Magneto-switchable electrocatalytic and bioelectrocatalytic transformations

Magnetic switching of redox reactions and bioelectrocatalytic transformations is accomplished in the presence of relay-functionalized magnetite particles (Fe₃O₄). The electrochemistry of a naphthoquinone (1), pyrroloquinoline quinone (2; PQQ), microperoxidase-11 (3), a ferrocene derivative (4) and a bipyridinium derivative (5), functionalized magnetic particles, is switched "ON" and "OFF" by an external magnet upon the attraction of the magnetic particles to an electrode or their retraction from the electrode, respectively. The magneto-switchable activation and deactivation of the electrochemical oxidation of the ferrocene-functionalized magnetic particles and the electrochemical reduction of the bipyridinium-functionalized magnetic particles are used for the triggering of mediated bioelectrocatalytic oxidation of glucose, in the presence of glucose oxidase (GOx), and bioelectrocatalytic reduction of nitrate (NO₃^-), in the presence of nitrate reductase (NR), respectively. Magnetic particles functionalized with a PQQ-NAD⁺ dyad are used for the magnetic switching of the bioelectrocatalytic oxidation of lactate in the presence of lactate dehydrogenase (LDH). The coupling of these particles with a ferrocene-monolayer-functionalized electrode allows the dual and selective sensing of lactate and glucose in the presence of LDH and GOx, respectively, by using an external magnet to switch the detection mode.