doi:10.1038/nindia.2014.19 Published online 12 February 2014
Researchers have synthesized fluorescent silver nanoparticles with antibacterial and anticancer properties by using the leaf extract of an endangered medicinal shrub1 . The nanoparticles can be potentially employed for diagnosis based on fluorescence imaging.
Silver nanoparticles are used in electronics, textiles, paints and biomedical applications, among others. This is the first time that biocompatible and fluorescent silver nanoparticles with anticancer and antibacterial properties have been produced.
The researchers synthesized these versatile silver nanoparticles from the leaf extract of a medicinal shrub and silver nitrate solution using water as a solvent. They studied the efficacy of the nanoparticles in inhibiting the growth of the bacterium Escherichia coli and killing human lung and breast cancer cells as well as mice skin cancer cells.
The nanoparticles killed the bacterial cells by rupturing their cell walls, resulting in the release of cellular cytoplasm. The nanoparticles decimated bacteria cells with an effectiveness comparable to similar doses of the synthetic antibacterial agent ampicillin. The silver nanoparticles also significantly inhibited the proliferation of the cancer cells. The acidic environment of the cancer cells caused the nanoparticles to release silver ions, which generated reactive oxygen species that stifled the growth of the cancer cells.
The silver nanoparticles were found to be biocompatible when they were grown with endothelial cells. After synthesis, the nanoparticles remained stable for more than two weeks. In addition, the leaf extract contained fluorescent phytochemicals that remained attached to the nanoparticles. The fluorescent nanoparticles entered the cancer cells, raising the possibility of using them for fluorescence imaging in the diagnosis of various cancers.
"In the future, such silver nanoparticles could be used for various biomedical applications after successful animal studies," says lead researcher Chittaranjan Patra.