Effect of nanoclays on the electrochemical performance of LbL catechol sensors

Abstract

Halloysite nanotubes (HNTs) are excellent candidates to improve the immobilization of electroactive materials or enzymes due to their tubular structure and properties. In this work, an improved LbL based catechol sensor has been developed using a combination of sensing materials with complementary activity. These include sulfonated copper phthalocyanine (CuPcSO3−) acting as electrocatalytic material, poly(ethyleneimine) (PEI) to increase the charge injection efficiency and the increase of the surface provided by HNTs. The LbL film has been used as the sensing platform to deposit tyrosinase in order to further enhance the performance of the developed sensor towards catechol. The LbL films were characterized by using UV–Vis, FTIR and cyclic voltammetry. The limits of detection, repeatability and reproducibility of the sensors and the biosensor were evaluated. The limits of detection were 1.23 μmol·L−1 for the optimized (PEI/CuPcSO3−) sensor, 0.987 μmol·L−1 for the (PEI/HNT/PEI/CuPcSO3−) sensor and 0.938 μmol·L−1 for the (PEI/HNT/PEI/CuPcSO3−)-Tyrosinase sensor.