By Will McElroy, Chris Heger, and Julie Yu Wei
Viral capsid content can impact gene therapy product efficacy and is therefore considered a Critical Quality Attribute (CQA) that must be properly evaluated during the development and manufacturing of AAVs. Traditional analytical tools such as transmission electron microscopy (TEM), analytical ultracentrifugation (AUC), and ion-exchange chromatography (IEX) can be used to characterize capsid content but are complex, labor-intensive, and pose challenges in data reproducibility, throughput, and scalability.
In this application note, we show how imaged-capillary isoelectric focusing (icIEF) technology on Maurice can be used to characterize empty, intermediate and full AAV capsids at native and stability screening conditions, providing robust and reproducible data. With Maurice’s absorbance and native fluorescence detection, AAV capsid content can be assessed with accuracy and reproducibility, while providing ease-of-use, short run times, and low sample volumes. This study demonstrates how a single method for AAV characterization was developed and used to test full, intermediate, and empty AAV8 samples. The absorbance and fluorescence detection modes yielded critical information on DNA content in capsids. Furthermore, the method was found to be stability-indicating and clearly showed the degradation of AAV8 samples under various stress conditions. With Maurice, we are able to quickly develop a method to characterize and assess the stability of empty, intermediate, and full AAVs, providing a critical, high-quality solution for safe, fast, and effective gene therapy development.