Brain Spheroids in Blood-Brain Barrier Research

The blood-brain barrier (BBB) is a specialized neurovascular unit that is composed of brain capillary endothelial cells, astrocyte endfeet, pericytes, and basement membrane. BBB has three essential properties, which are selective permeability, neuroprotection, and pathology. BBB dysfunction is closely associated with a variety of neurological diseases, such as Alzheimer's disease (Aβ deposition), multiple sclerosis (infiltration of immune cells), and brain tumors (drug delivery barriers), etc.

Combatting these challenges requires sophisticated research tools and innovative therapeutic strategies. Creative Biolabs, a leading biotechnology solutions provider, offers BBB modeling, targeted drug delivery systems, and neurovascular research services, enabling researchers to understand the complexities of the BBB and develop novel interventions for neurological diseases.

Traditional Models in BBB Research

2D Cell Models

2D cell cultures fail to provide correct simulations of cell functions and signaling pathways because they lack interactions between cells and three-dimensional structures. Also, the 2D cell model only takes into account the monolayer cells. The other main factors, such as shear stress due to blood flow, are not considered.

Animal Models

Animal models are expensive and time consuming, and therefore they are not suitable for large-scale screening and drug development applications such as drug screening, antibody screening, etc. More important, there are species differences between rodents and human beings, even other primate and human beings. No mechanism can be promoted 100% from animal models to human beings.

Figure 1 In vitro traditional BBB models.^1,3

BBB Spheroids

Structure Of Brain Spheroids

Brain spheroids are self-assembled, three-dimensional (3D) cellular culture models. These typically consist of several human cell types derived from human induced pluripotent stem cells (iPSCs) that form a sphere-shaped aggregate, mimicking some of the structural and functional features of the human brain. They show complex cell-cell interactions and some electrophysiological activities. Table 1 shows different brain spheroid cell's function and loctions.

• Brain spheroids are multi-cellular, consisting of neurons, astrocytes, oligodendrocytes and brain endothelial cells.
• These human brain-derived cells form a microenvironment that, in aggregate, can recapitulate some of the events of brain development including neuronal migration, integration and the formation of neural circuits, while also recapitulating the BBB mechanism of astrocyte formation.
• The core of the BBB structure is composed of astrocytes, while brain endothelial cells and pericytes coat the periphery to form a tightly regulated barrier controlling the transport of molecules.

Table 1 Brain spheroid cell composition.

Figure 2 The spheroids mimic BBB structure and function.^2,3

Advantage Of BBB Spheroids

Brain spheroids have advantages over traditional 2D models in better simulating in vivo environments for the following reasons.

• First, brain tissue spheroids can better replicate the three-dimensional structure and cell composition of the brain, provide cell-cell interactions and tissue organization similar to those in vivo, and thus reproduce complex neural functions more accurately.
• Second, brain organoids can be designed to model specific regions of the brain and co-culture multiple cell types to better simulate the functional and pathological state of the nervous system.
• Third, brain tissue spheroids have higher controllability and reproducibility in simulating in vivo environments. Brain tissue spheroids can be cultured under more controlled conditions to better simulate in vivo environments. For example, it is possible to control cell culture conditions such as flow rate, temperature, and pressure to a certain extent, thus increasing the reliability of experimental results.

Detection Of Tight Junctions and Permeability in BBB Spheres

• The expression levels of tight junction proteins (such as occludin, claudins, and ZO-1) are key indicators for assessing the integrity of the BBB tight junctions. Changes in the expression of these proteins can be detected using methods such as Western blotting or immunofluorescence staining, thereby determining the structural integrity of the BBB.
• TEER is a commonly used method for assessing BBB tightness. By integrating electrode materials into BBB chips for real-time measurement, the integrity and tightness of the cell layers in in vitro BBB models can be tracked and evaluated.
• Fluorescently labeled molecular tracers (e.g., FITC-dextran, sodium fluorescein) are used to quantify molecules that penetrate the BBB, thereby assessing the permeability of the barrier. Tracers of different molecular weights can be used to evaluate the quality of tight junctions. Additionally, the PAMPA-BBB model and μFlux-type permeability analyzers can be used to simulate BBB permeability.

These technologies can be used to observe the distribution and expression of tight junction proteins, thereby assessing the structural integrity of the BBB.

Contact us today to explore how Creative Biolabs' advanced brain spheroid and blood-brain barrier modeling services can accelerate your neurological research and drug development!

References

1. Choi, Jin-Ha, et al. "In Vitro Blood–Brain Barrier-Integrated Neurological Disorder Models Using a Microfluidic Device." Micromachines, vol. 11, no. 1, Dec. 2019, p. 21. DOI.org, https://doi.org/10.3390/mi11010021.
2. Paranjape, Anurag N., et al. "A Multicellular Brain Spheroid Model for Studying the Mechanisms and Bioeffects of Ultrasound-Enhanced Drug Penetration beyond the Blood‒brain Barrier." Scientific Reports, vol. 14, no. 1, Jan. 2024, p. 1909. DOI.org, https://doi.org/10.1038/s41598-023-50203-3.
3. Distributed under Open Access license CC BY 4.0, without modification.

Created June 2025

For Research Use Only. Not For Clinical Use.