Incorporation of soft shaped hydrogel sheets into microfluidic systems using a simple adhesion masking process

Abstract

We report the use of simple adhesion masking in fabricating shaped, photo-polymerizable hydrogel sheets with very small elastic moduli on glass substrates. Direct ink masking of surface crosslinking groups allows for low cost hydrogel patterning that is compatible with materials where crosslinking is both photo- and chemically initiated. Mechanical removal of the unwanted polymerized material reveals the shaped hydrogel. The mechanical properties of the shaped hydrogels were characterized by exposure to well-defined shear flow inside the microfluidic device. We show that hydrogel sheets with elastic moduli down to 7.5 Pa can be shaped with millimeter feature sizes using this approach. The shaped hydrogels are suitable for applications such as the detection of shear flow, cell culture, and traction force microscopy.