Bright blue emitting CuSe/ZnS/silica core/shell/shell quantum dots and their biocompatibility

In the in vivo scenario, the nanomaterials have to stay for a prolonged period in fluids like blood and therefore a detailed understanding of their interaction with blood elements is mandatory. We report the synthesis and characterization of highly blue emitting smaller size, 3.6 nm CuSe quantum dots (QDs) and its core/shell structure CuSe/ZnS. We modified QDs with a silica shell, which is the most accepted approach to lessen the toxic liabilities, and the blood compatibility of resultant CuSeanS/Silica QDs were evaluated. MTT assay and cellular uptake using HepG2 and C 6 glioma cancer cells were studied to show their potential as drug targeting vehicles. The documented observation to date about the silica on cells is its ability to cause apoptosis by the production of reactive oxygen species. However, its impact on the blood cells has never been addressed or studied in detail. Our data indicate that concentrations of <= 50 mu g/mL CuSe/ZnS/Silica QDs are blood compatible. The concentration dependant blood compatibility of silica modified QDs, point out the need for rethinking of using silica coatings over nanomaterials for diverse applications like drug targeting and cellular labeling. (c) 2012 Elsevier Ltd. All rights reserved.