]; [143]
Polyethylene glycol (PEG)	Immunogenic	[144]	[11]; [145]; [137]
Polyethylene phthalate (PEP)	Endocrine disruptor	[146]	[147]; [148]; [149]
Ethylene glycol	Adversely affects reproduction and development	[150]	[11]; [151]; [152]
Gelatin	Toxic	[153]	[154]; [155]
Polyvinyl alcohol (PVA)	Toxic	[156]; [157]	[158]; [159]; [160]
Polyvinyl pyrrolidine (PVP)	Weight increase in lab mice	[161]	[162]; [163]; [164]