Gold nanoparticles: effective as both entry inhibitors and virus neutralizing agents against HIV

Spherical gold nanoparticles of 2 – 10 nm diameter as well as gold nanoparticles coated with Polyethylene Glycol (PEG-AuNP) were tested for their cytotoxicity and anti-viral activity. Gold nano particles were synthesized by Turkevich’s chemical reduction method of gold ions; cytotoxicity of the gold nanoparticles and PEG coated gold nanoparticles was assessed by tissue culture based colorimetric MTT assay and anti-viral potential of HIV was assessed by P24 antigen inhibition assay. Both Au NP and AuNP+ PEG were allowed to interact respectively with viral particles before infecting the cells as well as interacted with HIV- infected CD4+ T cells. An increase in cytotoxicity was observed with increase in gold nanoparticle concentration. However, it was below 10% in both Au NP and PEG-AuNP at 2 ppm and 4ppm. Nanoparticles showed greater activity in the test where the viral particles were allowed to interact with the nanoparticles before infecting the cells as compared to the test where the cells, previously infected with the virus, were allowed to interact with the nanoparticles. AuNP at 4ppm concentration were found to be effective as virus neutralizing candidate when allowed to interact with virus infected cells.  Whereas, Au-PEG at 2ppm and 4ppm were more effective in inhibiting viral entry when interacted with viral particles directly. The results suggest that the gold nanoparticles are effective as both virus entry inhibitors as well as virus neutralizing agent. Key words: Gold nanoparticles, HIV, PEG, P24 ELISA.