Steric Exclusion Chromatography (SXC)
Single-use universal purification method for virus particles
What is it?
In order to ensure their safety and potency, virus products have to be purified to extremely high standards.
Chromatography is one of the few purification techniques that can be used for commercial production thanks to its superior scalability, cost-efficiency, and robustness.
However, traditional chromatography was originally developed for protein purification and is extremely inefficient for virus particles. In order to meet the current and future demands of viral gene therapy products, new more efficient purification technologies are urgently needed.
We have developed a membrane-based steric exclusion chromatography (SXC) purification method that thanks to its size-based selectivity and typically high product yields above 95% is superior to currently used purification alternatives.
Membrane-based SXC uses a low-cost porous membrane to concentrate, purify, and buffer exchange a wide variety of viruses relevant in gene therapy and vaccine applications.
Our Approach to SXC
In membrane-based SXC, an unpurified suspension containing virus particles is mixed with a solution of polyethylene glycol (PEG) and this mixture is fed onto a chromatography column that contains inside a hydrophilic porous membrane.
The virus particles are captured and purified inside the column thanks to the presence of the PEG, while smaller impurities such as cell DNA, proteins, and media components are not affected by the presence of the PEG and are washed away from the column.
After the impurities have been washed away, the virus particles are recovered by washing the column with a solution not containing PEG, thereby disrupting their interaction with the porous membrane.
Finally, a concentrated and purified solution containing the virus particles is obtained.
Typical Purification Performance with Our System
doses of attenuated yellow fever vaccine
in less than 3 hours
AAV viral genomes (vg)
from 250 mL of supernatant
in 45 minutes
doses of inactivated influenza vaccine
in 20 minutes
total protein clearance
cell DNA clearance
Tested for several viruses and their different strains/serotypes
Our Membrane-based SXC offers the following benefits over existing virus purification technologies:
Higher product yields
20–50% higher product yield compared to other chromatography methods and resins mean less wasted product and smaller columns needed for purification.
One-size-fits-all purification solution
Our capture chromatography uses a single recipe for a wide variety of virus classes and serotypes, thus significantly shortening process development times while simultaneously ensuring high product yields.
Flow-rates are 10–20× higher compared to bead-based matrices.
A membrane matrix avoids performing and validating packing procedures, shortening process times and avoiding delays.
Avoids impurity carry-over and cross-contamination.
Reduces CapEx and OpEx.
Increased product stability
Unlike other methods such as ion exchange chromatography or affinity ligands, product load and recovery in SXC are performed at physiological pH and salt concentrations, greatly reducing the risk of losing the biological activity of the product.
Unlike ultracentrifugation or bead-based size exclusion chromatography, SXC is not restricted by sample volume and can be used from lab to manufacturing scale, eliminating the need of changing/revalidating processes at larger scales.
Higher Robustness & Reliability
Lower susceptibility to matrix damage (e.g., breakage using monoliths) reduces the risk of unexpected process interruptions and delays.
Size-based purification unlike affinity ligands that are serotype-specific or can show great variability across serotypes.