Highly sensitive detection of DNA damage in living cells by SERS and electrochemical measurements using a flexible gold nanoelectrode.

Guanine (G) oxidation products, such as 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-oxo-guanine (8-OXOG), have been widely studied as promising biomarkers for DNA oxidative damage. In this work, we develop a new method to detect G oxidative products released from live cells after chromium (vi) ion or hydrogen peroxide treatments by using a glass nanopipette-based flexible gold nanoelectrode (fGNE). Specific response to G oxidative products with high sensitivity can be detected from the fGNE tip through integrated electrochemical measurements and surface-enhanced Raman spectroscopy. The fGNE apex can be positioned very close to the cell membrane noninvasively because of its high flexibility and nanoscale tip size. With the assistance of the electrophoretic force, the fGNEs can effectively collect and detect the G-derived DNA damage products released from individual cells in the cell culture medium with high sensitivity.