Mechanism Of Iron Oxide Nanoparticles Forming Lipid Corona To Induce Foaming Of RAW264.7 Cells

Iron oxide nanoparticles(IONPs)are one of the most widely used nanoparticles,which have been widely used in food industry,agricultural production,medical and other fields.In the food industry,IONPs are often used as food additives,fertilizers,food packaging materials,and nutrient carriers.With the increasing production and use of IONPs,the possibility of consumer exposure to IONPs through related foods has greatly increased.Due to the small size and high surface activity of nanoparticles,they are easy to interact with macromolecular substances such as proteins,lipids,and polysaccharides in vivo.The way IONPs are digested and absorbed through the gastrointestinal tract through food or inhaled in the air through processing will cause abnormal functions of cells and tissues and organs,which will bring many adverse effects on human health.IONPs have strong surface activity and can spontaneously interact with biological macromolecules and change the properties of the original IONPs to reduce cell survival.Therefore,controlling the interaction between nanoparticles and biological macromolecules plays a crucial role in maintaining the body environment.Lipid corona is the product of complex formation between nanoparticles and lipids,and lipids will endow nanoparticles with a new property and change the properties of the original nanoparticles in later biological effects.The damage of IONPs to tissues and organs has been confirmed,but the specific molecular mechanism of the toxic effect of IONPs on cells by forming complexes with lipid components is still unclear.In this study,the formation of lipid crowns by IONPs was taken as an entry point to clarify the role of lipids in the formation of lipid crowns by IONPs and the transformation of RAW264.7 cells into foaming induced by IONPs.Research on the safety of nanoparticles in the food field.Part Ⅰ: Taking two important types of IONPs,Fe3O4 NPs and Fe3O4-NH2 NPs,as the research objects,stable and reliable nanoparticles were obtained by improving the synthesis method;CCK-8 and lactate dehydrogenase(LDH)experiments were used to find that Fe3O4 NPs and Fe3O4-NH2 NPs can significantly reduce the The survival rate of RAW264.7 cells and the damage of cell membrane were determined,and the subsequent administration concentration was 100 μg/m L,and the administration time was 12 h.Subsequently,the loss of nanoparticles during magnetic separation of Fe3O4 NPs and Fe3O4-NH2 NPs is both about 4%,which is acceptable.Finally,it was determined that both 100 μg Fe3O4 NPs and Fe3O4-NH2 NPs could adsorb 400 μg dipalmitoyl-phosphatidylcholine(DPPC).Part Ⅱ: To study the specific molecular mechanism of RAW264.7 macrophages into foam cells after adsorption of DPPC by Fe3O4 NPs and Fe3O4-NH2 NPs to form a lipid corona.First,by ICP-OES and super-resolution confocal microscopy,it was observed that the lipid corona uptake in cells was significantly reduced compared with the control group(Bare Fe3O4 NPs and Fe3O4-NH2 NPs),but the cell survival rate was reduced,and it was found that oxidative stress was involved in the damage of lipid corona to RAW264.7 cells.Furthermore,electron paramagnetic resonance was used to detect that lipid crowns could generate hydroxyl radicals and further oxidative stress under the condition of H2O2.Oil red O was used to find that the participation of oxidative stress would lead to the accumulation of lipids in RAW264.7 cells.The detection of triglyceride and cholesterol kits indicated that lipid corona formation promotes lipid accumulation.Secondly,the Western-blot assay detected that the ATP-binding cassette transporters ABCA1 and ABCG1 were inhibited by oxidative stress and inhibited lipid efflux,while the lipid uptake receptor CD36 continuously promoted lipid uptake,further enabling RAW264.7 cells.The accumulation of internal lipids increases,and as a result,macrophages become foamy.Finally,exposure of the lipid corona significantly induced the expression of inflammatory factors relative to the control group.In addition,by means of Reverse Transcription-Polymerase Chain Reaction(RT-q PCR),it was found that the exposure of lipid corona induced significant expression of genes regulating lipid uptake in RAW264.7 cells,while the expression of excretion genes was significantly inhibited,and resulted in a significant enhancement of intracellular IL-6 gene expression.