Low-toxicity chitosan gold nanoparticles for small hairpin RNA delivery in human lung adenocarcinoma cells

The research for the present study focused on the preparation of low-toxicity gold nanoparticles (AuNPs) attached with small hairpin RNA (shRNA) and on monitoring their intracellular distribution by means of dark-field microscopy (DFM) and confocal Raman spectroscopy. The conjugation reactions of negatively charged shRNA onto positively charged chitosan AuNPs should occur via an electrostatic interaction as examined by visible absorption and infrared spectroscopy. Positively charged chitosan gold nanoparticles (AuNPs) prepared by chemical reduction were found to be well-internalized inside human lung adenocarcinoma A549 cells from transmission electron microscopy (TEM) images. We determined the localization of internalized AuNP-shRNA bioconjugates and found that AuNPs can be monitored inside a single cell using a confocal Raman spectroscopic tool. Chitosan AuNPs appeared to show good gene silencing efficiency with less toxicity than widely used branched polyethyleneimine (BPEI).