In Vitro Toxicity Assessment of Amphiphillic Polymer-Coated CdSe/ZnS Quantum Dots in Two Human Liver Cell Models

Semiconductor quantum dots (Qdots) are a promising new technology with benefits in the areas of medical diagnostics and therapeutics. Qdots generally consist of, a semiconductor core, capping shell, and surface coating. The semiconductor core of Qdots is often composed of group II and VI metals (e.g., Cd, Se, Te, Hg) that are known to have toxic properties. Various surface coatings have been shown to stabilize Qdots and thus shield cells from the toxic properties of their core elements In this study, HepG2 cells and primary human liver (PHI) cells were chosen as in vitro tissue culture models of human liver to examine the, possible adverse effects of tri-n-octylphosphine oxide, poly(maleic anhydride-alt-1-tetradecene) copolymer (TOPO-PMAT)-coated CdSe/ZnS Qdots (TOPO-PMAT Qdots). The TOPO-PMAT coating is desirable for increasing aqueous solubility and ease of conjugation to targeting moieties (e.g., aptamers and peptides). HepG2 cells avidly Incorporated these TOPO-PMAT Qdots into subcellular vesicles. However, PHI cells did not efficiently take up TOPO-PMAT Qdots, but nonparenchymal cells did (especially Kupffer cells). No acute toxicity or morphological changes were noted in either system at the exposure levels used (up to 40 nM). However, cellular stress markers and pro inflammatory cytokines/chemokines were increased in the PHI cell cultures, suggesting that TOPO-PMAT Qdots are not likely to cause acute cytotoxicity In the liver but may elicit inflammation/hepatitis, demonstrating the importance of relevant preclinical safety.. models. Thus, further in vivo studies ire warranted to ensure that TOPO-PMAT-coated Qdots used in biomedical applications do riot induce Inflammatory responses as a consequence of hepatic uptake.