Research

Toxicity of CdSe Nanoparticles in Caco-2 Cell Cultures

Lin Wang¹ , Dattatri K Nagesha² , Selvapraba Selvarasah³ , Mehmet R Dokmeci³ and Rebecca L Carrier¹

¹  Chemical Engineering Department, Northeastern University, Boston, MA, 02115, USA

²  Physics Department, Northeastern University, Boston, MA, 02115, USA

³  Electrical and Computer Engineering Department, Northeastern University, Boston, MA, 02115, USA

author email corresponding author email

Journal of Nanobiotechnology 2008, 6:11doi:10.1186/1477-3155-6-11

Published:	23 October 2008

Abstract

Background

Potential routes of nanomaterial exposure include inhalation, dermal contact, and ingestion. Toxicology of inhalation of ultra-fine particles has been extensively studied; however, risks of nanomaterial exposure via ingestion are currently almost unknown. Using enterocyte-like Caco-2 cells as a small intestine epithelial model, the possible toxicity of CdSe quantum dot (QD) exposure via ingestion was investigated. Effect of simulated gastric fluid treatment on CdSe QD cytotoxicity was also studied.

Results

Commercially available CdSe QDs, which have a ZnS shell and poly-ethylene glycol (PEG) coating, and in-house prepared surfactant coated CdSe QDs were dosed to Caco-2 cells. Cell viability and attachment were studied after 24 hours of incubation. It was found that cytotoxicity of CdSe QDs was modulated by surface coating, as PEG coated CdSe QDs had less of an effect on Caco-2 cell viability and attachment. Acid treatment increased the toxicity of PEG coated QDs, most likely due to damage or removal of the surface coating and exposure of CdSe core material. Incubation with un-dialyzed in-house prepared CdSe QD preparations, which contained an excess amount of free Cd²⁺, resulted in dramatically reduced cell viability.

Conclusion

Exposure to CdSe QDs resulted in cultured intestinal cell detachment and death; cytotoxicity depended largely, however, on the QD coating and treatment (e.g. acid treatment, dialysis). Experimental results generally indicated that Caco-2 cell viability correlated with concentration of free Cd²⁺ ions present in cell culture medium. Exposure to low (gastric) pH affected cytotoxicity of CdSe QDs, indicating that route of exposure may be an important factor in QD cytotoxicity.