Preparation And Characterization Of Magnetic Fluorescent Polymer Composite Microspheres

Superparamagnetic Fe3O4 magnetic particles have been widely used in the medical fields of magnetic-heat therapy,MRI,bio-separation technology etc.Quantum dots have a bright application in the medical domain of bio-labeling,biological imaging because of the superior luminescent property.Besides,polymer has attracted more and more attention due to the advantages of great hydrophilism and richness in functional groups.Currently,the single functional materials seem to be unable to meet the increasingly complex application demand,so the multi-functional composite materials improve.Combining the magnetic particles,quantum dots with high polymer not only satisfy the magnetic separation and fluorescence imaging,but also make it accessible to connecting biological molecules,which promote the development of Biotechnology.Therefore,the polymer composites with magnetic and fluorescent properties are valuable in the biomedical field of multimode fluorescence/MRI imaging,medical treatment and testing,drug targeting,magnetic separation etc.In this paper,three kinds of composites were synthesized by fitting magnetic particles,fluorescent materials and polymer materials together.The primary contents are as following:(1)The P(NIPAM-co-AA)microspores,as the template,are obtained by inverse suspension emulsion polymerization.The template microspores are amino-functionalized in order to react with the mercaptoacetic acid modified-CdTe quantum dots which are prepared by aqueous synthesis,which finally resulted in a new type of fluorescent polymer microspheres.(2)Fe3O4 nanoparticles were doped into the networks of the polymer template microspheres P(NIPAM-co-AA)by a simple swelling method.Amino-functional magnetic microspheres reacted with the mercaptoacetic acid modified-CdTe quantum dots,which finally come to the multifunctional CdTe@Fe3O4/P(NIPAM-co-AA)composite microspheres with superparamagnetic and fluorescent properties.(3)The mercaptoacetic acid modified-CdTe quantum dots which are obtained by aqueous synthesis bonds to the amino-functionalized Fe3O4 magnetofluid synthesized by chemical coprecipitation,which produced magnetic fluorescent nanoparticles Fe3O4@CdTe.Add the prepared Fe3O4@CdTe nanoparticles to the PNIPAM in aqueous phase and disperse uniformly.Finally the magnetic fluorescent polymeric microspheres are polymerized.Several techniques,e.g.scanning electron microscope,transmission electron microscopy,fluorescence microscopy and fluorescence spectrophotometer etc.were used to characterize structures and properties of the composites.In conclusion,the composites are uniformly regular sphericity with special morphology,as large as about 30?m,and exhibit excellent superparamagnetism and high efficient fluorescence quantum yield.