iPSC-derived microglia: the medium is the specification

The buying problem with microglia is that the product you receive is not finished. Every other cell type on this catalogue arrives as a thing with properties. Microglia arrive as a thing whose properties are set by what you put them in, and the supplier’s marker data was generated in one specific medium that is sold, priced and shipped as a separate line item.

At Axol that separation is visible on the invoice: the cells are $1,043.00 and the medium and supplement kit that the datasheet performance depends on is $515.00, captured live from the public store API on 2026-09-01. A buyer who orders the cells alone has bought roughly two thirds of the product.

The price table

Two suppliers publish a number and they price the category on completely different logic. Axol prices a vial of cells and a bottle of medium as two products. bit.bio prices viable cells in packs and does not vary the number by engineering.

Read the count convention before the price

The per-million column above is arithmetic on numbers the suppliers state, and the numbers do not mean the same thing.

bit.bio quotes viable cells. More than 1.5 million viable cells per vial, two vials per pack, is a claim about what survives the thaw. That is the harder claim to make and the one a buyer can plan against.

Axol quotes a minimum vial content of at least 1 million cells. The per-million figure is therefore an upper bound on the unit cost rather than a measurement, which is why the table shows ”≤$1,043” instead of a number pretending to be exact.

The comparison across those two conventions is not clean, and no amount of arithmetic makes it clean. What can be said is narrow and worth saying: at the stated counts, bit.bio’s per-million figure is roughly a third of Axol’s, and the gap is large enough that it survives any reasonable assumption about post-thaw loss. It is not a like-for-like comparison of two identical products, and anyone presenting it as one is selling something.

The pack curve that does not curve

Volume discounting is the default assumption in cell procurement and it is wrong here.

bit.bio’s small ioMicroglia pack is 999 for two vials of more than 1.5 million viable cells each, which is roughly 333 per million. The large pack, io1029L and io1021L, is 3,330 for two vials of more than 5 million viable cells each, which is exactly 333 per million.

Buying ten times the cells buys ten times the cells and nothing else. There is no volume tier, no per-million reduction, no reward for committing to a larger order. That is the opposite of how pack pricing behaves at nearly every other supplier in the cell catalogue, where the step from a one-million vial to a five-million vial is where the real saving sits.

The practical consequence is that pack size becomes a purely logistical decision rather than a financial one. Buy the large pack when you would otherwise thaw four small vials and want to avoid four independent thaw events introducing four sources of variance. Buy the small pack when you want the option of stopping after one experiment. Neither choice costs you anything, which is unusual enough to be worth knowing.

The 30 percent disease uplift is flat, and the engineering premium is zero

Two pricing patterns in this catalogue are worth extracting because they invert what buyers expect.

Engineered backgrounds carry no premium. The GFP reporter line (io1096S), the CRISPRko-Ready line (io1094S), the CRISPRa line (io1102S) and the CRISPRi-Ready line (io1103S) all sit at 999, the same as wild type. A reporter line and a CRISPR-ready line normally cost more than the parent, and here they do not. If your experiment would benefit from a reporter or from a line already configured for knockdown or activation, there is no budgetary reason to compromise.

Disease and knockout lines carry a flat uplift regardless of gene. APOE 4/4, APOE 4/3, TREM2 R47H homozygous, TREM2 R47H heterozygous, and the GPNMB and P2RY12 knockouts are all 1,298 against 999, which is a 30 percent uplift applied uniformly. The pricing tells you the uplift is a manufacturing and characterisation overhead rather than a scarcity signal. A rarer variant does not cost more than a common one.

That flatness matters for experimental design. An allelic series costs exactly what its member count implies. TREM2 R47H/WT alongside TREM2 R47H/R47H alongside wild type is three SKUs at 1,298, 1,298 and 999, and the heterozygote is not penalised for being the less-requested line. Buyers routinely drop the heterozygous arm to save money on the assumption that it will be expensive. Here it is not.

The published literature makes the heterozygote worth keeping. Work on TREM2 R47H in human iPSC-derived microglia has characterised the variant’s effect on purinergic receptor-mediated calcium signalling and motility (PMC8906810) and described a locked immunometabolic switch underlying loss of function (PMC7027848). Dropping the heterozygous arm removes the ability to say anything about dosage.

Medium is a specification, not an accessory

This is the single point on which microglial purchases go wrong most often, and it is the reason this page opens where it does.

Microglial identity in culture is not stable in the way that a cardiomyocyte’s is. It is set by the signalling environment, and a defined medium is what holds it. A characterisation of microglia in a defined medium published in Frontiers in Cellular Neuroscience (PMC7025516) documents functional and metabolic properties as a function of the medium, and a 2026 comparative lipidomics study of iPSC-derived microglia protocols in Stem Cell Reports (PMC12903089) reports lipid droplet and immune differences between differentiation protocols. Those are two independent statements of the same practical fact: what you grew them in and how you made them are variables in your result.

The procurement consequences follow directly.

The datasheet holds only in the datasheet’s medium. A supplier’s marker panel was generated under one condition. Substituting a cheaper medium does not give you the same cells at a lower price; it gives you a different phenotype and no supporting data.

Cross-supplier medium substitution is a design change. Running bit.bio cells in Axol’s medium kit, or either in a home-made formulation, voids the comparison to both datasheets. If you must do it, characterise it yourself and treat the result as your data, not theirs.

Price the medium into the cell cost. At Axol the standalone kit is $515.00 against $1,043.00 for the cells. Comparing $1,043.00 to bit.bio’s pack figure while ignoring the medium compares two thirds of one product against another.

The wider context is that even primary human microglia are not phenotypically fixed. A large transcriptomic analysis across brain regions, ageing and disease pathologies (PMC9245609) documents how much the human microglial transcriptome varies with region and condition. There is no single correct microglial state to be matched to, which is precisely why the culture condition has to be stated in the methods and held constant across arms.

Where the Axol bundle is genuinely the cheaper purchase

Kit SKUs are usually a convenience premium. This one is not, and it is worth naming because it is rare.

All three figures are Axol store API captures of 2026-09-01. Buying the parts costs $234.00 more than buying the whole. There is no scenario in which a first microglial order should be placed as two separate line items at these prices.

The one qualification: if you already hold a validated, in-date bottle of the matched medium, the cells-only SKU is obviously correct. The bundle is cheaper than the parts, not cheaper than parts you already own.

Microglia are almost always a co-culture purchase

Very few laboratories want microglia alone. They want the immune compartment of a neural model, and that reframes the order.

Published tri-culture work combining human iPSC-derived neurons, astrocytes and microglia (PMC13238601) is the shape most buyers are heading towards, and it imposes constraints that a microglia-only purchase order does not capture:

• All three cell types have to arrive in the same week. A microglial vial thawed six weeks after the neurons went down is a different experiment from one thawed alongside them.
• One medium has to serve all three populations, or a documented medium transition has to be scheduled. The microglial medium that the datasheet depends on may not be the medium the neurons matured in.
• The ratio is not on any product page. No supplier surveyed publishes a recommended neuron-to-astrocyte-to-microglia ratio as a product specification. That number comes from the published protocol you are following, and it should be fixed before the order rather than after the delivery.

The companion arithmetic is in iPSC astrocytes, microglia and glia, which carries the neuron-to-astrocyte ratios used in published multielectrode array work.

What is not available at any price

Stated plainly, because the absence is a finding:

• No GMP-grade microglia. No supplier surveyed on 2026-09-01 publishes a price for GMP-grade microglia, and we did not find a catalogue listing for one.
• No numeric purity threshold as a release criterion. Suppliers publish marker expression per datasheet. None surveyed publishes a percentage that a lot must exceed to ship. If your protocol needs one, that is a bespoke specification to be negotiated, not a catalogue field.
• No second published price for the engineered backgrounds. bit.bio is the only supplier in this survey publishing a price for CRISPR-ready, CRISPRa, CRISPRi-Ready and reporter microglia. There is no comparator, which means there is no way to tell whether 999 is a market rate.
• No microglia price from iXCells. The iXCells public store API returned no microglia SKU price on 2026-09-01, so that supplier appears in the candidate list without a figure.

QC checklist

Ask for these before the lot ships, not after it thaws.

• Lot-specific certificate of analysis, seen before you commit, not after delivery.
• Post-thaw viability specification and the assay used to measure it.
• The exact medium and supplement formulation the lot’s marker data was generated in, by catalogue number, with the lot number of the medium if the supplier will give it.
• Marker panel actually run on this lot, distinguished from the marker panel shown on the product page as representative data.
• Genotype confirmation for disease and knockout lines, at the named locus, with the method stated. For APOE and TREM2 SKUs this is the specification you are paying the 30 percent uplift for.
• Sterility and mycoplasma release testing per the supplier’s protocol, with the method named.
• Viable-versus-total count convention, stated in writing. This is the field that makes two quotes comparable.
• Shipping format, dry ice or dry shipper, and the receiving procedure it implies. A dry shipper arriving at a site with no liquid nitrogen is a wasted order.
• Storage temperature and the maximum acceptable time between receipt and transfer to storage.
• Passage or differentiation-day at cryopreservation, where the supplier documents it.

Specification checklist for a microglia quote

Send this and the answers become comparable across suppliers.

• Genetic background: wild type, APOE variant with zygosity, TREM2 variant with zygosity, knockout with gene named, CRISPR-ready, CRISPRa, CRISPRi-Ready, or reporter.
• Whether an isogenic comparator is required, and whether it is being ordered at the same time. Ordering the variant now and the control next quarter is how arms end up in different lots.
• Total viable cells required across the whole programme, not the next experiment, stated as viable cells.
• Pack size against that total, noting that at bit.bio the pack size does not change the per-million cost.
• Medium and supplement package, and explicitly whether the quoted price includes it.
• Co-culture partners, neurons, astrocytes, or both, and the delivery week they must share.
• Seeding ratio and plate format, taken from the protocol you intend to follow.
• Currency the catalogue figure will be billed in, where one number is published as valid in three currencies. Confirm this in writing before raising the purchase order.
• Licence terms for anything downstream that will be sold rather than published.
• Required delivery week, and whether a lot is currently in stock or you are waiting on a production run.

Where to go next

Astrocytes, microglia and glia carries the co-culture ratios and the wider glial price table. Astrocyte and glia pricing does the per-million arithmetic across the category. The datasheet for this line, unit, lead time and QC scope, is at ipsc-microglia. The generic version of the questions above is the cell supplier QC checklist.

How we can help

We hold these figures because we re-verify them, and we resell nothing. Tell us the background, the viable-cell count, the co-culture partners and the delivery week, and we will source current quotes, normalise them onto one counting convention, confirm the billing currency in writing, and ask the two questions suppliers do not volunteer: which medium lot the marker data came from, and what the licence permits downstream.

Where the catalogue item is simply the right answer, and for a single wild-type microglial order it usually is, we will tell you to buy it directly.