OSMOLYTE FLOCCULATION FOR VIRUS PURIFICATION AND DETECTION
Caryn L. Heldt1, Xue Mi1, Ashish Saksule1, Pratyusha Paidikondala1, Eugenia Yeo2, James Chen Yong Kah2
1Michigan Technological University, USA;
2National University of Singapore, Singapore
As medicine advances quickly, there is a great need to purify viral particles for medical applications, as well as detect indigenous viral infections to avoid antibiotic use on such infections. Our team as recently discovered that osmolytes (i.e. sugars and amino acids) have the ability to flocculate viruses while leaving proteins in solution. This flocculation by FDA approved compounds has been applied to viral particle purification processes and a gold nanoparticle (AuNP) aggregation assay for viral detection without the use of expensive and short shelf-life immunorecognition elements.
Flocculation is a common purification unit operation of virus species for vaccine and gene therapy applications. However, it is novel to use osmolytes as a flocculant. Both an enveloped and non-enveloped virus can be retained by a 0.1 μm filter after flocculation with 1 M mannitol while proteins are removed. Many different filtration properties were explored to optimize the purification. This is an inexpensive method that could be applied to future vaccine products as more production of vaccines shifts to southeast Asia.
Osmolyte flocculation can also be applied to induce AuNP aggregation and detection. Virus particles that are non-specifically adhered to the surface of a AuNP have a different aggregation pattern upon addition of 1 M mannitol or 1 M glycine than the control protein bovine serum albumin (BSA). The plasmon resonance of the aggregated AuNPs creates a noticeable shift in the UV absorbance, which can aid in the detection of viral particles. This demonstrates that upon osmolyte addition, virus containing solutions can be identified. Future work will explore the effect of other buffer conditions as well as the limit of detection of this virus sensing system.