Research Paper

Journal of Nanoparticle Research

, 14:1100

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications

  • Maarten BloemenAffiliated withDepartment of Chemistry, KU Leuven Email author 
  • , Ward BrullotAffiliated withDepartment of Chemistry, KU Leuven
  • , Tai Thien LuongAffiliated withDepartment of Chemistry, KU Leuven
  • , Nick GeukensAffiliated withPharmAbs, The KU Leuven Antibody Center, KU Leuven
  • , Ann GilsAffiliated withFaculty of Pharmaceutical Sciences, KU Leuven
  • , Thierry VerbiestAffiliated withDepartment of Chemistry, KU Leuven


Superparamagnetic iron oxide nanoparticles can provide multiple benefits for biomedical applications in aqueous environments such as magnetic separation or magnetic resonance imaging. To increase the colloidal stability and allow subsequent reactions, the introduction of hydrophilic functional groups onto the particles’ surface is essential. During this process, the original coating is exchanged by preferably covalently bonded ligands such as trialkoxysilanes. The duration of the silane exchange reaction, which commonly takes more than 24 h, is an important drawback for this approach. In this paper, we present a novel method, which introduces ultrasonication as an energy source to dramatically accelerate this process, resulting in high-quality water-dispersible nanoparticles around 10 nm in size. To prove the generic character, different functional groups were introduced on the surface including polyethylene glycol chains, carboxylic acid, amine, and thiol groups. Their colloidal stability in various aqueous buffer solutions as well as human plasma and serum was investigated to allow implementation in biomedical and sensing applications.


Oleic acid-coated nanoparticles Superparamagnetic Surface modification Silane Colloidal stability Iron oxide