(175ay) Utilizing Gold Nanoparticles and Osmolytes to Detect Virus Particles Non-Specifically

Viruses are responsible for many human diseases, including hepatitis B and C, poliovirus, and B-19 human parvovirus. Current virus detection methods such as polymerase chain reactions (PCR) and enzyme-linked immunosorbent assays (ELISA) are specific to only one virus at a time, and require costly equipment, highly trained personnel, and expensive reagents such as capture antibodies or complementary oligonucleotides that are specific to only the virus of interest. To avoid using expensive and time-consuming techniques for virus detection, we are developing a simple, non-specific virus assay using gold nanoparticles (AuNPs) and osmolytes.

It has been shown that AuNPs form a corona on the outside surface of biomolecules, such as proteins, through electrostatic interactions. Our lab used this interaction between biomolecules and AuNPs to form virus particle-AuNP complexes. To preferentially aggregate the virus-AuNP complexes, glycine or mannitol was added to the complexes. Previous results from our lab have shown that osmolytes preferentially aggregate viruses while leaving proteins in solution. This action by osmolytes can be used to preferentially aggregate virus-AuNP complexes as compared to potential contaminating protein-AuNP complexes in our assay.

Our assay was tested with a non-enveloped porcine parvovirus (PPV) and an enveloped bovine viral diarrhea virus (BVDV). The viruses bind to the AuNPs through electrostatic interactions, forming a complex that can be quantified by dynamic light scattering (DLS). We induced aggregation of the virus/AuNP complexes with glycine and mannitol. Results have shown that both viruses can be detected using DLS by comparing the hydrodynamic diameter of the virus-AuNP complexes before and after osmolyte-induced aggregation. PPV was detected with a limit of detection as low as 5.0 log₁₀ MTT₅₀/mL, and the limit of detection for BVDV was 4.7 log₁₀ MTT₅₀/mL. The presence of BSA in the PPV solution did not change the detection of the virus. The next step in optimizing our assay is to vary the size ratio between the virus particles and AuNPs to find an optimal ratio for binding between the two particles leading to an increased DLS signal and lower limit of detection. An optimized AuNP assay will be used to confirm virus presence in a spiked saliva sample or donated blood.