Table 1.

Side effects of NPs.

type of NPs	size	experimental target	treatment	effects	ref.
Au	30 nm	pregnant mice	intravenous injection	emphysema-like changes in lungs	[89]
Au	5.3 ± 1 nm	Mytilus edulis	exposed in tanks for 24 h in vivo	cause oxidative stress in Mytilus edulis within 24 h of exposure	[42]
Au	22 nm	human oral squamous cell carcinoma (HSC-3)	exposure to extracellular, cytoplasm, and nuclear localized AuNPs and AgNPs	decline in intracellular ATP; reduce HSC-3 cell viability; increased apoptotic population	[90]
Au	10 nm × 39 nm, 10 nm × 41 nm, 10 nm × 45 nm	human lung adenocarcinoma epithelial; human gastric adenocarcinoma cells; mouse embryonic fibroblast; porcine kidney; African green monkey kidney; human normal lung tissue	cell-impedance measurement system; monitoring platform; evaluation of cytotoxic effects with traditional in vitro assays	induce signaling and gene expression to regulate responses in cells	[91]
Ag	5–35 nm	Paracentrotus lividus	—	induced dose-dependent developmental defects: delayed development, bodily asymmetry, shortened or irregular arms and behavioral changes	[92]
Ag	—	calf thymus DNA	—	alter the conformation of DNA; bind DNA groove	[93]
Ag	50 nm, 3 μm, 30 μm	osteoclasts (OC) and osteoblasts (OB) cultures	murine osteoclasts (OC) and osteoblasts (OB) exposed to silver particles	dose-dependent cytotoxic effects on OB and OC in vitro	[94]
Cu	15 nm	adult mouse podocytes	treated with different concentrations of nano-Cu	increase oxidative stress; cause podocyte apoptosis	[95]
Cu	204 ± 1 nm	epithelial kidney cells of frog X. laevis	exposed to CuO particles of three different sizes	cause DNA damage, decrease cell viability and levels of reduced glutathione (GSH) and eventually cell death	[96]
Cu–Zn alloy	—	human lung epithelial cells	—	induce chromosomal damage and intracellular ROS formation	[97]