#animalstudyalternative

To have an accurate in vitro model its important to similar properties to the natural rodent brain. The brain develop in this study showed many of these specific characteristics:

Diverse cell types: Brain is build of different types of cells. The cultured brain contained a variety of essential neural support cells (glia). inhibitory neurons and excitatory neurons.

Electrically active: Neurons communicate by electrical signals. The neurons in the culture showed fire and spikes and form synaptic connections to a complex network. 

3D structure: Normal cell culture is in a 2D structure, while this tissue structure has a more realistic geometry, resulting in better cell connect and communication. 

Natural cell density: Brain is a compact structure with a dense amount of cells per cubic millimeter. The mini-brain have a density of a few hundred thousand cells per cubic millimeter and is similar to the natural rodent brain density. 

Physcial structure: The mini-brains show the same squishiness (mechanical strength) as a natural brain. This is due to the extracellular matrix formed by the mini-brain cell own protein expression. 

The miniature brain are made by isolation and concentration cells combination for a small sample of living tissue from a rodent. This sample is seeded onto an agarose spherical model. Brain tissue begins to form within a day of seeding and a complex 3D neural network was observed within two to three weeks and kept alive for at least a month. The mini-brains are third of a millimeter in diameter and one single rodent tissue sample can produce thousands of these miniature brains. The production cost is validated to 25 cents per mini-brain, showing a big potential for big scale research applications. 

https://news.brown.edu/articles/2015/10/minibrain

http://online.liebertpub.com/doi/abs/10.1089/ten.TEC.2015.0135