Simple and highly sensitive electrochemical detection of Listeria monocytogenes based on aptamer-regulated Pt nanoparticles/hollow carbon spheres nanozyme activity

Listeria monocytogenes (LM) is one of the deadliest and most hazardous pathogens, posing extremely serious harm to the human health, hence developing simple and effective method for its highly sensitive detection is very important. In this work, by preparing Pt nanoparticles/hollow carbon spheres (Pt/HCNs) nanohybrid as nanozyme, a simple and highly sensitive nanozyme-based electrochemical sensor was developed for the first time to detect LM based on aptamer (Apt)-regulated Pt/HCNs nanozyme activity. The as-prepared Pt/HCNs nanozyme can catalyze the oxidation of o-phenylenediamine to generate electroactive 2,3-diaminophenazinc (DAP) which offers an obvious reduction peak current. However, once bound to LM-Apt to form Apt/Pt/HCNs, the related enzyme-like activity of Pt/HCNs is inhibited remarkably and the reduction current of DAP nearly disappear owing to the covering of the active sites. Interestingly, in the presence of LM, the nanozyme activity can be recovered through the specific recognition of Apt towards LM. After optimizing various conditions, the designed Apt-regulated nanozyme-based electrochemical sensor shows excellent sensing performances for LM. Meanwhile, the designed sensors exhibits superior selectivity, specificity, reproducibility, stability and real applications. This work offers a simple and novel strategy for the effective and highly sensitive determination of various pathogens via altering simply the specific Apt.