Electrochemically produced local pH changes stimulating (bio)molecule release from pH-switchable electrode-immobilized avidin-biotin systems.

Immobilized avidin-biotin complexes were used to release biotinylated (bio)molecules upon producing local pH changes near an electrode surface by electrochemical reactions. The nitro-avidin complex with biotin was dissociated by increasing local pH with electrochemical O 2 reduction. The avidin complex with iminobiotin was split by decreasing local pH with electrochemical oxidation of ascorbate. Both studied systems were releasing molecule cargo species in response to small electrical potentials (-0.4 V or 0.2 V for the O 2 reduction or ascorbate oxidation, respectively) applied on the modified electrodes.