Poly(ethylene glycol) was shown to protect surfaces through hindering access of proteins thanks to repulsive elastic forces. During compression water molecules are removed from the hydrated polymer making penetration of other species thermodynamically unfavorable. However this effect is highly dependent on the density of chains and their length and is usually not attainable for physical adsorption or covalent attachment. PEG is hydrophilic, flexible and stable under sterilization but can suffer from autooxidation . PEG polymers can be also grafted with polypeptides e.g. with poly(l-lysine), which is highly cationic at physiological pH and through the interaction with electrode surface can help to orient PEG chains creating well-structured polymer brush . Modification of electrodes with Poly(l-lysine)-g-Poly(ethylene glycol) allowed to observe well-developed syringaldazine peaks(Figure ) of pH dependent position (50 mV/dec) throughout the whole course of the experiment in the cell culture medium.