Gold-Coated Iron Composite Nanospheres Targeted the Detection of Escherichia coli


Tamer U., Çetin D., Suludere Z., Boyacı İ. H., Temiz H. T., Yegenoglu H., ...More

INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES, vol.14, no.3, pp.6223-6240, 2013 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 14 Issue: 3
  • Publication Date: 2013
  • Doi Number: 10.3390/ijms14036223
  • Journal Name: INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.6223-6240
  • Keywords: magnetic gold nanoparticle, SERS, immunomagnetic separation, E. coli, surface functionalisation of particles, ENHANCED RAMAN-SCATTERING, CORE-SHELL NANOPARTICLES, MAGNETITE NANOPARTICLES, FE3O4 NANOPARTICLES, BACTERIA, PROTEIN, IMMOBILIZATION, RESISTANCE, CELLS, ARRAY
  • Gazi University Affiliated: Yes

Abstract

We report the preparation and characterization of spherical core-shell structured Fe3O4-Au magnetic nanoparticles, modified with two component self-assembled monolayers (SAMs) consisting of 3-mercaptophenylboronic acid (3-MBA) and 1-decanethiol (1-DT). The rapid and room temperature synthesis of magnetic nanoparticles was achieved using the hydroxylamine reduction of HAuCl4 on the surface of ethylenediaminetetraacetic acid (EDTA)-immobilized iron (magnetite Fe3O4) nanoparticles in the presence of an aqueous solution of hexadecyltrimetylammonium bromide (CTAB) as a dispersant. The reduction of gold on the surface of Fe3O4 nanoparticles exhibits a uniform, highly stable, and narrow particle size distribution of Fe3O4-Au nanoparticles with an average diameter of 9 +/- 2 nm. The saturation magnetization value for the resulting nanoparticles was found to be 15 emu/g at 298 K. Subsequent surface modification with SAMs against glucoside moieties on the surface of bacteria provided effective magnetic separation. Comparison of the bacteria capturing efficiency, by means of different molecular recognition agents 3-MBA, 1-DT and the mixed monolayer of 3-MBA and 1-DT was presented. The best capturing efficiency of E. coli was achieved with the mixed monolayer of 3-MBA and 1-DT-modified nanoparticles. Molecular specificity and selectivity were also demonstrated by comparing the surface-enhanced Raman scattering (SERS) spectrum of E. coli-nanoparticle conjugates with bacterial growth media.