Growth of anchorage-dependent mammalian cells on microstructures and microperforated silicon membranes

Anchorage-dependent cells (mouse fibroblasts L929 and 3T3) were cultivated on microstructures made by semiconductor technology. Both cell lines showed normal growth on silicon surfaces covered with microelectrode arrays as well as on microperforated silicon membranes with square pores made by anisotropic etching (5, 10 or 20 μm edge length at the top and 1.2, 6.2 or 16.2 μm at the bottom). The cells spread over the 5 and 10 μm pores, but mostly failed to cover the 20 μm ones. They were able to cross the silicon membrane through the pores and to grow and spread on the under side of the membrane. Small pores (about 1 μm²) impeded but did not prevent cells crossing the membrane. Medium and large pores were freely crossed. Negative dielectrophoresis was used to achieve accurate positioning of cells above pores or to repel them from the chip surface (a.c., square wave, 2.5 V peak-to-peak, 5 MHz). The results are discussed with respect to their microtool applications for single-cell technologies.