CN214252009U

CN214252009U - Electromagnetic induction transparent time-frequency double-domain super-surface sensor

Info

Publication number: CN214252009U
Application number: CN202022936993.7U
Authority: CN
Inventors: 邴丕彬; 国馨月; 张红涛; 谭联; 许若辰; 刘庆
Original assignee: North China University of Water Resources and Electric Power
Current assignee: North China University of Water Resources and Electric Power
Priority date: 2020-12-10
Filing date: 2020-12-10
Publication date: 2021-09-21
Anticipated expiration: 2030-12-10

Abstract

The utility model aims at providing an electromagnetic induction transparent time-frequency double-domain super surface sensor, the utility model discloses an electromagnetic induction transparent time-frequency double-domain super surface sensor, including the basement, at basement sculpture square metal ring, at the intra-annular basement sculpture metal ring of metal square, metal ring is provided with the open end, and the open end is corresponding with the intermediate position of metal square ring. The problems of complex operation and false positive of biological protein detection are effectively solved, and samples can be detected in time-frequency double domains simultaneously. Compared with the traditional SPP super-surface sensor, the EIT super-surface is extremely sensitive to the refractive index of the surrounding medium due to the limitation of high Q factors and strong electric fields, and the corresponding spectral response characteristics are greatly changed by the tiny disturbance of the boundary conditions of the interface, so that the sensitivity of the sensor is improved. The utility model provides possibility for solving the unmarked detection of trace cancer markers, finding the existence of cancer factors as soon as possible and striving for treatment time.

Description

Electromagnetic induction transparent time-frequency double-domain super-surface sensor

Technical Field

The utility model relates to a super surface is in the application in biosensing field, and concretely relates to is based on electromagnetic induction transparent time frequency double domain surpasses surface sensor.

Background

Biomacromolecule interactions are key factors in the generation of major life phenomena and lesions, with proteins being the most typical. The MK midkine is a low molecular weight protein, and the over-expression of the MK protein means the malignancy degree of cancer cells and is a potential biological index of the cancer deterioration degree. A commonly used method for detecting the midkine in the MK protein, namely enzyme-linked immunosorbent assay (ELISA), is characterized in that an antibody is combined with an enzyme complex, and finally, the detection is carried out by utilizing the color development change, but the method has the defects of long measuring time (usually taking 2-4 hours) and false positive problem. Terahertz (THz) waves refer to electromagnetic waves with the frequency within the range of 0.1-10 THz (the wavelength is 0.03mm-3 mm), coincide with millimeter waves (sub-millimeter waves) in a long wave band, and just cover the characteristic spectrum of organisms, biomacromolecules and other substances. Therefore, THz has great application value in biomedical detection. However, when the concentration of the substance to be detected is a trace amount, the interaction between the substance and the THz wave is not obvious due to the long electrical size of the THz wave relative to the substance to be detected, so that the problem of seeking other ways for enhancing the interaction between the terahertz wave and the substance becomes a urgent need to be solved. The super surface is defined as an artificial sub-wavelength composite structure material, and the electromagnetic property of the material can be flexibly controlled only by designing a resonance structure. Particularly, when the incident electric field is converted into Surface Plasmon Polaritons (SPPs) on the surface of the metamaterial, a strong local electric field can be generated, and the sensing sensitivity is greatly enhanced. Therefore, the super-surface working in the terahertz (THz) wave band has great potential in the aspect of biological detection, particularly in the aspect of high-sensitivity sensing and identification of biological samples, and provides an advanced technical means for early diagnosis and early treatment of current serious diseases.

SUMMERY OF THE UTILITY MODEL

Electromagnetic Induced Transparency (EIT) is a quantum mechanical phenomenon, and originally, the conventional EIT phenomenon is realized by a sharp transparent window in the quantum destructive interference effect generated in a three-level atomic system. The utility model discloses introduce the metamaterial system with EIT, produce the electromagnetic destructive interference in the design structure, appear sharp-pointed absorption peak. When the external boundary condition of the super surface is changed, the external substance attached to the changed surface absorbs the energy of the electric field, and the disturbance of the dielectric environment changes the boundary condition of the interface and greatly changes the corresponding spectral properties. Compared with the traditional SPP super-surface sensor, the EIT super-surface is extremely sensitive to the refractive index of the surrounding medium due to the limitation of high Q factors and strong electric fields, and the corresponding spectral response characteristics are greatly changed by the tiny disturbance of the boundary conditions of the interface, so that the sensitivity of the sensor is improved. The utility model provides possibility for solving the unmarked detection of trace cancer markers, finding the existence of cancer factors as soon as possible and striving for treatment time.

The utility model aims at providing an electromagnetic induction transparent time frequency double domain surpasses surface sensor, effectively solves the problem that biological protein detection operation is complicated, false positive to can be simultaneously time frequency double domain detection sample.

The purpose of the utility model is realized through the following technical scheme:

the utility model provides an electromagnetic induction transparent time-frequency double domain super surface sensor, includes the basement, etches the metal square ring on the basement, etches the metal ring on the basement in the metal square ring, and the metal ring is provided with the open end, and the open end corresponds with the intermediate position of metal square ring.

According to the electromagnetic induction transparent time-frequency double-domain super-surface sensor, the metal square ring is of a closed structure, and the metal circular ring is of an open structure.

According to the electromagnetic induction transparent time-frequency double-domain super-surface sensor, the closed metal square ring and the open metal circular ring form a periodic unit structure with an outer square and an inner circle.

The thicknesses of the metal square ring and the metal circular ring of the electromagnetic induction transparent time-frequency double-domain super-surface sensor are both 0.2 mu m.

According to the electromagnetically induced transparent time-frequency two-domain super-surface sensor, the substrate is a flexible polyimide substrate.

According to the electromagnetically induced transparent time-frequency two-domain super-surface sensor, the thickness of the substrate is 10 micrometers.

According to the electromagnetically induced transparent time-frequency double-domain super-surface sensor, the metal ring structure with the square outside and the round inside of the unit periodic structure is made of gold, the period is 140 micrometers, and the thickness is 0.2 micrometer.

According to the electromagnetic induction transparent time-frequency double-domain super-surface sensor, the outer radius of a metal circular ring is 31 micrometers, the width of an opening gap w is 12 micrometers, the length of an outer ring of an external closed square ring is 116 micrometers, and the line widths of the square ring and the opening circular ring are 10 micrometers.

Adopt above-mentioned technical scheme, the beneficial effects of the utility model are that:

1. the traditional method for detecting biological protease, namely a combined immunosorbent assay (ELISA) method, has the defects of long measurement time, low efficiency, false positive and the like, and the EIT phenomenon is that a sharp transparent window appears in the quantum destructive interference effect generated in a three-level atomic system. The utility model discloses introduce the metamaterial system with traditional quantum EIT, produce the electromagnetic destructive interference in the design structure, appear sharp-pointed absorption peak. When the external boundary conditions on the super-surface are changed, the external substances attached to the surface absorb the energy of the electric field, and the disturbance of the dielectric environment changes the boundary conditions of the interface, so that the corresponding spectral properties are changed to a large extent. Compared with the traditional SPP super-surface sensor, the EIT super-surface is extremely sensitive to the refractive index of a surrounding medium due to the limitation of a high Q factor and a strong electric field, and the corresponding spectral response characteristics are greatly changed by the tiny disturbance of the boundary condition of the interface, so that the sensitivity of the sensor is improved, the detection limit is reduced, and the possibility is provided for solving the problem of unmarked detection of trace cancer markers, discovering the existence of cancer factors as soon as possible and striving for treatment time.

2. Super surface sensing often only analyzes and studies the frequency domain, the utility model discloses a secondary Fourier transform obtains pseudo-time domain spectrum, researches pseudo-time domain spectrum and protein concentration relation within a definite time, and the result discovery is along with protein concentration increase, and the area that corresponds concentration spectral line crescent. Thus, the pseudo-time domain spectrum may also be used as an indicator of protein concentration levels. It is worth mentioning that if directly subtracting the air background in the time domain requires a series of complicated mathematical calculations to eliminate the influence of the air background, the frequency domain only requires simple division, so researchers are used to analyze the frequency domain and ignore the time domain. The utility model provides a pseudo-time domain spectrum is with the time domain spectrum symmetry of getting rid of the air background influence in the first quadrant to the spectral information reflection in the second quadrant for pseudo-spectrum, and this has not only solved the difficult problem of research time domain spectral line greatly, still detains simultaneously except being difficult to deduct the background on the time domain. The frequency shift is used as a transverse index for measuring the protein concentration, and a time domain pseudo spectrum obtained by amplitude difference is used as a longitudinal index for measuring the protein concentration, so that the possibility is provided for multi-dimensionally researching the potential relation between a spectral line and the protein concentration.

Drawings

Fig. 1 is a schematic structural diagram of the present invention.

FIG. 2 is a schematic diagram of electric field distribution at EIT transmission peak

FIG. 3 is a transmission spectrum of a super-surface producing EIT transmission peak direction for different concentrations of protein drop-coated in X polarization direction.

FIG. 4 is a graph of transmission shift and amplitude difference for a super-surface producing EIT transmission peak direction for different concentrations of protein dispensed in the X-polarization direction.

FIG. 5 is a pseudo-time domain plot of EIT transmission peak direction versus drop-coated protein of different concentrations in the X-polarization direction.

Detailed Description

The structure and operation of the present invention will be described in detail with reference to fig. 1, fig. 2, fig. 3, fig. 4 and fig. 5.

The utility model provides an electromagnetic induction transparent time-frequency double-domain super surface sensor, includes basement 1, etches metal square ring 2 on the basement, etches metal ring 3 on the basement of metal square intra-annular, and metal ring is provided with the open end, and the open end corresponds with the intermediate position of metal square ring, and basement, metal square ring and metal ring constitute the super surface sensor of circle in the foreign side.

The utility model discloses electromagnetic induction transparent time-frequency double-domain super surface sensor, the metal square ring is closed structure, and the metal ring is open structure. The closed metal square ring and the open metal circular ring form a periodic unit structure with an outer square and an inner circle. The thickness of the metal square ring and the metal circular ring is 0.2 μm.

The utility model discloses electromagnetic induction transparent time frequency double domain super surface sensor, the basement is flexible polyimide basement, and thickness is 10 mu m.

The specific method comprises the following steps: spin-coating a polyimide solution with the viscosity of 3600 centipoises on a cleaned silicon wafer, putting the spin-coated polyimide solution into a vacuum drying oven for curing, wherein the curing process comprises the steps of respectively baking for 1 hour at the temperature of 120 ℃, 200 ℃ and 230 ℃, then baking for 2 hours at the temperature of 250 ℃, and finally naturally cooling to the room temperature and taking out.

The utility model discloses transparent time frequency double domain super surface sensor of electromagnetic induction, the transparent time frequency double domain super surface sensor of above-mentioned electromagnetic induction, unit periodic structure outside the square inner circle metal loop structure material is gold, and the cycle is 140 μm, and thickness is 0.2 μm; the outer radius of the metal circular ring is 31 μm, the width of the opening gap w is 12 μm, the outer ring length of the external closed square ring is 116 μm, and the line widths of the square ring and the opening circular ring are both 10 μm.

The specific method for obtaining the metal structure comprises the following steps: placing the substrate coated with the photoresist and the prepared MASK plate (MASK) on a photoetching machine, aligning, tightly adhering the substrate and the MASK, observing by using a microscope on the photoetching machine, and adjusting the exposure time to be 9.8 seconds and exposing for 4 times. After the exposure, the substrate was subjected to reverse baking at 110 ℃ for 1 minute. And then carrying out back exposure for 45 seconds, finally developing by using a developing solution for 45 seconds, and carrying out post-baking after developing, wherein the baking temperature is 90 ℃ and the baking time is 10 minutes. Gold was evaporated to a thickness of 200nm on the exposed polyimide film. And soaking the metal evaporation sample in an acetone solution to strip and remove the remaining photoresist AZ5214 and the first layer of metal on the photoresist, wherein the soaking time is about 20 minutes. Then washed with isopropanol and deionized water.

The utility model is shown in figure 1. The structure comprises the following two layers: the bottom layer is made of flexible polyimide; the surface patterned metal layer of the surface layer consists of metal square rings 2 and metal circular rings 3 which are arranged at equal intervals (unit periodic structure). The metal opening circular ring 3 is positioned in the middle of the inside of the square ring 2, and the square ring 2 is of a closed structure and forms an outer square and inner circle metal ring unit. The flexible substrate layer and the surface patterned metal layer which is composed of the periodic unit structures which are square outside and round inside form the super-surface sensor. The structure generates an electromagnetic induction transparent peak with high Q value and high sensitivity on a transmission spectrum of incident electromagnetic waves oscillating along the x polarization direction, generates different degrees of frequency shift and amplitude difference on proteins dripped on a super surface and coated with different concentrations, the frequency shift is used as a transverse index for measuring the protein concentration, a time domain pseudo spectrum obtained by the amplitude difference is used as a longitudinal index for measuring the protein concentration, and the rapid label-free detection of the terahertz waveband high-sensitivity protein is realized through multi-dimensional analysis.

The entire EIT structure is broken down into two sub-parts: a square frame Structure (SF) and a bi-level metal line + circular ring (EW). The spectral response and electric field distribution of each sub-portion and the entire structure are shown in fig. 2. It is observed from the figure that at the EIT window, the interference between the bright mode supported by the SF cell and the dark mode supported by the EW produces EIT resonances in the whole structure. In this mechanism, the bright mode couples energy to the dark mode through near-field interaction, exciting the LC resonance of the EW structure. In a relatively wide absorption band, destructive interference between the LSP and the LC results in the appearance of a sharp transparent peak. At 0.64THz, the SF structure acts as a bright mode, the electric field is distributed mainly on the left and right sides of the square, and with current flowing along the upper and lower metal lines, LSP resonances with dipole modes typical of this are clearly formed. Acting as a dark mode for the EW structures, although the electric field remains on the left and right sides, the intensity is an order of magnitude less than for the SF structures, and is barely observable in the figure. Meanwhile, no obvious current distribution is generated by the metal wire and the inner circular ring. It is worth noting that only two sub-components are combined together, the inner split ring does not generate significant current before strong circulating currents are induced, and corresponding LC resonances are generated. Since this mode was not previously excited by incident terahertz waves, it means that bright modes couple energy to dark modes through near-field interactions. Therefore, the bright mode is completely suppressed due to destructive interference between the two modes, and the current density in the dipole mode along the metal frame becomes weak.

Since the bright mode in the electromagnetically induced transparent structure is completely suppressed, all spectral linetype changes are due to changes in the external dielectric environment, and thus have extremely high sensitivity. Different concentrations of MK protein solution are dropped on the super-surface sensor, the solution is evenly covered on the periodic unit structure, and FIG. 3 shows the transmission amplitude spectrum of the EIT super-surface under different MK protein concentrations. Compared with a blank sample, the EIT peak position frequency of the sample coated by the MK protein is obviously red-shifted, and the red-shift offset is larger along with the increase of the MK protein concentration.

FIG. 4 shows a further extracted frequency shift ΔfAnd the dependence of peak amplitude on MK protein concentration. As the MK protein concentration increases from 0.2. mu.g/ml to 50. mu.g/ml, the shift in clearing peak at 0.67THz gradually increases and reaches a maximum of 47 GHz. Due to the change of the effective dielectric constant of the near field of the super surface, DeltafBecomes a practically useful index, and facilitates rapid determination of the concentration of the marker-free MK protein.

Due to the advantages of intuition and accuracy, the direct research of the time domain signals can more comprehensively extract the multidimensional information of the data. Fig. 5 shows a pseudo-spectrum obtained by applying two fourier transforms to the difference in the full spectral amplitude of the sample. The method greatly solves the problem that the background signal is difficult to remove in the time domain. The results indicate that MK protein expression levels can be directly identified by pseudoprofiling. The pseudo-spectral intensity is highest when the MK protein concentration is increased to 20. mu.g/ml. When the MK protein concentration drops to a minimum of 0.5. mu.g/ml, the peak of the pseudospectrum approaches 0.02 and can still be clearly identified. Thus, the limit of detection (LOD) of this method is less than 0.5. mu.g/ml. Such a feature fully represents the superiority of the pseudo-temporal profile in the trace detection of MK proteins.

What has been described above is only the preferred embodiments of the present invention, and it should be noted that, for those skilled in the art, without departing from the overall concept of the present invention, a plurality of changes and improvements can be made, and these should also be regarded as the protection scope of the present invention, and these will not affect the effect of the present invention and the utility of the patent.

Claims

1. The utility model provides an electromagnetic induction transparent time-frequency double domain super surface sensor, includes the basement which characterized in that: the metal square ring is etched on the substrate, the metal circular ring is etched on the substrate in the metal square ring, the metal circular ring is provided with an opening end, the opening end corresponds to the middle position of the metal square ring, and the substrate, the metal square ring and the metal circular ring form the super-surface sensor with the outer square and the inner circle.

2. The electromagnetically-induced-transparent time-frequency dual-domain super-surface sensor as claimed in claim 1, wherein: the metal square ring is of a closed structure, and the metal circular ring is of an open structure.

3. The electromagnetically-induced-transparent time-frequency dual-domain super-surface sensor as claimed in claim 2, wherein: the closed metal square ring and the open metal circular ring form a periodic unit structure with an outer square and an inner circle.

4. The electromagnetically-induced-transparent time-frequency dual-domain super-surface sensor as claimed in claim 2, wherein: the thickness of the metal square ring and the metal circular ring is 0.2 μm.

5. The electromagnetically-induced-transparent time-frequency dual-domain super-surface sensor as claimed in claim 1, wherein: the substrate is a flexible polyimide substrate.

6. The electromagnetically-induced-transparent time-frequency dual-domain super-surface sensor as claimed in claim 1, wherein: the substrate thickness was 10 μm.

7. The electromagnetically-induced-transparent time-frequency dual-domain super-surface sensor as claimed in claim 3, wherein: the metal ring structure with the unit periodic structure, square outside and round inside is made of gold, the period is 140 μm, and the thickness is 0.2 μm.

8. The electromagnetically-induced-transparent time-frequency dual-domain super-surface sensor as claimed in claim 1, wherein: the outer radius of the metal circular ring is 31 μm, the width of the opening gap w is 12 μm, the outer ring length of the external closed square ring is 116 μm, and the line widths of the square ring and the opening circular ring are both 10 μm.