<![CDATA[Media City - Updates]]>Fri, 29 May 2026 12:17:05 +1000Weebly<![CDATA[Diganosing common challenges when going serum free]]>Wed, 20 May 2026 10:05:24 GMThttps://www.mediacityscientific.com/updates/may-20th-2026So, you want to grow your cells without fetal bovine serum? Be prepared to account for ALL of the myriad roles this golden cow elixir is currently playing in your cell culture.

Here are just a handful of the many roles FBS is playing:

Driving adhesion: Fibronectin and vitronectin are the key proteins found in serum which coat plastic surfaces and help cells stick. Remove serum and many adherent cell types won't attach.

Failure mode: Wonky, raised morphology or floating cells. This commonly reads as a viability issue, when you actually may be really close and just need to start coating your plates with adhesion protein.
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Delivering proliferation signals: Serum contains a complex, variable mixture of growth factors at biologically active concentrations. Different cell types often require different signals.

Failure mode: Slowed growth, usually within a few days.
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Buffering & antioxidant activity: Serum contains a variety of antioxidants which stabilise the culture environment. Without these agents, oxidative stress accumulates.

Failure mode: poor cell health, which worsens if your cells are seeded at lower-than-optimal densities.
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Source of lipids: Many cells need exogenous lipids, and yet lipids are nonexistent in most basal media.

Failure mode: This usually shows up after 3-5 passages, after intracellular stores have been depleted.
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Source of trace elements and hormones: These are present in serum at concentrations that are often important for primary cells and differentiation-sensitive applications.

Failure mode: Cells grow but behave differently, for example unexpected differentiation or altered morphology.
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Provides a carrier protein system: This allows fatty acids, hormones, and other small molecules to be shuttled in and out of cells.

Failure mode: This one usually shows up pretty quickly.
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A serum-free medium that addresses all of these simultaneously, and appropriately for a broad range of cell types is quite challenging to formulate. I’d know!

However, media development can be fairly efficient if you’re focused on one specific cell type. And what I find particularly interesting is that when an adaptation process goes wrong, the failure mode can actually be quite diagnostic if you know what to look for.

Somewhat forwards planning, but I'll be going deeper on all of this in a free seminar scheduled for August. We’ll chat about what a well formulated serum free system actually needs to do, plus how to troubleshoot each of these functions. (Big thanks to Sarah Farrow for suggesting this!)

You can register here: https://lnkd.in/gpJqgbJK]]><![CDATA[Troubleshooting tips for serum free media]]>Fri, 24 Apr 2026 01:31:20 GMThttps://www.mediacityscientific.com/updates/troubleshooting-tips-for-serum-free-mediaSo, you've moved your cells to a serum-free media and now they look bad. Been there 🙃 Here's what to check first, because your cells' disapproval might have nothing to do with the cell culture media formulation you've chosen.

1. Remove or reduce antibiotics by 5-10x

FBS binds and sequesters common cell culture antibiotics, so the activity level in culture is reduced compared to serum-free cultures. "1X" antibiotics in serum-free culture might impact your cells more than you'd expect.

2. Gentle passaging wins

FBS covers all manner of cell culture sins. Serum-free cultures often require gentler handling; minimise exposure to passaging reagents, keep cells and wash media warm, and try Accutase or TrypLE over trypsin. Trypsin also isn't inactivated by most serum-free media, so something to keep in mind!

3. Adaptation has an impact

Weaning cells gradually into a new media is gentlest on the cells and typically recommended. If using a direct adaptation process, move the cells into their new media when they aren't facing any other kind of passaging or thaw-related stress. For adherent cells, this means letting the cells attach to the plate and enter the exponential growth phase before performing a 100% feed to new media.

4. Adherent cells lifting up from the surface, looking like a viability issue? Rule out an adherence issue before playing with the media formulation.

Impaired attachment or spreading can very, very easily read as a viability issue, but requires a different trouble-shooting approach. Look for debris, check viability empirically, and consider eliminating FBS for the first time mid-passage, so (as much as possible) you can decouple the impacts of the media on viability/cell growth versus on attachment.

Not totally comprehensive, but the check list I wish I had when I started working in serum-free media dev ~6 years ago!]]><![CDATA[What causes FBS colour differential?]]>Wed, 15 Apr 2026 02:41:25 GMThttps://www.mediacityscientific.com/updates/what-causes-fbs-colour-differentialFetal bovine serum is this rather quite pretty reddish-amber colour, but most scientists don't think about its color much, except along one of two lines of thought: 1) "yep, checks out, it's a blood product" or 2) "this FBS looks weird, what's going on?"

We run into this when I drop off bottles of FRS Pioneer to research institutes for their regular FBS batch testing ritual. FRS is clear, so unfortunately it's not exactly a blinded head-to-head comparison.

The colour of FBS comes down to hemoglobin and its breakdown products. These heme-derived pigments carry over from blood collection and processing, which can vary from batch to batch. Because it’s commonly used as a processing quality indicator, certificates of analysis often flag FBS hemoglobin content. The same is not true of most sources of variability in FBS.

These variability sources range from the well-known, for example growth factor concentration variability, but extends to protease inhibitors, oxidant capacity, miRNA-containing extracellular vesicles, and dozens of other parameters which modulate cellular biology in completely unaccounted for ways that most scientists never ever think about, let alone record in the methods section of xyz journal.

So you've got some options. Moving to 100% chemically defined media eliminates this variability entirely, but FBS reduction also has a meaningful impact. The research institutes we work with are typically considering reduction of standard FBS concentrations down to 1–2%, and at that level you've already cut a significant fraction of the batch variability.

Plus much as we all love our ritual FBS batch testing processes, wouldn't it be even lovelier if it happened once a decade?

As always, journal articles below if you're keen to dive deeper!

FBS batch variability - https://www.sciencedirect.com/science/article/pii/S3050620425000429

Protease inhibitor deep dive and sources - https://www.linkedin.com/posts/kathleenbashantday_most-scientists-dont-think-about-this-but-activity-7416587209304203264-XT5T?utm_source=social_share_send&utm_medium=member_desktop_web&rcm=ACoAABxyS3cBZRJoB-cKhs2ybXkT-p4uHHtCnJk

miRNA extracellular vesicles deep dive and sources - https://www.linkedin.com/feed/update/urn:li:activity:7431801402559209472/?originTrackingId=MQz2KBX26vsc%2FLqOCAlJsA%3D%3D



]]><![CDATA[Early Momentum]]>Wed, 01 Apr 2026 05:29:36 GMThttps://www.mediacityscientific.com/updates/early-momentumBehind the scenes of building a biotech company: It’s been about 6 weeks since we’ve started shipping out our chemically defined FBS replacement every Monday.

We ship, I refresh my tracking app incessantly throughout the week, and we learn new things about new countries' import processes every single week. On the upside, I came into this accustomed to Australian import (one of the more complicated bars), so things have been smooth sailing more often than not.

The real world humbles us but also enthuses us. User guides get improved to prevent mistakes during onboarding. We publish new data on our website showing the limits and capabilities of the product. Folks have success with new cell lines and we add them to our tally.

In the background, we pull together application notes for fully chemically defined primary cell culture and operationally easy adherence in serum-free systems. We fall into a regular manufacturing and QC cadence; it’s boring and predicable, just the way I like my manufacturing processes.

In a few months, we’ll know even more about product performance and edge cases. We’ll start sending product to distributors globally, to make FRS more accessible to folks outside Australia. We’ll scale up the size of each manufactured batch.

And I guess that’s how a “real company” is born. Only took a few years!]]><![CDATA[Cell Culture Trends]]>Wed, 25 Mar 2026 11:32:05 GMThttps://www.mediacityscientific.com/updates/cell-culture-trendsTrends I’m seeing in the cell culture space lately:

→ AI meets biology is accelerating the already-in-progress trend towards chemically defined research tools. This is logical. If you’re training models using cell culture data, you want the inputs as clean and consistent as possible. For example, this makes the variability introduced by FBS more noticeable as well as problematic.

→ Completely anecdotal but there seem to be some bad batches of FBS circulating. I’m hearing from scientists who have used fetal bovine serum for years, but suddenly - despite certificates of analysis and in-house batch testing - their latest batch is testing positive for problematic viruses or has heavy precipitation/flocculants.

→ Cell culture media optimisation platforms are becoming more and more advanced. The result is highly specialised cell culture media built for specific cell types allowing for faster proliferation rates, cheaper costs per liter, and higher densities than ever.

→ Despite these advanced cell culture media, there are plenty of scientists looking for “this is easy to use and it grows the six different types of cells that my lab grows” instead. Knock out serum replacement (KSR) seems to be the best known "serum replacement", which is kind of interesting because it was designed primarily for pluripotent stem cells and usually doesn’t substitute well for serum in most other cell types.

→ In this vein: there’s increasingly a natural split between “exploratory biology media” and “production media.” Highly optimized, specialised media are necessary for high densities or cost optimisation at huge scales. But for exploratory work, operational simplicity is important; a single formulation that reliably grows a variety of cells and is sufficiently forgiving of handling variation is valuable.

→ Adherence is a sticking point (hah, I amuse myself anyway). In most serum-free media systems, coating plates with adherence proteins is the standard. This is operationally annoying relative to culturing adherent cells with serum-containing media. (Let’s do something about this, why don’t we? 😉)]]><![CDATA[FRS Pioneer in NZ]]>Thu, 05 Mar 2026 06:36:22 GMThttps://www.mediacityscientific.com/updates/frs-pioneer-in-nzHey New Zealand scientists, FRS Pioneer is travelling across the ditch!

This year, Beyond Animal Research is supporting NZ scientists in accessing Media City Scientific’s FBS replacement. The first shipments have already landed on NZ soil and we’ll be working together to develop additional case studies showing how scientists can easily replace FBS with a chemically defined, animal-origin-free alternative for cell culture or cryopreservation.

Being animal free AND being able to reproducibly control exactly what’s in your cell culture media makes this a win-win for everyone. Thanks Tara Jackson and the BAR team for making this happent!

Are you a NZ scientist keen on using FRS Pioneer in your research or teaching? You can get involved by emailing admin@beyondanimalresearch.org.nz.

Cheers ☺️
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]]><![CDATA[The role of antioxidant buffering]]>Tue, 03 Mar 2026 09:24:37 GMThttps://www.mediacityscientific.com/updates/the-role-of-antioxidant-bufferingMost cell culture troubleshooting focuses on what you might be doing wrong, while less attention goes to what FBS is correcting for in the background. That's something worth understanding when a batch behaves unexpectedly, or when you try to replace FBS entirely.

FBS is a remarkably effective antioxidant buffer. Not because it was human-designed to be so; it's a biological fluid, it just comes that way. But that function matters and it's almost never replaced when scientists DIY a serum-free cell culture media.

Most scientists think of FBS mostly as a source of growth factors and nutrients, but it also contains a sophisticated antioxidant pool that buffers the oxidative environment your cells are living in. Most serum-free formulations replace some of this, usually in the form of albumin, transferrin, and a selenium source, but there's considerably more to antioxidant buffering than that.

Strip out the wider pool without replacement and subtle shifts in ROS levels start affecting mitochondrial function, altering proliferation rates, and in sensitive cell types pushing cells toward senescence prematurely. These aren't dramatic phenotypes and you probably won't notice them immediately under the microscope. Instead, they usually show up as variability.

I frequently joke that FBS covers all manner of sins. It's forgiving in part because its antioxidant buffering absorbs a lot of handling variation: trypsin left on slightly too long, feeding with cold media, a suboptimal seeding density, media that's been in the fridge a month. But that buffering capacity isn't consistent between batches. Albumin, transferrin, selenium, tocopherols, and others - these are all biological and fluctuate with the source animal's condition, age, and processing. It's also a parameter that's not usually measured during batch testing.

Defined media tends to be more honest, because it reflects exactly what you give it. This is a real advantage, but only if the antioxidant pool has been engineered carefully. Get it wrong and you've traded one source of variability for another, potentially more confusing one.

This is why we spent a full year in external pilot testing before bringing our chemically defined FBS replacement to market, including trialing with students. We saw what happened when different passaging reagents, seeding densities, experience levels, and protocols were applied to one reagent. Some things broke. We made the product more robust wherever we could, and where specific handling processes were necessary, we documented it clearly. A formulation that can't handle real-world variation has no business replacing something as forgiving as FBS.

​Takeaway: antioxidant buffering is one of the most overlooked variables in cell culture, whether you're troubleshooting batch-to-batch inconsistency in FBS or building out a serum-free formulation. Something to pay attention to! And as always, more reading below if you want to dive deeper 😊

Roche M et al. (2008) covers the antioxidant properties of serum albumin - https://pubmed.ncbi.nlm.nih.gov/18474236/

Barry Halliwell has written extensively on ROS, Fenton chemistry, and biological antioxidant systems. His work is definitely some to check out if you’re interested in this space! One of his papers to get you started: https://www.sciencedirect.com/science/article/pii/S0014579303002357
]]><![CDATA[FBS contains bovine extracellular vesicles, loaded with bovine-derived miRNAs!]]>Tue, 24 Feb 2026 09:40:56 GMThttps://www.mediacityscientific.com/updates/fbs-contains-bovine-extracellular-vesicles-loaded-with-bovine-derived-mirnasHere’s something fairly uncomfortable to consider if you regularly culture cells with fetal bovine serum: there is a whole lot of cow protein and genetic material in that golden elixir, and the implications of this scientific reality are still being worked through.

Let’s zoom in super niche for a moment: FBS contains bovine extracellular vesicles, loaded with bovine-derived miRNAs. When you culture cells in FBS-containing media, those vesicles can be taken up by your cells. In some systems, their miRNA cargo has been shown to alter gene expression.

Here’s why: miRNAs are potent post-transcriptional regulators. A single miRNA can suppress a whole network of targets. Many bovine and human miRNA sequences are similar in the specific stretch of sequence that determines which genes they bind to. As a result, bovine miRNAs have been shown in some systems to engage human gene regulatory pathways after uptake from serum-derived vesicles. How strong or consequential that effect is in your specific model is almost never validated when changing batches of FBS.

For most routine cell culture, this is arguably background. But there are contexts where it may matter more: RNA biology experiments, EV research, gene expression studies, or any work where you’re trying to attribute a transcriptional phenotype to a specific treatment. In these cases, you may have an additional source of regulatory RNA entering your cells from your media. Unfortunately, it's one rarely flagged in the methods section.

The extracellular vesicle (EV) research community has been aware of this issue for some time; EV-depleted serum became common practice in that field for good reasons, even though depletion methods don’t fully eliminate bovine EVs. The implications may extend beyond EV workflows, and yet they’re almost never discussed outside that context.

This is one dimension of what “FBS batch variability” can mean biologically. Scientists usually focus on growth factor concentrations or adhesion proteins varying between lots. But variability extends to differences like this as well - differences most scientists have never even thought to consider, much less one quantified across batches.

Just something to think about, particularly if you’re validating a new lot of FBS and running sensitive transcriptional experiments. Exosome-depleted FBS can help reduce this variable, or a chemically defined alternative can eliminate it altogether.

Anyway. One more reason "the same experiment, same results" thing doesn't always pan out 🙃.

As always, literature below if you want to dive deeper!

Wei et al. demonstrates RNA present in fetal bovine serum contaminates extracellular RNA analyses and can be misattributed to cultured cells.
https://www.nature.com/articles/srep31175?

Beninson & Fleshner show experimental evidence that exosomes present in FBS can influence cell behaviour in vitro, specifically demonstrating suppression of macrophage inflammatory responses. https://www.sciencedirect.com/science/article/abs/pii/S0165247814002387?via%3Dihub

Urzì et al. is a great review detailing how FBS-derived extracellular vesicles and RNA complicate EV studies. https://pubmed.ncbi.nlm.nih.gov/36214482/
]]><![CDATA[Confusing Terminology]]>Mon, 23 Feb 2026 00:23:06 GMThttps://www.mediacityscientific.com/updates/confusing-terminologySomething that annoys me to an arguably irrational level about the “serum-free media” space is how confusing the vocabulary gets once you start digging.

I’ve lived and breathed this stuff for the better part of a decade, and it still sometimes takes me a beat to understand a serum-free supplement.

You see these words everywhere: Serum-free. Animal-free. Chemically defined. Reproducible alternative to FBS.

A quick Google and you’d be forgiven for thinking there are a wide variety of equivalent, high-quality serum replacements out there. But these words can be layered together in ways that blur real scientific differences.

First, some formulations simply replace FBS with another complex biological supplement. This is a reasonable strategy; for example, replacing FBS with human platelet lysate in cell therapy manufacturing to reduce cross-species risk. But you still have batch-to-batch variation.

”Animal-free” removes animal origin risk but can include other undefined extracts. Love this for ethics or regulatory positioning. It's less useful for having control over what’s in your media or batch reproducibility.

“Reproducible alternative to FBS” has given me the ick several times. I’ve seen this wording, dug into the supplement, then realized it isn’t chemically defined in the slightest. There may be process consistency or tighter QC than raw serum but if the inputs are undefined, reproducibility has a ceiling.

“Chemically defined” is the gold standard. Every component and concentration is known. This one tends to be safer, but there are levels. You’ll sometimes find purified bovine serum albumin or similar components, despite the fact that albumin is serum-derived and carries residual batch variability depending on purification and lipid loading.

To be clear, this is how the category evolved rather than a criticism of any specific product, and perfect shouldn't be the enemy of good.

People come to me because they’re over FBS for a lot of different reasons: Ethics. Reproducibility. Regulatory risk. Cost.

Most existing serum replacements were designed to tackle one or two of these, not eliminate all of them simultaneously - fair.

Still, when we built our replacement, we were deliberate about the vocabulary: fully chemically defined and fully animal-free, designed for reproducibility.

I am regularly challenged on these terms by people who’ve been burned before - by products that were "reproducible" but not defined, or animal-free at the product level but not across the supply chain. And frankly, I love it, because I know our language matches the technical reality.

The goal has always been to provide an alternative that can realistically compete with FBS on price, sustainability, regulatory AND experimental control/reproducibility across time, labs, and geographies.

This vocabulary, and how we use it, matters a lot if we as scientists want to achieve that.]]><![CDATA[How will you use FRS?]]>Tue, 10 Feb 2026 10:09:38 GMThttps://www.mediacityscientific.com/updates/how-will-you-use-frsTo help prospective customers quickly understand the breadth of what FRS Pioneer can do, we've put together this helpful diagram. As always, please get in touch if you have any questions about using FRS Pioneer in your laboratory.
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