In the rapidly developing field of gene therapy, adeno-associated virus (AAV) represents one of the most prominent and promising platforms for therapeutic application. Different serotypes of AAVs have demonstrated preferences for targeting specific tissues and represent an auspicious approach for delivering genetic information into patients. A critical quality attribute (CQA) of AVVs is their capsid loading because it influences dose and purity. Capsid loading reflects the efficiency of encapsulation of the genetic material into the viral capsid and is defined as the ratio of full to empty particles.
Quantification of capsid loading is an essential aspect of product characterization and can be determined by different analytical techniques, like AUC, SEC-MALLS, and AEX-FLR. AUC remains the gold standard, capable of resolving partially filled capsids in addition to full and empty capsids. SEC-MALLS and AEX-FLR are advantageous because they allow for GMP-compliance and higher throughput.
This paper highlights the importance of quality control strategies for AAVs with state-of-the-art analytical capabilities that can reveal signifificant variations of the quality of commercially available AAV products. For highly parallelized analysis, DLS is a suitable addition to AUC, SEC-MALLS and AEX-FLR to tackle quality control aspects of AAVs.