Site‐Directed Immobilization of Proteins Through Electrochemical Deprotection on Electroactive Self‐Assembled Monolayers

Self‐assembled monolayers (SAM) were obtained on gold electrodes using thioctic esters of benzo[1,3]dioxinol. These SAMs present a group that can be electroactivated selectively and was used for the directed, reagentless, covalent patterning of proteins. The advantage of this moiety is that it allows electroactivation at low potentials increasing selectivity and reliability. In this study, the efficiency of this patterning system is examined. Cyclic voltammetry (CV) was used to confirm the electroactive nature of SAM modified electrodes, showing fast and complete electrochemical deprotection with one scan. The enzymes glucose oxidase (GOx) and horseradish peroxidase (HRP) were patterned on the SAM‐modified electrode through Schiff's base formation after electrochemical deprotection, confirming the selective nature of the electroactive substrate. Amperometric response was measured after the GOx immobilization showing high selective response. Real time monitoring is shown by immobilization of HRP on the SAM modified surface using electrochemical surface plasmon resonance (ESPR) after electrochemical deprotection, again showing high selective response when compared to the protected control.