Defined Cell Culture Highlights

Naïve Pluripotency, Cell Therapy Controls, & Organoid Handling

September 21-27, 2026

New research in naïve pluripotent stem cells, cell therapy manufacturing, vascular and pancreatic organoids, image-based culture analytics, and organoid transport showed how culture workflows can be controlled beyond conventional endpoint testing. Media metabolites influenced early cell fate decisions, secreted proteins provided non-destructive process measurements, and physical handling conditions affected organoid quality and function.

Pyruvate metabolism directs naïve pluripotent stem cell fate

A Communications Biology study published September 22 examined the transition of human pluripotent stem cells from primed to naïve pluripotency at single-cell resolution.

The researchers identified two sequential cell fate decisions. The first separated surviving and dying cells during the early transition. Adding pyruvate significantly improved cell survival. A later decision separated cells entering naïve pluripotency from cells adopting extraembryonic lineage-like identities.

Inhibiting pyruvate transport into mitochondria increased the number of naïve colonies. The researchers used these findings to improve protocols for naïve human pluripotent stem cell derivation, maintenance, and blastoid formation.

The study illustrates why metabolic ingredients should not be treated only as energy sources. Pyruvate availability and utilization directly affected survival and lineage choice, meaning that both medium composition and cellular metabolism must be considered when optimizing pluripotent stem cell state transitions.

Read the study here. This article is shared as early access, and may be subject to further edits.

Secreted markers enable non-destructive cell therapy process controls

An npj Regenerative Medicine study published September 22 developed a strategy for monitoring pluripotent stem cell differentiation without removing or destroying the cells being manufactured.

The researchers combined single-cell RNA sequencing with quantitative proteomics across multiple stages of differentiation. They then searched for proteins that were both associated with the desired cellular state and released into the culture medium.

Using pluripotent stem cell differentiation into basal keratinocytes as a proof of concept, the team identified IGFBP6 and tenascin C as informative secreted markers. These proteins could be measured directly in culture supernatant and used to follow differentiation progress.

Most differentiation workflows rely on destructive measurements performed at selected time points. Secreted biomarkers could provide earlier indications that a culture is progressing correctly, drifting from specification, or should be terminated before additional manufacturing resources are used. The general strategy may also be applicable to other adherent cell therapy processes.

Read the paper here. This article is also shared as early access, and may be subject to further edits.

Defined bioprinting organizes vascular organoid sheets

A BMC Medicine study published September 25 created human vascular organoid sheets by bioprinting pluripotent stem cell-derived endothelial and smooth muscle cells.

The researchers combined the two populations at a defined ratio in a gelatin methacryloyl bioink and cultured the constructs under chemically defined conditions. Co-printing accelerated vascular network formation and produced stable, interconnected structures that continued to mature in culture.

After transplantation into a mouse hindlimb ischemia model, the organoid sheets improved blood perfusion and tissue repair. Imaging at days 14 and 28 showed that graft-derived vascular structures had connected with the host circulation. Single-cell analysis also revealed that the transplanted cells adapted to the ischemic environment, including shifts toward venous, inflammatory, and tissue remodeling states.

The study shows how cell composition, spatial organization, matrix properties, and medium conditions can be controlled together. Defined culture conditions provide a more consistent starting point, while bioprinting reduces the variability that can arise when multicellular organization depends entirely on spontaneous self-assembly.

Read the open access study here.

A staged 2D-to-3D workflow generates functional islet-like clusters

A Current Protocols publication released September 25 described a 40-day, seven-stage process for generating pancreatic islet-like clusters from human pluripotent stem cells.

Pluripotent stem cell maintenance and the first four differentiation stages are performed in two-dimensional monolayer culture. The cells are then transferred into microwells for three additional stages of three-dimensional differentiation and cluster formation.

The resulting stem cell-derived islets responded to glucose, expressed endocrine markers, contained intracellular insulin, and formed islet-like structures. Most clusters also expressed some markers associated with beta cell maturity, although the authors noted that complete in vitro maturation remains challenging.

The protocol treats the transition from monolayer to three-dimensional culture as a functional part of differentiation. This reinforces the importance of matching medium composition, signaling sequence, culture geometry, and aggregation timing to each developmental stage. The reported workflow uses Matrigel during pluripotent stem cell maintenance and is therefore not fully animal-free.

You can find the open access protocol here.

Brightfield imaging supports stage- and batch-aware brain organoid quality control

A Sensors study published September 20 evaluated whether routine brightfield images could support more quantitative quality assessment of brain organoid cultures.

The researchers analyzed 692 image regions from six culture batches. They compared 115 interpretable image features with pretrained deep learning representations and tested how well each approach reproduced expert quality labels.

A logistic regression model using handcrafted features achieved a pooled leave-one-batch-out (LOBO) area under the curve of 0.836. Performance varied substantially among batches, showing that a model that performs well on images from familiar cultures may not transfer reliably to a new production run.

The study provides a useful baseline for turning routine microscopy into a culture monitoring tool. It also highlights the importance of testing image-based quality systems across developmental stages and independent batches. The labels came from a single expert, and broader validation will be necessary before the approach can support standardized release decisions.

Read the study here.

Temperature control preserves retinal organoids during shipment

A FASEB BioAdvances study published online September 25 evaluated a temperature-controlled method for shipping mature human iPSC-derived retinal organoids.

The lithium-free system stabilized temperatures during overnight transport and reduced fluctuations compared with conventional ambient shipping. Shipped organoids retained retinal lamination, showed less cell death, and maintained expression of a rod photoreceptor marker.

Shipping is often treated as a logistical step outside the culture workflow, but temperature excursions can change tissue quality before an experiment begins. For organoid studies involving multiple laboratories, transport conditions should be validated alongside differentiation media, passage methods, and assay protocols.

Standardized shipping could also make it easier to separate differences caused by culture conditions from those introduced during transfer between research sites.

Read the open access paper here.

The week’s takeaway

Pyruvate metabolism influenced survival and lineage selection during the transition to naïve pluripotency. Secreted biomarkers created a way to monitor differentiation without sacrificing the manufactured cells. Defined bioprinting coordinated multiple vascular cell types, while a staged 2D to 3D workflow supported pancreatic islet formation.

Brightfield image analysis and temperature-controlled transport extended culture control beyond media formulation. Together, these studies show that reproducibility depends on managing the complete workflow, including metabolism, differentiation timing, tissue organization, in-process measurement, batch variation, and shipment.

Whether you are developing a PSC, organoid, cell therapy, or disease modeling workflow, reducing variability starts with well-characterized media and supplements. Defined Bioscience provides animal-free solutions and custom media development. Explore our products or contact us to discuss your workflow.