A signal “off–on” electrochemical aptamer sensor of Staphylococcus aureus based on ZIF8-derived carbon decorated with platinum nanoparticles

As one of the most poisonous and deadliest pathogens, Staphylococcus aureus ( S. aureus ) poses serious harm to human health, thus designing simple, sensitive and reliable method for its detection is of great significance. Herein, via synthesizing ZIF8-derived carbon decorated with platinum nanoparticles (Pt/C-ZIF-8) hybrids as the nanozyme, an innovatively signal “off–on” electrochemical aptamer (Apt) sensing platform was designed to detect S. aureus for the first time. As for this proposal, the Pt/C-ZIF-8 nanozyme can be able to catalyze 1,2-diaminobenzene to form diaminophenazinc (DAP, an electroactive substance). However, when Pt/C-ZIF-8 bounds to S. aureus -Apt, its enzyme-like activity would be inhibited since the active sites are covered by Apt and the DAP current disappears relatively (signal “off”). Interestingly, with the existence of S. aureus , the activity of Pt/C-ZIF-8 is called back because the specific binding between Apt and S. aureus can induce Apt away from the Pt/C-ZIF-8 surface, thus arising the increase of DAP current (signal “on’). By optimizing several key conditions, the as-designed signal “off–on” nanozyme-based electrochemical Apt sensor offers prominent detection performance for S. aureus , which may also offer a novel, simple and reliable strategy to detect various pathogens through altering the related Apt simply.