Graphene-based nano-pore monomolecular sensor and medium identification method thereof

[0014] In order to make the content of the present invention more obvious and understandable, further description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0015] Combine figure 1 , figure 2 As shown, the graphene-based nanopore monomolecular sensor of the present invention is a sandwich-like structure, and the radial electrode 2 is a single layer or multiple layers of graphene, sandwiched in the middle of the insulating layer 1, and the center of the sensor insulating layer is used A nanopore channel 8 is prepared by FIB. The graphene radial electrode 2 includes an anode and a cathode, which are respectively located at the two radial ends of the nanopore channel 8. The radial ammeter 7 is connected in series to the anode and cathode of the graphene radial electrode 2. Between; two Pt electrodes 5 are placed in the axial direction of the nanopore channel 8, respectively the anode and the cathode, and the axial ammeter 3 is connected in series between the anode and the cathode of the axial Pt electrode 5.

[0016] Combine figure 1 As shown, there are spare graphene radial electrodes 4 inside the insulating layer and in the radial direction of the nanopore channel, including an anode and a cathode, respectively located at both ends of the nanopore channel 8 in the radial direction, and two spare radial electrodes 4 The connection between the two and the connection between the two radial electrodes 2 are perpendicular to each other. This spare radial electrode can be used when the radial electrode is not working, or used to participate in the measurement at the same time, and comprehensively analyze the data to identify the medium more accurately.

[0017] The diameter of the nanopore channel 8 is between 1-100nm. When applied to medium identification, sensors of different sizes of nanochannels can be selected according to the diameter of the medium molecule to be measured. The general selection criterion is that the diameter of the nanopore channel is slightly larger than the The diameter of the molecules of the measuring medium, that is, the molecules of the measuring medium just pass through the nanopore channel. The identification process is to connect the two ends of the nanopore channel to the fluid cell unit of the medium to be measured, apply an axial voltage between the cathode and the anode of the axial Pt electrode, and apply between the anode and the cathode of the graphene radial electrode Radial voltage, when the medium molecule 9 to be tested passes through the nanopore, it will cause changes in the axial current and the radial current. The changes in the radial and axial ion currents in the nanopore channel are detected respectively, and the relationship between the current change and the properties of the medium is combined. , That is, the change of ionic current generated when molecules with different charges and structures on the surface pass through the hole is also different. The special uniqueness is used to identify the medium. At the same time, the change of radial current and the change of axial current are compared to obtain a comprehensive change law , Can identify the properties of the medium more accurately. In addition, according to the state of the measured medium passing through the nanopore, the properties of the medium can be further analyzed in the future, such as the surface charge distribution of biomolecules, the spatial folding structure of biomolecules and other properties.

[0018] The specific implementation cases described in the present invention are only preferred implementation cases of the present invention, and are not used to limit the scope of implementation of the present invention. That is, all equivalent changes and modifications made according to the content of the patent application scope of the present invention shall be regarded as the technical scope of the present invention.