Click-Conjugation of Nanogold-Functionalized PAMAM Dendrimer: Toward a Novel Electrochemical Detection Platform

This work reports a new electrochemical monitoring platform for sensitive detection of Cu2+ coupling click chemistry with nanogold-functionalized PAMAM dendrimer (AuNP-PAMAM). The system involved an alkyne-modified carbon electrode and an azide-functionalized AuNP-PAMAM. Initially, the added Cu2+ was reduced to Cu+ by the ascorbate, and then the azide-modified AuNP-PAMAM was covalently conjugated to the electrode via Cu+-catalyzed azide-alkyne click reaction. The carried AuNPs accompanying PAMAM dendrimer could be directly monitored by stripping voltammetry after acidic pretreatment. By introduction of high-loading PAMAM dendrimer with gold nanoparticles, as low as 2.8pM Cu2+ (ppt) could be detected, which was 125-fold lower than that of gold nanoparticle-based labeling strategy. The method exhibited high specificity toward target Cu2+ against other potentially interfering ions, and was applicable for monitoring Cu2+ in drinking water with satisfactory results.