Reversible molecular immobilization on a metal surface through electrochemical reaction

Abstract

The technology of mercaptide self assembly has previously been used to immobilize molecules onto epitaxial metals but is not practical for many surfaces. In this study, a designed tag was employed for the electrochemical immobilization of protein on metals (ECtag). In the case of protein, ECtag can be designed with a 6-mer amino acid (alfa-amino-1H-imidazole-4-propionic acid) homopeptide. It was employed as an ECtag ligand and was introduced to a objective protein molecule through genetical process. ECtag forms co-ordinate bonds with Ni²⁺ and other divalent metal ions. Protein A (specific affinity protein against igG) was chosen as a model protein for the immobilization, and was genetically tagged with an ECtag for immobilization onto a Pt electrode surface through the reduction of ECtag:Ni²⁺ to ECtag:Ni by the electrode potential. The immobilization process can be performed through very simple wet-electrochemical process.