Electrochemical and spectroscopic evaluation of 6-MP and its interaction with carbon dots and dsDNA

The 6-Mercaptopurine (6-MP) is an anti-cancer drug used for the treatment of acute lymphocytic leukaemia. Electrochemical signal of 6-MP over the unmodified Glassy carbon electrode (GCE) is poor and not suitable to probe the molecule through electrochemical measurements. In order to enhance the electrochemical signal from the molecule, the substrate has been fabricated by electrodepositing gold nano particles (AuNPs) on the surface of GCE. The electrochemical signal of 6-MP has been enhanced significantly over the modified substrate. The peak current of 6-MP obtained as a result of the electrochemical oxidation increases with subsequent addition of carbon nano dots (CD) in the solution, which revealed the strong interaction between the 6-MP with CD. The interaction between 6-MP and CD is established using UV-vis spectroscopy and fluorescence spectroscopy. The intensity of fluorescence of CD is quenched on interaction with 6-MP in the solution, strong quenching constant value beyond the diffusion-controlled limit, indicates stronger interaction between 6-MP and CD. Atomic force microscopy (AFM) investigations imaged the change of the texture of dsDNA upon its interaction with 6-MP.

Automated summary

6-Mercaptopurine (6-MP) is an anti-cancer drug used for acute lymphocytic leukaemia treatment. However, the electrochemical signal of 6-MP on unmodified Glassy carbon electrode (GCE) is weak. To enhance the signal, gold nano particles (AuNPs) were electrodeposited on the GCE. The addition of carbon nano dots (CD) in the solution further increased the peak current of 6-MP, indicating a strong interaction between 6-MP and CD. This interaction was confirmed using UV-vis and fluorescence spectroscopy. Atomic force microscopy (AFM) showed changes in dsDNA texture upon interaction with 6-MP.