Preparation Of Microgel Based On Multi-channel Centrifugal Microfluidics

Microgels possesses unique superiorities including structural adjustability,mechanical flexibility,etc.,and has widespread application values in biomedical engineering.The functions of microgels depend highly on their physicochemical properties.In particular,the size of microgels plays an important role in their thermodynamic and kinetic behaviors,as well as their interactions with the external environment.Accordingly,a good monodispersity of microgels will be beneficial for them to achieve satisfactory performances and there is an urgent need for high-throughput production of microgels with uniform size and controllable behaviors to meet the practical demands.To this end,various methods have been explored,among which the microfluidic technology is widely applied due to its unprecedented ability of microscale fluid manipulation.By massively paralleling the basic droplet generators or subjecting the fluid interface to a gradient of confinement,microfluidics has demonstrated feasibility in the large-scale production of droplets.However,these methods suffer from high fabrication costs accompanying an increased level of complexity of the system design.Besides,due to the lack of universality for accommodating different types of liquids(such as some organic solvents),mass production of microgels with tunable components and structures remains elusive.In this work,we developed a novel three-dimensional multi-channel centrifugal microfluidic system based on the principle of centrifugal microfluidics,and optimized the traditional two-dimensional model to three-dimensional model.Then we used this centrifugal microfluidic system to achieve controllable preparation of microgel with different materials,morphology and cross-linking mechanisms,and applied it to the controlled release of drugs.The detailed research contents are as follows:(1)Design and construction of the multi-channel centrifugal microfluidic system: Based on the working principle of the centrifugal microfluidic method,a novel three-dimensional centrifugal microfluidic system was designed and constructed.Each module was fabricated and assembled in detail,and the specific process of droplet generation was photographed and analyzed by a high-speed camera.The centrifugal microfluidic system provided a tool for subsequent microgel preparation.(2)Preparation of single-component microgels based on the multi-channel centrifugal microfluidic system: Based on the constructed multi-channel centrifugal microfluidic system,controlled preparation of different microgels was completed,and the yield of alginate microspheres was measured.Alginate-calcium chloride system and chitosan-sodium tripolyphosphate system based on ionic cross-linking reaction are applicable.Accurate control of morphology and size was achieved by varying rotational speed,capillary diameter and pre gel concentration.In addition,the drug loaded alginate microspheres prepared by thiscentrifugal microfluidic system were used for in vitro drug controlled release studies.(3)Preparation of two-component microgels based on the multi-channel centrifugal microfluidic system: Based on the multi-channel centrifugal microfluidic system,UV curable HAMA/PEGDA and Gel MA/PEGDA composite microgels were prepared.After that,the multi-channel centrifugal microfluidic system was further optimized.The double-layer centrifugal microfluidic system and the nesting centrifugal microfluidic system were constructed.The preparation of Janus microgels and core shell microgels were realized respectively.