阅读说明：本技术 一种频域量子弱测量生物分子传感器及其测量方法 (Frequency domain quantum weak measurement biomolecule sensor and measurement method thereof ) 是由 何永红 许杨 施力轩 周冲琪 于 2021-08-30 设计创作，主要内容包括：一种频域量子弱测量生物分子传感器及其测量方法,该传感器包括发光装置、偏振态制备装置、棱镜、偏振态选择装置、光谱分频装置和光电探测元件,被测样品与棱镜的反射表面接触,由发光装置发出的光束经偏振态制备装置变成偏振光,偏振光入射到棱镜的反射表面,经界面反射产生相位差,经过偏振态选择装置对偏振态进行选择,经光谱分频装置后被分离为不同频率区间的光束,再被光电探测元件分别接收并通过计算光强差值的方式获得样品折射率测量结果,由此可测定棱镜表面的样品分子的浓度和/或实现生化反应过程的监控。本发明能够在保证高灵敏度测量生物分子样品折射率的前提下,提升测量的稳定性,可重复性和对环境噪声干扰的抵抗能力。(A frequency domain quantum weak measurement biomolecule sensor and its measuring method, the sensor includes a light emitting device, a polarization state preparation device, a prism, a polarization state selection device, a spectrum frequency division device and a photoelectric detection element, the measured sample contacts with the reflection surface of the prism, the light beam emitted by the light emitting device is changed into polarized light by the polarization state preparation device, the polarized light is incident to the reflection surface of the prism, a phase difference is generated by the interface reflection, the polarization state is selected by the polarization state selection device, the polarized light is separated into light beams with different frequency intervals after passing through the spectrum frequency division device, and then the light beams are respectively received by the photoelectric detection element and the sample refractive index measurement result is obtained by calculating the light intensity difference, thereby the concentration of the sample molecule on the prism surface can be measured and/or the monitoring of the biochemical reaction process can be realized. The invention can improve the stability, repeatability and resistance to environmental noise interference of measurement on the premise of ensuring the high-sensitivity measurement of the refractive index of the biomolecule sample.)

1. A frequency domain quantum weak measurement biomolecule sensor is characterized by comprising a light emitting device, a polarization state preparation device, a prism, a polarization state selection device, a spectrum frequency division device and a photoelectric detection element, wherein a measured sample is in contact with a reflection surface of the prism, a light beam emitted by the light emitting device is changed into polarized light through the polarization state preparation device, the polarized light enters the reflection surface of the prism, a phase difference is generated through prism-sample interface total internal reflection, the polarization state is selected through the polarization state selection device, the polarized light is separated into light beams with different frequency intervals through the spectrum frequency division device, and the light beams are respectively received by the photoelectric detection element and a sample refractive index measurement result is obtained through calculating a light intensity difference; the method comprises the steps of measuring the phase difference brought by evanescent waves by selecting an incident light frequency spectrum and a polarization state and separating a frequency domain to obtain a high-precision phase or optical rotation angle measurement result, wherein the incident angle of polarized light incident to the inner surface of the prism and the surface of a sample medium generate evanescent waves, and measuring the concentration of sample molecules on the surface of the prism and/or monitoring the biochemical reaction process by utilizing the weak value amplification effect of quantum weak measurement.

2. The sensor according to claim 1, wherein the included angle between the polarizer optical axes of the polarization state preparation means and the polarization state selection means is 90 ° ± β or ± β, β ≦ 5 °.

3. The sensor according to claim 1 or 2, wherein the optical axis of the polarization state preparation means forms an angle α with the horizontal plane which satisfies 0< α <20 °.

4. A sensor according to any one of claims 1 to 3, wherein the polarization state preparation means adjusts the light beam incident on the polarization state preparation means to linearly polarized light or approximately elliptically polarized light, and the polarization state selection means makes the polarization state of the light beam reflected from the prism approximately orthogonal to the polarization state set by the polarization state selection means, thereby adjusting the elliptically polarized light or circularly polarized light incident on the polarization state selection means to approximately linearly polarized light.

5. The sensor of any one of claims 1 to 4, wherein the polarization state preparation means is a polarizer or a combination of a polarizer and a phase compensation system; the polarization state selection device is a polarizer or a combination of a phase compensation system and the polarizer; the polarizer is a Glan laser polarizing prism or a polarizing beam splitter or a polarization attenuation plate, and the phase compensation system is a phase compensator or a phase delay wave plate.

6. A sensor according to any one of claims 1 to 5, wherein the light-emitting device comprises a light source generator and an energy conditioner disposed in the path of the light emitted from the light source generator, the energy conditioner being arranged to condition the energy of the light beam emitted by the light source generator; preferably, the device also comprises an optical filter arranged on an emergent light path of the light source generator; the light source generator is a laser, a laser diode, a super-radiation light emitting diode, a white light generator or a quantum light source generator; the energy regulator is a half wave plate, a quarter wave plate, a Gaussian filter plate or a neutral attenuation plate, and for the half wave plate and the quarter wave plate, the adjustment of the light energy is realized by adjusting the included angle between the optical axis direction and the polarization direction of incident light.

7. The sensor of any one of claims 1 to 6, wherein the prism is a triangular prism, a quadrangular prism or a pentagonal prism, the spectral frequency dividing device is a dichroic mirror or a combination of a band-pass polarizer and a beam splitter prism, and the photodetecting element is a Charge Coupled Device (CCD), a Complementary Metal Oxide Semiconductor (CMOS) image sensor, a spectrometer or a photomultiplier tube.

8. A sensor as claimed in any one of claims 1 to 7, further comprising a flow channel and a flow channel coupling element, the flow channel being mounted at the reflective surface of the prism by the flow channel coupling element, the sample to be measured of liquid and gas being in contact with the reflective surface of the prism in the flow channel.

9. The sensor according to any one of claims 1 to 8, further comprising a prism replacement means for fixing the prism in a recessed or clamped manner, so as to replace the prism as required when performing biochemical reaction detection, and performing fine adjustment of the position of the prism.

10. A method for frequency domain quantum weak measurement of biomolecules, comprising using the sensor of any one of claims 1 to 9 for measurement, and in particular further comprising:

recording the light intensity I of the light beams of different frequency bands measured by the photoelectric detection element_γ；

Calculating the phase difference generated by the polarization components of the horizontal polarization direction H and the vertical polarization direction V of the reflected light beam reflected by the prism:

wherein, theta is the incident angle of the light beam incident to the sample interface, and n represents the refractive index ratio of the prism to the sample;

calculating the polarization states before and after the polarization state selection device as follows:

wherein α is Δ + δ, δ is the compensation phase of the polarization state selection device to the light beam, and β is the slight difference between the optical axis of the polarization state selection device and the orthogonal direction of the polarization state preparation device;

calculating the energy density of the light beam with different wavelengths after passing through the polarization state selection device as follows:

wherein

Calculating to obtain the refractive index of the sample after measuring the light intensity difference of the emitted light with different frequencies;

in particular, when the spectrum is separated into only high and low frequencies, the difference in light intensity is:

Technical Field

The invention relates to a quantum optical technology, in particular to a frequency domain quantum weak measurement biomolecule sensor and a measurement method thereof.

Background

The optical measurement method of the biomolecule concentration generally utilizes a Surface Plasmon Resonance (SPR) method to measure the refractive index or utilizes an ultraviolet spectrophotometric absorption method to measure the absorbance, but the methods have the problems of higher cost and difficult high-efficiency measurement, and the weak measurement method has the characteristic of lower cost under the same sensitivity and can improve the measurement processes.

The weak measurement method has the advantages of wide application range, sensitive measurement and real-time in-situ sensitive measurement. According to the report of the prior work (see Zhang Y, Li D, He Y, et al. optical beam measurement system with common path implementation for laboratory-free biomolecule sensing [ J ]. Optics letters,2016,41(22):5409 ^ -5412.), the sensor can reach the resolution of 10^ -6RIU, and is a high-sensitivity measurement method which is expected to replace surface plasmon resonance. However, the weak measurement method itself has a problem of difficult integration, and the reason is mainly that although the frequency domain weak measurement method has an excellent measurement effect, the frequency spectrum needs to be separated during measurement, the spatial angle response of light is very sensitive, the weak value state of the optical path is easily affected when different samples are replaced, and it is difficult to restore the optical path state again.

In summary, the method based on the optical weak measurement effect needs to be further improved, and a weak measurement system with stronger robustness and less sensitivity to environmental noise and technical noise is provided, so as to realize the integrated application of biomolecule sensing.

It is to be noted that the information disclosed in the above background section is only for understanding the background of the present application and thus may include information that does not constitute prior art known to a person of ordinary skill in the art.

Disclosure of Invention

The invention mainly aims to overcome the defects of the background technology and provide a frequency domain quantum weak measurement biomolecule sensor and a measurement method thereof.

In order to achieve the purpose, the invention adopts the following technical scheme:

a frequency domain quantum weak measurement biomolecule sensor comprises a light emitting device, a polarization state preparation device, a prism, a polarization state selection device, a spectrum frequency division device and a photoelectric detection element, wherein a measured sample is in contact with a reflection surface of the prism, a light beam emitted by the light emitting device is changed into polarized light through the polarization state preparation device, the polarized light enters the reflection surface of the prism, a phase difference is generated through prism-sample interface total internal reflection, the polarization state is selected through the polarization state selection device, the polarized light is separated into light beams with different frequency intervals through the spectrum frequency division device, and then the light beams are respectively received by the photoelectric detection element and a sample refractive index measurement result is obtained through a mode of calculating a light intensity difference; the method comprises the steps of measuring the phase difference brought by evanescent waves by selecting an incident light frequency spectrum and a polarization state and separating a frequency domain to obtain a high-precision phase or optical rotation angle measurement result, wherein the incident angle of polarized light incident to the inner surface of the prism and the surface of a sample medium generate evanescent waves, and measuring the concentration of sample molecules on the surface of the prism and/or monitoring the biochemical reaction process by utilizing the weak value amplification effect of quantum weak measurement.

Further:

the included angle between the polarizer optical axes of the polarization state preparation device and the polarization state selection device is 90 degrees +/-beta or +/-beta, and beta is less than or equal to 5 degrees.

The included angle alpha formed by the optical axis of the polarization state preparation device and the horizontal plane meets the condition that alpha is more than 0 and less than 20 degrees.

The polarization state selection device enables the polarization state of the light beam reflected by the prism to be approximately orthogonal to the polarization state set by the polarization state selection device, so that the elliptically polarized light or the circularly polarized light incident to the polarization state selection device is adjusted to be approximately linearly polarized.

The polarization state preparation device is a polarizer or a combination of the polarizer and a phase compensation system; the polarization state selection device is a polarizer or a combination of a phase compensation system and the polarizer; the polarizer is a Glan laser polarizing prism or a polarizing beam splitter or a polarization attenuation plate, and the phase compensation system is a phase compensator or a phase delay wave plate.

The light-emitting device comprises a light source generator and an energy regulator arranged on an emergent light path of the light source generator, and the energy regulator is used for regulating the energy of light beams emitted by the light source generator; preferably, the device also comprises an optical filter arranged on an emergent light path of the light source generator; the light source generator is a laser, a laser diode, a super-radiation light emitting diode, a white light generator or a quantum light source generator; the energy regulator is a half wave plate, a quarter wave plate, a Gaussian filter plate or a neutral attenuation plate, and for the half wave plate and the quarter wave plate, the adjustment of the light energy is realized by adjusting the included angle between the optical axis direction and the polarization direction of incident light.

The prism is a triangular prism, a quadrangular prism or a pentagonal prism, the spectrum frequency division device is a dichroic mirror or a combined device of a band-pass polarizing plate and a beam splitter prism, and the photoelectric detection element is a Charge Coupled Device (CCD), a complementary metal oxide semiconductor image sensor, a spectrometer or a photomultiplier.

The prism is characterized by further comprising a flow channel and a flow channel coupling element, wherein the flow channel is arranged on the reflecting surface of the prism through the flow channel coupling element, and liquid and gas samples to be detected are in contact with the reflecting surface of the prism in the flow channel.

The device also comprises a prism replacing device which fixes the prism in a groove or clamping mode so as to replace the prism as required when biochemical reaction detection is carried out and finely adjust the position of the prism.

A method for weak measurement of biomolecules by frequency domain quantum based on differential principle comprises the following steps:

recording the light intensity I of the light beams of different frequency bands measured by the photoelectric detection element_γ；

Calculating the phase difference generated by the polarization components of the horizontal polarization direction H and the vertical polarization direction V of the reflected light beam reflected by the prism:

wherein, theta is the incident angle of the light beam incident to the sample interface, and n represents the refractive index ratio of the prism to the sample;

calculating the polarization states before and after the polarization state selection device as follows:

wherein α is Δ + δ, δ is the compensation phase of the polarization state selection device to the light beam, and β is the slight difference between the optical axis of the polarization state selection device and the orthogonal direction of the polarization state preparation device;

calculating the energy density of the light beam with different wavelengths after passing through the polarization state selection device as follows:

wherein

Calculating to obtain the refractive index of the sample after measuring the light intensity difference of the emitted light with different frequencies;

in particular, when the spectrum is separated into only high and low frequencies, the difference in light intensity is:

the invention has the following beneficial effects:

the invention provides a frequency domain quantum weak measurement biomolecule sensor designed based on a difference principle and a measurement method thereof. The incident angle of the incident light to the surface of the prism and the surface of the sample medium generate evanescent waves, and the phase difference brought by the evanescent waves is measured through frequency domain separation so as to determine the molecular concentration of the surface of the prism and realize the monitoring of the biochemical reaction process. The invention can further improve the stability, repeatability and resistance to environmental noise interference of measurement on the premise of ensuring the high-sensitivity measurement of the refractive index of the biomolecule sample.

The invention realizes the measurement of the surface refractive index based on the differential quantum weak measurement principle, improves the measurement sensitivity by utilizing the weak value amplification characteristic of quantum weak measurement, and improves the robustness of the measurement system by detecting the light intensity difference of different frequencies, so that the measurement system can be integrated by replacing a lens. The invention can be applied to the high-sensitivity detection of the real-time unmarked weak molecular interaction process in the fields of biology, chemistry, food safety and the like.

Compared with the prior art, the invention has the following technical advantages:

(1) based on the quantum weak measurement technology, the polarization state of the light beam reflected by the inner surface of the prism is approximately orthogonal to the polarization state set by the polarization state selection device by setting a proper polarization state preparation device and a proper polarization state selection device, and the refractive index of the sample is obtained by utilizing the light intensity difference of different frequency bands obtained by the quantum weak measurement amplification effect;

(2) the invention improves the measuring method of frequency domain quantum weak measurement, converts the spectral measurement into light intensity measurement of different frequency domains, and measures the light intensity of different frequency spectrum ranges by separating light rays of different frequencies in space;

(3) the method is improved based on a frequency domain type quantum weak measurement method, emergent light does not need to enter a spectrometer through a coupling lens and a slit by improving a spectrum measurement mode, the loss of light intensity in the transmission process can be reduced, the measurement sensitivity is improved, the measurement reliability is improved, the response threshold value is reduced, and the measurement weak value has a further amplification space.

(4) The invention is a novel, nondestructive and repeatedly replaceable direct optical sensing molecule measurement technology based on a differential frequency domain quantum weak measurement method, can inhibit the influence of environmental noise and technical noise due to differential measurement in a frequency domain, can realize repeated and high-precision measurement of the refractive index change of a sample in a natural state, and can monitor and analyze the interaction process of molecules in real time and with high sensitivity. Has important application value in a plurality of technical fields of biomedicine, life science, analytical chemistry, physics, materials science and the like.

Drawings

Fig. 1 is a schematic structural diagram of a frequency domain quantum weak measurement biomolecule sensor designed based on a differential principle according to an embodiment of the invention.

Fig. 2 is a schematic diagram of a spectrum frequency division structure according to an embodiment of the present invention.

FIG. 3(a) is a real-time light intensity difference diagram obtained by detecting NaCl solutions with different concentrations; FIG. 3(b) is a graph of concentration response error fitted from the results of FIG. 3 (a).

FIG. 4 is a graph showing the results of experiments monitoring the binding process of rabbit IgG molecules and protein A at different concentrations.

Description of the labeling:

1. the device comprises a light-emitting device, 2, a polarization state preparation device, 3, a phase compensation system, 4, a prism, 5, a flow channel coupling element, 6, a prism replacement device, 7, a polarization state selection device, 8, a spectrum frequency division device, 9, emergent light after spectrum selection, 10, a photoelectric detection element, 11, incident light, 12, a frequency division device frame, 13, a spectrum frequency division element, 14, high-frequency emergent light, 15 and low-frequency emergent light

Detailed Description

The embodiments of the present invention will be described in detail below. It should be emphasized that the following description is merely exemplary in nature and is not intended to limit the scope of the invention or its application.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element. In addition, the connection may be for either a fixed or coupled or communicating function.

It is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for convenience in describing the embodiments of the present invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed in a particular orientation, and be in any way limiting of the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of the present invention, "a plurality" means two or more unless specifically limited otherwise.

Referring to fig. 1 and 2, an embodiment of the present invention provides a frequency domain quantum weak measurement biomolecule sensor designed based on a difference principle, including a light emitting device 1, a polarization state preparation device 2, a prism 4, a polarization state selection device 7, a spectrum frequency division device 8 and a photoelectric detection element 10, wherein a measured sample contacts with a reflection surface of the prism 4, a light beam emitted by the light emitting device 1 is changed into polarized light by the polarization state preparation device 2, the polarized light enters the reflection surface of the prism 4, a phase difference is generated by total internal reflection of the prism 4-sample interface, the polarization state selection device 7 selects the polarization state, the selected incident light 11 is further separated into emergent light 9 with different frequency intervals by the spectrum frequency division device 8, such as high-frequency emergent light 14 and low-frequency emergent light 5, and then is respectively received by the photoelectric detection element 10 and a sample refractive index measurement result is obtained by calculating a light intensity difference (ii) a The incident angle of polarized light incident on the inner surface of the prism 4 and the surface of a sample medium generate evanescent waves, the phase difference caused by the evanescent waves is measured by frequency domain separation through selecting an incident light frequency spectrum and a polarization state, a high-precision phase or optical rotation angle measurement result is obtained, and the concentration of biomolecules on the surface of the prism 4 is measured and/or the monitoring of a biochemical reaction process is realized by utilizing the weak value amplification effect of quantum weak measurement.

In a preferred embodiment, the included angle between the polarizer optical axes of the polarization state preparation means 2 and the polarization state selection means 7 is 90 ° ± β or ± β, β ≦ 5 °.

In a preferred embodiment, the included angle α between the optical axis of the polarization state preparation device 2 and the horizontal plane satisfies 0< α <20 °.

In a preferred embodiment, the polarization state preparation device 2 adjusts the light beam incident on the polarization state preparation device 2 into linearly polarized light or approximately elliptically polarized light, and the polarization state selection device 7 makes the polarization state of the light beam reflected from the prism 4 approximately orthogonal to the polarization state set by the polarization state selection device 7, so as to adjust the elliptically polarized light or circularly polarized light incident on the polarization state selection device 7 into approximately linearly polarized light.

In some embodiments, the polarization state preparation device 2 is a polarizer or a combination of a polarizer and a phase compensation system 3; the polarization state selection device 7 is a polarizer or a combination of the phase compensation system 3 and the polarizer; the polarizer is a Glan laser polarizing prism 4 or a polarizing beam splitter or a polarization attenuation plate, and the phase compensation system 3 is a phase compensator or a phase delay wave plate.

In a preferred embodiment, the light emitting device 1 comprises a light source generator and an energy regulator arranged on an emergent light path of the light source generator, wherein the energy regulator is used for regulating the energy of a light beam emitted by the light source generator; preferably, the device also comprises an optical filter arranged on an emergent light path of the light source generator; the light source generator is a laser, a laser diode, a super-radiation light emitting diode, a white light generator or a quantum light source generator; the energy regulator is a half wave plate, a quarter wave plate, a Gaussian filter plate or a neutral attenuation plate, and for the half wave plate and the quarter wave plate, the adjustment of the light energy is realized by adjusting the included angle between the optical axis direction and the polarization direction of incident light.

In some embodiments, the prism 4 is a triangular prism 4, a quadrangular prism 4 or a pentagonal prism 4, the spectral frequency-dividing device 8 is a dichroic mirror or a combined device of a band-pass polarizer and the spectral prism 4, and the photodetecting element 10 is a charge coupled device CCD, a complementary metal oxide semiconductor image sensor, a spectrometer or a photomultiplier tube. As shown in fig. 2, in one embodiment, the spectral frequency divider 8 may include a divider frame 12 and a spectral frequency dividing element 13 mounted on the divider frame 12.

As shown in fig. 1, in a preferred embodiment, the frequency domain quantum weak measurement biomolecule sensor further includes a flow channel and a flow channel coupling element 5, the flow channel is installed at the reflection surface of the prism 4 through the flow channel coupling element 5, and the to-be-measured sample of liquid and gas is in contact with the reflection surface of the prism 4 in the flow channel.

In a preferred embodiment, as shown in fig. 1, the frequency domain quantum weak measurement biomolecule sensor further comprises a prism replacement device 6, which can fix the prism 4 in a groove or clamping manner, so as to replace the prism 4 as required when biochemical reaction detection is carried out, and carry out fine adjustment on the position of the prism 4.

The embodiment of the invention also provides a method for weakly measuring biomolecules by using frequency domain quantum based on differential principle design, and the sensor of any one of the embodiments is used for measurement.

Specific embodiments of the present invention are further described below.

The sample aimed at can be transparent or translucent solids, liquids and gases. When the sample is a solid, a flow channel may not be required; when the sample is liquid or gas, the sample is placed in the flow channel and is in contact with the outer surface of the prism reflecting surface during measurement, different samples can be introduced into the flow channel during measurement of different samples, the prism and the flow channel can also be replaced by using the prism replacing device, and different samples to be detected are introduced.

The polarization state prepared by the polarization state preparation device is nearly perpendicular or parallel to the polarization state selected by the polarization state selection device, so that the weak value can be increased to improve the measurement sensitivity.

The flow channel coupling element comprises an embedded type assembly mode, a pressing type assembly mode, an adhesion type assembly mode, a push type assembly mode and the like, and is used for fixing the flow channel on the outer surface of the prism so as to ensure that a sample to be detected is in contact with the reflecting outer surface of the prism.

The polarization state preparation device is used for constructing the polarization state of a light beam incident to the prism, adjusting the light beam emitted by the light-emitting device into linearly polarized light or approximately elliptically polarized light, enabling the light beam to be incident to a prism-sample interface, and forming elliptically polarized light after being reflected by the interface; the polarization state selection device is used for constructing the polarization state of the light beam which is emitted by the prism and enters the polarization state selection device, and the polarization state of the light beam reflected by the prism is approximately orthogonal to the polarization state set by the polarization state selection device, so that the elliptically polarized light or the circularly polarized light entering the polarization state selection device is adjusted to be approximately linearly polarized light. The included angle between the polarization states of the polarization state preparation device and the polarization state selection device is 90 degrees +/-beta or +/-beta, beta is less than or equal to 5 degrees, so that a sufficient weak value is ensured, a weak value enhancement effect is generated, and high-resolution and high-sensitivity measurement is realized.

The included angle formed by the optical axis of the polarization state preparation device and the horizontal plane is about +/-45 degrees, so that the quantum weak value amplification effect is further guaranteed, and the measurement of high resolution and high sensitivity is realized.

The prism is used for generating an evanescent wave phase delay effect of total internal reflection, the prism can be a triangular prism, a quadrangular prism, a pentagonal prism and the like, and the prism can be made of glass, resin and the like.

The incident angle of the incident light on the inner surface of the prism reflecting surface satisfies the total reflection condition.

The prism replacing device comprises an automatic replacing device or a manual replacing device, the prism position can be fixed through a groove or a clamping design, the prism position can be finely adjusted through methods such as angle feedback and the like, repeatability of a measurement experiment is guaranteed, the prism replacing device can be used during biochemical reaction detection, and when the outer surface of the prism is covered by biochemical molecules or the reflecting surface of the prism reacts with the biochemical molecules and the state before measurement cannot be recovered, next biochemical reaction monitoring can be guaranteed in the same initial state through a prism replacing mode.

The spectrum frequency division device is used for separating light into spectrums with discrete frequency bands in a frequency domain, the spectrums can be only divided into high-frequency light and low-frequency light, or multiple frequency bands of the spectrums are separated, and emergent light of different frequency bands is received by different photoelectric detectors respectively.

During measurement, the standard sample can be used for light path adjustment, so that the system achieves higher sensitivity. And introducing a sample to be detected into the flow channel, and receiving the light intensity signal by using a photoelectric detector under the same light path condition. If the optical characteristics of the outer surface of the prism are changed by the sample in the measuring process or biochemical molecule combination reaction occurs between the sample and the sample, the prism needs to be replaced by the prism replacing device, and the angle of emergent light is ensured to be unchanged. With the change of the sample, the difference of the refractive indexes of the inner surface and the outer surface of the prism, which are totally reflected, is changed, the amplitude and the phase of the finally received reflected light are changed, the change quantity of the finally received reflected light can be amplified by the post-selected polarization state, and the received and measured through a spectrum frequency division method.

The embodiment of the invention provides a method for carrying out biomolecule sensing measurement by utilizing the frequency domain quantum weak measurement biomolecule sensor designed based on the difference principle, which comprises the following steps:

(1) adjusting the light path of the differential frequency domain quantum weak measurement biomolecule sensor to enable the polarization state preparation device to prepareThe light beam polarization state forms a quantum weak measurement light path part between the prism reflection and phase compensation system and the polarization state set by the polarization state selection device, the included angle between the two polarization states is 90 degrees +/-beta or +/-beta, and the beta is less than or equal to 5 degrees. A sample to be detected is contacted with the total reflection outer surface of the prism through a flow channel, light emitted by a light-emitting device is incident to the total reflection surface of the prism after passing through a polarization state preparation device, evanescent waves are generated in the reflection process, a polarization component S wave (when the reflection surface of the prism is vertically placed, the S wave is a horizontal polarization component H) with the polarization direction perpendicular to the reflection surface penetrates through the reflection surface for a distance, phase delay is generated, a polarization component P wave (when the reflection surface of the prism is vertically placed, the P wave is a vertical polarization component V) with the polarization direction parallel to the reflection surface is directly reflected, and phase delay is not generated. The reflected light beam passes through the phase compensation system and the polarization state selection device, then is subjected to spectrum frequency division through the spectrum frequency division device, and is received by the photoelectric detection element; recording the light intensity I of the received light beams of different frequency bands by a photoelectric detection element_γ；

(2) Obtaining the phase difference generated by the polarization components of the horizontal polarization direction H and the vertical polarization direction V of the reflected light beam reflected from the prism according to the following formula, wherein the phase difference is related to the refractive index of the sample, and the phase difference is as follows:

wherein, theta is the incident angle of the light beam incident to the sample interface, and n represents the refractive index ratio of the prism to the sample;

(3) the polarization states before and after the polarization state selection device are obtained according to the following formula (2):

wherein α is Δ + δ, δ is the compensation phase of the polarization state selection device to the light beam, and β is the slight difference between the optical axis of the polarization state selection device and the orthogonal direction of the polarization state preparation device;

the energy density of the light beams under different wavelengths after passing through the polarization state selection device is as follows:

wherein

(5) The refractive index of the sample can be calculated by measuring the light intensity difference of the emitted light with different frequencies.

(6) In particular, when the spectrum is separated into only high and low frequencies, the difference in light intensity is:

in order to facilitate operation, the method for measuring the refractive index of the biomolecule solution medium by using the differential frequency domain quantum weak measurement biomolecule sensor can firstly adjust the light path of the surface plasma sensor by using a standard sample with a known refractive index, and the specific mode is as follows:

(1) putting a standard sample into the flow channel;

(2) adjusting the included angle formed by the optical axis of the polarization state preparation device and the horizontal plane to be about 45 degrees;

(3) adjusting the polarization state selection device and the phase retarder to minimize the light intensity signal received by the photoelectric detector, wherein the polarization state between the polarization state selection device and the polarization state preparation device is 90 +/-beta or +/-beta, beta is less than or equal to 5 degrees, and the light intensity at the photoelectric detector can be recorded and the light intensity difference can be recorded as a calibration result;

(4) the concentration measurement and the monitoring biochemical reaction process of the biomolecule sample can be carried out through the mode of introducing liquid, the repeated consistency of the experiment can be ensured through the mode of replacing the prism, and the integration of the system and the standardization of the measurement process are realized.

The invention converts the refractive index of the sample into the amplitude and phase difference change associated with the polarization state, the change can cause the sensitive difference change of the light intensity of emergent light of different frequency bands in the light path, and the tiny change of the refractive index of the sample can be obtained by measuring the light intensity difference.

Example 1

The structure of the differential frequency domain quantum-based weak measurement biomolecule sensor provided by the embodiment is shown in fig. 1, and the sensor comprises a light-emitting device 1, a polarization state preparation device 2, a phase compensation system 3, a prism and flow channel device 4, a flow channel coupling element 5, a prism replacement device 6, a polarization state selection device 7, a spectrum frequency division device 8 and a photoelectric detection element 10. The light source generator 1 is a semiconductor laser, the polarization state preparation device 2 and the polarization state selection device 7 are polarization attenuation sheets, the phase compensation system 3 is a Sorley-Babinet phase compensator, the prism 4 is a regular prism, liquid can be introduced into a flow channel and is in contact with the reflecting surface of the prism, the spectrum frequency division device 8 is a dichroic mirror, and the photoelectric detection element 10 is a Charge Coupled Device (CCD).

The working principle of the differential frequency domain quantum weak measurement-based biomolecule sensor is as follows: laser beams emitted by the light emitting device 1 enter the polarization state preparation device 3, linearly polarized light is obtained by the polarization state preparation device, the linearly polarized light enters the phase compensation system 3, then enters the total reflection inner surface of the prism 4 to be contacted with a sample to be detected in the flow channel, phase difference is generated by reflection at the prism-sample interface, then the polarization state is selected by the polarization state selection device 9, and the laser beams are received by the photoelectric detector 10 after passing through the spectrum frequency division device. The included angle between the optical axes of the two polaroids is 90 degrees +/-beta or +/-beta, and beta is less than or equal to 5 degrees.

Example 2

In this embodiment, a surface plasmon sensor based on quantum weak measurement provided in embodiment 1 is used to measure a standard NaCl solution sample, and the following steps are performed:

(SI) preparing 10 parts of NaCl solution with known concentration, wherein the concentration of the NaCl solution is 0-1.8% (mass percentage); the solution with the concentration of 0 is deionized water and is taken as a standard solution.

(S2) placing deionized water into the sample coupler; the light-emitting device 1 is turned on, light enters the polarization state preparation device 2 and the phase compensation system 3 (the phase compensation delta is approximately equal to-1.275 rad), then enters a prism-sample interface to be detected at an incidence angle theta which meets the total reflection condition of 93.0 degrees, reflected light passes through the polarization state selection device 7, is divided into high-frequency light and low-frequency light by the spectrum frequency division device 8, and the high-frequency light and the low-frequency light are respectively received by the photoelectric detection element 10; adjusting an included angle of 45 degrees formed by an optical axis of the polarization state preparation device and a horizontal plane; the optical axes of the phase compensation system 3 and the polarization state selection device 7 are adjusted to minimize the light intensity signal received by the photodetection element, at this time, the included angle between the optical axis of the polarizer 7 and the horizontal direction is about-45 °, and the prism is made of schott SF5 with refractive index n _0 of 1.672 ═

(S3) NaCl solutions of different concentrations are added to the sample coupler, and the received light intensity signal I is detected by the photodetector 10 without changing the light path in the step (S2).

After passing through the phase compensator, the polarization state of the light beam reflected from the prism is as follows:

where | H > represents the polarization state in the horizontal direction and | V > represents the polarization state in the vertical direction. α + δ represents the total phase difference generated by the measuring optical path, δ represents the compensation phase of the polarization state selection device to the light beam, and Δ represents the phase difference generated in different polarization directions when the prism is totally internally reflected.

N is n₁/n₂Wherein n is₁Is the refractive index of the prism, n₂Is the sample refractive index. The polarization state selection device sets the polarization state as follows:

wherein beta is a small difference between the optical axis of the polarization state selection device and the orthogonal direction of the polarization state preparation device; the energy of the emergent light under different frequencies is as follows:

whereinAfter the polaroid is selected, emergent light is separated into high-frequency light and low-frequency light through the spectrum frequency division device and is received by the photoelectric coupling element, and the obtained light intensity difference is as follows:

for NaCl solutions with different concentrations, the refractive index of the NaCl solution can be determined according to the known concentration of the NaCl solution, the refractive index of (standard sample) deionized water is subtracted from the obtained refractive index to obtain the refractive index change value of the NaCl solution relative to the deionized water, and then a curve of the refractive index change value changing along with the light intensity difference is obtained according to the obtained refractive index change values of the NaCl solutions with different concentrations and the obtained light intensity of the corresponding NaCl solution. FIGS. 3(a) and 3(b) are graphs showing the measurement of the difference in light intensity of NaCl solutions when different concentration gradients are applied.

FIG. 3(a) shows the real-time light intensity differential effect obtained by detecting NaCl solutions with different concentrations, and the corresponding curves of the measurement light path for different refractive indexes can be obtained by fitting, as shown in FIG. 3 (b). It can be seen that the fitting curve linearity of the experimental data is good, the solution discrimination for the refractive index is large, the resolution ratio is high, the measurement sensitivity is high, the interference of environmental noise and technical noise can be well avoided, and the measurement stability under long time is good.

Example 3

In this embodiment, a surface plasmon sensor based on quantum weak measurement provided in embodiment 1 is used to measure the binding process of rabbit IgG molecules and protein a molecules, and the following steps are performed:

after standard sample calibration, we can monitor the biomolecule binding process. The binding process of rabbit IgG molecules and protein a at different concentrations was monitored in the optical path system of example 2 using a dopamine solution at 2mg/mL, pH 8.5 in 10mM tris buffer, phosphate buffered saline as the wash flow channel (PBS, pH7.4), Bovine Serum Albumin (BSA) as the blocking solution, and the results are schematically shown in fig. 4.

In the process of the molecular bonding test, firstly, dopamine solution is continuously introduced into a flow channel, and a layer of adhesive polydopamine film is deposited on the surface of a prism. Washed with PBS buffer. Protein A molecules were attached to the dopamine membrane by passing 50ug/mL of 10mM PBS buffered protein A solution to capture rabbit IgG. Then 0.3% Bovine Serum Albumin (BSA) and 10mM PBS were injected to fill the gaps between protein a, and finally rabbit IgG of different concentrations was injected into the flow channel. Obvious light intensity difference changes can be seen under different concentrations of protein A solution.

The background of the present invention may contain background information related to the problem or environment of the present invention and does not necessarily describe the prior art. Accordingly, the inclusion in the background section is not an admission of prior art by the applicant.

The foregoing is a more detailed description of the invention in connection with specific/preferred embodiments and is not intended to limit the practice of the invention to those descriptions. It will be apparent to those skilled in the art that various substitutions and modifications can be made to the described embodiments without departing from the spirit of the invention, and these substitutions and modifications should be considered to fall within the scope of the invention. In the description herein, references to the description of the term "one embodiment," "some embodiments," "preferred embodiments," "an example," "a specific example," or "some examples" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Various embodiments or examples and features of various embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction. Although embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the scope of the claims.