An electrochemical transducer based on vertically aligned carbon nanotubes (CNT) was prepared as a platform for biosensor development Prior to enzyme immobilization the CNT were treated using a microwave plasma system (CO2 and N-2/H-2) in order to functionalize the CNT surface with oxygenated and animated groups The morphological aspect of the electrode surface was examined by SEM and its chemical structure was also elucidated by XPS analysis It was found out that microwave plasma system (CO2 and N-2/H-2) not only functionalizes the CNT but also permits to avoid the collapse phenomena retaining thus the alignment structure of the electrode surface The electrochemical properties of the resulting new material based on CNT were carried out by cyclic voltammetry and were found suitable to develop high sensitive enzyme (HRP) biosensors operating on direct electron transfer process (C) 2010 Elsevier Ltd All rights reserved