Anti-HSV Activity of Metallic Nanoparticles Functionalized with Sulfonates vs. Polyphenols

Abstract

Metallic nanoparticles exhibit broad-spectrum activity against bacteria, fungi, and viruses. The antiviral activity of nanoparticles results from the multivalent interactions of nanoparticles with viral surface components, which result from the nanometer size of the material and the presence of functional compounds adsorbed on the nanomaterial surface. A critical step in the virus infection process is docking and entry of the virus into the host cell. This stage of the infection can be influenced by functional nanomaterials that exhibit high affinity to the virus surface and hence can disrupt the infection process. The affinity of the virus to the nanomaterial surface can be tuned by the specific surface functionalization of the nanomaterial. The main purpose of this work was to determine the influence of the ligand type present on nanomaterial on the antiviral properties against herpes simplex virus type 1 and 2. We investigated the metallic nanoparticles (gold and silver) with different sizes (5 nm and 30 nm), coated either with polyphenol (tannic acid) or sulfonates (ligands with terminated sulfonate groups). We found that the antiviral activity of nano-conjugates depends significantly on the ligand type present on the nanoparticle surface.

Keywords: antiviral nanoparticles; heparin-mimic ligands; natural-origin antivirals; tannic acid.

Figure 1

STEM images and DLS size distribution histograms of polyphenol-conjugated metallic nanoparticles: 5 nm AuNPs-TA (A); 30 nm AuNPs-TA (B); 5 nm AgNPs-TA (C); 30 nm AgNPs-TA (D).

Figure 2

STEM images and DLS size distribution histograms of sulfonate-conjugated metallic nanoparticles: 5 nm AuNPs-5 MES (A); 5 nm AgNPs-5 MES (B); 5 nm AuNPs-20 MES (C); 5 nm AgNPs-20MES (D); 30 nm AuNPs (E); 30 nm AgNPs (F); 30 nm AuNPs-5 MES (G); 30 nm AgNPs-5 MES (H); 30 nm AuNPs-20 MES (I); 30 nm AgNPs-20MES (J).

Figure 3

STEM images and DLS size distribution histograms of sulfonate-conjugated metallic nanoparticles: 5 nm AuNPs-5MUS (A); 5 nm AgNPs-5MUS (B); 5 nm AuNPs-20MUS (C); 5 nm AgNPs-20MUS (D); 30 nm AuNPs (E); 30 nm AgNPs (F); 30 nm AuNPs-5MUS (G); 30 nm AgNPs-5MUS (H); 30 nm AuNPs-20MUS (I); 30 nm AgNPs-20MUS (J).

Figure 3

STEM images and DLS size distribution histograms of sulfonate-conjugated metallic nanoparticles: 5 nm AuNPs-5MUS (A); 5 nm AgNPs-5MUS (B); 5 nm AuNPs-20MUS (C); 5 nm AgNPs-20MUS (D); 30 nm AuNPs (E); 30 nm AgNPs (F); 30 nm AuNPs-5MUS (G); 30 nm AgNPs-5MUS (H); 30 nm AuNPs-20MUS (I); 30 nm AgNPs-20MUS (J).

Figure 4

Inhibition of virus infection with the use of TA-conjugates (A), MES-conjugates (B), and MUS conjugates (C) of 5 and 30 nm AuNPs as well as 5 and 30 nm AgNPs. The efficiency of antiviral action was measured in plaque-forming units (PFU) and compared to untreated infected cultures. Results are expressed as % of untreated infection.

Figure 4

Inhibition of virus infection with the use of TA-conjugates (A), MES-conjugates (B), and MUS conjugates (C) of 5 and 30 nm AuNPs as well as 5 and 30 nm AgNPs. The efficiency of antiviral action was measured in plaque-forming units (PFU) and compared to untreated infected cultures. Results are expressed as % of untreated infection.

Figure 5

cryo-TEM images of unstained samples: HSV-1 virus (A), HSV-1 virus after incubation with: 5MUS_5nmAgNPs (B), 5MUS_30nmAgNPs (C) TA_5nmAgNPs (D), TA_30nmAgNPs (E) (samples imaged after about 30 s of incubation of virus with functional nanoparticles).