The studies were conducted to investigate the possibility of employing silver nanoparticles for multipurpose medical applications by altering the surface properties of the material. Glucose and lactose were attached to investigate the selective targeting of cancer versus non-cancer cells, and oligonucleoties were attached for possible gene therapy applications.

Both L929 (non-cancer) and A549 (lung cancer) cells were treated with the modified AgNPs. It was found that the cellular uptake and cytotoxicity of glucose- or lactose-modified AgNPs were almost at the same level in L929 cells, while the levels in A549 cells are rather different. The results indicate that the use of carbohydrates significantly enhances the cellular uptake of AgNPs into A549 cells. The lactose-modified AgNPs entered the A549 cells at a faster rate. In addition, it was observed that the first five hours are important for the cellular uptake of NPs and the NPs were mostly seen localized in the cytoplasm. The cytotoxicity study revealed that the presence of glucose, lactose and oligonucleotide or their combinations on the NP surface might help to diminish the toxicity. The cellular uptake and localization of lactose-modified AgNPs in the A549 cells (cancer cells) might help to develop new approaches for the selective killing of cancerous cells, for example, in photothermal therapy applications.

The group's results demonstrate that surface modification can be employed for the multipurpose use of silver nanoparticles in medicine. Examples include toxicity reduction, targeting, imaging and thermal killing. Work continues on the synthesis and evaluation of novel multifunctional noble metal NPs for cellular and biomedical applications.

Full details are available in the journal Nanotechnology.