An ultrasensitive aptasensor of SARS-CoV-2 N protein based on ion current rectification with nanopipettes

Since the outbreak of COVID-19 in the world, it has spread rapidly all over the world. Rapid and effective detection methods have been a focus of research. The SARS-CoV-2 N protein (NP) detection methods currently in use focus on specific recognition of antibodies, but the reagents are expensive and difficult to be produced. Here, aptamer-functionalized nanopipettes utilize the unique ion current rectification (ICR) of nanopipette to achieve rapid and highly sensitive detection of trace NP, and can significantly reduce the cost of NP detection. In the presence of NP, the surface charge at the tip of the nanopipette changes, which affects ion transport and changes the degree of rectification. Quantitative detection of NP is achieved through quantitative analysis. Relying on the high sensitivity of nanopipettes to charge fluctuations, this sensor platform achieves excellent sensing performance. The sensor platform exhibited a dynamic working range from 10²-10⁶ pg/mL with a detection limit of 73.204 pg/mL, which showed great potential as a tool for rapidly detecting SARS-CoV-2. As parallel and serial testing are widely used in the clinic to avoid missed diagnosis or misdiagnosis, we hope this platform can play a role in controlling the spread and prevention of COVID-19.