How a lot gets made, and what we keep on record.
Every SKU in the catalog traces back to a documented run, expressed, purified, formulated, and filled at our own facility in Cambridge, MA. This page walks the process end to end, for recombinant proteins, media, and resins, and explains what a lot number actually encodes.
Every lot on this site is expressed, purified, formulated, and filled under one roof at our Cambridge facility, not contracted out to an overseas manufacturer and relabeled. That matters less as a slogan than as an operating fact: it changes lead time, it changes what a cold-chain shipment has to survive, and it changes who picks up the phone when a lot needs a second look.
Made-to-order SKUs quote in days, not the six-to-ten weeks a transoceanic shipment adds before it even clears customs. The bottleneck is the purification train, not a customs broker.
A dry-ice shipment loses its margin the moment it sits on a tarmac. Every order here starts and ends its cold-chain leg on the same continent, often the same time zone, instead of surviving two intercontinental transfers before it reaches your bench.
The scientist who ran your purification and the QC team who released it work down the hall from the person who answers support@bramantebio.com. If a lot ever needs a second look, you're talking to someone who was in the room.
Because expression, purification, and fill all happen under one roof in Cambridge, a non-standard pack size or a formulation tweak is a scheduling conversation, not a renegotiation with an overseas contract manufacturer.
Express
Host per construct: E. coli (typically BL21(DE3)) for simple cytokines and growth factors, HEK293 or CHO when glycosylation or a mammalian fold is required.
Capture
Affinity matched to the construct: Ni-IMAC for His, Protein A/G for Fc, heparin or IEX for untagged factors. Most of the volume comes off here.
Polish
A second, orthogonal step (SEC or IEX) clears host-cell protein, aggregate, and endotoxin that survive capture.
Buffer exchange & filter
Exchanged into the final buffer on the datasheet, then 0.2 µm filtered. That filtrate is the finished product.
Fill & freeze
Liquid-filled into plastic vials from the filtrate and frozen at -80 °C. Not lyophilized, so thaw on ice and use.
Base media are formulated to a named recipe, adjusted to the pH and osmolality on the datasheet, and sterilized by 0.1–0.2 µm membrane filtration. Antibiotics and supplements follow the same filtration and fill path in smaller batches.
Filled lots stay in quarantine until sterility (USP <71>-style) and, for animal-cell media, mycoplasma testing come back clean.
A base matrix, typically cross-linked agarose, is chosen for its rigidity and flow properties and for the target format, bulk resin or a prepacked column. The ligand (recombinant Protein A, an anti-tag antibody, a lectin, an ion-exchange functional group) is then covalently coupled to the matrix at a controlled density, because coupling density is what sets the resin’s capacity.
Every functionalized lot is capacity-qualified before release: a reference protein is loaded to 10% breakthrough to measure dynamic binding capacity (DBC, reported in mg protein per mL resin), and ligand leakage is measured by ELISA against the ligand itself, which puts a published ceiling on how much of it ends up in your eluate. The clean-in-place (CIP) regime printed on the datasheet, usually a dilute NaOH exposure with a cycle-count limit, is validated against that same lot, not assumed from the matrix chemistry alone.
Once a batch clears release testing, it’s filled into its final pack sizes, labeled, and cartoned to the cold-chain class printed on the datasheet, ambient, cold-pack, or dry ice. Out-of-spec material is scrapped at this point, not relabeled or blended down.
Every unit carries a lot number. That number is the key into the batch record: it resolves to the specific manufacturing run, the raw materials consumed, the in-process checks taken along the way, and the release QC results, for the exact vial in your hand, not a catalog-wide typical value. That record is what we pull when you request a lot-specific Certificate of Analysis.
- Raw materials
Lot numbers of the expression construct, resin, and formulation buffer components consumed in the run.
- In-process checks
Yield and purity checkpoints taken between capture, polish, and fill, not just the final release assay.
- Release QC
The full identity, purity, endotoxin, activity, and sterility data set described on the Quality page, run against the finished, filled material.
- Disposition
The release decision itself, pass or scrap, signed off against the acceptance criteria on file for that SKU.
The QC that gates release
Acceptance criteria for every assay described above.
Documents →Request a lot-specific CoA
Pull the release record for the lot you have or are about to buy.