Migration of liver and kidney explants inside trapezoidal PDMS microchannels

We compared the migration of liver and kidney explants, harvested from chicken embryos, cultivated inside trapezoidal microchannels and onto flat samples made of polydimethylsiloxane (PDMS). In all cases, liver migration was faster and greater than kidney migration. The microchannels enhanced 3D migration when compared to the flat samples, which made only 2D migration possible. However, migration velocity was found to be higher in 2D than in 3D migration. The migration distances inside the trapezoidal microchannels were found to depend on microchannel periodicity between two parallel microchannels. The shorter the periodicity, the shorter is the migration distance. The number of microchannels involved in explant migration, however, increased with decreased periodicity. This resulted in a migration volume that was independent of microchannel periodicity. Furthermore, comparing the data obtained in rectangular microchannels with those from trapezoidal microchannels has shown that the migration volumes were also independent of microchannel design in the range of dimensions considered (50 to 150 μm in depth and 100 to 200 μm in width). We thus concluded that the explant played the role of “cell reservoir”, controlling cell migration up to a defined ratio of the initial explant volume.