Glutathione influence on the photoluminescence from semiconducting single-walled carbon nanotubes compared with other thiol compounds

Abstract

The influence of antioxidant glutathione (GSH) on the photoluminescence (PL) from the semiconducting single-walled carbon nanotubes (SWNTs) suspended with DNA in water has been studied in this research. The strong PL enhancement was found after GSH doping (10−6–10−4 M) of the nanotube suspension, which is explained by removing exciton quenching sites on the nanotube sidewall by GSH molecules due to the reactive thiol group in the structure. The PL increase depends on the sonication treatment of the nanotube suspension, the quantity of this increase also differs in the emission bands specified by the disordered biopolymer coverage of corresponding nanotubes. This observation allows the ratiometric PL detection of glutathione. The PL is less sensitive to GSH impact as compared to cysteine. Experiments with other thiol-containing compounds as dithiothreitol and dithioerythritol showed a tendency that the compound with lower redox potential causes a stronger increase of the PL from suspended SWNTs.