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.