Real-time monitoring of attenuated cytomegalovirus using Raman spectroscopy allows non-destructive characterization during flow

Abstract

Real-time monitoring of viral particles can have a crucial impact on vaccine manufacturing and can alleviate public health by supporting continuous supply. Spectroscopic methods such as Raman spectroscopy can provide rapid and non-invasive measurements. Here, we have developed a Raman spectroscopy-based tool to monitor the quality and quantity of viral particles in a continuous flow set-up. The attenuated human cytomegalovirus (CMV) is characterized across a wide range of concentrations (4.50 x 109 to 2.90 x 1011 particles/mL) and flow rates (100 {micro}m/s to 1000 {micro}m/s) within a square quartz capillary. This process analytical technology (PAT) tool enables the detection of viral particles even at high flow rates such as 1000 {micro}m/s. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and dynamic light scattering (DLS) demonstrated that the samples maintain their integrity even after laser exposure, reiterating the non-invasive nature of Raman spectroscopy. To the best of our knowledge, this is the first report on characterizing CMV particles using Raman spectroscopy. We have also demonstrated the limit of detection (LoD) (2.36 x 1010 particles/mL) for CMV particles in continuous flow (via the Raman spectroscopy method) by addressing the effect of flow rate, concentration, and integrity of samples. This technology could enhance our understanding of the quality control in bio-manufacturing processes required in vaccine production.