CN108717116A - A kind of lymphocyte Photobiology sensor and its method for sensing based on optofluidic capillary microcavity - Google Patents

Abstract

Present invention is disclosed a kind of lymphocyte Photobiology sensor and its method for sensing based on optofluidic capillary microcavity, the sensor includes frequency swept laser, capillary microcavity-micro-nano fiber coupling unit for carrying out sensing testing to cell solution, photodetector and feedback control system, frequency swept laser, capillary microcavity-micro-nano fiber coupling unit, photodetector and feedback control system are of coupled connections by fiber fuse between each other, feedback control system is electrically connected with photodetector and frequency swept laser respectively, capillary microcavity-micro-nano fiber coupling unit is mutually perpendicular to be coupled to form by micro-nano fiber and capillary microcavity.The sensor is using micro volume, heightQThe capillary microcavity of value is as lymphocyte sensing unit, by the control and interaction of light in microcavity and microfluid, realizes with highly sensitive, quick detection, unmarked, compact-sized, integrated level is high, Photobiology lymphocyte at low cost sensing.

Description

A bio-optical sensor for lymphocytes based on optofluidic capillary microcavity and its Sensing method

technical field

The invention relates to a lymphocyte bio-optical sensor based on an optofluidic capillary microcavity and a sensing method thereof, which can be used in the technical field of sensors.

Background technique

The ability to detect and quantify HIV is critical for physicians seeking to maximize treatment effectiveness, and one way to achieve this is by looking at CD4+ lymphocyte counts. The number of CD4+ cells in a healthy normal person is 1200/μL. As the degree of AIDS infection deepens, this number will decrease at the same time. When it drops to 200/μL, it will be diagnosed as AIDS.

Currently, the count of CD4+ lymphocytes can be accurately achieved by flow cytometry. These instruments work by labeling CD4+ receptors with fluorescent antibodies and counting the resulting fluorescent signal. But although flow cytometers are very accurate in counting, they also have limitations such as reliance on fluorescent labels, high equipment costs, high maintenance requirements, and long detection times.

Contents of the invention

The object of the present invention is to solve the above-mentioned problems existing in the prior art, and propose a lymphocyte bio-optical sensor based on an optofluidic capillary microcavity and a sensing method thereof.

The purpose of the present invention will be achieved through the following technical solutions: a lymphocyte bio-optical sensor based on optofluidic capillary microcavity, including frequency-sweeping laser, capillary microcavity-micro-nano optical fiber for sensing and testing cell solution Coupling unit, photodetector and feedback control system, the frequency-sweeping laser, capillary microcavity-micro-nano fiber coupling unit, photodetector and feedback control system are connected to each other through optical fiber fusion coupling, and the feedback control system is respectively connected with The photodetector is electrically connected to the frequency-sweeping laser, and the capillary microcavity-micro-nano fiber coupling unit is formed by coupling the micro-nano fiber and the capillary microcavity vertically, and the frequency-sweeping laser emits laser light from the end of the micro-nano fiber The micro-nano optical fiber cone area is coupled into the capillary microcavity through the evanescent field, and the resonance of the whispering gallery mode in the capillary microcavity is excited. The whispering gallery mode light field has a specific bio-optical interaction with the cell solution inside the microcavity. The light intensity output from the other end of the optical fiber is used to demodulate the cell concentration information of the measured lymphocyte solution. The feedback control system controls the output wavelength and intensity of the frequency-sweeping laser through an electrical connection, and at the same time controls the photodetector to detect The light intensity at the other output end of the micro-nano fiber realizes the control of the optical wavelength and optical power of the frequency-sweeping laser, and compares the light intensity measured at the output end of the micro-nano fiber with the input laser light intensity at a specific optical wavelength for feedback calculation, and obtains Whispering gallery mode resonance spectrum with multiple transmission peaks.

Preferably, the wavelength of the frequency-swept laser is tunable.

Preferably, the micro-nano optical fiber is prepared by melting and tapering a single-mode optical fiber through a tapering machine.

Preferably, the capillary microcavity is prepared by melting and tapering a hollow silica capillary optical fiber.

Preferably, the micro-nano fiber is close to the capillary micro-cavity, and the micro-nano fiber is perpendicular to the central axis of the capillary micro-cavity.

Preferably, the capillary microcavity is a highly symmetrical hollow cylindrical structure.

Preferably, only the resonance wavelength satisfying the resonance condition of the whispering gallery mode can generate resonance in the capillary microcavity, and the resonance wavelength λ satisfying the resonance condition of the whispering gallery mode is determined by the following formula:

λ＝ _2πrneff /m

where r is the cavity radius, n _eff is the effective index of refraction through which the optical resonant mode passes, and m is an integer.

Preferably, the resonant cycle period of the light wave in the capillary microcavity is determined by the quality factor Q of the capillary microcavity, and the relationship between the effective action length L _eff and the quality factor Q is given by the following formula:

L _eff =Qλ/2πn _eff .

The present invention also discloses a sensing method of a lymphocyte bio-optical sensor based on an optofluidic capillary microcavity, comprising the following steps:

S1: cleaning the microcavity;

Pass deionized water into the capillary microcavity to clean the capillary microcavity;

S2: acid cleaning;

Pass dilute nitric acid into the inside of the capillary microcavity cleaned in step S1, and seal the liquid in the capillary microcavity to stand still. After the end, alternately pass in deionized water and alcohol to clean the capillary microcavity;

S3: hydroxyl activation;

Pass the concentrated H ₂ SO ₄ hydrogen peroxide solution into the microcavity of the capillary after washing in step S2, seal the liquid in the microcavity of the capillary, and ensure that the hydroxyl groups on the surface of the microcavity of the capillary are fully activated. Clean the inside, and then keep the capillary microcavity hollow;

S4: Pass the 3-aminopropyltriethoxysilane solution into the capillary microcavity and let stand, wash with deionized water and alcohol, and remove the non-covalently bonded silane compound in the capillary microcavity;

S5: Pass the PBS solution containing CD4+ antibody into the capillary microcavity and let it stand still, so that the CD4+ antibody is cultivated on the surface of the inner wall of the silanized capillary microcavity. After the end, pour alcohol and deionized water into the capillary microcavity in sequence Clean the inside of the capillary microcavity;

S6: Pass the PBS solution of 1X CD4+ T cells to be tested into the capillary microcavity, and record the resonance spectrum of the whispering gallery mode at different times until the CD4+ T cells are completely combined with the antibody;

S7: Pass through the capillary microcavity after step S6 to wash with deionized water and PBS solution, and then pass through the PBS solution of 10×CD4+T cells, and record the resonance spectrum of the whispering gallery mode at different times until the CD4+T cells and The antibody is fully bound, and the resonance spectrum of the whispering gallery mode no longer drifts.

Preferably, in step S2, dilute nitric acid with a concentration of 5% is injected into the microcavity of the capillary cleaned by step S1; in step S6, the time for CD4+T cells to fully bind to the antibody is 30-40 minutes.

The advantages of the technical solution of the present invention are mainly reflected in: the sensor uses a capillary microcavity with a small volume and a high Q value as a lymphocyte sensing unit, and realizes high sensitivity, rapid Detection, label-free, compact, highly integrated, and low-cost bio-optical lymphocyte sensing. The method excites and detects the resonance spectrum of the whispering gallery mode in the optical microcavity by means of all-fiber coupling, without any means of fluorescent labeling, and combines optofluidic/microfluidic technology to detect the cell concentration. Fiber optic, fast, unmarked, low cost, repeatable test features. The bio-optical sensor realized by the invention has potential and huge application value in solving the problems of pre-diagnosis and treatment of AIDS.

Description of drawings

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

Fig. 2 is a physical diagram of the CD4+ T lymphocyte sensor of the present invention.

Fig. 3 is a schematic diagram of the cross section of the optical sensor of the present invention and a schematic diagram of light field transmission.

Fig. 4 is the resonance spectrum of the whispering gallery mode obtained after the microcavity inner wall surface of the present invention is not functionalized, and water, phosphate buffered saline, 1XCD4+T cell PBS solution, and 10XCD4+T cell PBS solution are respectively passed through.

Fig. 5 is a schematic diagram of the biospecific interaction between lymphocytes in the microcavity of the present invention, that is, the interaction process between CD4+T test cell antigen and CD+4 antibody.

Fig. 6 shows the shift of the resonance spectrum of the whispering gallery mode over time during the functionalization process of the antibody of the present invention.

Fig. 7 is the resonance spectrum of whispering gallery modes measured at different times after implanting specific receptors on the inner surface of the microcavity of the present invention and passing 1×CD4+ T cell solution into the microcavity.

Fig. 8 shows the variation of the wavelength shift with time of the resonance spectrum of the whispering gallery mode in the present invention, and the wavelength shifted by about 10pm.

Fig. 9 is the resonance spectrum of the whispering gallery mode obtained at different times after the CD4+ antibody is implanted on the inner surface of the microcavity of the present invention, and the PBS solution containing 10×CD4+ T cells is passed into the microcavity.

Fig. 10 shows the variation of the wavelength shift with time of the resonance spectrum of the whispering gallery mode in the present invention, and the wavelength shifted by about 14pm.

Detailed ways

Objects, advantages and features of the present invention will be illustrated and explained by the following non-limiting description of preferred embodiments. These embodiments are only typical examples of applying the technical solutions of the present invention, and all technical solutions formed by adopting equivalent replacements or equivalent transformations fall within the protection scope of the present invention.

The present invention discloses a lymphocyte bio-optical sensor based on optofluidic capillary microcavity, as shown in Figure 1, including a frequency-sweeping laser 1, capillary microcavity-micro-nano optical fiber coupling for sensing and testing the cell solution Unit 2, photodetector 3 and feedback control system 4, the frequency-sweeping laser 1, capillary microcavity-micro-nano fiber coupling unit 2, photodetector 3 and feedback control system 4 are connected to each other through optical fiber fusion coupling, so The feedback control system 4 is electrically connected to the photodetector 3 and the frequency-sweeping laser 1 respectively, the wavelength of the frequency-sweeping laser is tunable, and the capillary microcavity is a highly symmetrical hollow cylindrical structure.

The capillary microcavity-micro-nano fiber coupling unit is used for sensing and testing of the cell solution. The capillary micro-cavity-micro-nano fiber coupling unit 2 is formed by vertically coupling the micro-nano fiber 21 and the capillary micro-cavity 22. The frequency sweep Laser 1 emits laser light from the end of the micro-nano fiber into the taper region of the micro-nano fiber, and is coupled into the capillary microcavity through the evanescent field to excite the resonance of the whispering gallery mode in the capillary microcavity, and the whispering gallery mode light field and the cell solution inside the microcavity generate Specific bio-optical interaction, by detecting the light intensity output from the other end of the micro-nano fiber to demodulate the cell concentration information of the measured lymphocyte solution, the feedback control system controls the output wavelength and intensity of the frequency-sweeping laser through an electrical connection, and at the same time It also controls the photodetector to detect the light intensity at the other output end of the micro-nano fiber after passing through the capillary microcavity, realizes the control of the optical wavelength and optical power of the frequency-sweeping laser and compares the light intensity measured at the output end of the micro-nano fiber with the input laser light intensity A comparative feedback operation is performed at a specific light wavelength to obtain a resonance spectrum of a whispering gallery mode with multiple transmission peaks.

In order to excite the whispering gallery mode resonance, the micro-nano optical fiber is vertically coupled with the capillary microcavity. Figure 2(a) is a thin-walled cylindrical symmetric microcavity with a hollow pipe structure-tapered optical fiber cross-sectional physical diagram; Figure 2(b) is a thin-walled cylindrical symmetric microcavity. After the sample to be detected is passed into the cavity, it is coupled with the tapered optical fiber. The relative position of the two is shown in Figure 2(a). The setting can make the microcavity maintain a relatively stable coupling state with the micro-nano optical fiber after passing through the measured cell sample liquid, so as to improve the coupling efficiency, increase the intensity of the optical field in the cavity, and obtain The resonance spectrum of the whispering gallery mode with higher Q value and deeper transmission peak ensures the sensitivity and stability of the sensor.

The micro-nano optical fiber is prepared by melting and tapering a single-mode optical fiber through a tapering machine, and the diameter of the tapered area is 2-3 μm. 90 μm, wall thickness 2-3 μm, the capillary microcavity has the characteristics of high symmetry, thin wall and small volume.

Fig. 3 is a schematic cross-sectional view and a schematic view of light field transmission of the lymphocyte bio-optical sensor of the technical solution. The light field in the micro-nano fiber taper is coupled from the micro-nano fiber taper to the thin-walled microcavity of the capillary in the form of an evanescent field. Due to the total reflection effect, the light of a specific wavelength that satisfies the resonance condition forms a whispering gallery mode resonance in the microsphere cavity. Its light field distribution is shown in the 10-whispering gallery mode light field distribution in Figure 2, most of the light energy is distributed near the inner wall surface area of the capillary microcavity, and has a very small mode volume, so the distance between light and the measured object The strong interaction enables high-sensitivity sensing. When different measured samples are passed into the microcavity, the resonance spectrum of the whispering gallery mode will have different spectral shifts for samples with different concentrations due to the change of the refractive index inside the microcavity.

Only the resonance wavelength satisfying the resonance condition of the whispering gallery mode can resonate in the capillary microcavity, and the resonance wavelength λ satisfying the resonance condition of the whispering gallery mode is determined by the following formula:

λ＝ _2πrneff /m

where r is the cavity radius, n _eff is the effective index of refraction through which the optical resonant mode passes, and m is an integer.

The resonant cycle period of the light wave in the capillary microcavity is determined by the quality factor Q of the capillary microcavity, and the relationship between the effective length L _eff and the quality factor Q is given by the following formula:

L _eff =Qλ/2πn _eff .

Only the resonance wavelength satisfying the resonance condition of the whispering gallery mode can resonate in the capillary microcavity, and the resonance wavelength λ satisfying the resonance condition of the whispering gallery mode is determined by the following formula:

λ= _2πrneff /m.

where r is the cavity radius, n _eff is the effective index of refraction through which the optical resonant mode passes, and m is an integer. Since the resonance light field of the whispering gallery mode has a longer photon lifetime, the bio-optical interaction length and time between the light field and the tested lymphocyte solution are greatly increased. Among them, the interaction length depends on the cycle period of the light wave in the microcavity determined by the quality factor Q of the microcavity, and the relationship between the effective interaction length L _eff and the quality factor Q is given by the following formula:

L _eff =Qλ/2πn _eff

Taking the capillary microcavity and laser light source used in this technical solution as an example, the quality factor Q is 10 ⁶ , the effective refractive index n _eff =1.45, and the wavelength λ=1.5 μm, the effective action length can reach more than 15 cm.

The lymphocyte bio-optical sensor is aimed at using the optical device for biological testing, and the surface of the microcavity is functionalized to improve the significance of the specific interaction of the microcavity in the process of testing the lymphocyte solution. For comparison, the characteristics of the resonance spectrum of the whispering gallery mode of different concentrations of cell solutions injected into the microcavity without surface functionalization on the inner wall of the microcavity were tested experimentally. As shown in Figure 4, the resonance spectrum of the whispering gallery mode obtained after passing through water, phosphate buffer saline (phosphate buffer saline, PBS) solution, 1XCD4+T cell PBS solution, and 10XCD4+T cell PBS solution respectively, CD4+T cells are A kind of CD4+ lymphocyte is the object to be tested, and it is also an antigen. For a certain type of lymphocyte antigen, the antibody that needs to interact with the specific sex during the test is determined. In this technical solution, 1X and 10X concentrations correspond to 1000 CD4+ T cells/μm and 10000 CD4+ T cells/μm respectively, the same below. When the 1X and 10X CD4+T cell fluids passed through the unfunctionalized microcavity on the inner surface, the spectra shifted by 6.8pm and 16pm respectively. This is because a certain concentration of the cell solution will cause changes in the refractive index in the microcavity, which will cause echoes. Changes in the wall mode resonance spectrum.

Figure 5 is a schematic diagram of the biospecific interaction of lymphocytes in the microcavity, that is, the interaction process between the CD4+T test cell antigen and the CD+4 antibody, 22 is the capillary microcavity, 21 is the micro-nano optical fiber, and 5 is CD4+ T cell antigen and 6 are CD4+ antibodies. CD4+ antibody is first cultivated on the surface of the inner wall of the silanized microcavity, and then the CD4+ T cell antigen is passed through the microfluidic technology. The drift of the resonance spectrum of the whispering gallery mode is proportional to the concentration of the detected CD4+T cells, and the measurement of the number of lymphocytes is realized.

Bio-optical sensing is realized through the control and interaction of light and microfluid in the capillary microcavity. The microcavity has a small diameter, combined with microfluidic technology, a fully enclosed and micro-carrying channel for the lymphocyte solution is formed, and the analyte channel is realized. The separation from the detection channel improves the test stability.

The present invention also discloses a sensing method of lymphocyte bio-optical sensor based on optofluidic capillary microcavity, which performs hydroxyl activation and silanization on the surface of the inner wall of the capillary microcavity, that is, surface functionalization, so as to effectively enhance the inner wall of the microcavity. The specific bio-optical interaction between the whispering gallery mode light field and the lymphocyte solution in the vicinity of the region is significant, resulting in enhanced sensing sensitivity.

The method includes the following steps:

S1: Pass deionized water into the capillary microcavity to clean the inside of the capillary microcavity;

S2: Introduce dilute nitric acid with a concentration of 5% into the microcavity of the capillary after cleaning in step S1, and seal the liquid in the microcavity of the capillary for 2 hours and 30 minutes. After the end, alternately pass in deionized water and alcohol , to wash the inside of the capillary microcavity;

S3: Introduce concentrated H ₂ SO ₄ hydrogen peroxide solution into the capillary microcavity washed in step S2, seal the liquid in the capillary microcavity and let it stand for 1 hour to ensure that the hydroxyl groups on the inner wall surface of the capillary microcavity are fully activated. Wash the inside of the capillary microcavity, then keep the inside of the capillary microcavity hollow, and dry at a constant temperature of 40°C;

S4: Pass the 3-aminopropyltriethoxysilane solution into the capillary microcavity, let stand for 30 minutes, wash with deionized water and alcohol, and remove the non-covalently bonded silane compound in the capillary microcavity;

S5: Pass the PBS solution containing CD4+ antibody into the microcavity of the capillary, and let it stand for 1 hour, so that the CD4+ antibody can be cultivated on the surface of the inner wall of the silanized microcavity of the capillary. Ionized water to clean the inside of the capillary microcavity;

S6: Pass the 1XCD4+T cell PBS solution to be tested into the capillary microcavity, and record the resonance spectrum of the whispering gallery mode at different times, specifically, record the resonance spectrum of the whispering gallery mode every 3 minutes until the CD4+T cells interact with the antibody Complete combination; in step S6, the time for CD4+ T cells to fully combine with the antibody is 30-40 minutes.

S7: Clean the capillary microcavity treated in step S6 with deionized water and PBS solution, and then pass it into the PBS solution of 10×CD4+T cells, and record the resonance spectrum of the whispering gallery mode at different times, specifically, every three Record the resonance spectrum of the whispering gallery mode every minute until the CD4+T cells are fully combined with the antibody, and the resonance spectrum of the whispering gallery mode no longer drifts.

Figure 6 shows the variation of the resonance spectrum drift of the whispering gallery mode over time obtained by passing the PBS solution containing the CD4+ antibody into the microcavity after performing the above step S5. Within a certain action time, the antibody adheres to the microcavity. On the surface, due to the thickening of the wall thickness, the resonance spectrum of the whispering gallery mode also drifts.

Figure 7 is the resonance spectrum of the whispering gallery mode obtained by testing at different times after the PBS solution containing 1×CD4+ T cells was injected into the microcavity in the above S6 step. With cell binding, the resonance spectrum of the whispering gallery mode drifted and stabilized after 30 minutes. Figure 8 shows the variation of the wavelength shift of the resonance spectrum of the whispering gallery mode with time. The wavelength shifted by about 10pm, that is, the sensitivity reached 10pm/(1.66×10 ^-15 mol/L/L).

Figure 9 is the resonance spectrum of the whispering gallery mode obtained by testing at different times after the PBS solution containing 10×CD4+ T cells was passed into the microcavity after implementing the above S7 step. After a certain reaction time, CD4+ T antigen cells and CD4+ antibody cells Combined, the whispering gallery mode resonance spectrum drifted and stabilized after 20 minutes. Figure 10 shows the wavelength shift of the whispering gallery mode resonance spectrum over time. The wavelength shifted by about 14pm, that is, the sensitivity reached 14pm/(1.66×10 ^-14 mol/L), and the detection of unlabeled CD4+ T lymphocytes was achieved. detection.

On the one hand, the sensor uses the evanescent field coupling method between the micro-nano optical fiber and the capillary microcavity to excite the resonance of the whispering gallery mode in the microcavity. The strength of the specific bio-optical interaction, through the change of the resonance spectrum of the whispering gallery mode, can quickly and highly sensitively demodulate the characteristics of the tested lymphocytes, and the interaction process takes a short time and does not require any fluorescent labeling process. On the other hand, the capillary microcavity has a small diameter. During the test, combined with microfluidic technology, a fully enclosed micro-carrying channel for the lymphocyte solution was formed, which realized the separation of the analyte channel and the detection channel, and realized the detection of the lymphocyte solution. Micro-volume, high-stability bio-optical testing. The micro-nano optical fiber and capillary microcavity used in the sensor have the characteristics of all optical fibers, compact structure, and simple preparation. Therefore, the present invention has the advantages of high sensitivity, rapid detection, no label, compact structure, high integration, low cost, simple process and the like.

There are still many implementations in the present invention, and all technical solutions formed by equivalent transformation or equivalent transformation fall within the protection scope of the present invention.

Claims (10)

1. A lymphocyte bio-optical sensor based on an optofluidic capillary microcavity, characterized in that it includes a frequency-sweeping laser, a capillary microcavity-micro-nano optical fiber coupling unit and a photodetector for sensing and testing the cell solution and a feedback control system, the frequency-sweeping laser, the capillary microcavity-micro-nano fiber coupling unit, the photodetector and the feedback control system are connected to each other through optical fiber fusion coupling, and the feedback control system is connected to the photodetector and the frequency-sweeping system respectively The laser is electrically connected, the capillary microcavity-micro-nano fiber coupling unit is formed by vertically coupling the micro-nano fiber and the capillary micro-cavity, and the frequency-sweeping laser emits laser light from one end of the micro-nano fiber into the micro-nano fiber taper area, Through the evanescent field coupling into the capillary microcavity, the resonance of the whispering gallery mode in the capillary microcavity is excited, and the whispering gallery mode light field has a specific bio-optical interaction with the cell solution inside the microcavity. By detecting the light output from the other end of the micro-nano fiber To demodulate the cell concentration information of the measured lymphocyte solution, the feedback control system controls the output wavelength and intensity of the frequency-sweeping laser through electrical connections, and also controls the photodetector to detect another output of the micro-nano fiber after passing through the capillary microcavity The light intensity at the end of the frequency-sweeping laser is realized to control the optical wavelength and optical power of the frequency-sweeping laser, and the light intensity measured at the output end of the micro-nano fiber is compared with the input light laser light intensity at a specific light wavelength for feedback calculation, and the transmission peak with multiple transmission peaks is obtained. Whispering gallery mode resonance spectrum. 2. A lymphocyte bio-optical sensor based on an optofluidic capillary microcavity according to claim 1, characterized in that: the wavelength of the frequency-sweeping laser is tunable. 3. A lymphocyte bio-optical sensor based on an optofluidic capillary microcavity according to claim 1, characterized in that: the micro-nano optical fiber is prepared from a single-mode optical fiber through a tapering machine for melting and tapering. 4. A lymphocyte bio-optical sensor based on an optofluidic capillary microcavity according to claim 1, characterized in that: the capillary microcavity is prepared by melting and tapering a hollow quartz capillary optical fiber. 5. The lymphocyte bio-optical sensor based on optofluidic capillary microcavity according to claim 1, characterized in that: the micro-nano optical fiber is close to the capillary microcavity, and the micro-nano optical fiber is connected to the capillary microcavity. The central axis of the cavity remains perpendicular to the plane. 6 . The lymphocyte bio-optical sensor based on optofluidic capillary microcavity according to claim 1 , characterized in that: the capillary microcavity is a highly symmetrical hollow cylindrical structure. 7. A kind of lymphocyte bio-optical sensor based on optofluidic capillary microcavity according to claim 1, is characterized in that: only the resonant wavelength that satisfies the resonance condition of the whispering gallery mode can generate resonance in the capillary microcavity, satisfying The resonance wavelength λ of the resonance condition of the whispering gallery mode is determined by the following formula: λ＝ _2πrneff /m where r is the cavity radius, n _eff is the effective index of refraction through which the optical resonant mode passes, and m is an integer. 8. A kind of lymphocyte bio-optical sensor based on optofluidic capillary microcavity according to claim 1, is characterized in that: the resonant cycle period of light wave in capillary microcavity is determined by the quality factor Q of capillary microcavity, effectively The relationship between the action length L _eff and the quality factor Q is given by the following formula: L _eff =Qλ/2πn _eff . 9. A sensing method based on an optofluidic capillary microcavity lymphocyte bio-optical sensor, characterized in that: comprising the following steps: S1: cleaning the microcavity; Pass deionized water into the capillary microcavity to clean the capillary microcavity; S2: acid cleaning; Pass dilute nitric acid into the inside of the capillary microcavity cleaned in step S1, and seal the liquid in the capillary microcavity to stand still. After the end, alternately pass in deionized water and alcohol to clean the capillary microcavity; S3: hydroxyl activation; Pass the concentrated H ₂ SO ₄ hydrogen peroxide solution into the microcavity of the capillary after washing in step S2, seal the liquid in the microcavity of the capillary, and ensure that the hydroxyl groups on the surface of the microcavity of the capillary are fully activated. Clean the inside, and then keep the capillary microcavity hollow; S4: Pass the 3-aminopropyltriethoxysilane solution into the capillary microcavity and let stand, wash with deionized water and alcohol, and remove the non-covalently bonded silane compound in the capillary microcavity; S5: Pass the PBS solution containing CD4+ antibody into the capillary microcavity and let it stand still, so that the CD4+ antibody is cultivated on the surface of the inner wall of the silanized capillary microcavity. After the end, pour alcohol and deionized water into the capillary microcavity in sequence Clean the inside of the capillary microcavity; S6: Pass the PBS solution of 1X CD4+ T cells to be tested into the capillary microcavity, and record the resonance spectrum of the whispering gallery mode at different times until the CD4+ T cells are completely combined with the antibody; S7: Pass through the capillary microcavity after step S6 to wash with deionized water and PBS solution, and then pass through the PBS solution of 10×CD4+T cells, and record the resonance spectrum of the whispering gallery mode at different times until the CD4+T cells and The antibody is fully bound, and the resonance spectrum of the whispering gallery mode no longer drifts. 10. the sensing method of a kind of lymphocyte bio-optical sensor based on optofluidic capillary microcavity according to claim 9, it is characterized in that: in S2 step, to the capillary microcavity interior after cleaning through S1 step Add dilute nitric acid with a concentration of 5%; in step S6, the time for CD4+ T cells to fully combine with the antibody is 30-40 minutes.