Multi-Layered Channel Patterning by Local Heating of Hydrogels

In this letter, we conducted a new method to fabricate channels inside cell structures for tissue engineering applications. A cell-embedded hydrogel is locally melted to fabricate channels inside cell structures. The fabricated channels can be used as vascular-like networks to supply nutrition and oxygen to cells, or patterning another types of cells inside the cell structures. Microelectrodes were prepared as heaters on a glass substrate by photolithography techniques. The channel patterning was conducted using the microelectrodes. The channel width and height are controlled by the heating duration when the applied voltage to the microelectrodes is constant. The multi-layered channel fabrication was achieved by repeating melting-filling hydrogel. Patterning of different cell types in hydrogel was conducted using liver cells and fibroblast cells. The proposed method can fabricate vascular-like channels in cell structures to achieve in vitro 3-D co-culture cell systems.