Patterning alginate hydrogel through optically induced electrodes

Cell patterning is a crucial technique for cell properties analysis at different environment. This paper proposes a method to pattern calcium alginate hydrogel in a three dimensional (3D) manner through optically induced electrodes. First, one photosensitive layer is spin coated on one indium tin oxide (ITO) glass surface, which is put below another ITO glass. Then, sodium alginate solution with CaCO₃ particles is injected between these two glasses. In the bottom glass, patterns of electrodes follow patterns of light. Hydrogel would form on patterned electrodes due to electrochemical deposition. Shapes of hydrogel are determined by shapes of light and hydrogel´s height could be controlled by reaction time and DC voltage. The experiment results demonstrate that hydrogel´s patterns follow optical electrodes´ patterns exactly.