CN201159718Y - Plasmon Resonance Sensing Probe - Google Patents

Abstract

The utility model relates to a plasma resonance sensing probe, which comprises an optical fiber matrix (1), an inner cladding (5) and an outer cladding (6), and the optical fiber matrix (1) is arranged on the outer cladding ( 6), the inner cladding (5) is arranged in the optical fiber matrix (1), the inner cladding (5) is composed of a channel (2), the inner surface of the channel (2) is provided with a metal layer (3), and the metal layer (3 ) is provided with a sensing layer (7), and the utility model provides a plasma resonance sensing probe with wider refractive index range and enhanced measurement sensitivity.

Description

Plasmon Resonance Sensing Probe

technical field

The utility model relates to a sensing probe, in particular to a plasma resonance sensing probe.

Background technique

Surface plasmon resonance is a transverse magnetic electromagnetic wave guided by a thin metal film surrounded by an insulating material. A plasmon is a surface effect that fluctuates the electron density at the interface between a metal and an insulator. Surface plasmon resonance occurs when the energy in the evanescent field couples with the plasmon on the metal film. The amount of coupling is extremely sensitive to the refractive index of the insulating material on both sides of the metal film. If one side of the insulating layer is composed of a chemical sample, we can monitor the change in the refractive index of the sample by measuring the change in the coupling between the evanescent wave field and the plasmon resonance.

Initially, surface plasmon resonance was used as a probe to monitor metal surfaces and later as a chemical and biochemical sensor. In early applications, metal films were deposited on the surface of prisms. Reflection occurs at the prism/metal interface when polarized light is irradiated at an angle of incidence less than the critical angle, and is monitored with a photodetector. When the incident angle of the laser is swept from a high angle to close to the critical angle, it will be seen that at a discontinuous angle, the reflectivity suddenly changes to a minimum value. At this angle, the wave vector of light in the prism matches that of the plasma, and the laser's energy is transferred into the plasma through the evanescent field at the reflection point. The position of the minimum is mainly determined by the refractive index of the material deposited on the metal surface. An increase in the sample's refractive index will result in an increase in the angle at which the minimum reflectance occurs.

Surface plasmon resonance has been applied in the field of fiber-optic communications as the basis for ordered, all-fiber polarization devices. Chemical reaction monitoring can be performed using the plasmon resonance effect on the fiber surface clad with a metal film. However, only those samples with a refractive index greater than about 1.39 can be monitored. This is an inherent limitation of fiber optic surface plasmon resonance sensors. Most chemical and biochemical applications require measurements in aqueous solutions, where the refractive index is typically 1.33 to 1.35. In order to monitor samples in this refractive index range, it is necessary to improve the traditional metal fiber core-sheath structure.

The existing optical fiber surface plasmon resonance (SPR) device itself does not have the ability to measure the water system with a refractive index of 1.33-1.35, and the existing prism SPR device has been proved to be too complicated and bulky for online chemical detection and biochemical analysis.

Utility model content

In order to solve the above-mentioned technical problems in the background technology, the utility model provides a plasma resonance sensor probe with wider refractive index range and enhanced measurement sensitivity.

The technical solution of the utility model is: the utility model is a plasma resonance sensing probe, which is special in that: the plasma resonance sensing probe includes an optical fiber matrix 1, an inner cladding 5 and an outer cladding 6, the optical fiber matrix 1 is set in the outer cladding 6, the inner cladding 5 is set in the optical fiber matrix 1, the inner cladding 5 is composed of a channel 2, the inner surface of the channel 2 is provided with a metal layer 3, and a sensing layer 7 is provided on the metal layer 3.

The above-mentioned channels 2 are one or more.

When there are multiple channels 2, the inner cladding 5 is composed of periodically distributed channels 2 that are characteristic of microstructured optical fibers.

The material of the metal layer 3 is silver or gold.

The material of the sensing layer 7 is dielectric material, polymer material, metal oxide, sulfide, semiconductor material, organic layer, inorganic layer or glass material.

The material of the above-mentioned sensing layer 7 is acetate fiber.

The above optical fiber substrate 1 is polymethyl methacrylate, polystyrene or polycarbonate.

The principle adopted by the plasma resonance sensing probe of the present utility model is: surface plasmon resonance is a plasma resonance of free electrons existing on the metal surface, and this resonance is affected by the refractive index of the material adjacent to the metal surface. Surface plasmon resonance can be obtained by exploiting the evanescent waves generated when a beam of polarized light is totally reflected at an interface with a high dielectric constant (such as cellulose acetate). A beam of light from a laser source is directed into the inner surface of the polymer film, and a monitor monitors the internally reflected beam. The surface in the optical fiber channel is a noble metal thin film of silver, and it is coated with functional molecules or antibodies that contain sensitive optical responses to the measured object. When the liquid containing the analyte (antigen) contacts the specific substance fixed in the channel , causing a specific chemical or biochemical reaction, such as an antigen-antibody binding reaction. If a reaction occurs, the refractive index of the second film changes due to the increase in size of the pro-antibody complex compared to the size of the original antibody molecule, which can be detected using surface plasmon resonance techniques. Surface plasmon resonance can be observed by varying the angle of incidence of the incident light and measuring the intensity of internally reflected light. At a certain angle of incidence, the parallel component of the light momentum matches the surface plasmon dispersion on the opposite side of the metal film; if the thickness of the metal film is chosen correctly, there will be electromagnetic field coupling between the PMMA/metal interface and the metal/antibody interface, Leading to surface plasmon resonance, attenuation of the reflected beam is observed at particular angles. Therefore, the utility model provides a plasmon resonance sensing probe, which is a surface plasmon resonance sensor that can detect changes in the refractive index of chemical or biochemical samples, and an analysis method that does not require any special markers. It has a wider range of refractive indices than surface plasmon sensors known and described today. It has higher analysis sensitivity than traditional optical fiber surface plasmon resonance sensor, and the range of refractive index of the analyzed aqueous solution is wider. The optical fiber surface plasmon resonance sensor can be better applied in the fields of biochemistry and chemistry.

Description of drawings

Fig. 1 is the structural representation of the utility model.

Detailed ways

Referring to Fig. 1, the utility model comprises an optical fiber matrix 1, an inner cladding 5 and an outer cladding 6, the optical fiber matrix 1 is arranged in the outer cladding 6, the inner cladding 5 is arranged in the optical fiber matrix 1, the inner cladding 5 is composed of tunnels 2, and the tunnels 2 A metal layer 3 is disposed on the inner surface of the metal layer 3 , and a sensing layer 7 is disposed on the metal layer 3 . There are one or more tunnels 2, and when there are multiple tunnels 2, the inner cladding 5 is composed of periodically distributed tunnels 2 with characteristics of microstructured optical fibers. The material of the metal layer 3 is precious metal materials such as silver or gold. The material of the sensing layer 7 can be dielectric material, polymer material, metal oxide, sulfide, semiconductor material, organic layer, inorganic layer or glass material, etc. Acetate fiber is preferred. The material of the optical fiber matrix 1 is polymethyl methacrylate, polystyrene or polycarbonate.

During the operation of the utility model, the sample is in contact with the surface plasma resonance sensing probe. The sensing layer 7 (cellulose acetate film) on the utility model contains sensitive substances such as substances with specific reactions (such as antibodies specifically combined with antigens). The surface plasmon resonance of the evanescent wave field in the electromagnetic radiation generated by the metal layer 3 varies as a function of the refractive index of the sample. The strength of the effect of surface plasmons depends on the thickness, the refractive index, and the refractive index of the sample of the metal layer 3 and the sensing layer 7 . The interaction between the sample and the special substance in the sensing layer 7, or the change of the refractive index of the sample due to chemical reaction, etc. will cause the change of surface plasmon resonance, and the existence of antigen or antibody can be identified by detecting the change.

When using the utility model to carry out biological measurement, firstly, the aqueous solution of the sample to be tested is sucked into the probe of the utility model by using capillary action. The difference between this probe and the existing technology is that the refractive index cladding in the traditional technology is replaced by a porous cladding. The hole channel not only increases the sensing area, but also fixes the sample to be tested by using the capillary. For example, for the detection of urine or blood, the 2-3 cm long optical fiber probe of the present utility model can be directly placed on the upper end of the syringe needle, and the measured blood and urine enter the sensor probe by means of capillary action to directly read the data . The sensor probe of the utility model will have important application value in the biochemical analysis of the components of blood and urine.

Claims (7)

1, a kind of plasma resonance sensing probe, it is characterized in that: this plasma resonance sensing probe comprises fibre-optical substrate (1), inner cladding (5) and surrounding layer (6), described fibre-optical substrate (1) is arranged in the surrounding layer (6), described inner cladding (5) is arranged in the fibre-optical substrate (1), described inner cladding (5) is made up of duct (2), the inside surface in described duct (2) is provided with metal level (3), and described metal level (3) is provided with sensing layer (7).

2, plasma resonance sensing probe according to claim 1 is characterized in that: described duct (2) are for one or more.

3, plasma resonance sensing probe according to claim 2 is characterized in that: when described duct (2) were a plurality of, described inner cladding (5) was duct (2) formation by the periodic distribution with microstructured optical fibers feature.

4, according to claim 1 or 2 or 3 described plasma resonance sensing probes, it is characterized in that: the material of described metal level (3) is a silver or golden.

5, plasma resonance sensing probe according to claim 4 is characterized in that: the material of described sensing layer (7) is dielectric substance, polymeric material, metal oxide, sulfide, semiconductor material, organic layer, inorganic layer or glass material.

6, plasma resonance sensing probe according to claim 5 is characterized in that: the material of described sensing layer (7) is an acetate fiber.

7, plasma resonance sensing probe according to claim 5 is characterized in that: described fibre-optical substrate (1) is polymethylmethacrylate, polystyrene or polycarbonate.

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