STEMdiff Midbrain Organoid Diff Kit

STEMCELL Technologies' STEMdiff™ Midbrain Organoid Differentiation Kit supports matrix-free generation of three-dimensional organoids patterned to the midbrain from human pluripotent stem cells (hPSCs). According to the manufacturer, midbrain organoids can be produced at a scale of more than 500 per kit, enabling stronger statistical replication and more detailed longitudinal studies. The protocol is based on the Sergiu Paşca laboratory approach and yields organoids that represent the cellular composition and structural organisation of the developing human midbrain. Organoids are initially formed in AggreWell™800 plates and, after six days, transferred to suspension culture for growth and subsequent patterning to the midbrain, with hPSC-derived midbrain organoids achievable in 43 days. Long-term maintenance and further maturation are supported using the STEMdiff™ Neural Organoid Maintenance Kit.

Validated in the human ES cell line H7 and the iPS cell lines WLS-1C and STiPS-F016, the kit produces organoids with uniform size and spherical morphology at Day 25 and Day 50 in vitro. At Day 50, midbrain organoids display brain-region-specific marker expression, including comparatively lower PAX6 expression throughout, elevated FOXA2 around pseudoventricular regions, and GIRK2 expanding from FOXA2-expressing progenitor zones. The organoids also express the catecholaminergic neuron-specific marker tyrosine hydroxylase (TH). The floorplate precursor markers FOXA2, LMX1A, and EN1 are elevated at Day 25, while more mature marginal zone dopaminergic markers NURR1, TH, GIRK2, and PITX3 are elevated at Day 50.

Midbrain organoids produced with the kit can be combined with dorsal forebrain organoids generated using the STEMdiff™ Dorsal Forebrain Organoid Differentiation Kit to create midbrain–striatal assembloids (AssemBloid™). Once matured beyond 50 days, the organoids are intended for use in predictive assays, high-throughput phenotypic screening, and neurotoxicity assays.