Nanochannel–Ion Channel Hybrid Device for Ultrasensitive Monitoring of Biomolecular Recognition Events

We propose an in situ and label-free method for detection of biomolecular recognition events by use of a nanochannel–ion channel hybrid device integrated with an electrochemical detector. The aptamer is first immobilized on the outer surface of the nanochannel–ion channel hybrid. Its binding with target thrombin in solution considerably regulates the mass-transfer behavior of the device owing to the varied surface charge density and effective channel size. Via the electrochemical detector, the changed mass-transport property can be monitored in real time, which enables in situ and label-free detection of thrombin–aptamer recognition. The solution pH has a significant influence on detection sensitivity. Under optimal pH conditions, a detection limit as low as 0.22 fM thrombin can be achieved, which is much lower than most reported work. The present nanofluidic device provides a simple, ultrasensitive, and label-free platform for monitoring biomolecular recognition events, which would hold great potential in exploring the functions and reaction mechanisms of biomolecules in living systems