The brain is probably the least explored organ, much of which is due to the difficulty of studying it in situ rather than in slices under a microscope. Even growing small organoids out of neurons provide few clues, as this is not how brain tissue is normally organized. A possible breakthrough may have been found here by a group of researchers whose article in Cell Stem Cell details how they created functional human neural tissues using a commercial 3D bioprinter.
As detailed by [Yuanwei Yan] and colleagues in their research article, the issue with previous approaches was that although these would print layers of neurons, they would fail to integrate as in the brain. In the brain’s tissues, we see a wide variety of neurons and supportive cells, all of which integrate in a specific way to form functioning neuron-to-neuron and neuron-to-glial connections with expected neural activity. The accomplishment of this research team is 3D bioprinting of neural tissues with the necessary functional connections.
Core changes to the process were the use of a fibrin hydrogel, consisting primarily of fibrinogen and thrombin with hyaluronic acid mixed in to decrease the viscosity, along with printing the layers horizontally rather than the previous vertical approach. With this biocompatible support structure in place, the human pluripotent stem cells (hPSCs) in the bioink displayed clear neurite growth and synaptogenesis as they differentiated into specialized cell types and formed neural tissue reminiscent of that seen in the human brain.
Although the researchers admit that this printing approach has many limitations, it nevertheless should provide many advantages for research into the functioning of many parts of our brains and various pathologies that can afflict it.
Bioprinting more mundane organs is a hot topic lately. You might even print your next liver.
Source : https://hackaday.com/2024/02/12/3d-printing-functional-human-brain-tissue-for-research-purposes/