Cooperation Mode of Outer Surface and Inner Space of Nanochannel: Separation-Detection System Based on Integrated Nanochannel Electrode for Rapid and Facile Detection of Salmonella.

Nanochannels hold great prospects in intelligent systems; however, current research focuses on the inner space of the nanochannel while the outer surface is rarely explored. Here, we report on a cooperation mode of the outer surface and inner space of the nanochannel using an integrated nanochannel-electrode (INCE) and its application as a separation-detection system for rapid and facile detection of foodborne bacteria. Unlike conventional nanochannel systems, the INCE integrates two electrodes as a sensitive electrochemical interface and the nanochannel itself as nanofilter, generating a novel separation-detection system. The system is examined in a biosensing strategy based on magnetic nanoparticles (MNPs). Salmonella typhimurium (St) is taken as the target due to its severe threat to human health and food safety. By electrochemically probing the MNPs-St complex themselves on the surface of INCE, this method eliminates the requirement on additional signal labels. The biosensor presents a linear detection range from 102 to 107 CFU mL-1 and a limit of detection of 50 CFU mL-1, being comparable or even better than those of analogues with complicated signal amplification designs. Moreover, the biosensor exhibits good specificity against four types of interfering bacteria. This concept may bring new insight into the development of nanochannel research and contribute a new way to the fields of separation and detection.