Ag@Pyc Nanocapsules as Electrochemiluminescence Emitters for an Ultrasensitive Assay of the APE1 Activity.

Herein, Ag@pyrenecarboxaldehyde nanocapsules (Ag@Pyc nanocapsules) as emitters were prepared to construct an ultrasensitive electrochemiluminescence (ECL) biosensor for the detection of the human apurinic/apyrimidinic endonuclease1 (APE1) activity. Ag nanoparticles on the surface of Pyc nanocapsules as coreaction accelerators could significantly promote coreactant peroxydisulfate (SO) to generate massive reactive intermediates of sulfate radical anion (SO), which interacted with the Pyc nanocapsules to achieve a strong ECL response. In addition, with the aid of APE1-triggered 3D DNA machine, trace target could be converted into a large number of mimic targets (MTs), which were positively correlated with the activity of APE1. Consequently, the proposed ECL biosensor realized an ultrasensitive detection of APE1 activity with an exceptional linear working range from 5 × 10 to 5 × 10 U·μL and a lower limit of detection of 1.36 × 10 U·μL. This strategy provided a new approach to construct an efficient ternary system for the detection of biomolecules and early diagnosis of diseases.