A kind of spr sensor chip and preparation method thereof

Abstract

The invention discloses an SPR sensing chip and a preparation method thereof. The SPR sensing chip comprises a flat glass substrate covered with a first metal film with a thickness greater than 150nm, and micropores are arranged on the top surface of the first metal film. The bottom of each microhole is covered with a second metal film, and the top surface of the second metal film is provided with several nanometer metal wires arranged periodically. The SPR generated on the second metal film is coupled to the nano-metal wire to generate LSPR, which causes the local electromagnetic field to be enhanced; it also generates SPW at the bottom of the micropore, and the SPW is reflected by the inner wall of the micropore during the horizontal propagation process, so that it is different from the forward propagation. The SPW interference of the SPW forms a standing wave and is bound inside the microhole, and the electromagnetic field of the standing wave is also enhanced to a certain extent. The double enhancement can increase the sensitivity by 15 to 30 times; at the same time, the microhole limits the SPW to a certain area, avoiding signal interference. Cross-interference is beneficial to reduce noise and improve the signal-to-noise ratio of SPR sensing.

Description

technical field [0001] The invention belongs to the field of optical biosensing, and in particular relates to an SPR sensing chip and a preparation method thereof. Background technique [0002] Surface plasmon resonance (SPR) is a physical optical phenomenon. At the interface of two transparent media with different refractive index (such as glass and water), when a beam of light is incident from a medium with a high refractive index to a medium with a low refractive index, the light will be refracted and reflected. When the incident angle increases to a certain value, the refraction angle is equal to 90°, and the light is emitted along the direction tangent to the interface. The incident angle at this time is called the critical angle. If the incident angle exceeds the critical angle, the incident light will not enter another medium, but all will be reflected back into the incident medium, and total internal reflection will occur. [0003] In fact, although all incident li...

AI Technical Summary

Problems solved by technology

Compared with the complex system required for phase modulation, the light intensity modulation SPR imaging sensor has a simple structure, easy to use, and a large dynamic range, and has been widely used; but the current problem is that its resolution is within 10 -5 ~10 -6 Among RIUs, the sensitivity is generally lower than that of channel-type SPR sensors and phase-modulated SPR imaging sensors

The main reason is that its SPR sensor chip generally uses a flat metal film, that is, a layer of metal film is directly coated on a flat glass substrate, and its sensing sensitivity is low.