Neuroimplants and the Glial Scar: What Makes the Brain-Computer Link Work?

Neuroimplants are likely major technological breakthroughs of the next decade with the potential for unprecedented social impact. In addition to attractive and miracle-looking possibilities, the major obstacle for the industry is complicated, unpredictable, and unfavorable side effects due to tissue damage, biocompatibility limitations, and foreign body response at the brain-implant interface. Luckily, one major barrier preventing the connection of the neuroimplant to brain cells-the glial scar-has been studied previously for its role in brain trauma. This review highlights pharmacological and tissue engineering avenues that could be readily transferred from the brain trauma area to fast-growing neuroimplant engineering. The opportunities for chondroitinase ABC treatment, stem cells, and hydrogels for the prevention of glial scarring are emphasized. Alternatively, the glial scar may also be viewed not as an obstacle but as a possible regeneration-permissive component of the optimally working brain-neuroimplant interface. Feasible steps in that direction are discussed, including applications for chondroitin sulfate-binding peptides. Finally, the crucial role of new microscopy and data processing techniques for peri-implant glial scar monitoring is highlighted. To that end, we stress the importance of artificial intelligence, including artificial neuronal networks, for the analysis of cell morphology at the brain-neuroimplant interface.