Microchannel fabrication by local melting of hydrogel toward in vitro 3D cell structures

Abstract

In this paper, we propose a new method to fabricate microchannels inside cell embedded hydrogel blocks using local heating from electrodes on a substrate for tissue engineering applications. The cell embedded hydrogel blocks are locally melted and the melted area can be used as microchannels as like vascular networks. The size and fabrication timing of the microchannels can be controlled by the proposed method. The different hydrogels were tested to validate the cell growth and melting point to achieve the proposed method. Temperature distribution inside hydrogel during the heating was simulated using 1D unsteady heat conduction equation. The simulation results showed that the microchannel width and height can be controlled in several hundred microns by the time and amplitude of applied voltage to the microheater. Chrome/gold electrodes were fabricated as microheaters using lift-off process of photolithography technology. The gelatin-agar mixed hydrogel was melted by the fabricated electrodes and microchannel fabrication was experimentally validated. The results indicate that the proposed method can be used to making vascular-like networks inside cell structures to construct in vitro 3D cell systems.