Research Of Fluorescent Gold Nanoclusters For Viral Imaging And Antiviral

Fluorescence gold nanoclusters (Au NCs) exhibit unique photoelectrochemical properties due to their sub-nanoscale size, such as good light stability, high two-photon absorption cross-sectional area and good biocompatibility, etc. It has been reported in ion detection, biological molecular detection, cellular imaging, vivo diagnosis and anti-tumor. However, the impact of gold clusters on the virus rarely reported. In this paper,we investigated the effects of different modifiers gold clusters on porcine pseudorabies virus (PRV) and porcine reproductive and respiratory syndrome virus (PRRSV), and carried out cell imaging.1. Water-soluble fluorescent GSH-Au NCs were synthesized by chemical reduction method using glutathion (GSH) as modifier. The GSH-Au NCs were characterized by fluorescence spectroscopy (FL), ultraviolet spectroscopy (UV), hydrated particle size(DLS), transmission electron microscopy (TEM), fourier transform infrared spectroscopy(FT-IR) and X-ray photoelectron spectroscopy (XPS). The cytotoxicity of GSH-Au NCs in PK-15 and MARC-145 cells was evaluated by MTT method. The results showed that GSH-Au NCs had good light stability, when the concentration was less than 450 ?mol/L,the viablility of PK-15 and MARC- 145 cells were more than 80%. GSH-Au NCs were used to study the effects of PRV-invading PK-15 cells and PRRSV-invading MARC-145 cells. The results showed that GSH-Au NCs had a selective anti-PRRSV effect and had no obviously affected on PRV by plaque assay, indirect immunofluorescence assay and Weston blot. Finally, the process of PRV invasion PK-15 was observed by laser confocal scanning microscopy with GSH-Au NCs as a fluorescent probe. A significant green fluorescence was observed in the nucleus after 12 h of PRV invasion PK-15 cells,indicating that PRV could obviously destroy the nucleus of PK-15 cells. These results will provide some reference for the application of Au NCs in antiviral field.2. Water-soluble fluorescent BSA-Au NCs and Au-Ag NCs were synthesized by using bovine serum albumin (BSA) as modifier. And the as-prepared NCs were characterized by FL, UV, DLS and FT-IR. The cytotoxicity of BSA-Au NCs and Au-Ag NCs on PK-15 cells was evaluated by MTT method. The results showed the concentration of NCs was less than 600 ?mol/L, the viablility of PK-15 cells were more than 80%.Using BSA-Au NCs and Au-Ag NCs as fluorescent probes for PK-15 cell imaging studies,we found that these two gold clusters did not show obviously fluorescence in PK-15 cells.Finally, it was found that BSA-Au NCs and Au-Ag NCs had no obviously effect on PRV-invading PK-15 cells. These results expected to be further applied to the label viruses.