Synthesis and characterization of a flexible fluorescent magnetic Fe3O4@SiO2/CdTe-NH2 nanoprobe

J Inorg Biochem. 2018 Sep:186:307-316. doi: 10.1016/j.jinorgbio.2018.06.003. Epub 2018 Jun 15.

Abstract

In this study, we designed and synthesized two novel fluorescent magnetic nanoparticles. Fe3O4@SiO2-NH-GSH-CdTe (FSGC) (GSH = glutathione) nanoparticles were synthesized using amino-functionalized Fe3O4@SiO2 nanoparticles and GSH-stabilized CdTe quantum dots (CdTe QDs), while flexible Fe3O4@SiO2-NH-GSH-CdTe-NH-NH2 (FSGCN) nanoparticles were synthesized using the FSGC precursor and 1,6-hexamethylenediamine. These two kinds of nanoprobes exhibited excellent magnetic and fluorescent properties. By comparing the fluorescence quenching effect of folic acid (FA) on FSGC and FSGCN, we found that the quenching effect of FA on FSGC was acute and the process was too fast to determine the FA content. However, the quenching effect of FA on flexible FSGCN was mild and hence it could be used as a nanoprobe to determine FA concentration. At physiological pH, the fluorescence quenching effect of FA on the FSGCN nanoprobes was fitted according to the Stern-Volmer equation with a linear response in the concentration range of 0.14 to 4.20 μg mL-1 with a detection limit of 15.1 × 10-9 g mL-1 (S/N = 3) under optimized experimental conditions. The proposed flexible nanoprobe was successfully used to determine the content of FA in folic acid tablets. Recovery was found to be in the range of 92.7%-105.6% with a relative standard deviation of 1.12%-3.84%. Owing to their good stability, environment-friendly characteristics, high selectivity, and good optical properties and biocompatibility, these nanoprobes have potential for usage in practical applications.

Keywords: Amino-functionalized Fe(3)O(4)@SiO(2); Fe(3)O(4)@SiO(2)/CdTe; Fluorescent magnetic nanoprobes; Folic acid; Glutathione -stabilized CdTe QDs; Quenching.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cadmium Compounds / chemistry*
  • Ferrosoferric Oxide / chemistry*
  • Fluorescent Dyes / chemistry*
  • Quantum Dots / chemistry*
  • Tellurium / chemistry*

Substances

  • Cadmium Compounds
  • Fluorescent Dyes
  • Tellurium
  • cadmium telluride
  • Ferrosoferric Oxide