Analysis On Fabrication Of Micro-nano Hydrogel Arrays By Optical Fluid Maskless And Characteristics Of Microfluidic Capture

With the development of biomedical technology,personalized diagnosis and treatment of single cell level has become more and more important in the field of medicine.As one of the most powerful tools,microfluidic chips have shown great potential in various applications related to cell separation,cell proliferation and cell behavior analysis.The traditional processing method of microfluidic chips is complex,time-consuming,expensive,and not good at processing chips with small size.In recent years,the development of micro-nano machining technology can achieve small-scale chip manufacturing.At present,the hydrogel materials which are suitable for biomedical experiments and processing have attracted the attention of researchers.The application of micro-nano machining technology in hydrogels has become a hot research direction.In this paper,a kind of photofluid maskless lithography technology based on digital micromirror array(DMD)is used to fabricate microfluidic devices with micro holes.Through DMD maskless lithography technology,the on-line design of micropores is realized.In the photofluid maskless lithography system,peg-dma was solidified into different shape and size of micro pit array by adding photoinitiator.Scanning electron microscope(SEM)was used to scan the microporous array and observe the solidification effect of the array.The young modulus of the hydrogel array was measured by atomic force microscopy(AFM).The results show that the DMD maskless lithography system can achieve high-throughput processing of microporous arrays,and the microporous arrays have regular structure and uniform performance.Microfluidic chips were fabricated based on hydrogel microporous arrays.Through microinjection of polystyrene microspheres and breast cancer cell suspension to the hydrogel microfluidic chip,the capture of microspheres and cells was observed.The COMSOL simulation software was used to simulate the flow field of regular array and cross array of microporous arrays with different shapes and heights.Finally,theoretical analysis was carried out based on experimental and simulation results.The results show that the high performance microsphere capture can be achieved by the water coagulant microfluidic chip.The microsphere capture experiments of different structure hydrogel microporous arrays show that the captured microspheres and cells are located in the middle of the micropore,and the particles trapped in the shallow pits remain in the periphery of the pit,and small probability particles are captured.Based on the experiment,flow field simulation and analysis of the micro hole array,it is considered that the difference of Stokes force and additional mass force on the particles in different positions of the micro hole is the source of different capture effects.In this paper,based on the photofluid maskless lithography technology of digital micromirror array(DMD),the rapid fabrication,characterization and material performance measurement of pegdma micro hole array are realized.Based on the fabricated microfluidic chip,the microsphere and cell capture experiments and simulation analysis are carried out,and the single cell and multi cell capture are realized.By analyzing the experimental results,the influence of micropore structure parameters and suspension concentration on the capture results is summarized.It has practical significance for improving the performance of hydrogel chips in the future and realizing mass production.