Carboxylated Pillar[5]arene-Coated Gold Nanoparticles with Chemical Stability and Enzyme-like Activity

A facile synthesis of gold nanoparticles (AuNPs) covered with a multidentate macrocycle, carboxylated pillar[5]arene (CP), via a one-pot hydrothermal process is reported. The resulting AuNPs are highly stable against salts and pH variations, while their traditional counterparts are not stable at the same conditions. For the stabilization, multiple carboxylate groups of CP might contribute to electrostatic or steric stabilization. In addition, we found that CP-coated AuNPs exhibit greater peroxidase-like activity than citrate-stabilized AuNPs in the presence of silver cations. The system presented herein would provide a new scheme to fabricate unique sensory systems in combination with enzymes, which can bind to the pocket of CP.