Experimental Study Of Preparation Method Of Calcium Alginate Microspheres Based On Piezoelectric Injection

The clinical medical drugs are becoming more and more diversified with the development of technology and medical level.However,the medical drugs have some defects such as poor tolerance,strong cytotoxic side effects,p oor oral absorption,and short biological half-life,etc.Calcium alginate microsphere is one of the most widely studied carriers,because it can not only control the drug release rate,but also deliver the drug to a specific therapeutic target.The prepar ation technology of the calcium alginate microsphere directly affects the characteristics of the calcium alginate microsphere.To achieve the variable size and uniform size of calcium alginate microspheres,in this work,a piezoelectric micro-jet-based preparation method of calcium alginate microspheres has been studied based on the operation principle of piezoelectric micro-jet and piezoelectric micro-pump.The overseas and domestic research status of the preparation methods of calcium alginate microspheres was discussed.The purpose and significance of this work were clarified,and the main research contents of the work were introduced in detail.The expected functions of the preparation device for calcium alginate microspheres were determined.According to the requirement of preparing calcium alginate microspheres with controllable and uniform size,the overall design scheme is determined.The principle of the preparation device for calcium alginate microspheres is described.The scheme of the piezoelectric micro-jet device for the injection of alginate solution and the transmission of calcium alginate microspheres by piezoelectric micro-pump was proposed to complete the preparation of calcium alginate microspheres.According to the overall design scheme,t he structure design of the preparation device for calcium alginate microspheres was completed.According to the results of finite element analysis,the key dimensions of the device are optimized,and the preparation performance of the device is improved.Finally,the design of the experiment platform for the preparation device of calcium alginate microspheres is completed.The multiphysics coupling finite element model of the piezoelectric micro-jet device is established.By analyzing the simulation results of two-phase flow,the shape and initial velocity of microspheres under different driving signal types,duty cycle of driving signal,driving signal voltage,nozzle diameter,and liquid viscosity are extracted,the control method of the size of calcium al ginate microspheres by changing the needle and driving signal voltage was obtained.The multiphysics coupling finite element model of the piezoelectric micro-pump is established.The output flow of the piezoelectric micro-pump is extracted under different driving signal voltage and frequency.The control method of the transmission rate of calcium alginate microspheres by changing piezoelectric signal was proposed.The finite element model of the preparation device of calcium alginate microspheres is established.The simulation results show that the device can be used for the preparation of calcium alginate microspheres.The assembly and experimental system of the preparation device of calcium alginate microspheres were completed.The ejection process of sodium alginate solution was photographed by high-speed camera.The forming quality of calcium alginate microspheres was analyzed to determine the viscosity and concentration of the sprayed sodium alginate solution.The preparation experiments of calcium alginate microspheres under different driving signal duty cycle and amplitude were carried out,and the morphology and initial velocity of the microspheres were extracted under different experimental conditions.The experiment of calcium alginate microsphere transportation under different driving signal frequency and voltage was carried out,and the conveying speed under different experimental conditions was extracted.The above experimental results validated the feasibility of the control method.Calcium alginate microspheres containing adriamycin hydrochloride were prepared by the preparation device.The effective encapsulation rate and release curve were measured.The results showed that the preparation device of calcium alginate microspheres has the ability of preparing calcium alginate microspheres with controllable size and uniform size.