Direct detection of nucleotide radical cations produced by electron-transfer oxidation of DNA bases with electron-transfer state of 9-mesityl-10-methylacridinium ion and resulting efficient DNA cleavage without oxygen.

Photoinduced electron transfer of DNA as well as DNA bases with 9-mesityl-10-methylacridinium ion results in formation of all types of DNA base radical cations, which have been detected as the transient absorption spectra measurements, leading to efficient DNA cleavage in the absence of O2.