Preparation And Application Of Ferroferric Oxide-based Multifunctional Nanomedical Composite

Objective:In this study,a superparamagnetic nano-molecular imaging probe（Fe₃O₄-PEG/PAM@HA）with good water solubility was synthesized by the hydrothermal method.The probe has the dual functions of MRI imaging and drug loading and has a good effect on magnetic resonance imaging as well as a therapeutic effect.Methods:Fe₃O₄-PEG/PAM nanoparticles with good water solubility were prepared in an autoclave using ferric sulfate as an iron source,polyacrylamide,and polyethylene glycol as surfactants.Hyaluronic acid（HA）was coated on its surface by physical coating to obtain a superparamagnetic nanomolecular imaging probe（Fe₃O₄-PEG/PAM@HA）with tumor-targeting ability.The materials of each group were characterized by XRD,FTIR,SEM,TG,VSM,and DLS,and the biocompatibility,targeting,and MRI imaging ability of the nanoprobe materials were tested in vivo and in vitro.Finally,doxorubicin hydrochloride was loaded on Fe₃O₄-PEG/PAM@HA for drug loading,drug release,and tumor treatment.Results:The freeze-dried Fe₃O₄-PEG/PAM@HA material is brown powder,and there is no obvious precipitation after standing at room temperature for 1 day.XRD confirmed that the compound was Fe₃O₄.FTIR results showed that polyacrylamide,polyethylene glycol,and hyaluronic acid were successfully coated on the surface of Fe₃O₄nanoparticles.Nano-size analyzer showed that the hydrated particle size of Fe₃O₄-PEG/PAM@HA nanoparticles was407 nm±191.4 nm,and the particle size distribution was narrow.SEM results show that its morphology is spherical,usually by a number of nano-particles gathered into large spheres,the diameter is about 300 nm.The hysteresis curve of Fe₃O₄-PEG/PAM@HA shows that it has superparamagnetism and the saturation magnetization is about 48.83 emu/g.The surface charge of Fe₃O₄-PEG/PAM@HA measured by the Zeta potentiometer is-42.6m V±6.72 m V.The results of the hemolysis test in vitro showed that there was no obvious hemolysis in all concentrations of Fe₃O₄-PEG/PAM@HA nanoparticles,and the hemolysis rate of each group was lower than the national standard（GB/T16886）,so it had good blood compatibility.All concentrations of Fe₃O₄-PEG/PAM@HA materials were co-cultured with293 or Hep G2 cells and CCK8 cytotoxicity test was carried out.The results showed that there was no obvious cytotoxicity in all groups.The cell uptake experiment in vitro showed that the Fe₃O₄-PEG/PAM@HA material could be absorbed by PC12 cells.After co-cultured with the cells for 1 day,the cells were in good condition,and there were no signs of morphological abnormality or necrosis/apoptosis under the light microscope.Fluorescence images and flow cytometry results show that Fe₃O₄-PEG/PAM@HA@DOX has a higher fluorescence signal than Fe₃O₄-PEG/PAM@DOX,indicating that the targeting ability of the material modified by hyaluronic acid has been improved.The r2 relaxation efficiency of the probe measured by MRI imaging sequence was 201.97 m M^-1·s^-1.The magnetic resonance imaging experiment of tumor-bearing nude mice was carried out with T2WI sequence.The results showed that the MR signal of kidney,liver,and tumor tissue decreased significantly within 0-1.5 h.In addition,the material had good tumor-targeting properties,and the MR signal in the tumor area decreased significantly in 0.5-1.5 h,which confirmed that the nanoparticles had good targeting properties to tumor tissues.Studies have shown that the metabolic pathway of the material is kidney and liver,and the half-life in vivo is about 1.5h.The results of drug loading performance study showed that the drug loading rate and entrapment efficiency of Fe₃O₄-PEG/PAM@HA were 55.91%and 6.21%respectively.Within 72 hours,the drug release rate of the drug-loaded material was 18.66%in acidic condition and 12.07%in neutral environment,indicating that it had certain drug sustained release and p H response performance.The results of cell experiment showed that Fe₃O₄-PEG/PAM@HA@DOX nanoparticles could significantly inhibit the growth of tumor cells.The results of anti-tumor experiment in vivo showed that compared with the untreated nude mice,the bodyweight of nude mice treated with Fe₃O₄-PEG/PAM@HA@DOX for 10days was stable and the tumor volume did not develop further,indicating that the drug-loaded material had a good anti-tumor effect.Conclusion:In this study,multifunctional superparamagnetic nanomolecular imaging probes（Fe₃O₄-PEG/PAM@HA）with excellent water solubility,targeting ability,magnetic responsiveness,and drug loading properties were prepared by hydrothermal method.The probe material not only has excellent biocompatibility but also has excellent tumor targeting ability.In addition,the r2 relaxation efficiency of this probe is higher than that of most reported and commercial magnetic resonance contrast agents,indicating that it has excellent T2WI imaging performance.In vivo MRI imaging experiments show that the nanoparticles have long blood half-life and tumor targeting ability,and it is a tumor-targeting T2WI contrast agent with good clinical application potential.The results of drug loading and allograft tumor treatment showed that this material had ideal drug loading rate,entrapment efficiency,certain drug sustained release performance and p H response ability,and animal experiments showed a good effect on inhibiting tumor growth.To sum up,this paper successfully prepared a multi-functional molecular imaging probe with both drug loading and magnetic resonance imaging capabilities,which provides a new means for tumor diagnosis and targeted therapy.