Microfluidic Spinning Technology-based Fabrication Of Microfibers With Atypical Helical Structure For Applications

Helical fiber has attracted more and more attention because of its unique helical rotation geometry,three-dimensional stretability and shape recovery performance.It has been proven that it has potential application prospects in the field of biomedical engineering,micromotor,sensor and intelligence.However,it remains a challenge to fabricate novel helical structures at the microscale.Therefore,this paper proposes a continuous spinning method that can be used with a microfluidic-chip-based spinning device to precisely control the microfluidic flow and reaction kinetics,and fabricates microfibers（BT microfiber）with an atypical helical structure like Bulbine torta and ultrahigh strain sensitivity,and its application in the field of biomedicine and sensor intelligence.The specific research content is as follows.（1）Design and construct a multi-microchannel PDMS microfluidic spinning device,and prepare calcium alginate fibers based on the microfluidic spinning method.The influence of microfluid concentration,viscosity,speed,composition,etc.on microfluidic spinning is studied,and the optimal spinning parameters are selected for experiments to realize the preparation of BT microfibers.Analyze the formation mechanism of BT microfibers,propose the inhomogeneous viscosity rope-coil effect and use finite element（FM）to simulate the flow of microfluid in the microchannel and the continuous flow process after solidification,and compare the experimental results with theoretical research.In combination,explain the changing process of microfluidics and the formation of atypical spiral structures.Based on the"space-occupying effect"of the fluid and the laminar flow characteristics of the fluid in the microchannel,hollow BT microfibers were prepared.And during the formation of microfibers,the size of microfibers can be precisely controlled by changing the initial flow rate of the microfluid.（2）Analyze the mechanical properties of BT microfibers,and use finite element（FM）to simulate the strain distribution of typical spiral structure and atypical spiral structure fibers under the same tensile conditions to verify the atypical spiral structure.The structure has uneven strain distribution and is super sensitive to strain,making it an ideal sensing structure.To further explore the super strain sensitivity of atypical spiral knots,a Gel AM/atypical spiral structure microfiber composite membrane was prepared,and primary cardiomyocytes extracted from SD neonatal rats were seeded on the composite membrane and cultured to monitor the pulsating ability of cardiomyocytes.The contraction power of cardiomyocytes was detected to be approximately 9.07×10^-3 m N.（3）Using a microfluidic device for preparing hollow BT microfibers,human umbilical vein endothelial cells were wrapped with alginic acid,and the growth and physiological activity of the cells in the fibers were studied,which proved that the fibers were co-cultured in cells and constructed bionic blood vessels.The feasibility of the application in the system,the realization of the preliminary construction of the artificial blood vessel model,lays the foundation for the future in vitro simulation and research of blood vessels and other tissues or organs.（4）Microfluidic spinning technology is used to form poly（3,4-ethylenedioxythiophene）:polystyrene sulfonic acid（PEDOT:PSS）conductive core-shell BT microfibers in one step.The extrusion performance of PEDOT:PSS core-shell conductive BT-microfiber was characterized.In order to expand the application range of PEDOT:PSS core-shell conductive BT-microfiber/PDMS composite membrane was prepared by using PDMS.