Highlights in Chemical Biology

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Nano-labels allow stem cell imaging

23 November 2009

Iron-laden nanoparticles make non-toxic stem cell labels for magnetic resonance imaging. 

Imaging agents are used to enhance the resolution in magnetic resonance imaging (MRI), which allows internal structure of the body to be visualised. Xiaoyuan Chen at the National Institute of Health, Bethesda, has modified iron-oxide nanoparticles to make non-toxic and more efficient imaging agents. 

Iron nanoparticles

The iron nanoparticles can enter cells without killing them

Iron oxide has been used for cell labelling before but transfection agents are needed to aid uptake into cells. This can make them toxic and result in cell death, particularly in sensitive cell lines such as stem cells, explains Chen. Chen coated his iron oxide nanoparticles with a biologically compatible agent (human serum albium) and found that they could enter a variety of cells without adding external transfection agents and with no adverse effects on cell growth. 

'There's a massive incentive to label cells, such as stem cells, efficiently', says Chen as there are notorious difficulties surrounding stem cell tagging in an efficient and non-toxic manner, he explains. But with his method, he claims that the cell labelling was more efficient than the commercially available imaging agent, Feridex.

Chen used his nanoparticles to label a cell line that tracks specifically to areas of inflammation in the body, such as the brain in a stroke victim, or to tumours during their growth period. When the iron-tagged cells were injected to a mouse that had a tumour under the skin, they could be detected at the tumour site after just 6 hours using MRI - proving that the nanoparticles can be used as an efficient and non-invasive diagnostic tool.

'The main advance is a non-toxic imaging agent that has been specifically designed for cell entry', comments Kevin Dhaliwal, an expert in MRI and imaging agents from the Medical Research Council Centre for Inflammation Research, Edinburgh, UK. 'The particles could be widely applied in clinical applications,' continues Dhaliwal.

Chen indicates that future research may focus on coupling drugs to the nanoparticles to provide a site-specific drug delivery vehicle. 

Lois Alexander 


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Link to journal article

Human serum albumin coated iron oxide nanoparticles for efficient cell labeling
Jin Xie, Jinhua Wang, Gang Niu, Jing Huang, Kai Chen, Xingguo Li and Xiaoyuan Chen, Chem. Commun., 2010, 46, 433
DOI: 10.1039/b917195a

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