Preparation And Properties Of Magnetic Nanogels Based On HER2 Receptor

Breast cancer is a high incidence rate and recurrent tumor.Traditional chemotherapy has irreversibly toxic and negative effects on normal tissues.In order to improve drug utilization rate and reduce the negative effects on normal tissues,targeted and controlled release drug carriers has become a research area in the field of breast cancer treatment.The Fe₃O₄ ferrofluid was obtained by Chemical coprecipitation.The magnetic nanogel（MNL）were prepared by miniemulsion polymerization,using acrylic acid（AA）as the p H responsive monomer and N-isopropyl acrylamide（NIPAM）as the temperature responsive monomer.The experimental parameters were optimized to adjust the properties of the magnetic nanogel.Based on magnetic nanogels（MNL）,hydrophilic drug doxorubicin（DOX）and hydrophobic drug paclitaxel（PTX）were loaded,and the active targeting antibody Herceptin was grafted by carboxyl complexation reaction.The dual-targeting drug loading system of magnetic nanogel based on HER2 receptor was prepared,which can provide a theoretical basis and scientific method for exploring the application of magnetic nanogel drug delivery system in biomedicine.The main research contents and results are as follows:（1）The average particle size of Fe₃O₄ magnetic fluid prepared by chemical precipitation method is 4.8 nm and distributed evenly.By adjusting the content of acrylic acid（AA）,divinylbenzene（DVB）and magnetic fluid,the performance of magnetic nanogel（MNL）is optimized.The particle size,morphology and zeta potential of MNL were characterized by Fourier infrared spectroscopy（FTIR）,nano particle sizer and transmission electron microscope（TEM）.Then the magnetic properties of MNL were tested by vibrating sample magnetometer（VSM）.The results showed that the performance of MNL was the optimal when the content of DVB is 10 mol%,the content of AA is 5 mol%,and the amount of Fe₃O₄ magnetic fluid is 450 mg.The surface of MNL contains a large number of carboxyl groups,amide bonds and amino functional groups.The average particle size of MNL-6 was about 66 nm,and the dispersibility is uniform without obvious agglomeration.（2）Hydrophilic doxorubicin（DOX）was selected as the drug model.A magnetic nanogel drug-loading system containing DOX（MNL-6@DOX）was prepared by direct in-situ polymerization.Fourier transform infrared spectroscopy（FTIR）,transmission electron microscopy（TEM）and nano particle size analyzer were used to analyze MNL-6@DOX of the particle size and zeta potential.The sustained-release performance was characterized by UV spectrophotometer.The results showed that the average particle size of MNL-6@DOX is about 70 nm.Under the condition of 37℃and p H=6.0,the release rate of DOX can reach 53.79%after 372 h.When the addition concentration of MNL-6@DOX is more than 300μg/ml,the survival rate of MCF-7 cells was less than50%.（3）The hydrophobic drug paclitaxel（PTX）was selected as the drug model.In order to improve the drug loading rate,MNL containing cyclodextrin ligand（MNL-CD）was copolymerized by cyclodextrin（CD）.PTX was introduced into the oil phase to prepare magnetic nanogel containing cyclodextrin ligand loading with PTX（MNL-CD-3@PTX）.The particle size,Zeta potential and morphology of MNL-CD and MNL-CD-3@PTX were characterized by Fourier Transform infrared spectroscopy（FTIR）,nanometer particle size analyzer and transmission electron microscopy（TEM）.The magnetic properties of MNL-CD were characterized by vibrating sample magnetometer（VSM）.The drug-release behavior of MNL-CD-3@PTX was characterized by ultraviolet spectrophotometer.The results show that MNL-CD-3 has the best property when DVB content is 15 mol%,AA content is 5mol%,β-CD content is 0.179 g,and Fe₃O₄ content is 150 mg.The average particle size of MNL-CD-3 is about 84 nm,and the dispersion is uniform without obvious agglomeration.The particle size of MNL-CD-3@PTX ranges from 74 nm to 125 nm,with an average particle size of 87 nm.At37℃and p H=5.4,the release rate of PTX reached 26.42%after 313 h.When the concentration of MNL-CD-3@PTX reached 150μg/m L,the inhibition rate of MCF-7cells reached 33.08%.（4）On the basis of the MNL drug delivery system,the active targeting antibody Herceptin was grafted on MNL through ammonia carboxyl complexation reaction,and the MNL drug delivery system based on HER2 receptor was obtained.The particle size,Zeta potential and morphology of the MNL dual-targeted drug delivery system were characterized by Fourier Transform infrared spectroscopy（FTIR）,nanometer particle size analyzer（DLS）and transmission electron microscopy（TEM）.The sustained release properties of the dual-targeted drug delivery system were characterized by UV spectrophotometer.The results showed that DOX（20.45%）and PTX（26.25%）were released by MNL-6@DOX@Herceptin and MNL-CD-3@PTX@Herceptin at 37℃and p H=5.4,respectively.The dual-targeted drug delivery system has rich functional groups,which is expected to be applied in the targeted therapy of HER2 positive breast cancer.