Hepatitis B virus (HBV) chronically infects more than 250 million people worldwide and causes 680, 000 deaths annually due to liver failure and hepatocellular carcinoma (HCC). HBV core protein allosteric modulators (CpAMs) disrupt HBV capsid assembly by interacting with the hydrophobic interface of core protein (Cp) dimers, the building block of HBV capsid. This project intended to establish an in vivo capsid assembly assay, to further understand the mechanism of HBV capsid assembly through interaction between CpAMs and Cp dimer. To this end, the capsid assembly in E. coli and mammalian cells were studied through native agarose gel electrophoresis-based particle gel assay. The results emphasize the necessity to dismiss confounding effects. C-terminally His-tagged wild-type HBV Cp were successfully overexpressed in E. coli, and purified through affinity column chromatography.