The electrochemical redox behaviors of Cu(I) doped CdS nanoparticles in DNA-CTMA films are investigated in aqueous electrolyte. Both oxidation and reduction processes are electrochemically irreversible. The degradation of nanoparticles and the coupled chemical reactions in the electrochemical measurements can be avoided by fast potential scan as 1.5 V s(-1). It is hardly found the residual O-2 effect on the redox behavior of nanoparticles in DNA-CTMA film. The role of DNA-CTMA matrix in the charge transfer process between nanoparticles and the electrode is discussed. (C) 2014 Elsevier B.V. All rights reserved.