Surface tension confined digital light processing for hydrogel printing with high availability

Digital light processing (DLP) has emerged as one of the most promising methods for constructing intricate 3D hydrogel structures. However, the material availability of hydrogels is quite limited for resin vat-based printing. To overcome this issue, we propose a surface tension confined digital light processing (STC-DLP) technique that utilizes liquid surface tension and surface-treated substrates to confine the hydrogel solution during printing, to minimize the solution consumption. The “top-down” DLP printing enables layer-by-layer curing of hydrogel solutions into controlled 3D structures. A soft and a rigid hydrogel solution was selected as demonstration. By adding hydrogel solution with desired volume, highly accurate microtissue models, flexible sensors, and microfluidic chips with complex 3D structures were fabricated with high solution availability. This approach achieves efficient utilization of hydrogel solutions, and is expected to be especially applicable for printing of scarce or expensive materials.