Plasmon-Enhanced Electroactivity of AuRu Nanostructures for Electroanalysis Applications

An electrochemical sensing interface is limited by poor reproducibility and inevitable interferences present in practical applications due to the weak electrochemical signals of nanotags. This motivates the need for effective strategies to enhance the electroactivity performances of nanotags. In this contribution, a plasmon-enhanced electroactivity mechanism is proposed for AuRu-based nanostructures under illumination and applied for accurate detection of human epidermal growth factor receptor-2 (HER2). AuRu nanoparticles (NPs) harvested light energy through plasmon excitation and generated holes to participate in the electrooxidation process. The production of holes resulted in the electrooxidation signal enhancement of AuRu NPs. AuRu NPs were assembled with Au NPs using HER2 aptamers as linkers, and the plasmonic coupling between AuRu NPs and Au NPs produced an intense electromagnetic field, which further enhanced the electrooxidation signals of AuRu NPs. An AuRu-Au NP assembly-dependent electrochemical aptasensor was established for the accurate detection of HER2, and the limit of detection (LOD) was as low as 1.7 pg/mL. The plasmon-enhanced electroactivity mechanism endowed AuRu-based nanostructures with strong and noninterfering electrochemical signals for sensitive and accurate detection. This insight opens new horizons for the construction of desired electroactive nanostructures for electroanalysis applications.