US researchers have turned to surface-enhanced Raman scattering to help them spot a biochemical marker for the early stages of ovarian cancer. The technique, which involves using SERS-active silver nanoparticles to detect various forms of lysophosphatidic acid (LPA) could simplify detection of the disease and at the same time help reduce false positives and false negatives.

Ovarian cancer is one of the more insidious forms of cancer. It is difficult to detect and is usually only spotted when symptoms occur by which time it is often too late for treatment to be effective. A simpler test that could spot the disease sooner rather than later would save countless lives. Now, Leo Seballos and Jin Zhang of the University of California, Santa Cruz and Rebecca Sutphen of the University of South Florida, Tampa, have found a way to detect the biomarker of choice in ovarian cancer tests, LPA, more effectively. Their approach side-steps the need for complicated preparative steps, which otherwise lead to errors.

The team exploited the fact that silver nanoparticles can enhance the Raman modes of LPA molecules, particularly those associated with the molecule's acyl chain, which are in the 800 to 1300 wavenumber region. Moreover, Seballos and colleagues point out that this enhancement can also be used to look at the carbon-carbon vibration mode of the gauche-bonded chain at 1100 wavenumbers. This allowed the team to discriminate even between two similar LPA molecules.

"Given the molecular selectivity of this technique," say the researchers, "detection of LPA using SERS may eliminate the need for partial purification of samples prior to analysis in cancer screening."

Related links:

• Anal Bioanal Chem, 2005, 383, 763-767
• Zhang Page

Article by David Bradley