For example, it has been demonstrated that focal adhesion kinase, an essential mediator of signaling induced by integrin engagement with ECMs, plays conflicting roles in cell migration and metastasis; some papers report it is a positive regulator of cell migration and cancer metastasis, whereas others report the opposite function. Variations in the cadherin and integrin subtypes in the cells used in the studies or in the type of ECMs and the different degrees of ECM remodeling between the studies may be the source of these controversial outcomes. Therefore, the contribution of cellECM interactions to the regulation of migration collectivity needs to be explored under more chemically and biochemically defined conditions. In this regard, block copolymer micellar nanolithography offers an ideal platform. In this method, gold nanoparticles are kinase inhibitors periodically arrayed on a glass substrate in a well-defined nanoscopic geometry and thereafter functionalized with cell-adhesive ECM ligands. In contrast to the surfaces prepared by simple dilution of ligand molecules, this substrate allows for the precise non-stochastic control of ligand spacing and thereby enables the quantitative control of cell-ECM ligand interactions. In addition, matrix remodeling can be minimized by passivating the intervening glass regions with PEG and conjugating an ECM ligand via an ethylene glycol group. Therefore, the analysis of cell migration phenotypes on chemically defined cellECM ligand interactions becomes possible. Scratch wound healing assay has been widely used to study cell migration in the laboratory to examine the contribution of soluble factors and gene transcription to cell migration. However, the difficulty in precisely controlling the wound geometry and the inevitable production of cellular debris prevents the precise control of the cellular micro- or nano-environment by this approach. Alternative methods based on mechanical barriers or dynamic substrates have been developed to overcome these drawbacks. These methods allow for the analysis of cell migration from and/or along controlled geometrical confinements with well-defined migration frontiers.The cells are initially confined within given micro-scale regions, either by surrounding the regions with a mechanical barrier_ENREF_10 or by micropatterning the cell adhesiveness of substrates. Subsequently, the migration of the cells is induced by removing the barrier or by activating the previously inert areas of the dynamic substrates using an external stimulus. The dependency of collective migration modes on geometrical constraints and the role of intercellular physical forces in collective migration have been clearly demonstrated using these approaches. We also reported the impact of cell cluster geometry and incubation time on the frequency of leader cell appearance in collective migration using our original photoactivatable dynamic substrates based on photocleavable poly. It should be noted that this high dependency of the collective characteristics on cellular microenvironments.