Deposition Control of a FDM 3D Printer Based Direct Writing System for Hydrogel Molding in Microfluidic Devices Fabrication

Microfabrication-free methods such as wax printing and hydrogel molding have been developed in recent years for fabricating microfluidic devices to enable the applications of microfluidic devices to a broader range. A process has been developed to fabricate 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. In particular, agarose gels with various concentrations have been used to generate the channel molds inside PDMS. Recently, a 3D printer kit based on Fuse-deposition method (FDM) was modified to directly deposit hydrogel mold. The current study focuses on how to control the dispensing rate and the extruder motion of the 3D printer for this application. The paper presents a characterization process for determining optimal work ranges in terms of dispensing rate and the moving rate of the x-y table. Specifically, for a given hydrogel material and needle gauge, consistent dispensing volume rate was determined via varying the flow rate of syringe pump and analyzing recorded images. The ranges of the moving rate of the x-y table and the extrusion rate were then determined to generate the previous determined volume rate based on the experimental measurements. As the printer kit is controlled via open source software, the developed method will be applicable to characterization of depositing different material system.