Porphyrin decorated Cu₂O nanocrystals for electroanalytical detection of S-Nitrosothiols

S-nitrosothiols (RSNO) as the potential nitric oxide (NO) storage, transfer and delivery vehicles under physiological condition have been identified as important in a number of disease states. However, a detection and quantification of RSNO method with simple and sensitive in biological media is currently lacking. A novel electrochemical sensing platform based on ionic liquid (IL) and copper porphyrin (PorCu) decorated cuprous oxide (Cu₂O) nanocomposites was developed to detect RSNO under physiological condition. In this system, RSNO were decomposed by Cu(I) in IL/PorCu/Cu₂O to release NO, following the generated NO could be oxidized on the electrode to generate current signal. By taking advantage of the synergetic effect of IL, PorCu and Cu₂O, the sensor exhibited excellent sensitivity and linearity toward various RSNO species in phosphate buffer solution (PBS), pH 7.4. A low detection limit for N-Acetyl-3-(nitrososulfanyl)valine (SNAP), S-nitrosocysteine (CysNO) and S-nitrosoglutathione (GSNO) was 110 nM, 20 nM and 67 nM (S/N = 3), respectively. Furthermore, this method displayed good selectivity, which could be used in complex application. The detection scheme with the features of high sensitivity and ease of operation, implies the potential of IL/PorCu/Cu₂O for further various complex physiological studies.