An optical fiber biosensor, a biological detection device and a biological detection method thereof

Abstract

The present invention provides an optical fiber biosensor, a biological detection device and a biological detection method thereof. The above optical fiber biosensor includes a capillary with an inner cavity and a surface plasmon resonance optical fiber probe. The reflection end of the surface plasmon resonance optical fiber probe completely penetrates the inner cavity and does not contact the inner wall of the capillary. Wherein, the optical fiber biosensor further includes an AC power supply. The first end of the AC power supply is electrically connected to the capillary, and the second end of the AC power supply is electrically connected to the reflection end. The optical fiber biosensor provided by the present invention forms an alternating current electric field between the capillary and the reflection end. Charged particles in the solution to be detected are attracted to the surface plasmon resonance optical fiber probe due to electrophoresis under the action of the alternating current electric field, thereby reducing the detection period of the optical fiber biosensor. At the same time, due to the action of the alternating current electric field, originally non-specifically adsorbed particles are desorbed on the surface of the plasmon resonance optical fiber probe and separated from the charged particles to be detected, thereby improving the detection accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of biosensors, and in particular to an optical fiber biosensor, a biodetection device and a biodetection method thereof. Background Art

[0002] The detection of cancer markers plays an important role in the diagnosis, treatment and prognosis of cancer. With the development of molecular biology technology, detection methods based on macromolecules such as deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) have become a hot topic of research. These molecular markers can reflect the biological characteristics of cancer at the genome, epigenome and transcriptome levels of tumor cells. Fiber optic sensors have fast response and are not affected by electromagnetic interference. They overcome the limitations of traditional detection methods and have a wide range of applications. However, the optical transmission efficiency and optical signal acquisition efficiency of fiber optic probes are still limited by the design and manufacturing process of the probes, resulting in technical problems such as long detection cycles and complex operations.

[0003] Therefore, there is an urgent need to develop an optical fiber biosensor, a biodetection device and a biodetection method thereof to solve the above technical problems. Summary of the invention

[0004] The object of the present invention is to provide an optical fiber biosensor, a biodetection device and a biodetection method thereof, which are used to solve the technical problem of the optical fiber biosensor in the prior art having a detection cycle that is too long.

[0005] In order to solve the above technical problems, the present invention first provides an optical fiber biosensor, comprising a capillary having an inner cavity and a surface plasmon resonance optical fiber probe, wherein the reflection end of the surface plasmon resonance optical fiber probe completely penetrates the inner cavity and does not contact the inner wall of the capillary;

[0006] The optical fiber biosensor further includes an AC power source, a first end of the AC power source is electrically connected to the capillary, and a second end of the AC power source is electrically connected to the reflection end.

[0007] Preferably, the inner wall of the capillary is plated with a conductive layer, and the first end of the AC power source is electrically connected to the conductive layer.

[0008] Preferably, the material of the conductive layer is ITO or AZO, and the thickness of the conductive layer is 1-10 nm.

[0009] Preferably, the distance between the partially reflecting end located in the inner cavity and the inner wall of the capillary is 10-20 μm.

[0010] Preferably, the voltage of the AC power source is greater than 0 and less than or equal to 1.2V, and the frequency of the AC power source is 40-60kHz.

[0011] Preferably, the reflective end comprises an optical fiber, a metal layer coated on the outer surface and end surface of the optical fiber, and a low-dimensional nanolayer coated on the metal layer;

[0012] Among them, the low-dimensional nanolayer is a material in which at least one dimension in the three-dimensional space is at the nanoscale.

[0013] Preferably, the material of the metal layer is Au, and the thickness of the metal layer is 30-40 nm; the low-dimensional nanolayer is carbon quantum dots or graphene, and the thickness of the low-dimensional nanolayer is 20-50 nm.

[0014] Correspondingly, the present invention also provides a biological detection device, including a light source, a spectrometer and any of the above optical fiber biosensors, the light source is connected to the input end of the surface plasmon resonance optical fiber probe, and the spectrometer is connected to the output end of the surface plasmon resonance optical fiber probe.

[0015] Accordingly, the present invention further provides a biological detection method, which is based on the above biological detection device and includes:

[0016] S10, immersing the capillary and the reflective end together in a test liquid containing a cancer marker;

[0017] S20, turning on the switch of the AC power supply to form an AC electric field between the capillary and the reflection end;

[0018] S30, injecting a light signal into the surface plasmon resonance optical fiber probe through a light source, and the light signal generates a surface plasmon resonance effect at a reflection end;

[0019] S40, receiving a resonance light signal emitted by the surface plasmon resonance optical fiber probe at an output end through a spectrometer;

[0020] S50, determining the refractive index of the liquid to be tested according to the wavelength of the resonant light signal, and finally determining the concentration of the cancer marker in the liquid to be tested.

[0021] Preferably, in step S20, the charged polarity of the reflective end is opposite to the charged polarity of the cancer marker.

[0022] The beneficial effects of the present invention are as follows: Different from the prior art, the present invention provides an optical fiber biosensor, a biological detection device and a biological detection method thereof, wherein the optical fiber biosensor comprises a capillary having an inner cavity and a surface plasmon resonance optical fiber probe, wherein the reflection end of the surface plasmon resonance optical fiber probe completely penetrates the inner cavity and does not contact the inner wall of the capillary, wherein the optical fiber biosensor further comprises an alternating current power supply, wherein a first end of the alternating current power supply is electrically connected to the capillary, and a second end of the alternating current power supply is electrically connected to the reflection end; the optical fiber biosensor provided by the present invention forms an alternating current electric field between the capillary and the reflection end, and the charged particles in the solution to be tested move toward the electrode with opposite electrical properties due to the electrophoresis phenomenon under the action of the alternating current electric field, thereby being attracted to the surface plasmon resonance optical fiber probe, thereby reducing the detection cycle of the optical fiber biosensor; at the same time, due to the action of the alternating current electric field, the charged particles originally non-specifically adsorbed on the surface of the surface plasmon resonance optical fiber probe will undergo a special adsorption-desorption process, and as a result of the action of this periodic force, the particles originally non-specifically adsorbed will be desorbed on the surface of the plasmon resonance optical fiber probe and separated from the charged particles of the target to be tested, thereby reducing the influence of non-specific adsorption and improving the detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of the structure of the optical fiber biosensor provided by an embodiment of the present invention;

[0024] Figure 2 A diagram showing the positional relationship between a surface plasmon resonance optical fiber probe and a capillary in an optical fiber biosensor provided in an embodiment of the present invention;

[0025] Figure 3 A schematic diagram of the structure of a biological detection device provided by an embodiment of the present invention;

[0026] Figure 4 A flow chart of a biological detection method provided by an embodiment of the present invention;

[0027] In the figure: 100 - biological detection device; 10 - optical fiber biosensor; 11 - surface plasmon resonance optical fiber probe; 111 - input end; 112 - output end; 113 - reflection end; 12 - capillary; 13 - AC power supply; 20 - light source; 30 - spectrometer. DETAILED DESCRIPTION

[0028] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In view of the technical problem that the optical fiber biosensor 10 of the prior art has a long detection cycle, the present invention provides an optical fiber biosensor 10, a biological detection device 100 and a biological detection method thereof, which can overcome the limitations of the prior art and provide a fast, accurate and stable cancer marker solution. The optical fiber biosensor 10 has a short detection cycle, a highly sensitive light signal acquisition capability, strong anti-interference performance and the ability to monitor key cancer markers in real time, thus playing an important role in clinical medicine and biomedical research.

[0030] Specifically, see Figure 1 to Figure 2 , Figure 1 A schematic diagram of the structure of an optical fiber biosensor 10 provided in an embodiment of the present invention; Figure 2 A positional relationship diagram of a surface plasmon resonance optical fiber probe 11 and a capillary 12 in an optical fiber biosensor 10 provided in an embodiment of the present invention; the optical fiber biosensor 10 comprises a capillary 12 having an inner cavity and a surface plasmon resonance optical fiber probe 11, wherein a reflection end 113 of the surface plasmon resonance optical fiber probe 11 completely penetrates the inner cavity and does not contact the inner wall of the capillary 12;

[0031] The optical fiber biosensor 10 further includes an AC power source 13 , a first end of the AC power source 13 is electrically connected to the capillary 12 , and a second end of the AC power source 13 is electrically connected to the reflection end 113 .

[0032] Specifically, the length of the capillary 12 is 10 to 50 cm, the inner diameter of the capillary 12 is 1 to 3 mm, and the outer diameter of the capillary 12 is 1.5 to 3.5 mm; the function of the capillary 12 is, on the one hand, to provide a stable inner cavity environment to accommodate biological samples and other analytes, and on the other hand, to form an electric field with the reflection end 113 of the surface plasmon resonance fiber probe 11.

[0033] In one embodiment, the inner wall of the capillary 12 is coated with a conductive layer, and the first end of the AC power supply 13 is electrically connected to the conductive layer; wherein, coating the conductive layer on the inner wall of the capillary 12 can more directly and effectively form a directional electric field in the capillary 12, thereby prompting the charged particles to move in a directional manner in the inner cavity of the capillary 12.

[0034] Furthermore, a conductive layer can be added to the outer wall of the capillary 12, and the conductive layer added to the outer wall further enhances the range and strength of the electric field. The conductive layers on the inner and outer walls work together to make the electric field more uniform and stable in the capillary 12. This helps to reduce the edge effect of the electric field and ensure that the charged particles in the entire capillary 12 are subjected to a uniform electric field force, thereby improving the reliability of the experimental results.

[0035] In the embodiment of the present invention, the material of the conductive layer is ITO (indium tin oxide) and AZO (aluminum doped zinc oxide), and the thickness of the conductive layer is 1-10 nm.

[0036] In an embodiment of the present invention, the spacing between the partial reflection end 113 located in the inner cavity and the inner wall of the capillary 12 is 10-20 μm; this spacing range helps to achieve efficient surface plasmon resonance (SPR) excitation. The appropriate spacing enables the incident light to form a specific electromagnetic field distribution in the area between the reflection end 113 of the surface plasmon resonance fiber probe 11 and the inner wall of the capillary 12, thereby exciting the surface plasma wave. If the spacing is too small, it may cause the interaction between the reflection end 113 and the inner wall of the capillary 12 to be too strong, generating too much stray light and interference signals, and reducing the accuracy of the detection. When the spacing is within the range of 10-20 μm, it can reduce unnecessary interference while ensuring a certain signal strength, making the detection signal more stable and reliable.

[0037] In the embodiment of the present invention, the voltage of the AC power source 13 is greater than 0 and less than or equal to 1.2V, and the frequency of the AC power source 13 is 40-60kHz.

[0038] Specifically, the lower voltage range ensures safety during use. For biological samples such as biomolecules and cells, appropriate low voltage helps maintain their biological activity and structural integrity. Excessive voltage may cause denaturation, inactivation or destruction of biological samples. Appropriate frequency can enhance the surface plasmon resonance effect, improve detection sensitivity, and reduce noise and interference.

[0039] In the embodiment of the present invention, the surface plasmon resonance fiber probe 11 is a Y-type reflective SPR fiber, which includes an input end 111, a reflection end 113 and an output end 112, and the reflection end 113 includes an optical fiber, a metal layer coated on the outer surface and end face of the optical fiber, and a low-dimensional nanolayer coated on the metal layer;

[0040] Among them, the low-dimensional nanolayer is a material in which at least one dimension in the three-dimensional space is at the nanoscale.

[0041] Specifically, the metal layer has a high reflectivity and can effectively reflect the incident light. When the light propagates in the optical fiber and reaches the reflection end 113, the metal layer can reflect most of the light back, thereby improving the utilization rate of the light and the intensity of the detection signal. For the surface plasmon resonance optical fiber probe 11, the presence of the metal layer is the key to stimulating the SPR effect. The metal layer interacts with the incident light to generate surface plasmon waves, thereby enhancing the detection sensitivity of analytes such as biomolecules.

[0042] Specifically, low-dimensional nanolayers usually have a larger specific surface area, and at least one dimension in three-dimensional space is at the nanoscale, so that the material has more surface active sites, which can make more sufficient contact and interaction with biological molecules. The increased surface area improves the detection sensitivity of the optical fiber biosensor 10, and can adsorb more biological molecules, thereby generating a stronger detection signal.

[0043] Furthermore, low-dimensional nanomaterials can achieve specific adsorption of specific biomolecules through surface modification or functionalization. For example, specific biorecognition molecules such as antibodies and nucleic acid probes can be modified on the low-dimensional nanolayer to enable them to selectively bind to target biomolecules, thereby improving the specificity and accuracy of detection.

[0044] In one embodiment, the specific preparation process of the surface plasmon resonance optical fiber probe 11 is as follows:

[0045] First, a gold film is coated on the outer surface and end face of the optical fiber corresponding to the emitting end, and then cleaned to remove impurities and oil on the surface to ensure the firm adhesion of the subsequent low-dimensional nanolayer; then, the optical fiber surface is activated by chemical methods, such as using plasma treatment, to increase the surface energy and promote the anchoring of subsequent molecules; finally, a reagent with specific functional molecules is coupled to the activated optical fiber surface, and the functional molecules are made to form stable chemical bonds on the optical fiber surface through appropriate methods to obtain a low-dimensional nanolayer that can specifically identify the target cancer markers.

[0046] Preferably, the material of the metal layer is Au, and the thickness of the metal layer is 30-40 nm; the low-dimensional nanolayer is carbon quantum dots or graphene, and the thickness of the low-dimensional nanolayer is 20-50 nm.

[0047] See also Figure 3 , Figure 3 A schematic diagram of the structure of a biological detection device 100 provided in an embodiment of the present invention; the present invention also provides a biological detection device 100, comprising a light source 20, a spectrometer 30 and an optical fiber biosensor 10 as described above, wherein the light source 20 is connected to an input end 111 of a surface plasmon resonance optical fiber probe 11, and the spectrometer 30 is connected to an output end 112 of the surface plasmon resonance optical fiber probe 11;

[0048] Among them, the light source 20 provides incident light for the surface plasmon resonance fiber optic probe 11, and the light emitted by the light source 20 is transmitted to the input end 111 of the surface plasmon resonance fiber optic probe 11 through the optical fiber. When the light propagates in the surface plasmon resonance fiber optic probe 11 and reaches the reflection end 113, the surface plasmon resonance effect can be excited under specific conditions; the spectrometer 30 is connected to the output end 112 of the surface plasmon resonance fiber optic probe 11, and is used to analyze the optical signal output from the fiber optic probe.

[0049] In the bioassay device 100 provided by the present invention, due to the electrophoresis phenomenon, the charged particles move toward the electrode with opposite electrical properties under the action of the electric field, and are thereby attracted to the surface plasmon resonance fiber probe 11. During the electrophoresis process, the charged particles are driven by the electric field force and migrate in the direction of the electrode opposite to their charge properties. This phenomenon can be utilized by applying an electric field near the surface plasmon resonance fiber probe 11, thereby achieving selective capture and analysis of specific charged particles. Specifically, when an electric field is introduced into a solution containing cancer markers, according to Coulomb's law, each charged particle is subjected to a force that is proportional to the amount of charge it carries and is related to its direction of movement.

[0050] Specifically, for negatively charged particles, the direction of this force points to the positive electrode (anode), while positively charged particles are attracted to the negative electrode (cathode). Therefore, by adjusting the direction and intensity of the electric field, the movement trajectory of these charged particles can be precisely controlled to move toward the electrode where the surface plasmon resonance fiber probe 11 is located.

[0051] Specifically, the surface plasmon resonance fiber probe 11, as a light transmission and detection platform, can use its highly sensitive optical properties to analyze these charged particles guided to the surface of the surface plasmon resonance fiber probe 11 by the electric field. During detection, the surface plasmon resonance fiber probe 11 is functionalized and modified with low-dimensional nanolayers such as graphene, carbon quantum dots, etc., so that its surface has recognition sites that can bind to specific biomolecules. When these biomolecules migrate to the surface of the surface plasmon resonance fiber probe 11 as charged particles under the action of the electric field, they will specifically bind to the functionalized layer on the probe surface, thereby achieving selective detection.

[0052] Specifically, when an alternating electric field is applied to the biological detection device 100, its periodic changing characteristics have a dynamic effect on the charged particles in the sample. Under the action of this electric field, the charged particles that were originally non-specifically adsorbed on the sensor surface will undergo a special adsorption-desorption process. Specifically, whenever the direction of the current reverses, the direction of the electric field force on these particles also changes, causing their movement direction to reverse accordingly. As a result of the action of this periodic force, the particles that were originally non-specifically adsorbed are desorbed on the surface of the plasma resonance fiber probe and separated from the target charged particles to be detected, thereby reducing the impact of non-specific adsorption and ultimately increasing the detection accuracy of the biological detection device 100.

[0053] See also Figure 4 , Figure 4A flow chart of a biological detection method provided by an embodiment of the present invention; the biological detection method is based on the above biological detection device 100, and the biological detection method includes:

[0054] S10, immersing the capillary 12 and the reflection end 113 together in a liquid to be tested containing cancer markers.

[0055] Specifically, step S10 also includes:

[0056] The above-mentioned biological detection device 100 is provided, and the input end 111 of the surface plasmon resonance fiber optic probe 11 is connected to the light source 20 through a multimode optical fiber, and the output end 112 of the surface plasmon resonance fiber optic probe 11 is connected to the spectrometer 30 through another multimode optical fiber; then, the reflection end 113 of the surface plasmon resonance fiber optic probe 11 is completely penetrated through the inner cavity of the capillary 12; finally, the capillary 12 and the reflection end 113 are immersed together in a liquid to be tested containing cancer markers.

[0057] S20 , turning on the switch of the AC power source 13 to form an AC electric field between the capillary 12 and the reflection end 113 .

[0058] Specifically, step S20 also includes:

[0059] The switch of the AC power source 13 is turned on to form an AC electric field between the inner wall of the capillary 12 and the outer surface of the reflecting end 113 .

[0060] S30 , an optical signal is input to the surface plasmon resonance optical fiber probe 11 through the light source 20 , and the optical signal generates a surface plasmon resonance effect at the reflection end 113 .

[0061] Specifically, step S30 also includes:

[0062] An optical signal is incident on the surface plasmon resonance optical fiber probe 11 through the light source 20 , and the optical signal generates a surface plasmon resonance effect at the reflection end 113 . The generated resonant optical signal is reflected to the output end 112 through the reflection end 113 .

[0063] S40 , receiving the resonance light signal emitted by the surface plasmon resonance optical fiber probe 11 at the output end 112 through the spectrometer 30 .

[0064] S50, determining the refractive index of the liquid to be tested according to the wavelength of the resonant light signal, and finally determining the concentration of the cancer marker in the liquid to be tested.

[0065] Specifically, step S50 also includes:

[0066] According to the linear relationship between the wavelength of the resonance light signal and the refractive index of the liquid to be tested, the refractive index of the liquid to be tested is determined by the wavelength of the resonance light signal, and the concentration of the cancer marker in the liquid to be tested is finally determined by the refractive index of the liquid to be tested.

[0067] Compared with the prior art, the present invention has the following beneficial effects:

[0068] With the assistance of the alternating electric field, the selectivity and response speed of the optical fiber biosensor 10 can be greatly improved, the detection cycle can be shortened, and the target analyte can be detected quickly and accurately in complex samples. The electrophoresis phenomenon provides an effective means of enhancing signals and improving detection performance in the detection technology based on optical fiber sensors. At the same time, the electric field can also affect the charge distribution, intermolecular forces and spatial configuration of DNA molecules, thereby promoting the binding between complementary chains and promoting DNA hybridization. The adsorption mechanism based on the alternating electric field can be used to improve the detection accuracy of optical fiber sensors in biological detection. Optimization is achieved by adjusting the frequency and intensity of the electric field to achieve the best detection effect.

[0069] In summary, different from the prior art, the present invention provides an optical fiber biosensor 10, a biological detection device 100 and a biological detection method thereof, wherein the optical fiber biosensor 10 comprises a capillary 12 having an inner cavity and a surface plasmon resonance optical fiber probe 11, wherein a reflection end 113 of the surface plasmon resonance optical fiber probe 11 completely penetrates the inner cavity and does not contact the inner wall of the capillary 12, wherein the optical fiber biosensor 10 further comprises an AC power supply 13, wherein a first end of the AC power supply 13 is electrically connected to the capillary 12, and a second end of the AC power supply 13 is electrically connected to the reflection end 113; the optical fiber biosensor 10 provided by the present invention is electrically connected to the capillary 12 and the reflection end 113 An alternating electric field is formed between the electrodes, and the charged particles in the solution to be tested move toward the electrode with opposite electrical properties due to the electrophoresis phenomenon under the action of the alternating electric field, and are thereby attracted to the surface plasmon resonance optical fiber probe 11, thereby reducing the detection cycle of the optical fiber biosensor 10; at the same time, due to the action of the alternating electric field, the charged particles originally non-specifically adsorbed on the surface of the surface plasmon resonance optical fiber probe 11 will undergo a special adsorption-desorption process, and as a result of the action of this periodic force, the particles originally non-specifically adsorbed will be desorbed on the surface of the plasmon resonance optical fiber probe and separated from the charged particles to be tested, thereby reducing the impact of non-specific adsorption and improving the detection accuracy.

[0070] The above embodiments only express the implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An optical fiber biosensor, characterized in that: It comprises a capillary having an inner cavity and a surface plasmon resonance optical fiber probe, wherein the reflection end of the surface plasmon resonance optical fiber probe completely penetrates the inner cavity and does not contact the inner wall of the capillary, and the inner wall of the capillary is plated with a conductive layer; Wherein, the optical fiber biosensor further comprises an alternating current power supply, a first end of the alternating current power supply is electrically connected to the conductive layer, and a second end of the alternating current power supply is electrically connected to the reflective end.

2. The optical fiber biosensor according to claim 1, characterized in that: The material of the conductive layer is ITO or AZO, and the thickness of the conductive layer is 1-10 nm.

3. The optical fiber biosensor according to claim 1, characterized in that: The distance between the portion of the reflection end located in the inner cavity and the inner wall of the capillary is 10-20 μm.

4. The optical fiber biosensor according to claim 1, characterized in that: The voltage of the AC power supply is greater than 0 and less than or equal to 1.2V, and the frequency of the AC power supply is 40-60kHz.

5. The optical fiber biosensor according to claim 1, characterized in that: The reflective end includes an optical fiber, a metal layer coated on the outer surface and end surface of the optical fiber, and a low-dimensional nanolayer coated on the metal layer; The low-dimensional nanolayer is a material having at least one dimension at nanoscale in three-dimensional space.

6. The optical fiber biosensor according to claim 5, characterized in that: The material of the metal layer is Au, and the thickness of the metal layer is 30-40 nm; the low-dimensional nanolayer is carbon quantum dots or graphene, and the thickness of the low-dimensional nanolayer is 20-50 nm.

7. A biological detection device, characterized in that: It comprises a light source, a spectrometer and the optical fiber biosensor according to any one of claims 1 to 6, wherein the light source is connected to the input end of the surface plasmon resonance optical fiber probe, and the spectrometer is connected to the output end of the surface plasmon resonance optical fiber probe.

8. A biological detection method, characterized in that: The biological detection method is based on the biological detection device according to claim 7, and the biological detection method comprises: S10, immersing the capillary and the reflecting end together in a liquid to be tested containing a cancer marker; S20, turning on the switch of the AC power supply to form an AC electric field between the capillary and the reflecting end; S30, injecting a light signal into the surface plasmon resonance optical fiber probe through the light source, so that the light signal generates a surface plasmon resonance effect at the reflection end; S40, receiving, by the spectrometer, a resonance light signal emitted by the surface plasmon resonance optical fiber probe at the output end; S50, determining the refractive index of the liquid to be tested according to the wavelength of the resonant light signal, and finally determining the concentration of the cancer marker in the liquid to be tested.

9. The biological detection method according to claim 8, characterized in that: In the step S20, the charged polarity of the reflective end is opposite to the charged polarity of the cancer marker.

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