Colourimetric assay for beta-estradiol based on the peroxidase-like activity of Fe3O4@mSiO(2)@HP-beta-CD nanoparticles

摘要

Magnetic mesoporous nanoparticles of Fe3O4@mSiO(2) were prepared through co-precipitation and tetraethoxysilane hydrolysis at 60 degrees C and pH 10 with hexadecyl trimethyl ammonium bromide as the template. Hydroxypropyl beta-cyclodextrin was modified onto Fe3O4@mSiO(2) under sodium citrate and N-2 protection via an ultrasound process to increase the catalytic efficiency. The prepared nanoparticles were characterized by Fourier transform infrared spectrometry, X-ray diffraction, scanning electron microscopy and a peroxidase-like activity assay. The results showed that the prepared nanoparticles have magnetic properties, peroxidase-like activity and a loose spherical cluster structure. Compared with Fe3O4@mSiO(2) nanoparticles, Fe3O4@mSiO(2)@HP-beta-CD nanoparticles exhibit higher catalytic ability toward both H2O2 and 3,3',5,5'-tetramethylbenzidine. Fe3O4@mSiO(2)@HP-beta-CD nanoparticles can catalyse beta-estradiol (beta-E-2) oxidation in the presence of H2O2 and be used as a colourimetric sensor for indirect detection of beta-E-2. A good linear relationship was obtained from 0.8 mu M to 16 mu M. The limit of detection of the proposed method was 0.2 mu M. The visual method was successfully used in the analysis of beta-E-2 in commercial tablets and animal feeds, with recovery ranging from 92.6% to 110%.