Rapid monitoring of virus-like particles using an optical biosensor: a feasibility study.

Virus-like particles (VLPs) are multimeric proteins expressed by Saccharomyces cerevisiae. The particles are approximately 80 nm in diameter and they are used as a framework for a range of biological products; for example as carriers of viral antigens. Rapid monitoring of purified VLPs was investigated using an optical biosensor. The aim was to develop an assay which may be employed for real-time bioprocess monitoring of VLPs. Problems of mass transfer of analyte were overcome through selection of a planar biosensor surface, in preference to the traditional polymer-coated surface. To prolong the surface activity for interaction analysis, a sandwich assay was developed which involved the use of a secondary capture species. It was shown that VLP concentration in pure solution could be determined within 10 min.