Study On Preparation And Biological Activity Of Magnetic Targeting Cell Membrane-coated Nano Drug Delivery Materials

Compared with surgery,radiotherapy,and chemotherapy,cancer treatment based on nano drug carrier materials can significantly improve the solubility and metabolic properties of drugs,optimize tissue distribution in vivo,target tissue aggregation,and significantly improve the circulation of drugs in vivo,showing attractive applications.Among them,the use of cell membranes,especially tumor cell membranes,to modify the surface of nanoparticles can further confer a homogenous effect on the drug-loading system and enhance its immune escape and targeted transport capabilities.However,the current cell membrane drug carrier materials are mainly modified and loaded with nanoparticles by physical encapsulation,which results in defects such as low drug loading rate,insufficient material stability,and the unexpected-release of drugs;in addition,cell membrane drug carriers mainly realize the targeted transport and absorption of drugs through the"homologous effect".Although this biological target has a very high specificity,it also depends on that the nano-drug can be quickly and effectively enriched in the lesion.Therefore,this requires cell membrane drug carrier materials to possess other targeting properties,such as magnetic targeting properties,in addition to biological targeting properties.In view of this,this subject used 2,3-diaminopropionic acid as a bridging group,and via its three active functional groups anti-tumor drug molecules（such as lapatinib）,magnetic iron oxide nanoparticles and click reaction Active groups（including maleimide groups and lipoic acid groups）were employed to obtain cell membrane-modified ligands,which then reacted with sulfhydryl groups widely present in cell membranes by a click reaction method to achieve chemical covalent bonding with A431 cell membranes,giving the magnetic targeting cell membrane drug carrier materials（ie Fe₃O₄@9-2,Fe₃O₄@10-2）.In addition,in order to observe and study the distribution and mode of action of this type of nano drug delivery system in vivo and in vivo,and to achieve the integration of diagnosis and treatment,we have also introduced fluorescent molecular groups to replace tumor drug molecules,and prepared carrier materials with fluorescent properties（ie Fe₃O₄@9-1,Fe₃O₄@10-1）.In order to compare the activity difference between the cell membrane covalent bond modification and the physical encapsulation method,we have prepared a cell membrane modification ligand that does not contain a click reaction group,and then the corresponding carrier material（ie Fe₃O₄@8）was prepared by the physical encapsulation method.Dynamic light scattering（DLS）and transmission electron microscopy（TEM）characterization showed that the nanoparticles were relatively uniform vesicles or granules,dark iron nanoparticles were visible in the core,and a grey organic layer was found on the outer shell,with a particle size of 40-160 nm,in line with the optimal size of the nano drug loading system.The protein composition of the carrier material analyzed by SDS-PAGE was consistent with the protein composition of the cell membrane,indicating that the cell membrane was successfully modified to the surface of the nanoparticles.The iron content of the nanocarrier material was detected by ICP-MS,and iron was detected in the prepared drug-loaded materials,indicating that the iron nanoparticles were successfully loaded into the cell membrane.Further analysis found that the iron content of the drug-loaded material prepared by covalent modification was significantly higher than that of the drug-loaded material prepared by physical coating,suggesting that the drug loading rate of the drug-loaded material prepared by covalent modification was higher.The vibrating sample magnetometer（VSM）test also showed that the nanoparticles retained good superparamagnetic properties of ferric oxide,indicating that the drug can be targeted to the tumor site by the action of an external magnetic field.In the nanoparticle stability experiment,Fe₃O₄@8 was the most unstable due to the physical coating to modify the cell membrane to the surface of the nanoparticles;while the covalently bonded Fe₃O₄@9 and Fe₃O₄@10 were stable within 72 h as no obvious change in particle size was observed.Cell uptake experiments showed that the tumor cell membrane modified drug-loading system had a higher uptake rate in homologous tumor strains,while the normal cells only showed a low uptake rate.Combining the results of protein detection,it can be concluded that the membrane-modified magnetic nano drug-loading system retained most of the functions on the A431 cell membrane and successfully inherited part of the membrane function of the tumor cell membrane,thus showing a significant homologous effect.In the in vitro anti-tumor experiments,the carrier material without the lapatinib fragment showed no effect on the tested cells,indicating a good sfaty.In contrast,the carrier material containing the pharmacodynamic fragment of lapatinib showed clear tumor inhibitory activity,and the inhibitory activity against homologous tumor cell lines was higher than other cell lines.