A Single Platform for icIEF and CE-SDS Analysis of Adeno-Associated Virus (AAV) for Gene Therapy

Adeno-associated viruses (AAV) are promising vectors for the delivery of genetic material in gene therapy. During the manufacture of AAV, critical quality attributes like charge heterogeneity and purity must be carefully monitored because they can impact the products safety and efficacy.

Imaged capillary isoelectric focusing (icIEF) and capillary electrophoresis sodium dodecyl sulfate (CE-SDS) are two powerful methods to respectively characterize charge heterogeneity and purity, but traditionally two separate platforms are required to run these methods. Here, we used a single platform to develop icIEF and CE-SDS methods to analyze AAV2 and AAV6 serotypes to monitor product stability, identity and purity.

We show that these methods could reproducibly quantify both intact (by icIEF) and denatured AAV (by icIEF and CE-SDS) samples. The CE-SDS method could separate and quantify individual AAV capsid proteins, showed robust repeatability (<5% RSD) while also detecting impurities. The icIEF method was useful for measuring both denatured and intact particles with high repeatability (<4% RSD). Interestingly, preliminary evidence suggests that icIEF can also distinguish between full (1 x 10^13 GC/mL) and ‘empty' (<10^12 GC/mL) AAV capsids.