Solaris® Protein ABeta

Frequently asked questions

Do I need to filter the feed before loading?

Yes — the feed has to be clarified, as for any chromatography step. Centrifugation followed by depth filtration is the usual route, and it is what protects a column from the debris that drives back-pressure up over a run. Whether you add a 0.22 or 0.45 µm step immediately before the column is a separate decision: it matters most where the narrowest part of the flow path is the gap between packed particles. A 15 µm open channel leaves more margin there, but a feed that has been standing and has begun to precipitate will still cause trouble. Match the filter train to the feed you actually have rather than to the one from the last project — every filtration stage also costs you product through adsorption.

What does “controlled by light, not chemistry” mean in practice?

The ligand carries a photoswitch. Under red light (630 nm) it sits in its high-affinity conformation and binds the target at native pH and ionic strength; a blue-light pulse (480 nm) triggers a reversible isomerisation, the affinity collapses, and the product elutes in the buffer you chose. The release is a physical trigger rather than a change of solution chemistry.

Which buffer do I elute into?

The one your next step wants. Because the release does not depend on pH or salt, the elution buffer is a process decision rather than a constraint imposed by the ligand — which is the point of the technology.

Does this remove the low-pH step from my process?

It removes it from the elution. It does not remove the low-pH viral inactivation hold, which is a separate, validated step in a licensed Fc process and typically the longest acid exposure the product sees. Where a product cannot take that hold either, the inactivation has to be solved on its own terms.

How many cycles has it been demonstrated for?

Over 100 binding and elution cycles with IgG. Performance does decline over that range — the cycle count is what we can verify, and we do not claim more than that.

Is it available for viral vectors?

Not yet. Solaris® Protein A binds Fc. Affinity capture of AAV runs on camelid VHH ligands and lentiviral capture usually on anion exchange, so for vectors the acid problem is real but the ligand does not exist on this platform. Extending beyond Protein A is what the platform is designed for; it is a programme, not a product.

Can I buy it?

Not today. Solaris® Protein A is in Beta evaluation by application. We are open to working with biotech and CDMO partners on application-specific evaluations — what has been demonstrated is the release mechanism with IgG, so a bispecific, an ADC or a vector on this matrix is an experiment we would rather run with you than claim.

How does light-controlled capture scale?

By area rather than by bed depth. The switch only happens where the light arrives, so illumination has to be uniform across the adsorbent — the physical constraint on any photo-controlled chromatography, and the reason the ligand sits on a flat convective monolith rather than in a deep packed column. It is a real engineering boundary and we would rather name it than leave it to a scale-up surprise.

When is light not the right answer?

Most of the time, honestly. If the product aggregates because the eluate sits in acid before neutralisation, faster neutralisation fixes it for nothing. If half a pH unit would be enough, a mild-elution ligand is a drop-in change. Light is worth evaluating when the elution itself is the step limiting the molecule and the milder chemical routes have run out — the full comparison is on our page about eluting from Protein A without acid.