(194i) Rapid and Facile Fabrication of Thermoplastic Organs-on-Chips

Introduction: Micro physiological cell culture systems or “organs-on-chips” have garnered interest from both academia and industry. The scientific community has predicted that organs-on-chips will be used to study disease pathology and facilitate drug discovery. Furthermore, it has been postulated that seeding patient derived cells within organs-on-chips will enable personalized medicine. However, the currently prevalent microfabrication of organs-on-chips via poly(dimethylsiloxane) (PDMS) soft lithography may limit widespread access to microphysiological systems and their use toward drug discovery. PDMS soft lithography requires specialized microfabrication training and facilities which aren’t widely accessible. Furthermore, PDMS absorbs hydrophobic molecules which is problematic for screening hydrophobic drug candidates. Finally, PDMS is highly gas permeable which is problematic for modeling hypoxic tissues like the intestine.

Methods: Here we present the facile, rapid, and scalable fabrication of a human intestine-on-a-chip using a commercial laser engraver systems, acrylic sheets, double sided adhesives, and a polycarbonate track etch membrane. The human intestine was recapitulated by culturing human Caco-2 cells in the apical fluidic compartment on a 1.0µm membrane while a syringe pump introduced cell culture medium into both the apical and basal fluid compartments. Caco-2 cells on chip were compared to control cultures of Caco-2 cells on commercial Transwell inserts via immunofluorescent staining for tight junction protein, F-actin, and cell nuclei. Mucus production on chip was compared to control Transwell cultures via immunofluorescent staining for mucin protein MUC2 and alcian blue staining.

Results: The fabrication methodology presented here boasts several key improvements compared to PDMS soft lithography: chip fabrication throughput was increased from days to hours while keeping material cost < $2 per chip, the technique doesn’t require any specialized microfabrication, the thermoplastic chip construction enables oxygen tension control, and the double sided adhesives simultaneously act as fluidic compartments and provide a leak free bond without additional surface treatments like oxygen plasma or silanization. Immunofluorescent staining revealed the chip construction was biocompatible with human Caco-2 cells that similarly expressed tight junctions and F-actin compared to Transwell control cultures. Immunofluorescent staining and alcian blue staining showed that Caco-2 cells on chip produced more mucus compared to Transwell control cultures. We envision that the low cost, rapid, facile fabrication technique presented here will enable widespread access to micro physiological systems for researchers without microfabrication infrastructure or training.