04 Oct, 2023: Scientists at the University of Oxford have used 3D printing technology to create engineered tissue that mimics a simplified cerebral cortex using human stem cells. This groundbreaking method has the potential to offer customised solutions for individuals dealing with brain injuries in the future. In their pioneering work, the researchers, for the very first time, exhibited the capability to 3D print neural cells, replicating the intricate structure of the cerebral cortex.

In this new research, scientists employed 3D printing techniques to create a two-layered brain tissue using human neural stem cells. When these tissue constructs were introduced into sections of mouse brain tissue, they displayed notable compatibility in both structure and function with the surrounding host tissue.

In a publication by the University of Oxford, Lead author Dr. Yongcheng Jin (Department of Chemistry, University of Oxford) said, “This advance marks a significant step towards the fabrication of materials with the full structure and function of natural brain tissues. The work will provide a unique opportunity to explore the workings of the human cortex and, in the long term, it will offer hope to individuals who sustain brain injuries.”

The cortical framework was crafted from human induced pluripotent stem cells (hiPSCs), which possess the capacity to generate various cell types present in the majority of human tissues. By employing specific combinations of growth factors and chemical agents, the hiPSCs were directed to differentiate into neural progenitor cells for two distinct layers of the cerebral cortex. These cells were subsequently suspended in a solution, resulting in the creation of two distinct 'bioinks' that were employed in the printing process to form a two-layered structure. During their time in culture, these printed tissues retained their layered cellular structure for several weeks.

When the printed tissue samples were introduced into mouse brain slices, they exhibited robust integration. This was evidenced by the extension of neural processes and the movement of neurons across the boundary between the implant and the host tissue. Moreover, the implanted cells displayed signalling activity that correlated with that of the host cells, signifying effective communication between human and mouse cells, thus demonstrating both structural and functional integration.

The scientists are planning to enhance the droplet printing method for producing intricate multi-layered cerebral cortex tissues that closely resemble the structural complexity of the human brain. In addition to their potential in brain injury repair, these engineered tissues could possibly find applications in drug testing, research on brain development and advancing our knowledge of the foundations of cognitive processes.