Clicked Bifunctional Dendrimeric and Cyclopeptidic Addressable Redox Scaffolds for the Functionalization of Carbon Nanotubes with Redox Molecules and Enzymes

Carbon nanotube electrodes were modified with ferrocene and laccase using two different click reactions strategies and taking advantage of bifunctional dendrimers and cyclopeptides. Using diazonium functionalization and the efficiency of oxime ligation, the combination of both multiwalled carbon nanotube surfaces and modified dendrimers or cyclopeptides allows the access to a high surface coverage of ferrocene in the order of 50 nmol cm(-2), a 50-fold increase compared to a classic click reaction without oxime ligation of these highly branched macromolecules. Furthermore, this original immobilization strategy allows the immobilization of mono- and bi-functionalized active multicopper enzymes, laccases, via copper(I)-catalyzed azide-allcyne cycloaddition. Electrochemical studies underline the high efficiency of the oxime-ligated dendrimers or cyclopeptides for the immobilization of redox entities on surfaces while being detrimental to electron tunneling with enzyme active sites despite controlled orientation.

Automated summary

Carbon nanotube electrodes were modified with ferrocene and laccase using click reactions strategies involving diazonium functionalization and oxime ligation, achieving a high surface coverage of ferrocene. The immobilization of active multicopper enzymes, laccases, on surfaces via copper(I)-catalyzed azide-alcyne cycloaddition was also successful, highlighting the efficiency of oxime-ligated dendrimers or cyclopeptides. Despite controlled orientation, this immobilization strategy was found to impact electron tunneling with enzyme active sites.