The Study On Fixed-point Aggregation Of Magnetized Red Blood Cells Controlled By Magnetic Field In Blood Vessels

In recent years,drug targeting has received more and more attention,and many carriers have been applied in achieving targeting in blood vessels.Although there have been many treatments that have been developed on nano delivery systems,including nanoparticles,microspheres,microbubbles,and liposomes.However,the above targeted therapies still have obvious drawbacks,their target efficiency needs to be improved and the biocompatibility needs to be improved.Biological cells have many advantages compared to their target carriers,such as good biosafety,self-degradation and long circulation time.Therefore,cell membranes,vesicles and cells including red blood cells（RBCs）,mesenchymal stem cells,neural stem cells,tumor cells,and macrophages have great potential as drug carriers.Compared with other targeting methods,the magnetic targeting is more convenient,faster,safer and higher targeting efficiency.The article describes a method about RBCs encapsulating Fe₃O₄@DMSA to achieve blood vessels targets by guidance of external magnetic field.Different sources of RBCs were used to optimize the magnetized RBCs.The gradient magnetic field with excellent focusing ability was used to remotely control the aggregation of magnetized RBCs at specific sites.Experiments showed that long-term retention of magnetized RBCs in blood vessels could be achieved by repeated action of magnetic fields.The simulation results show that the focusing ability of gradient magnetic field is better than that of general magnetic field.And the in vivo targeting experiment proves that,compared with the control group,the gradient magnetic field group significantly enhances the targeting ability of magnetized RBCs in blood vessels.Different sources of RBCs can further enhance the targeting efficiency of magnetized RBCs in blood vessels.The specific content is as follows:1.Magnetized RBCs are prepared by hypotonic dilution and isobaric sealing,the preparation process was improved by the traditional low-osmotic dilution-isostatic sealing method.Secondly,the degree of magnetic response of magnetized RBCs is increased by adjusting the concentration of magnetic particles added.Finally,it’s found that the degree of magnetic response could be further improved by using different sources of RBCs.2.Magnetized RBCs can achieve targeting in blood vessels under the remote control of a gradient magnetic field.The gradient magnetic field used in the experiment was simulated by ANSYS.Then the Fluent was used to simulate and analyze the flow of magnetized RBCs in the blood vessel.By adjusting the strength of the magnetic field and the time of the magnetic field,we assembled the magnetized red blood cells at different positions in the mouse body under the guidance of an external magnetic field.Different methods such as fluorescence imaging,nuclear magnetic resonance,ultrasound,and tissue sections were used to characterize different target sites in mice.3.Compared to the traditional drug carrier system,a new drug carrying system,which combines magnetized RBCs with gradient magnetic field of excellent focusing performance,has better target efficiency.Preliminary conclusions can be obtained that the magnetized RBCs in the body can be targeted and a long time retention in the target position through the guidance of the gradient magnetic field.This new drug carrying system has great potential for clinical treatment.