Gold nanoparticles may help detect tumour cells in blood

Researchers at Emory and Georgia Tech have found that tiny gold particles can help doctors detect tumour cells circulating in the blood of patients with head and neck cancer.

The gold particles, which are embedded with dyes allowing their detection by laser spectroscopy, could enhance this technique's specificity by reducing the number of false positives.

Researchers show that polymer-coated and dye-studded gold particles, directly linked to a growth factor peptide rather than an antibody, can detect circulating tumour cells in the blood of patients with head and neck cancer.

"The key technological advance here is our finding that polymer-coated gold nanoparticles that are conjugated with low molecular weight peptides such as EGF are much less sticky than particles conjugated to whole antibodies," said Shuming Nie, a professor in the Wallace H Coulter, department of biomedical engineering at Georgia Tech and Emory University.

"This effect has led to a major improvement in discriminating tumor cells from non-tumour cells in the blood."

The particles are linked to EGF (epithelial growth factor), whose counterpart EGFR (epithelial growth factor receptor) is over-produced on the surfaces of several types of tumour cells.

Upon laser illumination, the particles display a sharp fingerprint-like pattern that is specific to the dye, because the gold enhances the signal coming from the dyes.

In collaboration with oncologists at Winship Cancer Institute, researchers used nanoparticles to test for CTCs in blood samples from 19 patients with head and neck cancer. Of these patients, 17 had positive signals for CTCs in their blood. The two with low signals were verified to have no circulating cells by a different technique.

The study has been published online in the journal Cancer Research.