抄録
Cell migration is essential for a variety of biological and pathological processes such as wound healing, inflammation and tumor metastasis. However, a mechanical field within a group of multiple cells during a collective migration has not been characterized well. In this study, a polydimethylsiloxane-made multichannel device was fabricated using photolithography and soft lithography, and was used to monitor traction forces generated by cells during migration. The device consists of a reservoir for establishing a confluent cell monolayer, attached with 24 microchannels for cell migration. Four patterns of micropillars were designed on the bottom surface of the microchannels to measure cell traction forces during migration on four combinations of substrate stiffness and topography. Collective cell migration from the reservoir into the microchannels was initiated when the channels were backfilled with culture medium. Migration rate of 5.7 pm/h was measured in the microchannel equipped with micropillars whose dimensions were 6.5 pm in height, 2 pm in diameter and 7 pm in spacing. In detail, cells on the moving front of the migration, leading cells, generated the traction forces toward the backward and the maximum magnitude of 14 nN was measured at their front side. Traction forces generated by the cells behind the leading cells directed backward at both the front and the rear sides. However, traction forces generated by the cells behind the second row directed random directions with smaller magnitudes compared to those on the front and the second lines. It is assumed that cells on the front line generated a large magnitude of traction forces and migrated actively as single cells, pulling adjacent cells forward, whereas the movement of cells after third row was restricted by mechanical linkages between their neighboring cells, generating a small magnitude of traction forces.
