doi:10.1038/nindia.2012.183 Published online 13 December 2012
Researchers have devised a new multi-component magnetic nanosystem to capture, detect and image circulating tumour cells (CTCs) in the bloodstream. This nanosystem was developed using a blood glycoprotein, iron oxide nanoparticles, a fluorescent molecule, a polymer molecule, and a glutathione molecule.
The nanosystem will be useful in detecting metastatic cancer in which cancer cells spread to other parts of the body from the organ of origin.
CTCs are a telltale sign of metastatic cancer, but are extremely difficult to detect. Most of the nanosized detection systems being explored are slow to latch onto cancer cells, delaying diagnosis. To develop a faster CTC-detection technique, the researchers designed a multi-component magnetic nanosystem. They attached transferrin (Tf), an iron-binding blood glycoprotein, to the nanosystem because most cancer cells have receptor molecules that selectively bind to Tf.
To test the efficacy of the Tf-based magnetic nanosystem in capturing cancer cells, these nanoparticles were treated with human colon cancer cells that express Tf receptor on their membranes. The nanoparticles could capture cancer cells within five minutes of exposure.
The nanoparticles also selectively captured and isolated Tf-containing colon cancer cells from a mixed population of colon cancer cells and human peripheral blood mononuclear cells within five minutes, even when the number of cancer cells was very small.
Sophisticated fluorescence imaging showed that the nanoparticles were localized on the membrane of cancer cells, proving that the Tf in nanoparticles only binds to membrane-based Tf receptors.
The researchers say that the nanosystem could directly capture and count cancer cell numbers. This could yield a new diagnostic technique called liquid biopsy, helping to assess patient prognosis and thus allowing tailored cancer treatment.