Comprehensive Comparison of AAV Purification Methods: Iodixanol Gradient Centrifugation vs. Immuno-Affinity Chromatography

Figure 4

Transmission electron micrographs of AAV8 purified by iodixanol gradient centrifugation (a) or by POROS AAVX column (b). Both samples were imaged at 5E9 vg/μL with a negative stain. More impurities were identified from iodixanol gradient centrifugation (a) including ferritin, as indicated by white arrows, as identified by previous studies [14]. Empty capsids—indicated by yellow arrows—were observed as denser virions from affinity column purified vectors (b). The empty capsid amount was estimated and shown on the lower panels. Black arrows indicate full capsids; scale  nm.

(a) AAV8 IOD

(b) AAV8 POR