Electrochemical methods provide attractive sensing techniques for biology. Electrochemical devices can be easily manufactured, miniaturized and are sometimes the only direct sensing method available. However, stability of these sensors is problematic, as foreign-body type reactions may induce distortions of the signal (biofouling). As a consequence, investigating the interactions with the biological matrix is of paramount importance to achieve reliable sensing. Different types of electrodes (boron doped diamond and different preparations of glassy carbon) and various electrode coatings were tested, in the presence of biological molecules. The results showed that boron doped diamond and fibronectin coated sensors offer good stability, even in the presence of high concentrations of proteins. A generally applicable protocol to assess the quality of electrode materials in biofouling conditions is also presented. Fibronectin has also been found to be a highly biocompatible coating, perfectly suited for cell-based measurements. This fibronectin coating was used on an electrode array to study the pathway leading to angiogenic factor induced nitric oxide release. Vascular endothelial growth factor, a well known angiogenic factor, was initially used and allowed me to setup a reliable and robust protocol for the use of electrode arrays in biology. It was then demonstrated that angiogenin, another angiogenic factor, leads to nitric oxide exocytosis through PI-3 kinase transduction.