The channel interaction chip has been developed to study cells co-cultured in three adjacent channels, to each of which a microfluidic flow can be applied. The three channels are divided from each other by transmissive pillar barriers. On each channel interaction chip five independent co-culture units can be found, which differ in the width of the pillar barrier. One potential co-culture setting is the use of the two outer channels in perfusion mode, while the inner channel can be easily filled with a cell- containing gelatinous extracellular matrix, for static 3D culture conditions.