Additive-manufactured microporous polymer membranes for biomedical in vitro applications

Microscale porous membranes are used in a wide range of technical and medical applications such as water treatment, dialysis and in vitro test systems. A promising approach to control membrane properties and overcome limitations of conventional fabrication techniques is given by additive manufacturing (AM). In this study, we designed and printed a microporous membrane via digital light processing and validated its use for biomedical in vitro applications based on the example of a cell culture insert. A multi-layer technique was developed, resulting in an eight-layer membrane with an average pore diameter of 25 µm. Image analyses proved the printing accuracy to be high with small deviations for an increasing number of layers. Permeability tests with brilliant blue FCF (E133, triarylmethane dye) and growth factors comparing the printed to track-etched membranes showed similar transfer dynamics and confirmed sufficient separation properties. Overall, the results showed that printing microporous polymer membranes is possible and highlight the potential of AM for biomedical in vitro applications such as cell culture inserts, scaffolds for tissue engineering or bioreactors.