Microfluidics-based Fabrication Of Cell-laden Hydrogel Microfibers For Biomedical Applications

Microfluidics is an emerging technology that precisely manipulates tiny fluids through microchannels.It has been widely used in DNA sequencing,protein separation and in vitro diagnostics,and its application in the preparation of micro-scale structures such as microspheres and microfibers is an emerging research field in the past decade.Hydrogel microfibers have attracted much attention in tissue engineering due to their excellent biocompatibihty,flexibility and assembly ability.The process of preparing materials by microfluidic technology can be carried out under mild conditions without exposure to harsh conditions such as high temperatures,high pressures,organic solvents or high stress.Therefore,hydrogel microfibers having good biocompatibility can be prepared by this technique,and cells can be loaded into the microfibers without losing activity.In recent years,the preparation of hydrogel microfibers by microfluidic technology has become a research hotspot,and cell-laden microfibers have also shown great value in tissue engineering and organ chips.In order to meet the needs of various applications,it is necessary to prepare microfibers of different structures.For this reason,it is often necessary to design a plurality of complicated microfluidic devices,which limits the application of microfluidic technology in more fields.Therefore,the first part of this paper introduces a simple and flexible two-layer flow microfluidic system,through which single-layer,double-layer and hollow cell-laden hydrogel microfibers can be prepared on the same microfluidic device.They can be applied to bionic construction of different engineering organizations.In addition,helical structures such as DNA,spirulina and spiral blood vessels play an important role in nature.However,there are very few studies on the preparation of helical microfibers,and the preparation of helical microfibers with complex structures such as multilayers and hollows is more challenging.In the second part of this thesis,we successfully prepared helical hydrogel microfibers with complex structures such as multilayer,hollow and superhelical through microfluidic technology,and the size and structure of helical microfibers can be precisely controlled by adjusting the device and flow rate.Moreover,in order to establish an in vitro helical vessel model,we also fabricated cell-laden helical microfibers and explored its application in vessel-on-a-chip.In summary,this thesis prepared various cell-laden hydrogel microfibers with linear or helical structures,and explored their potential biomedical applications.