| In recent decades,the fabrication of spherical polymer microparticles is a classic research field in polymer science.Common preparation methods include suspension polymerization,emulsion polymerization,dispersion polymerization,soap-free emulsion polymerization,seed swelling polymerization,etc.Among them,the mini-emulsion method is one of the most popular methods for preparing spherical polymer particles.It has the advantages of easy operation,low experimental device request and less energy consumption,which makes it the most widely used method in nanomaterial research.Micro/nano motor has attracted great attention from researchers by the virtues of its self-driving ability and motion controllability.Micro/nano motor's research has become a multidisciplinary and cutting-edge research field due to its huge potential in biology application such as precise drug delivery,micro surge and targeting cell maneuver.There are many typical driven sources such as chemical fuel drives,magnetic drives,optical drives,ultrasonic drives,etc.In this dissertation,the mini-emulsion method and micro/nano motors are combined to prepare a hydrogen peroxide driven magnetic field-guided micro/nano motor and a magnetic fielddriven micro/nano motor,and the hydrogen-permeable magnetic field-guided micro/nano motor realizes one-step multi-functionalization in the preparation process,self-driving motion in the hydrogen peroxide water and magnetic field guidance;on this basis,the magnetic control platform is used to further realize the controllable motion of the magnetic field-driven micro/nano motor in a twodimensional plane,and the feasibility and possibility of magnetron motor in biochemical application direction are initially explored.In this dissertation,a hydrogen peroxide-driven magnetic field-oriented composite fluorescent micro/nano motor was prepared by mini-emulsion method.The toluene solution of polystyrene(including magnetic particles and Nile red fluorescent dye)was used as the oil phase and sodium dodecyl sulfate(SDS)solution was used as the aqueous phase.Then the polystyrene sphere was obtained by emulsification,and the influence of the shearing speed of the shearing machine on the particle size of the polystyrene sphere and the loading rate of the polystyrene sphere for the Nile red fluorescent dye were investigated.The results show that the particle size of the polystyrene spheres becomes smaller as the shearing speed of the shearing machine increases.Although the particle size of the polystyrene spheres is different,the encapsulation efficiency of the polystyrene spheres for the Nile red dyes is at around 0.39%,and less than 0.67%,which provides a possibility for subsequent micro/nanomotor drug loading.After the polystyrene sphere was obtained,the surface of the polystyrene sphere was plated with metal platinum to make a hydrogen-permeable magnetic field-driven micro/nano motor.The motion observation of the micro/nano motor in hydrogen peroxide was carried out,and the magnetic response of the micro/nano motor was proved.Experiments on the deflection of the moving direction of the nanomotor under the action of the external magnetic field successfully achieved the nearlinear motion of the hydrogen-driven magnetic field-guided micro/nano motor driven by hydrogen peroxide decomposition,the average speed is about 3.2 ?m/s,and then the magnetic field is applied in the vertical direction.The orientation changes the direction of motion,and the average velocity in the vertical direction is approximately 2.3 ?m/s.Hydrogen peroxide driven motors are not suitable in many biomedical settings due to the biotoxicity of hydrogen peroxide.Therefore,we used the mini-emulsion method to prepare a magnetic field-driven micro/nano motor.The magnetic field drive avoids the biotoxicity of hydrogen peroxide and improves the biocompatibility of the micro/nano motor.The movement speed of the micro/nano motor in different concentrations of sodium chloride solution was investigated.The results show that the larger the concentration of sodium chloride solution is,the smaller the movement speed of the micro/nano motor is,which proves that driving the micro/nano motor is not immune to ion concentration.Besides,we used the magnetic control platform to realize the movement control and cell transport of the magnetic field-driven micro/nano motor,which provided the possibility for the subsequent micro/nano motor in the targeted drug loading. |
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