Method for improving liquid crystal droplet sensing efficiency

Abstract

The invention discloses a method for improving the sensing efficiency of liquid crystal droplets, which comprises the following steps: adding a biological sample to be detected into a sensor based on the liquid crystal droplets, and then applying ultrasonic waves with the ultrasonic frequency of 500-550kHz to the liquid crystal droplets. The research shows that the ultrasonic wave with the frequency of 500-550kHz has no influence on the orientation of the liquid crystal liquid drop, and the sample detection speed can be obviously improved by using the ultrasonic wave to drive the liquid crystal liquid drop. The invention further provides a liquid crystal droplet sensing device based on ultrasonic driving, and the liquid crystal droplets can be obviously driven by ultrasonic waves in a microenvironment and keep a good motion state in a complex sample. Meanwhile, the method and the device can be used for improving the sensing efficiency of the liquid crystal droplets on the rhamnolipid. The liquid crystal liquid drops driven by the ultrasonic waves can still move well in a complex actual environment. Therefore, the method for improving the sensing efficiency by ultrasonically driving the liquid crystal droplets has a wide application prospect.

Description

Technical Field

[0001] The present invention belongs to the field of optical sensing, and in particular, relates to a method for improving the sensing efficiency of liquid crystal droplets. Background Art

[0002] Liquid crystal-based sensing technology is a powerful optical sensing technology widely used in fields such as disease diagnosis or environmental testing due to its advantages such as rapidity, sensitivity, simple operation, and ease of on-site detection. It can be applied to microfluidic chips to detect target samples in very small environments, requiring less sample and having great potential value. The simplest way to detect target samples is to prepare a liquid crystal droplet-based microsensor with a surfactant layer (such as sodium dodecyl sulfate). Once in contact with a specific analytical target, the ordered orientation of the liquid crystal molecules themselves, that is, their birefringent morphology, will change, and this change can be detected by a polarized light microscope system. Ensuring that the amount or concentration of the target substance in close contact with the microsensor is greater than the detection limit is a key factor in ensuring the accuracy of the detection results and subsequent experiments. However, unlike other optical detection techniques such as surface-enhanced Raman spectroscopy, quantum dot fluorescence detection, and nanogold colorimetry, samples containing liquid crystal-based microsensors cannot usually be mixed by external forces (mechanical oscillation or stirring) to enhance mass transfer and accelerate molecular diffusion. There are two reasons for this: (1) Violent oscillation or stirring can significantly reduce the size of the liquid crystal droplets, affecting the observation of the birefringence of the liquid crystal; (2) When detecting targets at some special locations in the chip, such as cavities or channels, increasing the liquid flow rate will wash away the liquid crystal, and the liquid flow will also cause the orderly orientation of the liquid crystal droplets to change. In order to overcome the disadvantage of low molecular diffusion efficiency in liquid crystal-based sensing technology, it is of great significance to develop a method to improve the sensing efficiency of liquid crystal droplets without interfering with the birefringence of the liquid crystal. Summary of the invention

[0003] The purpose of the present invention is to overcome the above-mentioned defects and shortcomings in the prior art and provide a method for improving the efficiency of liquid crystal droplet sensing detection.

[0004] The second object of the present invention is to provide a liquid crystal droplet sensing device based on ultrasonically driven liquid crystal.

[0005] The third object of the present invention is to provide an application of the method or the liquid crystal droplet sensing device in improving the efficiency of detecting rhamnolipids in proteins or samples.

[0006] The above-mentioned object of the present invention is achieved through the following technical solutions:

[0007] The present invention firstly provides a method for improving the sensing detection efficiency of liquid crystal droplets. After adding a biological sample to be tested into a sensor based on liquid crystal droplets, ultrasonic waves with an ultrasonic frequency of 500 to 550 kHz are applied to the liquid crystal droplets.

[0008] The present invention has found that when using ultrasound to drive liquid crystal, the liquid crystal droplets show movement behaviors of individuals tending to cluster and move in groups when the ultrasound frequency is 500-600kHz and 1690kHz. Further research has found that when applying ultrasound with a frequency of 500-550kHz, the size and orientation of the liquid crystal droplets are not affected, while when applying ultrasound with a frequency of 590kHz, the birefringence of the liquid crystal droplets (original orientation is radial orientation) will change, which is not conducive to observing its response to protein. This is the premise for using ultrasound to drive liquid crystal to improve sensing efficiency. The present invention uses a special device to apply ultrasound in the sample tank, so that the liquid in the sample tank generates microflows, enhances mass transfer, and accelerates the diffusion rate of the liquid crystal droplets (original orientation is radial orientation) and the sample (BSA, bovine serum albumin), thereby significantly improving the speed of contact between the liquid crystal and the sample, and greatly shortening the time for the orientation change of the liquid crystal droplets, thereby improving the sensing efficiency. Therefore, the above research shows that the use of fixed-frequency ultrasonic waves to drive liquid crystal droplets can increase the contact speed with the sample without affecting the size and orientation of the liquid crystal droplets. The present invention introduces the concept of self-driven micromotors in liquid crystal droplet-based sensing for the first time, and uses ultrasonically driven liquid crystal droplets to reduce the time required for liquid crystal droplets to contact the sample, so as to improve the sensing detection efficiency based on liquid crystal droplets. This provides an innovative and effective method to overcome the bottleneck in the field of liquid crystal sensing, that is, the slow free diffusion speed of sample molecules. At the same time, ultrasonically driven liquid crystal droplets can still move well in complex actual environments. Therefore, the method of ultrasonically driving liquid crystal droplets to improve sensing efficiency has broad application prospects.

[0009] Furthermore, ultrasonic waves with an ultrasonic frequency of 540 to 550 kHz are applied.

[0010] Furthermore, the original orientation of the liquid crystal droplets is radial orientation or bipolar orientation.

[0011] The present invention provides a liquid crystal droplet sensing device based on ultrasonic drive, comprising a sample slot, an ultrasonic generating module and a polarized light detection module; the sample slot is loaded with liquid crystal droplets; the ultrasonic generating module is fixed under the sample slot to drive the liquid crystal droplets; the polarized light detection module is used to observe the optical signals of the liquid crystal droplets.

[0012] Furthermore, the original orientation of the liquid crystal droplet is radial orientation or bipolar orientation. Wherein, a point defect at the center of the liquid crystal droplet is radial orientation, and a point defect at the two poles of the liquid crystal droplet is bipolar orientation.

[0013] Furthermore, the ultrasonic generating module is a piezoelectric ceramic ultrasonic transducer.

[0014] Furthermore, the polarized light detection module is a polarized light microscope.

[0015] Preferably, the polarized light microscope is a reflective polarized light microscope.

[0016] The present invention also provides the use of the above method or the liquid crystal droplet sensing device in improving the efficiency of detecting rhamnolipids in proteins or samples.

[0017] Furthermore, when detecting proteins, the original orientation of the liquid crystal droplets in the liquid crystal droplet sensing device is radial orientation; when detecting rhamnolipids in a sample, the original orientation of the liquid crystal droplets is bipolar orientation.

[0018] Furthermore, the protein is bovine serum albumin.

[0019] The present invention provides a method for improving the efficiency of detecting rhamnolipid in protein or sample based on the liquid crystal droplet sensing device, comprising adding the sample to be tested into a sample tank, starting an ultrasonic generating module to apply 500-550kHz ultrasonic waves, and then using a polarized light detection module for detection and observation.

[0020] Furthermore, when detecting proteins, the sample slot is loaded with radially oriented liquid crystal droplets; when detecting rhamnolipids in the sample, the sample slot is loaded with bipolar oriented liquid crystal droplets.

[0021] Furthermore, when detecting protein, the ultrasonic generating module is started to apply 540 kHz ultrasonic waves; when detecting rhamnolipid in the sample, the ultrasonic generating module is started to apply 550 kHz ultrasonic waves.

[0022] Preferably, the protein is bovine serum albumin.

[0023] Furthermore, the sample is plasma or bacterial culture fluid.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention provides a method for improving the sensing efficiency of liquid crystal droplets by using ultrasound. The method is to apply ultrasound with an ultrasound frequency of 500 to 550 kHz after adding a biological sample to be tested to a sensor based on liquid crystal droplets. The present invention proposes for the first time a method for improving the sensing efficiency by using ultrasound to drive liquid crystal droplets. Studies have shown that ultrasound with a frequency of 500 to 550 kHz has no effect on the orientation of liquid crystal droplets, which is the premise for using ultrasound to drive liquid crystal to improve the sensing efficiency. Multiple experiments have shown that the use of ultrasound to drive liquid crystal droplets can significantly increase the speed of detecting samples. The present invention further provides a liquid crystal droplet sensing device based on ultrasound drive, in which the liquid crystal droplets can be significantly driven by ultrasound in a microenvironment and maintain a good motion state in a complex environment (cell culture medium and juice). At the same time, the method and device of the present invention can be used to improve the sensing efficiency of liquid crystal droplets for rhamnolipids. Ultrasonic-driven liquid crystal droplets can still move well in a complex actual environment. Therefore, the method of ultrasonically driving liquid crystal droplets to improve the sensing efficiency has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the modification of the coaxial light microscope; wherein, A is the modification at the light source of the coaxial light microscope, B is the modification at the CCD camera, C is a schematic diagram of the light path inside the microscope when using the modified polarized light microscope to adjust the two polarizers to the orthogonal position (darkest field of view) to observe a sample with birefringence (a) and a physical picture of the modified polarized light microscope system (b).

[0027] Figure 2 Schematic diagram of the sample tank and ultrasonic generating module in the sensing device.

[0028] Figure 3 The preparation of liquid crystal droplets and ultrasonic drive devices; wherein A is the use of the sensor device (a) and the sample slot component diagram (b), and B is the comparison of the ultrasonic frequency generated by the piezoelectric ceramic (a) and the ultrasonic frequency generated by the original piezoelectric ceramic (b) detected by an oscilloscope (c).

[0029] Figure 4 The radial orientation (i) and bipolar orientation (iv) of liquid crystal droplets observed using a reflective polarized light microscope.

[0030] Figure 5 Figure 3 is the effect of ultrasonic driving on the contact time of liquid crystal with the sample; A is a schematic diagram of a liquid crystal droplet with an original radial orientation accelerating to contact the sample and changing to a bipolar orientation when the BSA sample is added under ultrasonic driving; B is the orientation change of the ultrasonically driven liquid crystal, the time change (a) and the liquid crystal motion trajectory (b), where i, ii, iii, and iv in (a) correspond to the same liquid crystal at different time points in (b), respectively.

[0031] Figure 6 Figure 3 is the effect of different ultrasonic frequency driving on the movement behavior of liquid crystal droplets; wherein, A is the movement behavior of liquid crystal droplets at 545kHz and 1690kHz, B is the comparison of the mean square displacement of the movement behavior of liquid crystal droplets driven by ultrasonic waves at 545kHz and 1690kHz and at rest (a) and the change of liquid crystal morphology under ultrasonic driving of different frequencies (b), and C is the movement phenomenon of micro-clusters formed by liquid crystal droplets when the ultrasonic frequencies are 540, 545, and 550kHz.

[0032] Figure 7 Figure 3 is the effect of ultrasonically driven liquid crystal on the sensing efficiency; A is a schematic diagram of the motion state of liquid crystal droplets and sample molecules in the sample tank before (a) and after (b) ultrasound is turned on when ultrasonic drive is used to improve the sensing efficiency of liquid crystal droplets; B is the effect of ultrasonically driven liquid crystal droplets on the liquid crystal sensing speed in two different experiments.

[0033] Figure 8 The motion behavior analysis of ultrasonically driven liquid crystal droplets in actual samples and microenvironments; A is the motion of liquid crystal droplets in actual samples; B is the motion of liquid crystal droplets in the sample loading holes of a microfluidic chip.

[0034] Fig. 9 The figure shows the effect of ultrasonic driving on the sensing efficiency of liquid crystal droplets in detecting rhamnolipid; wherein, A is a simulation diagram of the mechanism of bipolar oriented liquid crystal droplets responding to rhamnolipid, B is the time of liquid crystal droplets contacting rhamnolipid and the orientation change before and after ultrasound is turned on, C is the relationship between rhamnolipid concentration and the ratio of the number of liquid crystal droplets whose orientation changes after sample addition to the total number of liquid crystal droplets observable in the sample addition tank, D is the response of the bipolar oriented liquid crystal droplets prepared by the present invention to rhamnolipid and several different biological molecules, and E is the response of the liquid crystal droplets to the addition of rhamnolipid samples with rat plasma as solvent (a), rhamnolipid samples with ultrapure water as solvent (b), rat plasma (c), rhamnolipid samples with bacterial culture medium as solvent (d), and bacterial culture medium (e). DETAILED DESCRIPTION

[0035] The present invention is further described below in conjunction with the accompanying drawings and specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0036] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0037] Example 1: Microsensor based on ultrasonically driven liquid crystal droplets to improve sensing efficiency

[0038] A microsensor device based on ultrasonically driven liquid crystal droplets and a method for improving sensing efficiency using the same. The main components of the device include: a signal generator, piezoelectric ceramics, a glass slide, a sample tank, a PDMS sheet (polydimethylsiloxane, a high molecular polymer), and a modified polarized light coaxial light microscope. The reagents used include: liquid crystal (type: 5CB, 4-cyano-4'-pentylbiphenyl), sodium dodecyl sulfate (SDS), and a simulated sample: bovine serum albumin (BSA).

[0039] (I) Construction of the device:

[0040] 1. Modify the coaxial light microscope: Place two polarizers at the light source of the purchased coaxial light microscope and at the camera receiving light signals. Specifically, add a polarizer (plastic material) at the light source of the coaxial light microscope (light emitting end) ( Figure 1 A), add a polarizing film (glass material) at the CCD camera (light receiving end) ( Figure 1 B), through the optical path shown in the figure, that is, adjusting the two polarizers to the orthogonal position (the darkest field of view), the internal light path of the microscope when observing a sample with birefringence properties ( Figure 1 C(a)), the coaxial light microscope was transformed into a reflective polarized light microscope ( Figure 1 C(b)). The purpose of this step is to facilitate the observation of the birefringence changes of the liquid crystal droplets.

[0041] 2. Make sample slot:

[0042] Paste ten layers of high-temperature resistant polyimide tape to a thickness of about 0.58mm, use a 5mm hole puncher to punch holes and cut the tape to about 10×10mm, and stick this tape groove tightly to the glass slide. This is the main part of the sample groove; cut the PDMS sheet (polydimethylsiloxane, a high molecular polymer, 20μm thick) to just cover the hole punched on the tape, punch a hole in the center of the PDMS sheet (about 500μm in diameter), and scrape off the excess material outside the hole. This is the sample well for adding the sample to be tested. Specific details are as follows Figure 3 As shown in A(b).

[0043] The electrodes of the disc-shaped piezoelectric ceramic are correspondingly connected to the signal generator to generate ultrasonic waves.

[0044] Place a glass slide on the piezoelectric ceramic. At this time, add an appropriate amount of ultrasonic coupling agent between the glass slide and the piezoelectric ceramic and press until the distance between the bottom of the glass slide and the top of the piezoelectric ceramic is as small as possible ( Figure 2 ).

[0045] In order to verify whether the ultrasonic frequency generated by the piezoelectric ceramic is accurate, the present invention uses another piezoelectric ceramic to receive the vibration generated by the original piezoelectric ceramic and convert it into an electrical signal, which is then tested using an oscilloscope. Figure 3As shown in Figure B (a~c), the results show that the ultrasonic frequency generated by the original piezoelectric ceramic is the same as the signal given by the signal generator.

[0046] (II) Preparation of liquid crystal droplets and samples to be tested:

[0047] 1. Liquid crystal droplets: Take a certain amount of sodium dodecyl sulfate solution (using ultrapure water as solvent) of different concentrations and add a proper amount of liquid crystal. Shake and mix in a plastic or glass container (glass container is required to make bipolar oriented liquid crystal droplets) to obtain a radial orientation ( Figure 4 i) and polar orientation ( Figure 4 iv) liquid crystal droplets.

[0048] 2. Samples to be tested:

[0049] Bovine serum albumin (BSA): Prepare appropriate concentration using ultrapure water as solvent.

[0050] (III) Experimental plan:

[0051] 1. Study the effect of ultrasonic driving on liquid crystal droplets

[0052] Add an appropriate amount of prepared liquid crystal to the sample tank, use a pipette to add a small amount of the sample solution to be tested (here, protein: BSA) into the sample tank through the device injection hole and observe. Figure 5 A is a schematic diagram of a liquid crystal droplet originally oriented radially, which is accelerated to contact the sample and change to a bipolar orientation after being driven by ultrasound. When ultrasound is not turned on, the process of contacting the sample is slow. After ultrasound is turned on, the process of contacting the sample is accelerated, so the orientation change speed is accelerated. In a static state (ultrasound is not turned on), the protein is slowly distributed in the sample tank by free diffusion, and it takes a long time to contact the liquid crystal droplet and change its birefringence morphology. After turning on the signal generator switch, the piezoelectric ceramic generates ultrasonic waves and transmits them to the sample tank. The liquid in the sample tank generates microflows, and the liquid crystal droplets quickly contact the proteins, causing the birefringence morphology of the liquid crystal droplets to change. Figure 5 As shown in B, i, ii, iii, and iv in (a) correspond to the same liquid crystal at different time points in (b), and (b) is the movement trajectory of the same liquid crystal at different time points. Under ultrasonic drive, the movement speed of the liquid crystal is accelerated and the contact time with the sample is shortened.

[0053] 2. Investigating the motion behavior of liquid crystal droplets driven by ultrasound

[0054] Since the motion of liquid crystal droplets caused by ultrasonic driving may affect the liquid crystal sensing efficiency, the present invention investigates the influence of ultrasonic frequency and intensity on the motion of liquid crystal droplets. Figure 6As shown in A, when the ultrasonic frequency is 545kHz and 1690kHz, the liquid crystal droplets tend to move towards clusters. If the ultrasonic wave is continuously turned on, they will eventually become liquid crystal clusters. After investigation, it is found that the time it takes for the liquid crystal droplet clusters to form decreases as the voltage applied by the signal generator increases. Figure 6 As shown in B (a, b), the present invention investigates the mean square displacement (MSD) of the motion behavior of liquid crystal droplets driven by ultrasound at different frequencies, and compares it with the liquid crystal that is not under the influence of ultrasound. It can be seen from the MSD results and the actual motion pictures that when the ultrasound frequency is 545kHz and 1690kHz, the liquid crystal droplets have obvious motion behavior. The present invention studies the effect of ultrasound on the orientation of liquid crystal droplets. When the ultrasound frequency is 590kHz and 1690kHz, the morphology of the liquid crystal droplets changes, and this effect decreases as the voltage applied by the signal generator decreases, while this phenomenon was not observed when the experiment was conducted using ultrasound at 540kHz and 510kHz. Therefore, the present invention selects ultrasound at 540kHz to improve the sensing efficiency of liquid crystal droplets. At the same time, when the present invention continuously adjusts the ultrasound frequency to 540, 545, and 550kHz, the micro-clusters formed by the liquid crystal droplets have obvious collective movement phenomenon ( Figure 6 C).

[0055] 3Ultrasound-driven liquid crystal improves sensing efficiency

[0056] In order to prove that using ultrasound to drive liquid crystal droplets can indeed improve the sensing efficiency, the present invention compares the speed of liquid crystal detection (contact) of analytes in the sample tank when ultrasound is turned off and turned on. Figure 7 As shown in A and B, the present invention uses BSA (bovine serum albumin) as an analyte. After the liquid crystal droplets contact BSA, the SDS on the surface of the droplets is affected and causes the radially oriented liquid crystal droplets to change to a bipolar orientation. When the ultrasound is kept off, the BSA solution (1μL, 1mg / mL) added from the sample loading hole at the top of the sample tank contacts the liquid crystal through free diffusion, so the time for the liquid crystal orientation to change is relatively slow, and only the liquid crystal with a spatial position close to the sample loading hole produces an orientation change. At this time, ultrasound is turned on (540kHz, intensity of 20V), and the microflow in the liquid simultaneously accelerates the movement speed of the liquid crystal droplets and BSA, which greatly shortens the time for the liquid crystal droplets to contact BSA and produce orientation changes. The ultrasound is continuously turned on, and finally the orientation of all liquid crystal droplets changes. The present invention has repeated experiments many times to ensure that the phenomenon of ultrasonic drive improving the sensing efficiency of liquid crystal droplets can be stably reproduced.

[0057] 4. Ultrasound-driven motion of liquid crystal droplets in real samples and microenvironments

[0058] In order to verify the flexibility of this method in possible practical applications, the motion behavior of ultrasonically driven liquid crystal droplets in real samples (cell culture medium, juice) was studied without pretreatment. The results show that ( Figure 8 A), the liquid crystal droplets still showed motion in the above sample, indicating that this method has great potential for further application in improving the efficiency of detecting targets in actual samples. In addition, the liquid crystal sensor located in the microfluidic chip can usually only contact the detection object through free diffusion, and cannot speed up the detection speed through mechanical stirring or oscillation. The ultrasonic wave generated by the piezoelectric transducer can drive the liquid crystal droplets to move in the chamber of the microfluidic chip ( Figure 8 B).

[0059] Example 2

[0060] The samples to be tested used in this example are rhamnolipids and other biological sample molecules (bacterial endotoxin lipopolysaccharide, quorum sensing signal molecule Boc-L-homoserine lactone and acylase), as follows:

[0061] a. Use ultrapure water as solvent to prepare appropriate concentration;

[0062] b. Use rat plasma as solvent to prepare appropriate concentrations;

[0063] c. Use bacterial culture solution as solvent to prepare appropriate concentration;

[0064] d. Other biomolecule samples: Use ultrapure water as solvent to prepare appropriate concentrations.

[0065] In this embodiment, a stable bipolar oriented liquid crystal droplet (SDS concentration: 10 μM) is prepared. When the liquid crystal droplet contacts rhamnolipid, the rhamnolipid is adsorbed on the surface of the liquid crystal droplet and changes its bipolar orientation to radial orientation ( Fig. 9 A). When ultrasound is turned off, the rhamnolipid solution (1 μL) added from the sample well at the top of the sample tank contacts the liquid crystal through free diffusion, so the liquid crystal orientation changes slowly, and only a few liquid crystals undergo slight changes. At this time, ultrasound is turned on (550 kHz, 20 V intensity), and the microflow in the liquid accelerates the movement of both the liquid crystal droplets and the rhamnolipid molecules, which greatly shortens the time it takes for the liquid crystal droplets to contact the rhamnolipid and produce orientation changes. Ultrasound is kept on, and eventually all liquid crystal droplets change from bipolar orientation to radial orientation ( Fig. 9 B). After repeated experiments, it can be concluded that ultrasound can increase the sensing speed of liquid crystal droplets detecting rhamnolipid. Under the same other conditions, increasing the concentration of rhamnolipid in the sample, the proportion of liquid crystal droplets that change orientation within a certain period of time increases within a certain range ( Fig. 9C). The bipolar oriented liquid crystal droplets produced by the present invention have no response to other bacterial biomolecules, such as bacterial endotoxin lipopolysaccharide (LPS), quorum sensing signal molecule Boc-L-homoserine lactone (Boc-L-AHL) and acylase ( Fig. 9 D). At the same time, the present invention uses actual samples with a certain concentration of rhamnolipid added to perform detection. Specifically, the response of the liquid crystal droplets to rhamnolipid samples with rat plasma as solvent, rhamnolipid samples with ultrapure water as solvent, rat plasma, rhamnolipid samples with bacterial culture solution as solvent, rhamnolipid samples with ultrapure water as solvent, and bacterial culture solution is detected. In all the above samples with rhamnolipid added, the concentration of rhamnolipid is the same; the volume of the sample added to the sample tank is the same. The results show that rat plasma and bacterial culture solution did not affect the response of the liquid crystal droplets to rhamnolipid ( Fig. 9 E). Therefore, the ultrasound-driven liquid crystal droplet microsensor proposed in the present invention has great potential to improve the efficiency of rhamnolipid detection in actual samples.

Claims

1. A method for improving the sensing efficiency of liquid crystal droplets, characterized in that: After adding the biological sample to be tested into the sensor based on liquid crystal droplets, ultrasonic waves with an ultrasonic frequency of 500 to 550 kHz are applied to the liquid crystal droplets.

2. The method according to claim 1, characterized in that: Ultrasonic waves with an ultrasonic frequency of 540 to 550 kHz are applied.

3. The method according to claim 1, characterized in that: The original orientation of the liquid crystal droplets is a bipolar orientation or a radial orientation.

4. A liquid crystal droplet sensing device based on ultrasonic drive, characterized in that: It includes a sample tank, an ultrasonic generating module and a polarized light detection module; the sample tank is loaded with liquid crystal droplets; the ultrasonic generating module is fixed under the sample tank to drive the liquid crystal droplets; the polarized light detection module is used to observe the optical signals of the liquid crystal droplets.

5. The device according to claim 4, characterized in that: The ultrasonic generating module is a piezoelectric ceramic ultrasonic transducer.

6. The device according to claim 4, characterized in that: The original orientation of the liquid crystal droplets is radial orientation or bipolar orientation.

7. Use of the method according to any one of claims 1 to 3 or the liquid crystal droplet sensing device according to claims 4 to 6 in improving the efficiency of detecting rhamnolipids in proteins or samples.

8. The use according to claim 7, characterized in that: The protein is bovine serum albumin.

9. A method for improving the efficiency of detecting rhamnolipids in proteins or samples based on the liquid crystal droplet sensor device according to claims 4 to 6, characterized in that: The method includes adding a sample to be tested into a sample tank, starting an ultrasonic generating module to apply 500-550kHz ultrasonic waves, and then using a polarized light detection module for observation.

10. The method according to claim 9, characterized in that: The sample is plasma or bacterial culture fluid.

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