Methods of protection of electrochemical sensors against biofouling in cell culture applications

In this work we have evaluated more than ten antifouling layers for electrochemical sensors presenting different modes of action. These layers included porous materials, permselective membranes, hydrogels, silicate sol-gels, proteins, and sp³ hybridized carbon. To evaluate the protective effects of the antifouling modification as well as its impact on the catalyst, a redox mediator was adsorbed on the electrode surface. Five of the tested coatings allowed to preserve the electrochemical properties of the tested mediator. Later studies showed that sol-gel silicate layer, poly-L-lactic acid and poly(l-lysine)-g-poly(ethylene glycol) were the only ones capable of sustaining the catalyst's performance during prolonged incubation in cell culture medium. The highest deterioration of signal was observed, as expected during the first few hours of incubation in cell culture environment. Tested layers exhibited different dynamics of the protective effect. Poly-L-lactic acid layer presented lower changes in the first hours of study but suffered complete deterioration of signal after 72 hours. Whereas the signal intensity of the silicate layer was lowered by half after just 3 hours but could be still visible after 6 weeks of constant incubation in the cell culture.