Microfabricated free standing, tuneable, porous microfilters from an epoxy based photoresist for effective bioseparation

SU-8 is an epoxy-based, biocompatible thermosetting polymer, which has been utilized mainly to fabricate biomedical devices and scaffolds. In this study, thin, single-layered, freestanding tuneable porous SU-8 membranes were microfabricated and surface hydrophilized for efficient bioseparation. Unlike the previous thicker membranes of 200–300 μm, these thin SU-8 membranes of 50–60 μm thickness and pores with 6–10 μm diameter were fabricated and tested for blood-plasma separation, without any additional support structure. The method is based on making a patterned SU-8 layer by electrospin coating and UV lithography on a sacrificial polyethylene terephthalate (PET) sheet attached to a silicon wafer. Poor adhesion between PET and SU-8 aid in the convenient release of the thin porous membranes with uniform pore formation. The single-layered self-supporting membranes were strong, safe, sterilizable, reusable, and suitable for plasma separation and postfermentation broth enrichment.