Jump to main content
Jump to site search


Amphiphilic coatings for the protection of upconverting nanoparticles against dissolution in aqueous media

Author affiliations

Abstract

Upconverting nanoparticles (UCNPs) of β-NaYF4, co-doped with Yb3+ and Tm3+ and 21–36 nm large, were synthesized using a modified thermal decomposition method. The as-synthesized UCNPs were coated with oleic acid and dispersed in nonpolar media. Their morphology, size and crystal structure were analysed with transmission electron microscopy and X-ray diffraction. The UCNPs showed a fluorescence emission spectrum characteristic of Tm3+. Their dissolution in water (pH ∼ 4–5) and phosphate buffered saline (PBS, pH = 7.4) was determined from the fraction of dissolved fluoride ions using a fluoride-ion-selective electrode. The dissolution of bare UCNPs was much more prominent in PBS than in water. Two amphiphilic coatings, poly(maleic anhydride-alt-1-octadecene)−bis(hexamethylene)triamine (PMAO–BHMT) and D-α-tocopheryl polyethylene glycol succinate (TPGS) were tested for their effects on the dissolution of the UCNPs. The coatings were formed directly on the as-synthesized UCNPs as was confirmed with electrokinetic measurements, infrared spectroscopy and thermogravimetric analyses. Both coatings enabled the dispersion of UCNPs in water, and improved the fluorescence emission intensity with respect to the bare UCNPs. However, only the PMAO–BHMT coating provided an effective protection against the dissolution of the UCNPs and long-term colloidal stability in PBS, and did not show cytotoxicity in EAhy926 endothelial cells.

Graphical abstract: Amphiphilic coatings for the protection of upconverting nanoparticles against dissolution in aqueous media

Back to tab navigation
Please wait while Download options loads

Supplementary files

Publication details

The article was received on 13 Feb 2017, accepted on 30 Apr 2017 and first published on 01 May 2017


Article type: Paper
DOI: 10.1039/C7DT00529F
Citation: Dalton Trans., 2017, Advance Article
  •   Request permissions

    Amphiphilic coatings for the protection of upconverting nanoparticles against dissolution in aqueous media

    O. Plohl, S. Kralj, B. Majaron, E. Fröhlich, M. Ponikvar-Svet, D. Makovec and D. Lisjak, Dalton Trans., 2017, Advance Article , DOI: 10.1039/C7DT00529F

Search articles by author