Research Of The Novel Preparation Of Magnetic Fluorescent Bifunctional Nanomaterials

Nanoscale materials because of their size decrease with the unique and exceptional various performances in thermal, electrical, mechanical, optical, magnetics and chemical aspects. When the size of the particles in different dimensions( one-dimensional,two-dimensional or three-dimensional) is smaller than the free path of electron transmission, many of their performance turn up a huge change or be enhanced. Has one of the most practical value and development prospect are quantum dots with fluorescence and magnetic nano microspheres. A variety of nanoparticle composite each other not only can reach a transformation from nano particles to the functional components, but also can realize a functional integration between the materials. So, for the double function of nano compound qualitative research has become a hotspot in the research of the material science.Fluorescent semiconductor quantum dots and the integration of magnetic nano microsphere is a good example, Between the compound fluorescent tags in the biomedical and with magnetic separation step to complete, this technology will greatly promote the development of biological science and technology. Fluorescent magnetic nano microsphere has both additional Magnetic separation characteristics of magnetic microspheres and the fluorescence properties of quantum dots, this has a very good prospects for development,and is expected to be widely used in the cells of the immune cells or tissues, separation,targeted therapy, or other fields.This paper mainly through the electrostatic attraction, preparation of Fe3O4 / PMIDA@ CdTe and Fe3O4 / PMIDA @ CdSe/CdS fluorescent magnetic nano microsphere.According to the study, we have done the following work:(1)Using chemical coprecipitation, Fe3O4 magnetic particles was produced first, then uses a certain amount of TMAOH surfactant to form hydrophilic type magnetic nanoparticles, and makes the Fe3O4 take- OH. And then to the produced hydrophilic ferroferric oxide as the kernel, then in its outer package by using the method of electrostatic attraction coat PMIDA, make its surface with functional carboxyl, a greater degree of increase of the magnetic water soluble. Based on experimental study of modified PMIDA pH, coated temperature, concentration, which obtained the best experimental production conditions, and characterizated by XRD, TEM, ir, etc.(2)Production of CdTe quantum dots in Water phase : CdTe quantum dots in Water phase have be Produced with three steps of colloid chemistry synthesis, then modify thioglycolic acid by thioglycolic acid(TGA) on its surface, and make it with carboxylic functional group. Respectively make a discussion on influence Factors of the fluorescence intensity,such as the precursor concentration, reaction temperature, reaction of PH and so on, finally we can get size for 5-6 nm CdTe quantum dots, not only the size is small, but also fluorescence intensity is high, and scattered evenly.(3)Production of CdSe/CdS quantum dots in oil phase: It produced CdSe/CdS quantum dots in oil phase when Oleic acid, liquid paraffin wax both as solvent, reoccupy thioglycolic acid(TGA) as modifier, and then transferred to the PBS phosphate buffer, get the solution of water-soluble quantum dots. We were studied in the experiment of stabilizers, CdSe/CdS quantum dots Se and S the amount of substance ratio and pH on the influence of the intensity of fluorescence quantum dots, eventually got CdSe/CdS quantum dots, it’s intensity of fluorescence is higher and has a better stability.(4)With ethylenediamine as coupling agent, EDC as activator, through the functional carboxyl on the surface of the magnetic microsphere Fe3O4 and quantum dots on the surface of the carboxyl, through chemical bond, the magnetic Fe3O4 nanoparticles and fluorescence quantum dots are combined, synthesis of the double function of both magnetic and fluorescent nano composite microspheres. It characterizated by TEM,infrared spectrophotometer, thermogravimetric analyzer, EDS, fluorescence spectrophotometer, etc. According to the results of the characterization, Fe3O4 / PMIDA @CdTe and Fe3O4 / PMIDA @ CdSe/CdS fluorescent nanometer magnetic composite microspheres dispersibility in water is good, it’s size is about 70-80 nm, magnetic property and fluorescent property is very good.