Mn-doped Zn Series Of Magnetic-Fluorescent Nanoparticles:Preparation And Interaction With Serum Albumin

This paper aimed to construct low toxic magnetic-fluorescent nanoparticles (MFNPs), the interaction and damage of MFNPs to serum albumin with or without UV illumination was also investigated. This work may be useful for further development of MFNPs in vivo biological applications. The main works and conclusions in the present study are as follows:1、Synthesis and characterizations of thioglycolic acid-capped ZnSe quantum dotsZnSe quantum dots (ZnSe QDs) were prepared in aqueous media and characterized by ultraviolet-visible absorption, fluorescence emission spectroscopy, X-ray powder diffraction, transmission electron microscopy, energy-dispersive spectroscopy, and inductively coupled plasma atomic emission spectroscopy. The influences of various experimental variables on the photoluminescence properties of ZnSe QDs were investigated. The results showed that the average diameter of these nanocrystals was4nm with narrow size distribution. The optimized conditions were as follows:pH value of9.5, Zn/NaHSe molar ratio of10:1, Zn/TGA molar ratio of1:3, heating time of1h, and irradiation time of19h. Under optimized conditions, the photo luminesce nce quantum yield of ZnSe QDs in aqueous solution reached20%.2、Synthesis and characterizations of CS-Fe3O4@ZnSe:Mn/ZnS MFNPsCS-Fe3O4@ZnSeMn/ZnS MFNPs were synthesized by incorporating chitosan coated Fe3O4magnetic nanoparticles CS-Fe3O4and ZnSe:Mn/ZnS QDs via electrostatic interaction. Effects of experimental variables, such as nucleation temperature, Zn/NaHSe molar ratio, the amount of Mn2+, the kind of stabilizer, Zn/MPA molar ratio, pH value, reaction time and QDs/CS-Fe3O4molar ratio on the fluorescence performance of CS-Fe3O4@ZnSe:Mn/ZnS MFNPs were discussed. The optimized synthetic conditions were found as follows:nucleation temperature as4℃, Zn/NaHSe=5:3, the amount of Mn2+was4%, Zn/MPA=1:24, reaction pH=11, growth duration as7h, QDs/CS-Fe3O4=2.5:1. The synthesized nanocrystals were characterized and analyzed with TEM, XRD, UV-vis, FL spectra, VSM and FT-IR. The obtained CS-Fe3O4@ZnSe:Mn/ZnS MFNPs exhibit orange fluorescent and superparamagnetic behavior, the saturation magnetization was17.8emu/g.3、Novel magnetic-fluorescent CS-Fe3O4@ZnS:Mn nanoparticles:preparation and interaction with serum albuminCS-Fe3O4@ZnS:Mn MFNPs were synthesized in aqueous media under ambient pressure and characterized by X-ray diffraction, UV-vis absorption, fluorescence emission, transmission electron microscope and energy dispersion spectrum. The effects of experimental conditions on the fluorescence properties of CS-Fe3O4@ZnS:Mn were studied. The optimal conditions were that:the amount of CS was1.0%,[CS-Fe3O4]=0.2mol-L-1, [Zn2+]=[S2-]=0.1mol·L-1, Mn2+was50%, reaction pH=7, reaction temperature was100℃In addition, the interaction of CS-Fe3O4@ZnS:Mn with bovine serum albumin (BSA) was studied by means of ultraviolet-visible and fluorescence spectra. The results show that the dominating fluorescence quenching mechanism of CS-Fe3O4@ZnS:Mn with BSA belongs to static quenching. The thermodynamic parameters indicated that electrostatic interaction play major roles in CS-Fe3O4@ZnSMn-BSA, while binding processes exist spontaneously. The damage of BSA is prone to happen in the presence of CS-Fe3O4@ZnS:Mn under UV illumination. The fluorescence quenching of BSA by CS-Fe3O4@ZnS:Mn MFNPs under UV illumination is mainly a result of a combination of FRET and photo-induced free radical procedure.4、Novel magnetic-fluorescent CS-Fe3O4@ZnSMn/ZnS nanoparticles:preparation and interaction with serum albuminNovel magnetic-fluorescent CS-Fe3O4@ZnS:Mn/ZnS nanoparticles were prepared and characterized. The optimum synthetic conditions were the molar ratio of C/S was6:1, the amount of Mn2+was31%. Introduction of ZnS shell significantly enhanced the photo luminescence intensity by3.5times. The interaction of CS-Fe3O4@ZnS:Mn/ZnS with BSA was investigated by ultraviolet-visible and fluorescence spectra. The results show that electrostatic interaction is the major force for the binding processes of BSA to the surface of CS-Fe3O4@ZnS:Mn/ZnS. The damage of BSA is prone to happen in the presence of CS-Fe3O4@ZnS:Mn/ZnS under UV illumination.5、 Effect of some ions on interaction of CS-Fe3O4@ZnS:Mn/ZnS MFNPs with serum albuminThe effect of Na+、K+、Fe2+、Fe3+and simulated body fluid (SBF) on the interaction of CS-Fe3O4@ZnS:Mn/ZnS MFNPs with BSA was studied by fluorescence spectra. The fluorescence intensity of CS-Fe3O4@ZnS:Mn/ZnS MFNPs, BSA, and CS-Fe3O4@ZnS:Mn/ZnS-BSA system is not influenced by the presence of Na+and K+. But the fluorescence intensity of CS-Fe3O4@ZnS:Mn/ZnS MFNPs, BSA, and CS-Fe3O4@ZnS:Mn/ZnS-BSA system is quenched by Fe2+or Fe3+. The dominating fluorescence quenching mechanism of Fe2+or Fe3+with CS-Fe3O4@ZnS:Mn/ZnS MFNPs and BSA belongs to static quenching and dynamic quenching, respectively. There is synergic effect of Fe2+or Fe3+and CS-Fe3O4@ZnS:Mn/ZnS MFNPs on the damage of BSA. SBF slightly increases the fluorescence intensity of CS-Fe3O4@ZnS:Mn/ZnS-BSA system.