Gold nanorods, when linked to an antibody that binds to tumor cells, will align themselves in an ordered fashion on the surface of cancer cells. That further intensifies the optical signal the nanorods produce and prove a unique optical signature for tumor cells.

According to study results published in the September issue of Nano Letters, investigators prepared gold nanoparticles linked to an antibody that binds to the cell-surface receptor EGFR. When incubated with both normal cells and those from a human oral tumor and imaged using several different spectroscopic techniques, the gold nanorods produce a strong, sharp image only for the tumor cells. The optical signal from tumor cells was twice as bright as from normal cells.

The investigators suspect that this difference results from the gold nanoparticles becoming aligned with one another when bound to the tumor cell surface through their linked antibody; previous research has shown that EGFR molecules occur in clusters on the surfaces of many types of tumor cells. When aligned with one another, adjacent nanorods interact electronically in such as way as to boost their combined optical output. The investigators note that this output boost can serve as a molecular signature unique to tumor cells.

Nano Letters is an American Cancer Society publication.