Interactive control of micro-mixing and in-situ gelation of hydrogels for cell-laden cylindrical microgel fabrication

In this paper, we present a system for an interactive control of micro-mixing and in-situ gelation of hydrogels. The performance and stability of micro-mixing in the system were simulated using the computer-aided finite element analysis. The fabricated system was tested to confirm the effectiveness of micro-mixing using Rhodamine B solution (RB), brilliant blue solution (BB), and deionized water (DW). The experimental results demonstrated that the system can effectively perform the micro-mixing of RB and BB solutions by changing the DW flow rates. The interactive control of micro-mixing and insitu gelation of N-carboxyethyl chitosan (NCC) and gelatin by oxidized dextran (ODX) was experimentally confirmed, resulting in a successful fabrication of in-situ gelable cellfree and cell-laden cylindrical microgels of a variety of lengths. The biocompatibility and non-cytotoxicity were demonstrated using human umbilical vein endothelial cells (HUVECs), showing a high cell viability. Therefore, the suggested system can serve as a highly effective tool for the fabrication of in-situ gelable cell-free or cell-laden cylindrical microgels in biomedical research.