Recently, substrate stiffness has been involved in the physiology and pathology of the nervous system. However, the role and function of substrate stiffness remain unclear. Here, we review known effects of substrate stiffness on nerve cell morphology and function in the central and peripheral nervous systems and their involvement in pathology. We hope this review will clarify the research status of substrate stiffness in nerve cells and neurological disorder.

The proper formation of synapses is essential for brain function. Synaptic cell adhesion molecules (CAMs) are thought to play essential roles in the initiation of the synapse formation process. The artificial synapse formation assay, in which non-neuronal cells and neurons are co-cultured, has been shown to be a powerful system for screening CAMs. However, controlling a large number of cell pools in co-culture is complicated, creating a potential barrier for high-throughput screening. This protocol describes a new co-culture method in which cDNA plasmid is transfected into human embryonic kidney 293T cells using polyetherimide 24 h after cells were mixed with neurons, and immunostaining and confocal imaging are employed for analyzing synaptogenesis. This optimized method is simpler and easier to perform than the traditional method for the examination of the synaptogenic activities of individual cell-surface proteins in isolation, and provides an unbiased screening platform for synaptogenic proteins.