Cellular uptake and cytotoxicity of modified silver nanoparticles

In this study, for A549 (human lung cancer cells) and L929 (immortalized mouse fibroblast cells) cells; cellular uptake, cytoplasmic localizations or behaviors and cytotoxicity of silver nanoparticles (SNPs) and their chemically modifications one by one and by different combinations with glucose, lactose, oligonucleotide and fluorescence dye (Cy5) are investigated. The modified SNPs (MSNPs) prepared as Ag/Glucose, Ag/Lactose, Ag/ssDNA, Ag/Glucose/ssDNA, Ag/Lactose/ssDNA, Ag/ssDNA/Cy5, Ag/Glucose/ssDNA/Cy5, Ag/Lactose/ssDNA/Cy5 were incubated with A549 and L929 cells during 1 h, 6 h and 24 h, and cellular uptake of these nanoparticles (NPs) was examined. Additionally, by MTS (cell proliferation assay) assay, it was investigated whether the applied concentration of these NPs had cytotoxic effect or not. DMSO (Dymethylsulfoxide) was used for positive control, medium was used for negative control in the cytotoxicity test. For the cells incubated with different SNPs, variant cellular uptake ratios were detected during different incubation times. Among these NPs, while for L929 cells, cellular uptake of Ag/Glucose at the first hour was the most amount NPs with 33%; for A549 cells cellular uptake of Ag/Lactose was the most amount NPs with 68% at 6th hour. As for cytoplasmic localization of NPs, whereas the NPs in the L929 cells formed small aggregates and they diffused randomly in the cell cytoplasm; in A549 cells, especially dye included SNPs formed large aggregates in the cytoplasm. When this concentration of all SNPs was applied to L929 cells, no cytotoxicity was observed. In A549 cells, on the other hand, Ag/Glucose/ssDNA/Cy5 had the most cytotoxic effect with 24%. These results showed that when prepared SNPs are applied to healthy and cancer cells, some of the NPs are uptaken selectively for cancer cells; and in the terms of cytoplasmic localization and aggregations of NPs become an important tool for the phototermal cancer therapy applications. While the applied concentration of the nanoparticles didn?t show toxic effect to the L929 cells but they were toxic to A549 cells; enhanced treatment opportunities of cancer cells via SNPs was risen due to spontaneous toxic effect only in the cancer cells.