Electrografting of aryl diazonium on thin layer platinum microbands: Towards customized surface functionalization within microsystems

The formation of organic thin layers on platinum microbands prepared by photolithography and sputtering techniques following the electrografting of a 4-azidobenzene diazonium salt was evaluated. The electrografting process was characterized by cyclic voltammetry in the presence of reversible redox probes. Further modification of the azide-modified platinum surfaces was achieved by the covalent attachment of ethynylferrocene via the copper(I)-catalyzed azide-alkyne cycloaddition-“click” reaction (CuAAC). Optimization of the electrografting method was performed based on the active ferrocene surface coverage reaching a maximum of 2.5 × 10^{− 10} mol cm^{− 2} after ten voltammetric scans. In addition, the modified microbands exhibited a high stability with a recovery of over 75% of the initial ferrocene response after 3 weeks of bench storage. This data supports the possibility of rapid and straightforward functionalization of platinum microbands for a range of analytical applications prior to their integration into microdevices.