Construction of 3D Micro-Tissue Based on Electrodeposition and Robotic Manipulation

In 3D microtissue fabrication, assembly is a significant scale up process for bottom-up artificial tissue construction. In this paper, gear-like cell laden 3D microstructures with a center hole were fabricated by using calcium (Ca)-alginate hydrogel and poly-L-Iysine (PLL). The microelectrode based on indium tin oxide (ITO)glass was applied in Ca-alginate hydrogel electrodeposition. After long time culture, the full of Hepg2 cell microstructures were selected to proceed the assembly process. A modified rail-guided microrobotic manipulation system was proposed to accomplish the microstructure capture by using fluidic force. After the pick-up of microstructures, the surface tension was applied to align the gear-like structures. The gelatin methacryloyl (GeIMA)was applied to achieve the initial fixation. With flexible microstructure unit fabrication method, Hepg2 cells were encapsulated in the Alginate-PLL-alginate (APA)chamber. After 11 days culture, the microstructures were full of cells and carry out to the microrobotic assembly. During the culture, the cell viability got a rapid increase and reach to 95% at 5^th day. Based on the high efficiency 3D assembly system, six pieces of microstructures were captured in 2 min. After the GelMA fixation, the final microtissue was made. These microtissue were formed in complex architecture to mimic the natural human liver lobule, which has a wide range of application prospects in drug test and tissue regeneration.