Specific Detection of Infected Cells using Optical Drag-Tags in Laser Force Cytology

Performance Period: 10/1/2020 to 1/31/2022

This proposal aims to use a generic, label-free approach to assay cultured cells in-process during viral vaccine production for extent of infection based on laser-force cytology (LFC). LFC has no requirement for the use of specific probes, giving a general test of viral infectivity, and has been applied to viral infectivity and in-process measurements in vaccine production. This particular application presents challenges; one is that the cells need to be isolated from microcarriers for LFC analysis and another is that any infection by adventitious agent (AA) needs to be discriminated from infection by the production viral carrier (VC).

We will address these by implementing a microfluidic device to isolate cells from microcarriers and by quantifying levels of AA and VC in spiked bioprocesses using high-affinity nucleic acid probes in a rapid, high-sensitivity form of electrophoresis (micelle-tagging electrophoresis, MTE). This information will be fed into a mathematical model of infection progress to better predict the concentration of infected and non-infected cells at time points and maximize the sensitivity of LFC. We will also demonstrate the effectiveness of LFC for non-viral biomanufacturing processes, and to establish MTE as a rapid and quantitative means to assay viral capsids in bioprocesses.