Synthesis And Magnetic Induction Heating Properties Of Nanomaterials For Magnetic Hyperthermia

Magnetic nanomaterials are increasingly used in magnetic hyperthermia,but the control of hyperthermia temperature mainly depends on circulating cooling water and regulating magnetic field intensity,which increases the difficulty and complexity of clinical treatment.Magnetic nanomaterials with Curie temperature of 42-46? may realize self-regulating temperature through magnetic phase transition,but most of nanomaterials used in clinical treatment are Fe3O4 or CoFe2O4 nanoparticles and their Curie temperatures are as high as several hundred degrees Celsius,which can not be used in self-regulating temperature hyperthermia.Preparation of magnetic nanomaterials with low Curie temperature is a new direction for magnetic hyperthermia in recent years.Here,we focused on decreasing Curie temperature of CoFe2O4 nanoparticles by reducing super-exchange interaction between sublattices through Cr3+and Zn2+ substitution.Magnetic induction heating experiments demonstrated that the obtained nanoparticles can self-regulate temperature at 42-46?.Besides,to realize synergistic sensitization effect of magnetic hyperthermia and chemotherapy drugs,we prepared magnetic carbon nanotubes and injectable magnetic hydrogels based on the obtained nanoparticles,and then investigated their self-regulating temperature ability and drug release behavior.The main contents are as follows.Non-magnetic Cr3+ was introduced into CoFe2O4 through hydrothermal method.CoCrxFe2-xO4(0?x?1.2)nanoparticles were obtained and the influence of Cr3+ on magnetic properties was studied systematically.The addition of Cr3+ could decrease magnetic moments of B site,and the super-exchange interaction between A site and B site was correspondingly reduced,resulting in the decrease of Curie temperature.When x increased from 0 to 1.2,Curie temperature decreased from 417.5? to 345.8?.To futher reduce Curie temperature,non-magnetic Zn2+ was substituted into the obtained CoCro0.6Fe1.4O4 nanoparticles.ZnxCo1-xCr0.6Fe1.4O4(0?x?0.56)nanoparticles with Curie temperature ranging from 34.3?to 361.7? were prepared.Among them,the Curie temperature of Zn0.54Co0.46Cr0.6Fe1.4O4 nanoparticles was 45.7?,magnetic induction heating experinents demonstrated that these nanoparticles could generate heat and self-regulate temperature at 44-44.6? with specific absorption rate(SAR)of 774 W/kg under clinical alternating magnetic field,which met the temperature requirements of magnetic hyperthermia.Cytotoxicity experiments showed that Zn0.54Co0.46Cr0.6Fe1.4O4 nanoparticles had the good biocompatibility.Magnetic carbon nanotubes and injectable magnetic hydrogels were prepared based on the obtained Zn0.54Co0.46Cr0.6Fe1.4O4 nanoparticles,and then were used to load antitumor drug doxorubicin hydrochloride(DOX).Magnetic induction heating experiments and in vitro drug release experiments demonstrated that both magnetic carbon nanotubes and magnetic hydrogels could be used in self-regulating temperature magnetic hyperthermia and sustained drugs release.On one hand,magnetic carbon nanotubes and magnetic hydrogels could self-regulate temperature at 42.6-43.1? under alternating magnetic field,which were suitable for self-regulating temperature magnetic hyperthermia;on the other hand,during magnetic induction heating process,DOX release percentages of magnetic carbon nanotubes and magnetic hydrogels under tumor pH environment were 23.5%and 22%in 2 hours,and the final release percentages reached 71.7%and 75%,which met the requirements of drug sustained-release in Chinese pharmacopoeia.