We characterized pH effect on hole transport through DNA duplexes possessing a partial triplex-forming region. Direct electrochemical measurement of the current response of photosensitizer-tethered DNA immobilized on a gold electrode revealed that the partial triplex formation under acidic conditions suppressed photocurrent due to hole transport, while dissociation of the triplex into the duple...

This special issue on photodynamic therapy (PDT) and detection has been assembled by the guest editor by soliciting individual contributions from specialists in the field throughout the world. Photodynamic therapy is a combination of light with photosensitizing agents and oxygen present in a tumor, leading to photochemical and photobiological reactions that result in irreversible photodamage to...

Photodynamic therapy consists of the uptake of a photosensitizing dye, often a porphyrin, by tumor tissue and subsequent irradiation of the tumor with visible light of an appropriate wavelength matched to the absorption spectrum of the photosensitizing dye. This class of molecules produces reactive oxygen species when activated by light, resulting in a direct or indirect cytotoxic effect on the...