PDMS-free microfluidic cell culture with integrated gas supply through a porous membrane of anodized aluminum oxide.

Microfluidic cell cultures are often used in academic research but only rarely in pharmaceutical research because of unsuitable designs, inappropriate choice of materials or incompatibility with standard equipment. In particular, microfluidic cell cultures to control the gaseous microenvironment rely on PDMS despite its disadvantages. We present a novel concept for such a cell culture device that addresses these issues and is made out of hard materials instead of PDMS. Our device contains two microfluidic chambers that are separated by a porous membrane of anodized aluminum oxide. Because of the small pore sizes but high porosity, this design allows a gas supply from one chamber to the other while leakage of the medium is avoided. Furthermore, the cells can be cultured directly on the membrane which induces the same advantageous cell response as cultivation on very soft materials. Furthermore, the chip, made out of silicon and glass, is fabricated with clean-room technologies and thus allows mass production. The interfaces to the outer world are small reservoirs which are accessible with conventional pipettes so that the setup does not require any pump. The fabricated chip is characterized regarding its diffusion characteristics. HaCaT-cells are cultivated successfully up to 14 days inside the chip but can be also removed for further processes. The presented chip is a step to bring cell cultivation with controlled gas supply from academic to industrial applications.