Application Of Microfluidic Agarose Hydrogel Chip In The Study Of Cell In Vitro Culture Model

Microfluidics has received enough attention in the last twenty years with its broad application in academic studies,assisted by the development and maturation of chip manufacturing techniques such as soft lithography and PDMS casting.However,as the employment of microchip in cell biology study become more and more frequent,chip design based on single material can be dissatisfactory to meet up with complex functionality requests.Under this background,multi-material combined microchip is a popular solution to overcome the challenge.Assembling hydrogel material with conventional polymer to form hybrid microchip could largely improve its functionality.In this thesis,we studied agarose hydrogel as a fundamental microchip building block and relevant methods to construct micro scale structures upon it.And furthermore,the hybrid microchip was applied for cell in vitro culture model.Contents of this thesis include:1.Agarose hydrogel based micro well array was fabricated and assembled with PDMS microchip for efficient cell capture.Cell suspension was infused from the upper layer PDMS channel.Real-time and continuous observation of the captured cells can be realized under microscopy with or without fluorescence labelling,due to the fine transparency of agarose hydrogel.Influence of well diameters and distances between two neighboring wells was studied and optimized.With the assistance of computer simulation of flow dynamics,cell capture mechanism was revealed,which was related to the waster absorbing ability of hydrogel.2.Based on the highly efficient cell capture by hydrogel well array,different geometrical structures of PDMS channel were designed to limit the cell pattern area by controlling flow pathways.This method allowed for co-localization of different cell types on the same hydrogel chip with different resident areas,which established a multi-cell co-culture and observation platform.In our experiments,we studied the co-culture model of human umbilical vein endothelial cell with human glioma cell upon hydrogel well array under the stimulation of anti-tumor medicine.Through adjusting the relative positons and population size between two cell types,we observed that the existence of endothelial cells improved the survivability of glioma cells.3.Channel formation on hydrogel by template imprinting was further explored,and channels with different parameters were constructed.Substance transportation by flow and molecules diffusion into hydrogel were both observed for channels upon hydrogel chip,which were similar with the functionality of human vascular.We then paved endothelial cells along the hydrogel channels to form an open lumen vessel structure by controlling flow dynamics,and the structure can be clearly identified under microscopy.Influence of channel geometries to vessel structure formation was studied.This work can be hopefully applied to build in vitro vascular model and organ engineering.