Mitochondrial Targeted Fe₃O₄ Nanoparticles For In Vitro Magnetic Hyperthermia

With the fast development of nanotechnology,nanomaterials and their biomedicine applications have attracted much attention.Fe₃O₄ nanoparticles,which possess superb biocompatibility and unique magnetic properties,have attracted much attentions in the biomedical application,such as magnetic hyperthermia,magnetic resonance imaging.As the prevailing biomedical magnetic nanoplatform,iron oxide nanoparticles usually show low-efficient magnetic hyperthermia,which hinder their application as a high-performance theranostic nanoagent in cancer medicine.Herein,we developed mitochondrial targeted Fe₃O₄nanoparticles for in vitro magnetic hyperthermia.Investigations on controllable synthesis,surface decoration and magnetic hyperthermia have been carried out.The main content includes the following aspects:?1?The monodispersed superparamagnetic iron oxide nanoparticles were synthesized via high-temperature solution phase reaction and transfer hydrophobic Fe₃O₄ nanoparticles to an aqueous phase by ligand exchange.TEM images shows that the size of Fe₃O₄ nanoparticles were about 7 nm with a narrow distribution.The power X-ray diffraction patterns of as-prepared Fe₃O₄ nanoparticles demonstrated high crystallinity.DLS results showed the hydrodynamic diameter of Fe₃O₄ nanoparticles were about 12 nm.VSM results showed Fe₃O₄ nanoparticles were superparamagnetic and the saturation magnetization of Fe₃O₄ nanoparticles were 58.8emu/g.?2?We developed mitochondrial targeted Fe₃O₄ nanoparticles by adopting mitochondrial-guiding agents?e.g.,triarylphosphonium?TPP?cations?as a high-performance theranostic nanoagent in cancer medicine.We analyzed the shape,size,the magnetic properties and the surface decoration of TPP-Fe₃O₄.FTIR spectrum showed the band at 1637 and 1560 cm^-1,which arose from the amido bond stretching vibration.The TPP-Fe₃O₄ nanoparticles contain Fe,O,N,C and P elements.The nitrogen peak and phosphine peak are attributed to the TPP.When exposed to 30 A alternating current field,the TPP-Fe₃O₄ nanoparticles solution at 0.34mg/mL showed¹3oC increase in temperature within 10 min.The results showed TPP-Fe₃O₄nanoparticles have an excellent magnetothermal conversion efficiency.?3?TPP-Fe₃O₄ nanoparticles show insignificant toxicity with Fe concentration of 100?g/mL,the cell viability of HepG2 liver cancer cells were more than 80%after 24 h of incubation with nanoparticles.The uptake of Fe₃O₄ nanoparticles significantly increased,and the uptake rate gradually slowed and reached a plateau at 10 h,the cellular uptake of Fe₃O₄ nanoparticles reach a maximal value.And bio-TEM shows except the distribution in the lysosome,some TPP-Fe₃O₄ NPs were location in the mitochondria clearly.?4?We examined the cell viability of HepG2 liver cancer cells that were incubated with TPP-Fe₃O₄ nanoparticles,followed by magnetic hyperthermia?MHT?treatment.The results showed a remarkable cytotoxic effect was observed for TPP-Fe₃O₄ nanoparticles with the Fe concentration 100?g/mL after hyperthermia treatment within 10 min,the cell viability reduced to nearly 25%.Thus,using the TPP-Fe₃O₄ NPs for tumor magnetic hyperthermia may provide an new approach for developing high efficiency magnetic hyperthermia nanoagents.?5?We introduce a simple method for producing millimeter-sized organoids with spheroid conformation,liver organoid is formed by co-culturing 3T3 fibroblasts and HepG2 cells in droplets hanging from pipette tiptop.We reveal that organoids formed in hanging droplets share a layered structure with 3T3 fibroblasts as cell and HepG2 at core.We examined magnetic hyperthermia effect of Fe₃O₄ nanoparticles on liver tumor organoid.The uptake of Fe₃O₄nanoparticles per cell is assessed by digesting liver organoid and measure the Fe content,and the results showed Fe₃O₄ uptake amount is the highest during monolayer HepG2 cell culture,and lowest in the form of organoid.MHT effect induced cell apoptosis is most significant when HepG2 cells are maintained as monolayer,and least effective during treatment to liver organoids.Our studies offer possibilities for organoid simulating tumor for magnetic hyperthermia.