Jul 18, 2012
Glucose wrapping increases cellular uptake of magnetic nanoparticles
Investigating the magnetic properties of hybrid nanoparticles and the influence of their surface composition on cellular internalization processes is a critical step in the design and development of new-generation composite materials. They can be remarkably useful in biological and medical applications, including magnetically induced hyperthermia, magnetic responsive drug delivery and magnetic resonance imaging. Researchers from the Faculty of Science and Technology at the University of the Basque Country (UPV/EHU) and the BioNanoSurf group from the INA at the University of Zaragoza have teamed up to pursue these opportunities. Specifically, they have formed a collaborative network to explore the potential of nanomaterials in the promising field of magnetic hyperthermia for cancer thermotherapy.
In their latest study, the team has prepared and characterized monodisperse nanometric magnetite cores covered by a layer of gold and protected by a corona of organic molecules. The utility of electron magnetic resonance spectroscopy (EMR) is demonstrated in confirming the enhancement of the superparamagnetic behaviour due to the gold layer and the organic corona.
Appropriate modification of the surface of the particles by incorporating carboxyl groups as anchor points enabled further functionalization. In turn, this allowed the scientists to tailor surface compositions, overcoming biocompatibility issues and providing a versatile platform to evaluate nanoparticle–cell interactions.
Molecules relevant for bioapplications, such as poly(ethylene glycol) (PEG) and glucose, were covalently conjugated to the particle surface via amidation reactions, and a dye was also grafted to monitor cell response upon incubation with the developed particles. Using confocal microscopy it was discovered that glucose-coated particles showed increased penetration across the cell membrane of HeLa cells (see image) in comparison with PEG-coated particles. These results suggest that glucose could be used to tailor a nanoparticle shield in applications that require high cellular uptake.
The group is currently developing new magnetic nanomaterials with various morphologies, compositions and biofunctionalities. This is with two aims in mind; to evaluate the heat generated by the nanoparticles in terms of the specific absorption rate (SAR) and to assess the endocytic mechanism of particles upon incubation with different cell lines.
Additional information can be found in the journal Nanotechnology.
About the author
This study was part of the PhD of Dr Javier Salado under the supervision of Dr Maite Insausti and Prof. Teofilo Rojo. The current study has enabled the sharing of expertise and capabilities in several fields: nanoparticle preparation, electron microscopy and magnetic characterization in the Department of Inorganic Chemistry at the University of the Basque Country (UPV/EHU) and surface functionalization and cell–nanoparticle interaction at the Instituto de Nanociencia de Aragon. Dr Javier Salado is now a research fellow in the Nanoscale Physics Research Laboratory at the University of Birmingham and his research interests are focused on microstructural characterization of hybrid nanocomposite materials.