(191cd) Colorimetric Virus Detection Using Gold Nanoparticle Aggregation

Recent studies have shown that the plasmonic shift caused by the aggregation of gold nanoparticles (AuNPs) can be applied to virus detection. A typical biochemical detection involves either antibodies for capturing virus capsid proteins or complementary oligonucleotides for detecting virus nucleic acids. The antibodies and oligonucleotides are very expensive, have limited chemical stability, and can only detect one specific type of virus at a time. Therefore, the use of AuNPs red-shift to detect the presence of virus without the need of expensive antibody or oligonucleotides functionalization has drawn our interest.

Our model virus porcine parvovirus (PPV), can be non-specifically adsorbed to AuNPs to form a virus corona. The AuNPs coated in virus have a measurable aggregation when osmolyte is present as compared to AuNPs coated in model protein bovine serum albumin (BSA) and exposed to osmolyte. Osmolytes are natural, organic compounds that are found in many organisms. Our lab has shown that osmolytes preferentially flocculate both an enveloped and non-enveloped virus but not model proteins. In order to create a quick, sensitive, inexpensive and portable method for detecting the presence of viral particles, we are employing the preferential flocculation of virus particles with osmolytes in the presence of AuNPs.

To distinguish the aggregation of AuNPs with virus solutions from that with BSA, solutions at various ionic strengths and with different concentration of osmolyte solutions was explored. Glycine at 1 M can be used to distinguish the AuNP aggregation of coronas formed from PPV and BSA. Lower ionic strength buffer used for corona formation give the largest difference between BSA and PPV. In addition, the key parameters that increase the sensitivity and decrease the limit of detection of PPV will be discussed. This unique method can easily be transferred to other virus systems and be used in the detection of norovirus on cruise ships.