Study of Brain Organoids 
Brain organoids are artificially grown 3D aggregates that resemble the embryonic human brain, usually generated from human induced pluripotent stem cells (h-iPSC).
MaxTwo, a multi-well high resolution microelectrode array (MEA) system, is best suited for long-term and label-free analysis of brain organoids. MaxTwo’s large sensor array at high-resolution enables recording of every active cell across multiple areas of biological samples.
Readout at different scales:
- Network level (population spike times, bursts)
- Cell level (individual spike time, waveform)
- Sub-cellular level (spatially resolved waveforms)
Webinar
Watch our Organoids webinar that introduces high-resolution functional imaging of Brain Organoids
Watch the replay
What You Can Do
Capture high quality activity maps from organoids
MaxTwo enables recording of neuronal activity at high spatio-temporal resolution and label-free electrical imaging of organoids.
- “See” all the active cells on top of the array and identify the activity of each cell.
- Detect small spikes from developing neurons and from cell compartments, such as axonal action potentials.
- Analyze full organoids and determine initiation and propagation of network activity.
Microscopy image of three h-iPSC-derived organoids (DIV 60) overlaid with firing rate and amplitude activity maps.1
Pharmacological manipulation of network bursts in organoids
The network bursting activity of h-iPSC-derived cortical organoids (DIV 60) was modulated using
NMDA (N-methyl-D-aspartic acid) receptor inhibitor 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and an NMDA noncompetitive antagonist (MK801). CNQX decreased the network activity, but increased the mean spike firing rate and mean spike amplitude. MK801 decreased both the network burst activity and the mean spike firing rate, but did not affect the mean spike amplitude.1
Functional characterization of organoids modeling different brain regions
High-resolution allows to precisely identify and isolate active areas in all the analyzed preparations. The progressive complexity of the modeled regions correlates with an increased synchrony in the recorded network activity.2
Activity maps and distributions of spike amplitude and firing rate for a
h-iPSC-derived fused (dorsal + ventral) cerebral organoid (DIV 56).
Network activity for distinct organoid preparations.
Effects of serotonin exposure during cerebellar maturation
Cerebellar dysfunction often involves a prominent loss of Purkinje cells (Taroni and DiDonato, 2004). Serotonin (5-hydroxytryptoamine, 5-HT) is reported in the regulation of the morphological maturation of Purkinje cells (Kondoh et al., 2004; Oostland and van Hooft, 2013). 5-HT treatment during the maturation protocol of cerebellar organoids is hypothesized to lead to higher efficiency of morphological and physiological maturation of Purkinje cells. Treated organoids showcase synchronized bursting activity, an indicator of synaptic maturation.2
Activity maps and distributions of spike amplitude and firing rate for a
5-HT-treated h-iPSC-derived cerebellar organoid (DIV 56).
Effect of 5-HT treatment on the network activity of a cerebellar organoid.
Single cell tracking in organoids
Neurons up to a depth of 100 μm (Frey et al., 2009; Obien et al., 2019) can be precisely detected and isolated in brain organoids. Electrical footprints and single cell-spiking patterns can be extracted to analyze signal propagation and cell activation dynamics.1
Traces expressing different activation patterns of the three identified neurons (left). Three neurons identified from one area of an organoid; circles indicate the electrode used to obtain the electrical footprints for each neuron (right).
Electrical footprints of the three identified neurons.
1 Data obtained in collaboration with Hopstem Bioengineering Co., Ltd., Hangzhou, Zhejiang, China. Organoid image on the first page, top right is courtesy of Dr. Anxin Wang.
2 Data obtained in collaboration with the Stem Cell Engineering Research Group (SCERG) at iBB – Institute for Biosciences and Bioengineering of Instituto Superior Técnico, Universidade de Lisboa, Portugal. Special thanks to Ana Rita Gomes, MsC, for carrying out the experiments.
References
A. Wang, et al., “Comparison of Electrophysiological Tools of Brain Organoids derived from Human Induced Pluripotent Stem Cells,” ISSCR 2020 Virtual, June 23-27, 2020.
F. Taroni & S. DiDonato, “Pathways to motor incoordination: the inherited ataxia,” Nature Reviews Neuroscience, 5(8), 641-655, 2004.
M. Kondoh, et al., “Kondoh, Mayumi, Takashi Shiga, and Nobuo Okado. “Regulation of dendrite formation of Purkinje cells by serotonin through serotonin1A and serotonin2A receptors in culture,” Neuroscience research, 48(1), 101-109, 2004.
M. Obien, et al., “Accurate signal-source localization in brain slices by means of high-density microelectrode arrays,” Scientific Reports, 9(1), 1-10, 2019.
M. Oostland & J. A. Van Hooft, “The role of serotonin in cerebellar development,” Neuroscience, 248, 201-212, 2013.
T. P. Silva, et al., “Maturation of Human Pluripotent Stem Cell-Derived Cerebellar Neurons in the Absense of Co-Culture,” Front. Bioeng. Biotechnol., 8, 70, 2020.
U. Frey, et al., “Depth recording capabilities of planar high-density microelectrode arrays,” 4th Intl. IEEE/EMBS Conf. on Neural Engineering, 207-210, 2009.