Profiling Tumor Cells

Cancerous and noncancerous cells can be distinguished by comparing spectral lines from surface-enhanced Raman spectroscopy, or SERS (J. Phys. Chem. Lett. 2010, 1, 1595). The results point to a way to use spectroscopic fingerprinting to identify biomarkers on cell surfaces and improve cancer diagnosis, say Boston University’s Bo Yan and Björn M. Reinhard, who developed the technique. The approach has potential for in vivo diagnostics if techniques such as endoscopic SERS imaging are developed. Working with tumor and nontumor breast and prostate cell lines, Yan and Reinhard evaluated SERS spectra of whole cells mounted onto a nanostructured silver substrate. They were able to distinguish between the cancerous and noncancerous cells by comparing the intensity ratio of spectral bands at 722 cm^–1 and 655 cm^–1. The 722 band likely arises from the C–N bond in quaternary ammonium groups in components of cell membrane lipids. The 655 band is commonly observed in Raman spectra of sialic acid sugars; its intensity likely increases in cancerous cells because such cells commonly overexpress glycosylated cell-surface proteins. The researchers found that the intensity ratio of the two bands is lower in tumor cells.