Laccase-catalyzed functionalization of phenol-modified carbon nanotubes: from grafting of metallopolyphenols to enzyme self-immobilization

We report the unprecedented use of laccase to functionalize phenol-modified carbon nanotubes (CNTs). Enzymatically-generated metallopolyphenols or the laccase itself can be mildly and efficiently immobilized using the ability of laccase to generate phenoxyl radicals. Electrochemistry, XPS and EPR spectroscopy were used to assess the enzyme-catalyzed CNT functionalization. The efficient immobilization of laccase is confirmed by the high direct bioelectrocatalytic reduction of oxygen with a maximum current density of 1.95 mA cm(-2).