Many CE-based technologies such as imaged capillary IEF, CE-SDS, CZE, and MEKC are well established for analyzing proteins, viruses, or other biomolecules such as polysaccharides. For example, imaged capillary isoelectric focusing (charge-based protein separation) and CE-SDS (size-based protein separation) are standard replacement methods in biopharmaceutical industries for tedious and labor intensive IEF and SDS-PAGE methods, respectively. Another important analytical tool for protein characterization is a Western blot, where after size-based separation in SDS-PAGE the proteins are transferred to a membrane and blotted with specific monoclonal or polyclonal antibodies. Western blotting analysis is applied in many areas such as biomarker research, therapeutic target identification, and vaccine development. Currently, the procedure is very manual, laborious, and time consuming. Here, we evaluate a new technology called Simple Western™ (or Simon™) for performing automated Western analysis. This new technology is based on CE-SDS where the separated proteins are attached to the wall of capillary by a proprietary photo activated chemical crosslink. Subsequent blotting is done automatically by incubating and washing the capillary with primary and secondary antibodies conjugated with horseradish peroxidase and detected with chemiluminescence. Typically, Western blots are not quantitative, hence we also evaluated the quantitative aspect of this new technology. We demonstrate that Simon™ can quantitate specific components in one of our vaccine candidates and it provides good reproducibility and intermediate precision with CV <10%.

The hepatitis B virus vaccine consists of a major surface antigen called HBsAg, which is a lipid‐bound protein that self‐assembles into 22 nm spherical noninfectious virus‐like particles (VLPs). The HBsAg VLP particles are expressed in yeast and have been well‐characterized biochemically and biophysically employing various analytical techniques. In fact, a CZE method has been developed for monitoring process purification of the hepatitis B vaccine. Another CE‐based method, imaged capillary IEF (icIEF) has been used extensively in the field of protein‐based drug development as a tool for product identification, stability monitoring, and characterization. Here we describe the development of the icIEF method using the iCE280 instrument from ProteinSimple for measuring the pI and monitoring the profiles of HBsAg VLP particles. This method was applied to characterize the stability of the HBsAg VLP particles in three different formulation buffers. The results show that HBsAg VLP particles have a pI of 2.7 and it is one of most acidic particles that we have measured by icIEF. In addition to icIEF, we have also employed a CZE method to measure the electrophoretic mobility of HBsAg VLP particles and compared the results with icIEF and dynamic light scattering methods, showing consistent correlation among the three methods in terms of HBsAg VLP particles aggregation.

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