Optotransfection of mammalian cells based on a femtosecond laser and facilitated by gold nanorods.

The optotransfection of cells based on a femtosecond laser has attracted much attention owing to its high transfection efficiency and high cell viability since its first report by Konig. However, the low throughput in the original method also limits its use in practical applications. Gold nanoparticles (GNPs) have been reported to function as local receivers of light to relax the requirement of accurate optical alignment for the optotransfection of single cells. However, the visible light used in such work is not suitable for penetrating deep tissues in certain applications. In this study, we employed gold nanorods (GNRs) and an infrared femtosecond laser at the wavelength of 980 nm to realize optotransfection of cells with GFP. It was found that the surface coating of GNRs exhibited a significant effect on the process of cell permeabilization.

In vitro effect of CTAB- and PEG-coated gold nanorods on the induction of eryptosis/erythroptosis in human erythrocytes.

Gold nanorods (Au-NRs) have attracted enormous interest due to their size and unique optical properties. Many studies have demonstrated their use in biomedical systems. However, their potential toxicity is not fully understood. This study evaluated the effects of the Au-NRs (15 nM × 64 nM) coated with CTAB (cetyltrimethylammonium bromide) or PEG (polyethylene glycol) in human erythrocytes on the induction of haemolysis and erythroptosis. In our study, erythroptosis (also known as eryptosis) was determined systematically through the measurement of feature events of apoptosis by flow cytometry. We found that the CTAB- and PEG-coated Au-NRs up to 0.5 nM did not cause severe haemolysis. However, the CTAB-Au-NRs were more toxic than the PEG-Au-NRs. The toxicity of the CTAB-Au-NRs was largely due to the CTAB residues from desorption or incomplete purification. Mechanistically, cytosolic Ca(2+) ions seem to be the key mediator in the eryptosis/erythroptosis mediated by the CTAB or CTAB-Au-NRs while caspase-3 and reactive oxygen species did not contribute much to the process.