Researchers from the Federal University of Sao Paulo (UNIFESP) in Brazil have developed a new way to 3D print brain cells that survive for at least 14 days after printing.
Funded by a research grant from the Foundation for Research in Sao Paulo (FAPESP), the study has produced a model that is said to be more similar to neural tissue than existing schemes, which can be used to better understand the functions of nerve cells in relation to central nervous system diseases.
The researchers are also using their new approach to explore materials that could be used in the future to repair brain regions damaged by trauma or stroke.
Marimelia Porcionatto, a professor at UNIFESP Medical School and co-author of the paper, told FAPESP: "In living organisms, cells are three-dimensional, but when grown in the laboratory, they are above the plastic and below the medium. This is very different from the natural organization of tissues or organs, where cells are arranged in three dimensions. "The bio-ink we've developed attempts to recreate the relationship between cells and their microenvironment and other cells, a system that is a cross between 2D cultures and animal experiments."
Bioink configuration process
Astrocytes are the most abundant cells in the nervous system and play an important role in many neural processes and diseases affecting the brain. These particular cells form the basis of the researchers' study, but the process they developed could also be adapted to study other cell types.
For example, as part of another FAPESP-funded project, the team is currently using the method to analyze astrocytes and neurons infected with SARS-CoV-2, the virus that causes COVID-19.
Lead author Bruna Alice GOMes de Melo said: "We are testing the compatibility of different biomaterials with nerve tissue cells -- neurons and neural stem cells, as well as astrocytes. Bioprinting is a recent technology in tissue engineering, and neural tissue cells are particularly sensitive, so this scheme could be useful for researchers working with astrocytes and other brain cells as well as other cell types."
The new approach involves using an extrusion-based 3D printer from 3D Biotechnology Solutions to 3D print a new bio-ink filled with astrocytes to form a neural-like tissue structure. The bioink itself is a solution of astrocytes extracted from mouse cerebral cortex and composed of gelatin, laminin, and other naturally occurring biomaterials. Instead of importing GelMA from abroad, the team produces its own GelMA in the lab, so the cost is much lower.
Melo adds, "Among other components, many cells survive the stress of 3D printing for some time, but astrocytic morphology is incompatible with living tissue, and GelMA and laminin are essential. "
The shape of the bioprinted astrocytes: the nucleus is stained blue and the rest is stained red, showing a very similar state to that found in neural tissue. Image from FAPESP/ Archives of researchers.
To make living brain cells
A few days after the 3D-printed structures took shape, astrocytes reportedly began to replicate and act in a manner similar to that observed in neural tissue. The viability of astrocytes was significantly increased after one week of culture, indicating that the 3D structure provides a suitable microenvironment for cell growth.
According to the researchers, astrocytes are able to survive for at least 14 days after printing, providing a considerable window of time to study their mechanisms and behavior.
Going forward, the team plans to increase the complexity of its 3D printing approach by adding neural stem cells to the bioink mixture.
"The idea is to get as close as possible to the complexity of neural tissue," Porcionatto told FAPESP. "When these processes are fully validated in mouse cells, we will be able to develop other human cells. They will aid research as diverse as drug candidate trials, tests to identify genes expressed during brain development, and disease modeling.
Researchers at UNIFESP are working on bioprinting nerve cells. Photo from FAPESP
More information about this research can be found in the paper titled: "3D Bioprinting of Murine Cortical Astrocytes for Engineeringneural-like Tissue" published in Jove Bioengineering. The study was co-authored by B. Melo, E. Cruz, T. Ribeiro, M. Undim, and M. Porcionatto.
Relevant papers link: https://www.jove.com/t/62691/3d-... neering-neural-like
Advance neurological treatment with AM
Bioprinting has attracted increasing attention for the opportunities it offers to study neurological diseases and potentially new therapies. While the UNIFESP team's research is novel in its ability to keep astrocytes alive for more than two weeks, there have been other major breakthroughs in bio-printing brain cells in the past year.
In January last year, medical technology company Fluicell teamed up with clinical research and development company Cellectricon and Karolinska Institute University to 3D print nerve cells into complex patterns. Scientists were able to precisely arrange rat brain cells in 3D structures without compromising their ability to survive, which could be used to model the progression of neurological diseases.
Meanwhile, the ongoing European Union-funded Meso-Brain research project, led by Aston University, is developing 3D nanoprinting technology to produce a new generation of accurate modelling and testing tools. The project partners hope to generate customizable networks of 3D-printed neurons derived from stem cells, which they believe will revolutionize treatment modalities for diseases such as Parkinson's and dementia.
Last August, award-winning researchers from Tel Aviv University 3D printed a first-of-its kind glioblastoma using a patient's cells, which could give new ways to improve brain cancer treatment. Claimed to be the world's first fully functional 3D model of glioblastoma, the customizable model allows researchers to test the efficacy of new drugs in an environment that accurately mimics a patient's individual tumor and brain.
Recently, a research team from the University of Montreal, Concordia University, and Federal University of Santa Carina successfully 3D-printed living mouse brain cells using their newly developed laser-induced lateral transfer (LIST) 3D biopharting technology. LIST has been reported to overcome various limitations of other bioprinting technologies, such as the challenges of donor preparation, the viscosity of the ink, and the viability of the cells.