Synthesis Of Magnetic Fluorescent Nanoprobes And Its Application In Determination Of Folic Acid And Separation Of Membrane Proteins

In recent years,bi-functional magnetic fluorescent composites with unique tracer and separation functions have attracted strong interests of researchers of biology,chemistry and medicine.At the same time,these bi-functional composites have been widely used in cell labeling,targeted drug delivery and the detection,separation and enrichment of trace component.In this work,a novel magnetic fluorescent nanocomposite was synthesized,and two new magnetic fluorescent nanoprobes were synthetised by amino-functionalized and further folic acid?FA?functionalized respectively.In the determination of actual samples,satisfactory results were obtained.The main research of the work is as were follows:?1?Fe₃O₄@SiO₂/CdTe magnetic fluorescent composites were successfully constructed by amidation reaction,using GSH-modified CdTe QDs as fluorescent materials and amino functionalized Fe₃O₄@SiO₂ magnetic nanoparticles as magnetic source.The results indicated that composites have both superparamagnetic and fluorescent properties.?2?Fe₃O₄@SiO₂/CdTe-NH-NH₂ magnetic fluorescent nanoprobe for determination of folic acid was successfully synthesized by amidation reaction,using Fe₃O₄@SiO₂/CdTe as precursor and 1,6-hexamethylenediamine as functionalization group.Due to the extension of the functional group in nanoprobe,the electron transfer rate between the nanoprobe and FA is reduced,and the fluorescence quenching is relatively moderate.The fluorescence intensity is proportional to the concentration of FA in the range of 0.14-4.20?g/mL.The limit of detection for FA is 15.1 ng/mL and with good selectivity.In the detection experiment of Folic Acid Tablets,the recoveries of standard addition were 92.7%-105.6%.The results showed that this method has the advantages of simplicity,rapidity,low detection limit and good selectivity.?3?Fe₃O₄@SiO₂/CdTe-NH-NH-FA magnetic fluorescent probe was successfully synthesized using Fe₃O₄@SiO₂/CdTe-NH-NH₂ as precursor and FA as functional group.Based on the specific binding of FA and FA receptor,the FA receptors on the surface of HepG2 tumor cells were successfully labeled and collected.A novel method for the detection of cell membrane proteins was established,and it provided a new approach for the study of membrane proteins and clinical diagnosis of cancer.