Printability of Hydrogels for Hydrogel Molding Based Microfluidic Device Fabrication

Microfabrication-free methods have been developed in recent years for fabricating microfluidic devices to enable the applications of microfluidic devices to a broader range. Our group has been working on developing a process for fabricating electrospun fiber embedded microfluidic devices by integrating hydrogel molding (HGM) and electrospinning (ES), and the feasibility of this integrated method has been demonstrated through our initial study. Recently, we have modified an extrusion based 3D printer kit to deposit hydrogels and form microchannels. Agarose has been used for our previous studies owning to its temperature dependent gelation. In this study, we examined the feasibility of using gelatin gel as an alternative material for hydrogel molding. Gel materials with various concentrations were examined via printability assessments; and optimal gel materials were identified. Upon completion of pattern printing, the samples were then encapsulated in polydimethylsiloxane (PDMS) and cured; formed microchannels were then characterized via micrographic image analysis. The results show that three gels, 2% w/v agarose gel, 7.5% w/v gelatin gel, and a mixture of 2% w/v agarose gel and 7.5% w/v gelatin gel (1:1 ratio), yield consistent printed patterns and form consistent microchannels subsequently.