TABLE 2.

Summary of Quantum Dot Toxicity Studies Published Prior to September 2005.

QD composition	Cell, tissue, or organism tested	[QD] used	Exposure time	Observed toxicity	Reference
CdTe	PC12 (rat pheochronocytoma) and N9 (murine microglia) cell lines	0.01–100 μg/ml	2–24 h	Cytotoxic: 10 μg/ml	(Lovric et al., 2005)
CdSe/ZnS-DHLA QDs	B16F10 cells injected into mice	Injected 20,000–40,000 QD-treated cells into mice.	4–6 h cell incubation time, mice sacrificed at 1–6 h	Not toxic: No toxicity observed in cells or mice.	(Voura et al., 2004)
CdSe/ZnS-MUA	Vero and HeLa cell lines; primary human hepatocytes	0–0.4 mg/ml	24 h	Cytotoxic: 0.2 mg/ml in Vero cells, 0.1 mg/ml in HeLa cells, 0.1 mg/ml in hepatocytes.	(Shiohara et al., 2004)
CdSe/ZnS-SSA	EL-4 cells (mouse lymphocytes)	0.1–0.4 mg/ml	0–24 h	Cytotoxic: 0.1 mg/ml altered cell growth; most cells nonviable at 0.4 mg/ml.	(Hoshino et al., 2004b)
CdSe/ZnS-SSA	EL-4 cells labelled with QDs and injected into mice	0.1 mg/ml QDs per 5 × 107 cells	2 h to 7 days	Not toxic: No toxicity observed in mice in vivo.	(Hoshino et al., 2004b)
CdSe/ZnS conjugates: NH2, OH, OH/COOH, H2/OH, MUA, COOH	WTK1 cells	1–2μM	12 h	Cytotoxic: 2μM QD-COOH induced DNA damage at 2 h.	(Hoshino et al., 2004a)
CdSe-MAA, TOPO QDs	Primary rat hepatocytes	62.5–1000 μg/ml	1–8 h	Cytotoxic: A concentration of 62.5 μg/ml was cytotoxic under oxidative/photolytic conditions. No toxicity observed on addition of ZnS cap to QDs.	(Derfus et al., 2004)
CdSe/ZnS	HeLa cells	10 pmol QDs per 10,000 cells (approx. 10nM)	10 days (cell culture)	Not cytotoxic: 10nM QD had minimal impact on cell survival.	(Chen and Gerion, 2004)
CdSe/ZnS amp-QDs, and mPEG QDs	Mice—QDs injected into tail vein	Injections of approx. 180nM, or 20 pmol/g animal weight	15-min cell incubations, 1–133 days in vivo	Not toxic: No signs of localized necrosis at the sites of deposition.	(Ballou et al., 2004)
CdSe/ZnS-amphiphilic micelle	Mice—QDs injected into tail vein	60μM/gram animal weight, 1μM and 20nM final [QD].	Not indicated.	Mice showed no noticeable ill effects upon imaging.	(Larson et al., 2003)
CdSe/ZnS-DHLA	Dictyostelium discoideum and HeLa cells	400–600nM	45–60 min	No effects on cell growth noted.	(Jaiswal et al., 2003)
Avidin-conjugated CdSe/ZnS QDs	HeLa cells	0.5–1.0μM	15 min	No effect on cell growth or development noted.	(Jaiswal et al., 2003)
CdSe/ZnS-MUA QDs; QD-SSA complexes	Vero cells	0.24 mg/ml	2 h	Not cytotoxic: 0.4 mg/ml MUA/SSA-QD complexes did not affect the viability of Vero cells.	(Hanaki et al., 2003)
QD micelles: CdSe/ZnS QDs in (PEG-PE)and phosphati-dylcholine	Xenopus blastomeres	5 × 109 QDs/cell (approx. 0.23 pmol/cell)	Days	Toxic: At a threshold of 5 × 109 QDs/cell, observed cell abnormalities, altered viability and motility.	(Dubertret et al., 2002)

Note. PEG, polyethylene glycol.