Synthesis And Biological Applications Of Iron Oxide Nanocubes Based Micro/nano-sized Composite Spheres

To meet the requirement in varying fields,multifunctional nanocomposites have been designed and fabricated by integrating a variety of functional nanocomponents.Magnetic nanomaterials are important functional building blocks to fabricate multifunctional nanocomposites.There is a challenge to effectively and facilely assemble magnetic iron oxide nanoparticles with other functional nanomaterials,which has attracted great attentions in the field of biomedicine.Herein,we employed iron oxide nanocubes as the building blocks,and obtained a series of micro-and nano-sized composite spheres by the orderly assembling at the micrometer and nanometer scales.In the first work,we synthesized hydrophobic ferrimagnetic iron oxide nanocubes（denoted as FION）and indium phosphide quantum dots by the decomposition at the high temperature in organic solvents,and modified them with the block copolymer PEG-b-PHEP to obtain magnetic fluorescent nanosized micelles(denoted as MFM^PHEP).The morphology,surface potential and particle size of the obtained MFM^PHEP were systematically evaluated.This MFM^PHEP can be manipulated under an external magnetic field,exhibiting the excellent magnetic targeting and optical responsiveness.Under an external magnetic field,this MFM^PHEP were accumulated in the tumor area,and the T₂MR contrast performance provided the possibility of MR tracking in vivo.At the same time,the magnetic fluorescence micelles had a significant heating effect in an alternating magnetic field,which realized the integrated effect of diagnosis and magnetic hyperthermia treatment against tumors.Furthermore,we used magnetic iron oxide nanoparticles（FION）to fabricate magnetic microspheres.At first,chitosan-silver nanowire microspheres were synthesized by the microfluidic synthesis procedure from the chitosan and silver nanowire aqueous mixture,followed by the supercritical drying.Then,the obtained microspheres were mixed with FION,and the effective adsorption resulted in the final product of chitosan-silver nanowire magnetic composite microspheres.The uniform morphology and size distribution were observed by the SEM,TEM and sizer.The uniform distribution of FION contributed to the excellent magnetic targeting as well as magnetothermal properties.The silver nanowires contributed to the photothermal and CT imaging effects.These combined performances of the obtained magnetic microspheres promoted their applications in biomedicine.