Sunday, 20 February 2011 05:19
Tracking magnetic nanoparticles attached to stem cells transplanted into spinal cords to heal injuries could be an effective way to monitor the healing process non-invasively say UK scientists.
Dr Nguyen TK Thanh at the Davy Faraday Research Laboratory, University College London and the Royal Institution, and colleagues, have developed hollow biocompatible cobalt-platinum (CoPt) nanoparticles that stay stable for months and have a strong tendency to align with a magnetic field, allowing low concentrations to be detected with magnetic resonance imaging (MRI).
Although research shows that neural stem cells, because they can regenerate tissue, are a promising treatment to repair spinal cord injuries, there is currently no effective way of monitoring their progress in the longer term once they are transplanted.
Thanh and colleagues attached their newly-developed CoPt nanoparticles to rat neural stem cells, injected them into cultured spinal cord slices that closely mimic the real tissue, and then took MRI scans of their progress from time to time.
They found they could still pick out low numbers of the nanoparticle-tagged stem cells two weeks after transplant.
Thanh, who holds a Royal Society University Research Fellowship and is Associate Professor in Nanotechnology, told the press that:
"The new method demonstrates the feasibility of reliable, noninvasive MRI imaging of nanoparticle-labelled cells."
Dr Samir Pal, an expert in biological-nanoparticle interactions at the California Institute of Technology in the US, said:
"Magnetic nanoparticles are emerging as novel contrast and tracking agents in medical imaging."
"When used as a contrast agent for MRI, the nanoparticles allow researchers and clinicians to enhance the tissue contrast of an area of interest by increasing the relaxation rate of water," said Pal.
(The relaxation rate reflects how fast the spins of the hydrogen protons in the water molecules in the tissue revert to their natural state after having been "flipped over" when the MRI machine magnetized them).
Thanh said she hopes their new way of tracking stem cells will also be used in stem cell replacement therapy for many diseases of the central nervous system.
She and her colleagues are already working on ways to make nanoparticles to diagnose and treat such diseases.
"Magnetic CoPt nanoparticles as MRI contrast agent for transplanted neural stem cells detection."
Xiaoting Meng, Hugh C. Seton, Le T. Lu, Ian A. Prior, Nguyen T. K. Thanh and Bing Song.
Nanoscale Advance Article, first published online 4 Feb 2011.
DOI: 10.1039/C0NR00846J, Paper