The Application Of Iron-based Nanoparticles In Nanoenzymes And Nuclear Magnetic Resonance Imaging

As a new generation of artificial mimic enzymes,nanozymes are inorganic nanomaterials that can show the characterization of enzyme at the nanometer scale.Nanozymes can also as the enzymes to catalyze the decomposition of substrates efficiently under mild physiological conditions,and produce the same product.The emergence of nanozymes reveal the biological activity of inorganic nanomaterials,and which is not only to expand the application of nanomaterials in biomedicine,but also provide new ideas for artificial mimic enzymes research,and open up a new world for nanobiology.Many natural enzymes that have been successfully simulated until now,include oxidase,peroxidase,catalase,and superoxide dismutase.And based on these studies,nanozymes have been widely used in biosensing,cancer diagnosis and treatment and environmental protection.Iron-based nanomaterials are currently the most widely studied and also are one of the fastest nanozymes to be commercialized,and which have outstanding advantages in simulating peroxidase.In this work,We have done two things with iron-based nanoparticles:1.Ultrasound-enhanced catalytic activity of Fe@Fe₃O₄ nanozymes and its synergistic treatment for tumor chemotherapy.The nanoparticles which based on the Fe₃O₄ could be used to simulate the peroxidase properties.We synthesized crystalline Fe₃O₄ nanoparticles and the Fe@Fe₃O₄ nanoparticles with amorphous shell,and measured the the activity and the maximum reaction rate(?18??6?of two kinds of nanoparticles.The activity and maximum reaction rate(?18??6?of Fe@Fe₃O₄ nanoparticles are ¹0 times higher than those of Fe₃O₄ nanoparticles.A further study showed that the ultrasonic condition could enhance the maximum reaction rate(?18??6?of Fe@Fe₃O₄ nanozymes.We further constructed a tumor model with high concentration of H2O2 through ?-lapachone,and then injected nanozymes through the tail vein,and finally the growth of tumor was inhibited successfully under the conditions of ultrasound.2.The research of MR imaging about hollow Fe₃O₄ nanoparticles with renal metabolic capacity.We synthesized two sizes of hollow Fe₃O₄ nanoparticles,and weaken the magnetic anisotropy of Fe₃O₄ nanoparticles by reducing the size for smaller magnetic moment.The hollow structure make the nanoparticles has a spin disordered shell on both inner and outer surfaces,which could enhance the Longitudina relaxation rate.Then,we improved its water solubility by modification with water-soluble zwitterionic dopamine sulfonate?ZDS?,and the MRI result reveled that two nanomaterials can be used as MRI contrast agent,and can be metabolized by the kidney.