Li Hui, Li Mengyan, Shih Wan Y, Lelkes Peter I, Shih Wei-Heng
Department of Materials Science and Engineering, Drexel University, Philadelphia, PA 19104, USA.
J Nanosci Nanotechnol. 2011 Apr;11(4):3543-51. doi: 10.1166/jnn.2011.3803.
Cytotoxicity tests of zinc sulfide (ZnS) and cadmium sulfide (CdS) quantum dots (QDs) synthesized via all-aqueous process with various surface conditions were carried out with human endothelial cells (EA hy926) using two independent viability assays, i.e., by cell counting following Trypan blue staining and by measuring Alamar Blue (AB) fluorescence. The ZnS QDs with all four distinct types of surface conditions were nontoxic at both 1 microM and 10 microM concentrations for at least 6 days. On the other hand, the CdS QDs were nontoxic only at 1 microM, and showed significant cytotoxicity at 10 microM after 3 days in the cell counting assay and after 4 days in the AB fluorescence assay. The CdS QDs with (3-mercaptopropyl)trimethoxysilane (MPS)-replacement plus silica capping were less cytotoxic than those with 3-mercaptopropionic acid (MPA) capping and those with MPS-replacement capping. Comparing the results of ZnS and CdS QDs with the same particle size, surface condition and concentration, it is indicated that the cytotoxicity of CdS QDs and the lack of it in ZnS QDs were probably due to the presence and absence of the toxic Cd element, respectively. The nontoxicity of the aqueous ZnS QDs makes them favorable for in vivo imaging applications.
采用两种独立的活力测定方法，即台盼蓝染色后细胞计数法和阿拉玛蓝（AB）荧光测定法，对通过全水相法合成的、具有不同表面条件的硫化锌（ZnS）和硫化镉（CdS）量子点（QDs）与人内皮细胞（EA hy926）进行细胞毒性测试。在1 microM和10 microM浓度下，具有所有四种不同表面条件的ZnS量子点至少6天均无毒性。另一方面，CdS量子点仅在1 microM时无毒性，在细胞计数试验中3天后以及在AB荧光试验中4天后，在10 microM时显示出显著的细胞毒性。用（3-巯基丙基）三甲氧基硅烷（MPS）取代并加二氧化硅封端的CdS量子点的细胞毒性低于用3-巯基丙酸（MPA）封端和用MPS取代封端的CdS量子点。比较相同粒径、表面条件和浓度的ZnS和CdS量子点的结果表明，CdS量子点的细胞毒性以及ZnS量子点缺乏细胞毒性可能分别归因于有毒Cd元素的存在与否。水性ZnS量子点的无毒性使其有利于体内成像应用。
