This work demonstrated the feasibility of detecting hydrocortisone in cosmetics using a novel CdSe/CdS quan- tum dots-based competitive fluoroimmunoassay with magnetic core/shell Fe3Oa/Au nanoparticles （MCFN） as sol...This work demonstrated the feasibility of detecting hydrocortisone in cosmetics using a novel CdSe/CdS quan- tum dots-based competitive fluoroimmunoassay with magnetic core/shell Fe3Oa/Au nanoparticles （MCFN） as solid carriers. Hydrocortisone antigen was labeled with the synthesized core/shell CdSe/CdS quantum dots （QDs） to form the antigen-QDs conjugate. Meanwhile, hydrocortisone antibody was incubated with MCFN and the immobilized antibody was obtained. The immobilized antibody was then mixed sequentially with hydrocortisone and a slightly excess amount of the QDs-labeled hydrocortisone antigen, allowing their competition for binding with the antibody immobilized on MCFN. The bound hydrocortisone and the antigen-QDs conjugates on MCFN were removed subsequently after the mixture was applied to a magnetic force. The analyte concentration was obtained by measuring the fluorescence intensity of the unbound hydrocortisone antigen-QDs conjugates. The proposed method was characterized by simplicity, rapidity, and high sensitivity with a wide linear working range of 0.5 to 15000 pg·mL^-1 and a low detection limit of 0.5 pg.mL^- 1. The proposed method was successfully applied to the determination of hydrocortisone in cosmetics with satisfactory results.展开更多
Magnetic Fe304@SiO2 nanoparticles with superparamagnetic properties were prepared via a reverse mi-croemulsion method at room temperature. The as-prepared samples were characterized by transmission electron mi-croscop...Magnetic Fe304@SiO2 nanoparticles with superparamagnetic properties were prepared via a reverse mi-croemulsion method at room temperature. The as-prepared samples were characterized by transmission electron mi-croscopy（TEM）, X-ray diffractometry（XRD）, and vibrating sample magnetometry（VSM）. The Fe304@SiO2 nanopar-ticles were modified by （3-aminopropyl）triethoxysilane（APTES） and subsequently activated by glutaraldehyde（Glu）.Protein A was successfully immobilized covalently onto the Glu activated Fe304@SiO2 nanoparticles. The adsorptioncapacity of the nanoparticles was determined on an ultraviolet spectrophotometer（UV） and approximately up to 203mg/g of protein A could be uniformly immobilized onto the modified Fe304@SiO2 magnetic beads. The core-shell ofthe Fe304@SiO2 magnetic beads decorated with protein A showed a good binding capacity for the chime-ric anti-EGFR monoclonal antibody（anti-EGFR mAb）. The purity of the anti-EGFR mAb was analyzed by virtue ofHPLC. The protein A immobilized affinity beads provided a purity of about 95.4%.展开更多
A fast approach was described for the synthesis of water-dispersible monodisperse dopamine-coated Fe304 nanoparticles （DA- Fe304） with uniform size and shape via ligand-exchange of oleic acid on Fe304 using only 2 m...A fast approach was described for the synthesis of water-dispersible monodisperse dopamine-coated Fe304 nanoparticles （DA- Fe304） with uniform size and shape via ligand-exchange of oleic acid on Fe304 using only 2 min. The prepared DA-Fe304 nanoparticles were characterized by transmission electron microscopy, Fourier transform infrared spectrometry, and vibrating sample magnetometer. The results indicated that the resulting DA-Fe304 nanoparticles had an average diameter of about 19.2 nm. The magnetic saturation value of the prepared DA-Fe304 nanoparticles was determined to be 72.87 emu/g, which indicating a well- established superparamagnetic property.展开更多
Fe oxide core/Au shell nanoparticles were prepared by the reduction of Au3+ onto the surfaces of Fe oxide nanoparticles and characterized by scanning electron microscopy(SEM). The results reveal that the prepared core...Fe oxide core/Au shell nanoparticles were prepared by the reduction of Au3+ onto the surfaces of Fe oxide nanoparticles and characterized by scanning electron microscopy(SEM). The results reveal that the prepared core/shell nanoparticles were covered by Au shell and the surfaces of the core/shell particles are jagged after the initial addition of Au3+. Surface enhanced Raman scattering(SERS) activities of these magnetic nanoparticles were studied by using pyridine(Py) as a probe molecule after a magnet was used to concentrate the colloid. It was found that the SERS intensity depends on the Au shell thickness of the core/shell nanoparticles and strengthens with the increasing shell thickness. The detection limit for Py can be very low when the magnetic Fe oxide core/Au shell nanoparticles were used and even down to 10-7 mol/L.展开更多
基金Project supported by the National Natural Science Foundation of China （Nos. 20345006 and 20575043）.
文摘This work demonstrated the feasibility of detecting hydrocortisone in cosmetics using a novel CdSe/CdS quan- tum dots-based competitive fluoroimmunoassay with magnetic core/shell Fe3Oa/Au nanoparticles （MCFN） as solid carriers. Hydrocortisone antigen was labeled with the synthesized core/shell CdSe/CdS quantum dots （QDs） to form the antigen-QDs conjugate. Meanwhile, hydrocortisone antibody was incubated with MCFN and the immobilized antibody was obtained. The immobilized antibody was then mixed sequentially with hydrocortisone and a slightly excess amount of the QDs-labeled hydrocortisone antigen, allowing their competition for binding with the antibody immobilized on MCFN. The bound hydrocortisone and the antigen-QDs conjugates on MCFN were removed subsequently after the mixture was applied to a magnetic force. The analyte concentration was obtained by measuring the fluorescence intensity of the unbound hydrocortisone antigen-QDs conjugates. The proposed method was characterized by simplicity, rapidity, and high sensitivity with a wide linear working range of 0.5 to 15000 pg·mL^-1 and a low detection limit of 0.5 pg.mL^- 1. The proposed method was successfully applied to the determination of hydrocortisone in cosmetics with satisfactory results.
文摘Magnetic Fe304@SiO2 nanoparticles with superparamagnetic properties were prepared via a reverse mi-croemulsion method at room temperature. The as-prepared samples were characterized by transmission electron mi-croscopy（TEM）, X-ray diffractometry（XRD）, and vibrating sample magnetometry（VSM）. The Fe304@SiO2 nanopar-ticles were modified by （3-aminopropyl）triethoxysilane（APTES） and subsequently activated by glutaraldehyde（Glu）.Protein A was successfully immobilized covalently onto the Glu activated Fe304@SiO2 nanoparticles. The adsorptioncapacity of the nanoparticles was determined on an ultraviolet spectrophotometer（UV） and approximately up to 203mg/g of protein A could be uniformly immobilized onto the modified Fe304@SiO2 magnetic beads. The core-shell ofthe Fe304@SiO2 magnetic beads decorated with protein A showed a good binding capacity for the chime-ric anti-EGFR monoclonal antibody（anti-EGFR mAb）. The purity of the anti-EGFR mAb was analyzed by virtue ofHPLC. The protein A immobilized affinity beads provided a purity of about 95.4%.
基金supported by the National Natural Science Foundation of China(No.50903011)the Fundamental Research Funds for the Central Universities(No.11NZYQN23)+1 种基金the Talents Introduction Foundation of Southwest University for Nationalities(No.2010RC06)the Open Fund(No.PLN1112)of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Southwest Petroleum University,SWPU)
文摘A fast approach was described for the synthesis of water-dispersible monodisperse dopamine-coated Fe304 nanoparticles （DA- Fe304） with uniform size and shape via ligand-exchange of oleic acid on Fe304 using only 2 min. The prepared DA-Fe304 nanoparticles were characterized by transmission electron microscopy, Fourier transform infrared spectrometry, and vibrating sample magnetometer. The results indicated that the resulting DA-Fe304 nanoparticles had an average diameter of about 19.2 nm. The magnetic saturation value of the prepared DA-Fe304 nanoparticles was determined to be 72.87 emu/g, which indicating a well- established superparamagnetic property.
文摘Fe oxide core/Au shell nanoparticles were prepared by the reduction of Au3+ onto the surfaces of Fe oxide nanoparticles and characterized by scanning electron microscopy(SEM). The results reveal that the prepared core/shell nanoparticles were covered by Au shell and the surfaces of the core/shell particles are jagged after the initial addition of Au3+. Surface enhanced Raman scattering(SERS) activities of these magnetic nanoparticles were studied by using pyridine(Py) as a probe molecule after a magnet was used to concentrate the colloid. It was found that the SERS intensity depends on the Au shell thickness of the core/shell nanoparticles and strengthens with the increasing shell thickness. The detection limit for Py can be very low when the magnetic Fe oxide core/Au shell nanoparticles were used and even down to 10-7 mol/L.
