25 second cocaine sensing by membrane protein channel integrated in a microfluidic device

This paper describes a cocaine sensing using a membrane protein channel integrated in a microfluidic device (Figure 1). Protein channel (1.5 nm dia.) was reconstituted in planar lipid bilayers (BLMs) spanning at nanometer-sized parylene nanopore (400 nm dia., Figure 1b). DNA dissolved in solution can be driven through an alpha-hemolysin (αHL) channel by an applied electric field (Figure 1c left), and it was recognized as single molecular level by monitoring the channel currents. It was revealed in this study that a cocaine was discriminated by the protein channel as changing the structure from a cocaine molecule to a cocaine aptamer complex as shown Figure 1c right. We demonstrated that the cocaine aptamer can be sensed for only 25 second in the 3D microfluidic device.