Cytotoxicity screening of a series of semiconductor quantum dots for their potential biomedical use

Abstract

BackgroundQuantum dots (QDs) are promising candidates for a wide variety of biomedical applications, such as imaging, biosensing and drug delivery. However, the major drawback of QDs is their potential cytotoxicity. The major goal of the present study was to examine cytotoxic effects of a series of newly synthesized CdTe or CdSe QDs with/without ZnS shell and different cappings to estimate their potential use in biomedicine.Methods & ResultsProliferation studies using the human pancreatic carcinoid cell line BON and the esophageal squamous carcinoma cell line Kyse70 revealed that CdTe and CdSe QDs with or without ZnS shell and coated with 3‐mercaptopropionic acid were highly cytotoxic even at low nanomolar concentrations. By contrast capping with L‐glutathione (GSH) or thioglycolic acid (TGA) reduced the cytotoxicity of CdTe and CdSe QDs to reach IC50 values in the micromolar range. Additional investigations using chorioallantoic membranes of fertilized chicken eggs (CAM assay) to which QDs were applied topically or injected intravenously confirmed the good tolerability in vivo.ConclusionThe specific surface coating as well as core material has significant impact on QD toxicity in cells and tissues. The novel TGA‐ and GSH‐capped QDs characterized in this investigation merit further elucidation as promising candidates for biomedical applications.