Application Of New Biomimetic Temozolomide Nanoparticles In The Targeted Therapy Of Glioma

Temozolomide is the main traditional chemotherapy drug for glioma,but the treatment effect is not satisfactory.Many other chemotherapeutic drugs have performed well in vitro,but their efficacy in vivo is compromised by their low water solubility.If the dose is increased,drug resistance is likely to develop,with serious side effects.In this study,the insoluble chemotherapeutic drug temozolomide(TMZ)was prepared into nanocrystals(TNDs)by using nanocrystals to solve the problem of poor water solubility.Meanwhile,the purified erythrocyte membrane was wrapped on the surface of TNDs to camouflage it.The stealth effect of nanomaterials can prolong the cycle of the body and avoid being removed by the agglutination of circulating proteins.In addition,tumor penetrating peptide i RGD was modified on erythrocyte membrane to increase the active targeting ability of bionic nanometer preparation.Finally,a multi-functional bionic nanometer platform i RGD-EM:TNDs was constructed.This nanoparticle not only has perfect biocompatibility and stealth ability to escape the trap of the reticuloendothelial system,but also cross the blood-brain barrier to enter the tumor site through active and passive targeting functions,which improves the bioavailability of the drug and reduces the toxic and side effects of the drug.The following are the main contents of this study:1.Preparation of bionic nano-targeting preparation(i RGD-EM:TNDs).In this study,the O/W/O complex emulsion method was first used to synthesize a uniform outer layer coated with TNDs(? 15nm)F127,with positive zeta potential.Then,the erythrocyte membrane was wrapped on the surface of TNDs nanocrystals by repeated extrusion process,and i RGD targeting peptide was modified on the membrane.At this point,nanoparticles with spherical shape and erythrocyte membrane coating can be observed through electronic transmission mirror.The diameter of the nanometer preparation was measured by dynamic light scattering at about 22 nm,the zeta potential was negative,and the drug loading capacity was high,up to 72 wt%.The physical and chemical properties of the nanomaterial were studied in accordance with the expected design.2.In vitro evaluation of i RGD-EM:TNDs cell uptake and cytotoxicity.In this study,different TMZ formulations were co-incubated with U87 MG cells,and the results showed that the internalization of TNDs by U87 MG cells was better than that by TMZ cells.Among them,i RGD-EM:TNDs had the highest intracellular uptake and could be better absorbed by cells.In the cytotoxicity experiment of the four groups of formula at the same TMZ concentration,the viability of cells decreased gradually: TMZ,TNDs,EM:TNDs,i RGD-EM:TNDs.IRGD-EM:TNDs showed more obvious cytotoxicity to glioma cells.3.Assessment of penetration of 3d tumor spheres.In this study,a multicellular tumor globular model of U87 MG cells was prepared to replace the traditional monolayer cell system.The results showed that pure TMZ was trapped in the outermost cells,while TNDs,EM:TNDs and i RGD-EM:TNDs had greater advantages in penetration depth,among which i RGD-EM:TNDs had the strongest penetration.4.Ability assessment of nanometer preparation to cross blood-brain barrier.Endocytosis of the blood-brain barrier was performed on different TMZ formulations.The results showed that the transfer rates of TMZ,TNDs,EM:TNDs and i RGD-EM:TNDs at 8 h were 10%,18.6%,22% and 29%,respectively.In addition,considering the relationship between i RGD and BBB transcytosis,we detected the presence of drugs in the brain through multi-photon microscopy after intravenous administration of FITC-labeled i RGD-EM:TNDs.5.Study on glioma targeting ability and anti-tumor efficacy.Through the establishment of in vivo imaging system of intracranial in-situ model of brain glioma,we found that the brain tissue of the group i RGD-EM:TNDs group emitted strong fluorescence,indicating its effective homing ability for brain tumors.In vivo anti-tumor efficacy studies showed that among the four groups of different TMZ formulations,i RGD-EM:TNDs group had the best inhibitory effect on brain tumors,and significantly prolonged the survival time of tumor-bearing mice.6.Evaluation of toxic and side effects of bionic nanometer preparation.Histological sections of the heart,liver,spleen,lung and kidney of the model mice showed no significant toxic or inflammatory infiltration.Meanwhile,the i RGD-EM:TNDs group showed delayed weight loss compared to the other three treatments.The Ig E levels and hematological parameters of all erythrocyte membrane nanocrystalline were almost unchanged,confirming the good biocompatibility of our biomimetic nanoparticles and the prevention of severe hemotoxicity.