Consideration of the Mechanical Properties of Hydrogels for Brain Tissue Engineering and Brain-on-a-chip

To present a more physiologically relevant microenvironment for cells, hydrogel-based threedimensional culture platforms have been widely adopted. As noted by multiple pioneering reports, the neural cells are sensitive with the change of mechanical properties of the microenvironment. Therefore, in the context of brain tissue engineering and brain-on-a-chip, there is a need to consider the brain-tissue-specific mechanical properties of hydrogels. In this review, we overview the influence the mechanical properties of hydrogel on the behavior of brain tissue cells. For this purpose, in addition to the stiffness, the viscoelasticity and degradability of hydrogels are considered to be mechanical cues, and we summarize how those mechanical properties can affect cell behavior, such as viability, proliferation, differentiation, and spreading. Consideration of the brain tissue-specific mechanical microenvironment may guide the design of 3D cell culture platforms for brain tissue engineering and brain- on-a-chip.