A flexible array microchannel liquid crystal sensor, preparation method thereof, liquid crystal filling method and application thereof

Abstract

The present invention relates to a flexible array microchannel liquid crystal sensor, and a preparation method, a liquid crystal filling method and application thereof. The sensor comprises an upper cover plate and a lower substrate based on polydimethylsiloxane (PDMS) flexible material, the upper cover plate surface has a concave microchannel structure, the lower substrate surface has a microstructure grid, the non-channel part of the upper cover plate is sealed with the non-microstructure grid part of the lower substrate, the microchannel and the microstructure grid are arranged relative to form a closed channel, the closed channel is provided with a fluid inlet and outlet and is connected to the outside; the liquid crystal forms a liquid crystal film of a specific thickness in the microstructure grid, and an amphiphilic molecule aqueous solution covers the liquid crystal film. The liquid crystal sensor does not need to pre-treat the substrate, the operation is simple and fast, the liquid crystal can be filled in situ to form a liquid crystal film, the thickness of the liquid crystal film can be controlled independently, a uniform liquid crystal pattern texture can be generated, the detection sensitivity is improved, and it can be reused.

Description

Technical Field

[0001] The present invention belongs to the technical field of sensors, and relates to a flexible array microchannel liquid crystal biosensor composed of microstructure grids, a liquid crystal filling method based on the sensor, a preparation method of the sensor and applications thereof. Background Art

[0002] Liquid crystal molecules have been gradually applied to the field of sensors since the early 20th century due to their unique optical properties. Liquid crystal sensors have the advantages of high sensitivity, high selectivity, no labeling, fast and convenient device construction, and especially no reaction with biological molecules, and are widely used in biological protein-related detection.

[0003] The sensing principle of liquid crystal is based on the long-range orientation order and birefringence of liquid crystal to light. Liquid crystal film with fixed structure and consistent initial molecular arrangement is used to change the arrangement orientation of interface molecules on the liquid crystal film under the stimulation of external environment, and then the optical morphology characteristics of liquid crystal are observed through a polarizing microscope with vertically crossed linear polarizers to feedback the detection signal of the object being measured.

[0004] At present, nematic liquid crystal (5CB) is often used as a sensitive element of liquid crystal biosensors. When detecting biological molecules, sensors often use liquid-liquid crystal interface systems, which have the advantages of simple pre-treatment and suitability for studying the dynamic processes of biological molecules. This type of sensor is usually divided into three parts: a functionalized glass slide modified substrate, a liquid crystal film of a specific thickness, and a liquid solution that responds to the liquid crystal molecules on the upper interface. Among them, the functionalized substrate modification often uses a silanization agent with a long alkyl chain, the purpose of which is to induce the molecules at the bottom of the liquid crystal film to be arranged vertically. The liquid crystal film is generally fixed using a commercial electron microscope (TEM) grid to confine the liquid crystal in the TEM grid array. When the sensor is used, the aqueous solution of the test object is passed over the liquid crystal array for detection.

[0005] However, there are several problems with liquid-liquid crystal interface liquid crystal sensors: the optimal concentration of the modified substrate needs to be explored before preparing the liquid crystal biosensor; the modified substrate requires a long pretreatment and the substrate cannot be reused; it is generally an open system and cannot detect toxic gases or harmful molecules, which can easily cause environmental pollution and harm to the human body; a large number of studies have shown that there is an optimal range of liquid crystal biosensor film thickness, and the thickness control of the liquid crystal film is the key to sensing sensitivity. The structure of the confined liquid crystal film is generally a commercial TEM grid with a fixed structure. The thickness of the liquid crystal film cannot be controlled independently, and the grid size is large (side length is 275μm). The resulting liquid crystal texture is chaotic and cannot form a stable and uniform liquid crystal pattern texture. Therefore, it can only be detected by observing the "bright" or "dark" signal of the liquid crystal optical morphology under a microscope, which to a certain extent affects the subsequent calculation of the liquid crystal texture grayscale value (the processing method of corresponding the liquid crystal optical image to the concentration of the detected object), which may cause the sensor "false positive" problem. Summary of the invention

[0006] Based on the above problems, the present invention provides a flexible array microchannel liquid crystal sensor, and a preparation method, liquid crystal filling method and application thereof. The liquid crystal sensor does not require pretreatment of the substrate, is simple and quick to operate, can autonomously fill liquid crystal in situ to form a liquid crystal film, the thickness of the liquid crystal film can be autonomously controlled, can produce a uniform liquid crystal pattern texture, improve detection sensitivity, and can be reused.

[0007] The present invention provides the following technical solutions:

[0008] The first aspect of the present invention provides a flexible array microchannel liquid crystal sensor, comprising an upper cover plate and a lower substrate based on PDMS (polydimethylsiloxane) flexible material, wherein the upper cover plate has a recessed microchannel structure on its surface, and the lower substrate has a microstructure grid on its surface, wherein a non-channel portion of the upper cover plate is sealed to a non-microstructure grid portion of the lower substrate, wherein the microchannel and the microstructure grid are arranged relative to each other to form a closed channel, wherein a fluid inlet and an outlet are arranged in the closed channel and the closed channel is connected to the outside; wherein the liquid crystal forms a liquid crystal film of a specific thickness in the microstructure grid, and an aqueous solution of amphiphilic molecules covers the liquid crystal film.

[0009] Among them, the purpose of setting the microchannel structure in the upper cover plate is to make the liquid crystal, target water phase, and molecules to be tested flow within a set range in the closed channel; the purpose of setting the microstructure grid in the lower substrate is to make the liquid crystal form a liquid crystal film of a specific thickness in a confined area in the closed channel.

[0010] In a specific embodiment, the liquid crystal is selected from 5CB or E7;

[0011] The amphiphilic molecule alkyl chain has more than 8 carbon atoms; including sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, dodecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide;

[0012] Preferably, the concentration of the amphiphilic molecule aqueous solution is 10 to 500 μM; preferably, the concentration is 10 to 100 μM.

[0013] In a specific embodiment, the microchannel has a height of 25 to 75 μm, preferably a height of 50 μm; a length of 2 to 3.5 cm; a width of 2 to 4 mm, preferably a width of 3 mm;

[0014] The microstructure grid depth is 10 to 45 μm, preferably 25 μm;

[0015] Further, the array unit geometry of the microstructure grid includes triangle, quadrilateral, and hexagon;

[0016] Preferably, the side length of the array unit geometric structure is 40 to 250 μm, preferably 60 to 100 μm;

[0017] The spacing between adjacent array units is 10 to 30 μm, preferably 20 μm;

[0018] The distance between the array and the border is 0.1-0.3 mm, preferably 0.2 mm.

[0019] Preferably, the number of the fluid inlet and the fluid outlet is at least one; the fluid inlet and the outlet are respectively arranged on the same side or on different sides of the sensor; preferably, the fluid inlet and the outlet are respectively arranged on opposite sides of the sensor;

[0020] Preferably, the fluid inlet comprises a liquid crystal inlet and a target water phase inlet, and the outlet is a mixed fluid outlet; the liquid crystal inlet and the target water phase inlet are located on the same side of the sensor, and the distance between the liquid crystal inlet and the target water phase inlet is greater than 5 mm; wherein the liquid crystal inlet is used to transport liquid crystals, and the target water phase inlet is used to transport amphiphilic molecule aqueous solution and target detection objects;

[0021] Or, the fluid inlet includes a liquid crystal inlet, an amphiphilic molecule aqueous solution inlet, and a target detection object inlet, which are used to transport liquid crystal, amphiphilic molecule aqueous solution and target detection object respectively;

[0022] Preferably, the diameters of the fluid inlet and outlet are 1.0-3.0 mm, preferably 1.5 mm.

[0023] In a specific embodiment, the non-channel portion of the upper cover plate and the non-microstructure portion of the lower substrate are sealed by chemical bonding.

[0024] A second aspect of the present invention provides a liquid crystal filling method based on the above-mentioned flexible array microchannel liquid crystal sensor, comprising the following steps:

[0025] (1) Liquid crystal is introduced into the liquid crystal sensor through a fluid inlet at a certain flow rate so that the microstructure grid is filled with liquid crystal;

[0026] (2) A specific amphiphilic molecule aqueous solution is introduced at a certain flow rate through the same or different fluid inlet as step (1) to remove excess liquid crystal above the microstructure grid in the channel.

[0027] After the microstructure grid in the channel is filled with liquid crystal, the birefringence of the liquid crystal cannot be accurately observed due to the liquid crystal being too thick. After an amphiphilic molecule aqueous solution is passed in to remove excess liquid crystal above the microstructure grid, the liquid crystal thickness can be made appropriate, thus solving the problem.

[0028] In a specific embodiment, the liquid crystal or amphiphilic molecule aqueous solution is introduced into the liquid crystal sensor by connecting the flexible array microchannel liquid crystal sensor to a fluid transport device, and using the fluid transport device to introduce the liquid crystal or amphiphilic molecule aqueous solution into the liquid crystal sensor through a fluid inlet;

[0029] Preferably, the fluid transport device is composed of a syringe injection pump and an injection needle, and the liquid crystal sensor is connected to the fluid transport device through a silicone hose; preferably, the inner diameter of the silicone hose is 0.5 mm and the outer diameter is 1.5 mm;

[0030] In a specific embodiment, the minimum flow rate of the liquid crystal is 80 μL·min -1 The minimum flow rate of the amphiphilic molecule aqueous solution is 150 μL min -1 The maximum flow rate of all fluids entering the channel is 500 μL min -1 , too high a flow rate will cause the upper and lower substrates to lose their bonding ability.

[0031] The third aspect of the present invention provides a method for preparing the above-mentioned flexible array microchannel liquid crystal sensor, comprising the following steps:

[0032] (1) Designing the microchannel of the upper cover plate and the microstructure grid pattern of the lower substrate of the microchannel liquid crystal sensor, preparing the pattern into a mask, and etching the mask onto a silicon wafer through photoresist using photolithography technology;

[0033] (2) pouring a PDMS precursor onto the silicon wafer prepared in step (1) for thermal curing, transferring the microstructure of the silicon wafer, and cutting the PDMS substrate formed after thermal curing to obtain an upper cover plate containing a microchannel structure and a lower substrate containing a microstructure grid;

[0034] (3) After shielding the microchannel portion of the upper cover plate and the microstructure grid portion of the lower substrate, plasma cleaning is performed on the non-channel portion and the non-microstructure grid portion. After the cleaning is completed, the microchannel portion of the upper cover plate and the microstructure grid portion of the lower substrate are arranged relative to each other, so that the non-channel portion of the upper cover plate and the non-microstructure portion of the lower substrate are chemically bonded to form an irreversible seal, so that the microchannel and the microstructure grid form a closed channel, and a microchannel sensor device is prepared;

[0035] (4) using a punch to set at least one fluid inlet and at least one fluid outlet on the microchannel sensing device obtained in step (3), wherein the fluid inlet and the fluid outlet are connected to the outside and the closed channel respectively;

[0036] (5) Liquid crystal is introduced into the liquid crystal sensor through a fluid inlet at a certain flow rate so that the microstructure grid is filled with liquid crystal; then, a specific amphiphilic molecule aqueous solution is introduced through the same or different fluid inlet as the previous step at a certain flow rate to remove excess liquid crystal above the microstructure grid in the channel, thereby preparing a flexible array microchannel liquid crystal sensor.

[0037] In a specific embodiment, in step (1), the mask plate can be of any size, but the size is matched with the mask device of the photolithography machine; the mask plate design selects the light-shielding part according to the type of photoresist;

[0038] The size of the silicon wafer can be any size, but the size needs to correspond to the photolithography machine and mask.

[0039] In a specific embodiment, the photoresist is selected from SU-8 3000 series, and the SU-8 3000 series includes SU-8 3005, 3010, 3025, 3035, and 3050 photoresists.

[0040] In a specific embodiment, the photolithography steps are sequentially coating, pre-baking, ultraviolet exposure, post-baking, developing, hardening, and vapor deposition.

[0041] Preferably, the silicon wafer is rinsed with deionized water before photolithography, blown dry with nitrogen, and then placed on a hot plate for drying. The drying temperature is preferably 100°C.

[0042] In a specific embodiment, the spin coating parameters in the glue coating step are: Step 1: speed 500 rpm, acceleration 500 rpm·s -1 , time 5s; Step 2: speed 1800~2500rpm, acceleration 1800~2500rpm·s -1 , time 60s;

[0043] In a specific embodiment, the temperatures of the pre-baking and post-baking are set as follows: the first step is heating from room temperature to 50°C and maintaining at 50°C for 10 minutes; the second step is heating from 50°C to 65°C and maintaining at 65°C for 10 minutes; the third step is heating from 65°C to 80-95°C and maintaining for 10 minutes; the fourth step is cooling from 80-95°C to room temperature.

[0044] In a specific embodiment, the UV exposure parameters are: exposure time 25-30s, UV intensity 126-132 μM·cm -2 Preferably, the exposure time is 25 s and the UV intensity is 126 μM·cm -2 .

[0045] In a specific embodiment, in the development step, the developer is propylene glycol methyl ether acetate (PGMEA), and the development time is 4 to 7.5 minutes, preferably 4 minutes.

[0046] In a specific embodiment, the temperature parameters of the hard mold are heating from room temperature to 120° C., maintaining the temperature of 120° C. for 30 minutes, and then cooling to room temperature.

[0047] In a specific embodiment, the photolithographically fabricated microstructure grid requires instrumentation to measure the actual thickness.

[0048] In a specific embodiment, in step (2), the PDMS precursor ratio is a monomer: curing agent mass ratio of 5 to 15:1, preferably 10:1;

[0049] Alternatively, the thermal curing temperature is 70-110° C., and the thermal curing time is 15-45 min; preferably, the thermal curing temperature is 90° C., and the curing time is 30 min.

[0050] In a specific embodiment, in step (3), the microchannel portion of the upper cover plate and the microstructure grid portion of the lower substrate are masked using 3M tape;

[0051] In a specific embodiment, in step (3), a plasma cleaning machine is used to clean the non-microchannel portion of the upper cover plate and the non-microstructure grid portion of the lower substrate, wherein the plasma cleaning machine uses air as gas and the use time is 5 to 10 minutes, preferably 6 minutes;

[0052] The purpose of cleaning is to remove impurities from the connecting part of the substrate and expose excess hydroxyl groups to facilitate chemical bonding between the upper cover and the lower substrate, thereby achieving sealing.

[0053] In a specific embodiment, in step (3), the bonding process requires removing the masking materials of the upper cover plate and the lower substrate; preferably, after the bonding is completed, it is necessary to wait for 30 minutes before proceeding to the subsequent steps.

[0054] In a specific embodiment, in step (4), the liquid crystal inlet and the target water phase inlet are respectively arranged on the same side or on different sides of the liquid crystal sensor, and preferably, the fluid inlet and outlet are respectively arranged on opposite sides of the sensor;

[0055] Preferably, the fluid inlet comprises a liquid crystal inlet and a target water phase inlet, and the outlet is a mixed fluid outlet; the liquid crystal inlet and the target water phase inlet are located on the same side of the sensor, and the distance between the liquid crystal inlet and the target water phase inlet is greater than 5 mm;

[0056] Or, the fluid inlet includes a liquid crystal inlet, an amphiphilic molecule aqueous solution inlet, and a target detection object inlet;

[0057] The distance between the liquid crystal inlet and the target water phase inlet is greater than 5 mm;

[0058] Preferably, the outer diameter of the punch is 1.0-3.0 mm, preferably 1.5 mm.

[0059] In a specific embodiment, in step (5), the liquid crystal or amphiphilic molecule aqueous solution is introduced into the liquid crystal sensor by connecting the flexible array microchannel liquid crystal sensor to a fluid transport device, and using the fluid transport device to introduce the liquid crystal or amphiphilic molecule aqueous solution into the liquid crystal sensor through a fluid inlet;

[0060] Preferably, the fluid transport device is composed of a syringe injection pump and an injection needle, and the liquid crystal sensor is connected to the fluid transport device through a silicone hose; preferably, the inner diameter of the silicone hose is 0.5 mm and the outer diameter is 1.5 mm;

[0061] In a specific embodiment, the minimum flow rate of the liquid crystal is 80 μL·min -1 The minimum flow rate of the amphiphilic molecule aqueous solution is 150 μL min -1 The maximum flow rate of all fluids entering the channel is 500 μL min -1 .

[0062] A fourth aspect of the present invention provides the use of the flexible array type microchannel liquid crystal sensor or the flexible array type microchannel liquid crystal sensor prepared by the above preparation method in the detection of toxic and hazardous substances.

[0063] In a specific embodiment, the toxic and harmful substances include toxic and harmful gases and biological toxins.

[0064] The toxic and harmful gases include, but are not limited to, carbon monoxide, sulfur dioxide, sulfur trioxide, dimethyl sulfate, chlorine, phosgene, diphosgene, hydrogen cyanide, mustard gas, Lewis gas, VX, sarin, BZ, tabun, soman, ammonia, hydrogen cyanide, nitrogen oxides, hydrogen fluoride, hydrogen sulfide, nitrogen, methane, ethane, ethylene, and nitrobenzene.

[0065] The biological toxins include bacterial toxins, true toxins, and animal toxins, specifically including but not limited to: ricin, abrin, volkensin, viscumin, modeccin, luffin, trichosanthin, pokeweed antiviral protein, saporin, dianthin, gelonin, snake venom, bee venom, scorpion venom, spider venom, centipede venom, ant venom, pufferfish venom, octopus venom, nereis venom, scallop toxin, saxitoxin, dolastatin, ergot toxin, aflatoxin, mushroom toxin, diphtheria toxin, cholera toxin, and botulinum toxin.

[0066] According to the application of flexible array microchannel liquid crystal sensor in the detection of toxic and hazardous substances, the detection method is:

[0067] The flexible array microchannel liquid crystal sensor is placed between two vertically crossed linear polarizers of a polarizing microscope, and the target detection molecules are introduced through the fluid inlet. The detection light beam is received by one side of the liquid crystal sensor, and the light beam passing through the sensor is detected from the other side. The optical signal of the liquid crystal sensor is received by the microscope CCD electronic element.

[0068] The detection principle of the flexible array microchannel liquid crystal sensor of the present invention for the target detection molecules is as follows: in the flexible array microchannel liquid crystal sensor, the PDMS substrate can drive the liquid crystal molecules of the substrate part in the microstructure grid to be arranged vertically, and the introduced amphiphilic molecules also guide the liquid crystal molecules on the interface of the liquid crystal film to be oriented vertically. In a polarizing microscope, the cross polarizer can only pass the light beam generated by the birefringence of the liquid crystal. The liquid crystal molecules cannot birefractive when they are oriented vertically, so the cross polarizer cannot transmit light. After the target detection molecules are introduced, the target detection molecules cause disturbances to the orientation of the liquid crystal layer, change the ability of the liquid crystal sensor to refract light, and thus affect the light path passing through the liquid crystal film. The cross polarizer can transmit light, resulting in a change in the optical texture pattern of the liquid crystal, thereby realizing the detection of the target molecules.

[0069] In a specific implementation, the exposure parameters, focal length and image parameters processed by the CCD of the microscope must be consistent, and the microscope adopts the transmission mode.

[0070] Beneficial Effects

[0071] The flexible array microchannel liquid crystal sensor provided by the present invention does not need to modify the sensitive element, i.e. the microstructure grid substrate forming the liquid crystal film, during the construction process. The substrate based on the PDMS material, i.e., the substrate can drive the liquid crystal molecules of the substrate to be arranged vertically. No professional personnel are required to operate the sensor during the preparation process, which reduces the time and cost of sensor production and makes the operation faster and more convenient. The microstructure filled with the liquid crystal film can adjust the size according to the photolithography operation, so that a liquid crystal film with controllable thickness can be formed in situ to improve the sensitivity of the sensor.

[0072] The flexible array microchannel liquid crystal sensor provided by the present invention can be precisely designed and controlled through photolithography technology to have a microstructure grid size smaller than that of a commercial TEM copper mesh. The smaller size (side length of 60 to 100 μm) has a stronger boundary effect, driving the liquid crystal in the microstructure to form a uniform and stable windmill-shaped texture. During the detection process, the area of ​​the pattern texture in the microstructure can correspond to the different concentrations of the detected object, reducing the error in calculating the liquid crystal gray value (the processing method of corresponding the liquid crystal optical image to the concentration of the detected object), further improving the sensitivity of the liquid crystal sensor, and eliminating the "false positive" situation of the sensor.

[0073] The flexible array microchannel liquid crystal sensor provided by the present invention first fills the liquid crystal material so that the microchannel is full of liquid crystal, then introduces the amphiphilic molecules that specifically bind to the target molecules to remove the excess liquid crystal above the microstructure, forms a liquid crystal film of a certain thickness, and anchors the liquid crystal molecules on the interface of the liquid crystal film to be arranged vertically, and finally introduces the target water phase to observe the change of the optical texture of the liquid crystal molecules, so as to achieve the purpose of detecting the target molecules. The liquid crystal sensor does not require any pretreatment, and the microchannel can be reused, further reducing the cost of the liquid crystal sensor. In addition, the setting of the closed channel of the sensor makes it have broad application value in the detection of toxic gases or toxic biological molecules. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Figure 1 The mask design drawing of step (1) of Example 1;

[0075] Figure 2 The geometric structure diagram of the two-dimensional microstructure grid in step (1) of Example 1;

[0076] Figure 3 The top view and cross-sectional view of the microstructure grid square characterized by SEM in step (3) of Example 1;

[0077] Figure 4Schematic diagram of the liquid crystal sensing device under a polarizing microscope in step (3) of Example 1;

[0078] Figure 5 The left picture is a real picture of the device under a polarizing microscope in step (3) of Example 1, and the right picture is an enlarged picture of the liquid crystal sensor;

[0079] Figure 6 The flowchart (upper and middle figures) and the sensing principle diagram (lower figure) of the liquid crystal film filling method of Example 2 are shown;

[0080] Figure 7 Polarization diagram of the liquid crystal sensor detection experiment in Example 2; left: liquid crystal is introduced; middle: SDS is introduced; right: PVA is introduced;

[0081] Figure 8 Polarization diagram of the liquid crystal sensor detection experiment in Example 3; left: liquid crystal is introduced; middle: SDS is introduced; right: PVA is introduced;

[0082] Fig. 9 Polarization diagram of the liquid crystal sensor detection experiment in Example 4; left: liquid crystal is introduced; middle: SDS is introduced; right: PVA is introduced;

[0083] Fig.10 Polarization diagram of the liquid crystal sensor detection experiment in Example 5; left: liquid crystal is introduced; middle: CTAB is introduced; right: BSA is introduced;

[0084] Among them, 1-microscope CCD, 2-linear polarizer (analyzer), 3-microchannel liquid crystal sensor, 4-amphiphilic molecule solution, 5-liquid crystal solution, 6-linear polarizer (polarizer), 7-microscope light source, 8-target solution to be detected. DETAILED DESCRIPTION

[0085] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below through the accompanying drawings and embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0086] In this document, “liquid crystal sensor”, “sensing device” and “liquid crystal sensing device” are used interchangeably.

[0087] Unless otherwise specified, the equipment used in the present embodiment, comparative example and experimental example are all conventional experimental equipment, and the materials and reagents used are all commercially available.

[0088] Example 1 Preparation of Flexible Array Microchannel Liquid Crystal Sensor

[0089] The preparation process includes the following steps:

[0090] (1) Design a two-dimensional microstructure grid and microchannel pattern through a mask. The mask size is 5 inches * 5 inches * 2.3 mm. The pattern film faces downward, and the black color is opaque and the white color is translucent. The design diagram is as follows: Figure 1 The microstructure grid design dimensions are: unit side length 40-250μm, unit spacing 20μm, array and boundary distance 0.2mm, and the designed geometric structure is as follows Figure 2 shown.

[0091] (2) Photolithography of microstructure grids and microchannels, including the following steps:

[0092] The photolithography silicon wafer was rinsed with DI-water, blown dry with nitrogen, and dried on a hot plate at 100°C.

[0093] Photoresist spin coating: Spin the photoresist on the silicon wafer treated in the above steps. The photoresist used is SU-8 3000 series. The spin coating is carried out in steps. The spin coating parameters are as follows: speed 500 rpm, acceleration 500 rpm·s -1 , time 5s; Step 2: speed 2500rpm, acceleration 2500rpm·s -1 , time 60s. Spin coating thickness is about 25μm, and the lower substrate of the liquid crystal sensor with microstructure grid is prepared; speed 500rpm, acceleration 500rpm·s -1 , time 5s; Step 2: speed 1800rpm, acceleration 1800rpm·s -1 The spin coating thickness is about 50 μm, and the upper cover plate with microchannels is prepared.

[0094] Step-by-step pre-baking: The silicon wafers processed in the above steps are pre-baked in steps: the first step is to heat from room temperature to 50°C and keep at 50°C for 10 minutes; the second step is to heat from 50°C to 65°C and keep at 65°C for 10 minutes; the third step is to heat from 65°C to 95°C and keep at 95°C for 10 minutes; the fourth step is to cool from 95°C to room temperature.

[0095] UV exposure lithography: After natural cooling in the above steps, align the silicon wafer in the lithography machine for lithography. Lithography exposure parameters: exposure time 25s, UV intensity 126μM·cm -2 .

[0096] Post-baking in steps: The silicon wafers processed in the above steps are post-baked in steps: the first step is to heat from room temperature to 50℃ and keep at 50℃ for 10 minutes; the second step is to heat from 50℃ to 65℃ and keep at 65℃ for 10 minutes; the third step is to heat from 65℃ to 80℃ and keep at 80℃ for 10 minutes; the fourth step is to cool from 80℃ to room temperature.

[0097] Development: After the silicon wafer is naturally cooled down through the above steps, it is developed with the developer propylene glycol methyl ether acetate (PGMEA) for 4 minutes. After the development is completed, it is cleaned with isopropyl alcohol and dried with nitrogen.

[0098] Hardening: Heat the silicon wafer treated in the above steps from room temperature to 120°C, maintain the temperature at 120°C for 30 minutes, and then cool it to room temperature to further solidify the photolithography pattern.

[0099] The instrument measures the actual thickness of the microstructure grid produced by photolithography.

[0100] (3) Construction of liquid crystal sensor device: Pour PDMS monomer and curing agent (10:1, mass ratio) on the silicon wafer for thermal curing to transfer the microstructure of the silicon wafer. The thermal curing temperature is 90°C and the curing time is 30 minutes. After curing, the PDMS printed with microstructure is cut into the upper cover plate containing microchannels and the lower substrate containing microstructure grids. The PDMS microstructure is characterized by SEM. Figure 3 The top view and cut cross-section view of the square microstructure grid unit show that the lithography structure is complete and can be subsequently tested.

[0101] The microchannel part and the microstructure grid part of the two PDMS substrates are shielded with 3M tape, and the non-microchannel part and the non-microstructure grid part are cleaned with a plasma cleaner, wherein the plasma gas is air and the cleaning time is 6 minutes. After the cleaning is completed, the shielding materials of the upper and lower substrates are removed, and the microchannel part of the upper cover plate and the microstructure grid part of the lower substrate are arranged relative to each other, so that the non-channel of the upper cover plate and the non-microstructure part of the lower substrate are chemically bonded to form an irreversible seal, so that the microchannel and the microstructure grid form a closed channel.

[0102] The liquid crystal sensor device is provided with a liquid crystal inlet, a target water phase inlet and a mixed fluid outlet using a punch with an outer diameter of 1.5 mm, wherein the fluid inlet and outlet are both connected to the outside and the closed channel, and a liquid crystal sensor is prepared. The fluid inlet and outlet are arranged on opposite sides of the sensor, and the liquid crystal inlet and the target water phase inlet are arranged on the same side of the sensor, and the distance between the two is greater than 5 mm.

[0103] (4) Filling of liquid crystal film

[0104] A silicone hose with an inner diameter of 0.5 mm and an outer diameter of 1.5 mm is used to connect the fluid inlet of the liquid crystal sensor to a fluid delivery device consisting of a syringe injection pump and an injection needle. In the fluid delivery device, liquid crystal and amphiphilic molecule aqueous solution are pre-filled into different injection needles and then fixed in the injection pump (the liquid crystal sensor device is as follows Figure 5 As shown, Figure 5The left picture shows a liquid crystal sensor placed on a microscope stage, and the right picture shows an enlarged picture of the liquid crystal sensor).

[0105] The filling process is as follows Figure 6 As shown: First, the fluid delivery device is controlled to pass through the liquid crystal inlet at a rate of 80 to 500 μL / min -1 Liquid crystal is introduced into the sensing device at a flow rate to fill the microchannel with liquid crystal ( Figure 6 Then, the target aqueous phase was passed through the inlet at a rate of 150 to 500 μL min -1 The specific amphiphilic molecule aqueous solution is passed through the channel at a flow rate to remove the excess liquid crystal above the microstructure grid in the channel ( Figure 6 (middle picture) forms a liquid crystal film of a certain thickness while anchoring the liquid crystal molecules on the interface of the liquid crystal film to be arranged vertically. Figure 5 This is a schematic diagram of the filling of the liquid crystal film of the sensing device under a polarizing microscope, in which the liquid crystal sensor demonstrates the situation of introducing amphiphilic molecules to flush away excess liquid crystal.

[0106] Example 2 Liquid crystal sensing optical detection:

[0107] The unfilled liquid crystal sensor prepared according to steps (1)-(3) in Example 1 is placed on the stage of a polarizing microscope. The two linear polarizers of the microscope are vertically crossed. The detection beam is received by one side of the liquid crystal sensor. Detection is achieved based on the change of the beam passing through the liquid crystal sensor on the other side. The optical image of the liquid crystal sensor is received by a CCD electronic component.

[0108] The liquid crystal inlet and the target aqueous phase inlet of the liquid crystal sensor are connected to a fluid delivery device composed of a syringe pump and an injection needle using a silicone hose with an inner diameter of 0.5 mm and an outer diameter of 1.5 mm. In the fluid delivery device, the liquid crystal, the amphiphilic molecule aqueous solution, and the target solution to be detected are respectively filled into different injection needles and then fixed in the syringe pump. According to the method of step (4) of Example 1, the liquid crystal is first filled through the liquid crystal inlet, and the PDMS substrate drives the liquid crystal molecules of the substrate to be arranged vertically; then the amphiphilic molecule is introduced through the target aqueous phase inlet as a detection intermediate ( Figure 6 Middle figure), observe whether the liquid crystal film in the channel can exist stably. When the amphiphilic molecules successfully anchor the liquid crystal molecules perpendicular to the plane, the optical image observed by the polarized light microscope is dark. Then, the target detection object is introduced into the microstructure grid through the target water phase inlet ( Figure 6 As shown in the figure below, the target object interacts with the amphiphilic molecules, changing the vertical orientation of the liquid crystal molecules on the interface of the liquid crystal film, thereby causing the optical morphology of the liquid crystal to change. After stabilization, the liquid crystal optical pattern is observed through a microscope to detect the target object.

[0109] Example 3 Optimization of microstructure grid side length

[0110] A sensing device not filled with liquid crystal was prepared according to steps (1) to (3) in Example 1. The microchannel in the sensing device had a height of 50 μm and a length of 2.5 cm. The microstructure grid had a side length of 100 μm and a depth of 25 μm, and the geometric structure was a triangle.

[0111] The prepared sensing device without liquid crystal filling was placed on the stage of a polarizing microscope. According to the method of Example 2, 5CB liquid crystal, 50 μM sodium dodecyl sulfate (SDS) solution, and 3% polyvinyl alcohol (PVA) solution were introduced into the sensing device respectively, and the liquid crystal optical pattern was observed under a microscope.

[0112] Figure 7 is a liquid crystal optical pattern with a grid unit side length of 100 μm, wherein: Figure 7 On the left is the optical pattern after the liquid crystal is filled; Figure 7 The middle one is the pattern after filling with SDS solution. SDS anchors the liquid crystal molecules perpendicular to the plane, so it appears dark. Figure 7 The right side shows the pattern after filling with PVA, which is a windmill-like texture.

[0113] Subsequent Examples 4 and 5 also explored the cases where the side length of the grid unit was 80 μm and 60 μm, and found that a uniform liquid crystal optical pattern could be observed in the range of 60 to 100 μm, which can be preferably used for liquid crystal detection.

[0114] Example 4 Effect of Microstructure Grid Geometry

[0115] A sensing device not filled with liquid crystal was prepared according to steps (1) to (3) in Example 1. In the sensing device, the microchannel had a height of 50 μm and a length of 2.5 cm; the microstructure grid had a side length of 80 μm and a depth of 25 μm, and the geometric structure was a quadrilateral.

[0116] The sensor device without liquid crystal filling was placed on the stage of a polarizing microscope, and 5CB liquid crystal, 50 μM SDS, and 3% PVA solution were introduced into the sensor device according to the method of Example 2, and the liquid crystal optical pattern was observed through a microscope.

[0117] Figure 8 The observed liquid crystal optical pattern is the same as the triangular microstructure grid in Example 3. The liquid crystal optical pattern in this example also presents a windmill texture, which proves that different geometric structures have no obvious effect on sensing detection and can be applied to liquid crystal sensing detection.

[0118] Example 5: Detection of PVA using a flexible array microchannel liquid crystal sensor

[0119] A sensing device without liquid crystal filling was prepared according to steps (1) to (3) of the method in Example 1. In the sensing device, the microchannel had a height of 50 μm and a length of 2.5 cm; the microstructure grid had a side length of 60 μm and a depth of 25 μm, and the geometric structure was a triangle.

[0120] The sensor device without liquid crystal filling was placed on the stage of a polarizing microscope. According to the method of Example 2, 5CB liquid crystal, 50 μM SDS, and 3% PVA solution were introduced into the sensor device respectively. The flow rates of the liquid crystal introduction into the 5CB liquid crystal, 50 μM SDS aqueous solution, and the simulated target detection molecule PVA were 80 μL·min -1 、150μL·min -1 , 25μL·min -1 .

[0121] like Fig. 9 As shown in FIG. 1 , after the liquid crystal is introduced into the liquid crystal sensor, the microchannel is filled with liquid crystal, as shown in FIG. Fig. 9 As shown in the left figure, the birefringence of the liquid crystal cannot be accurately observed because the thickness of the liquid crystal is too thick. After the excess liquid crystal above the microstructure grid in the channel is removed by introducing 50μM SDS aqueous solution, the SDS aqueous solution guides the interface liquid crystal molecules on the liquid crystal film in the microstructure grid to be vertically oriented. Fig. 9 As shown in the middle figure, the observed optical image is mostly dark. The bright light at the microstructure boundary observed in the picture is affected by the boundary effect and does not affect the sensing result. After the simulated target detection molecule PVA is introduced, PVA changes the orientation of the liquid crystal molecules on the interface of the liquid crystal sensor. After stabilization for 5s, as shown in Fig. 9 In the right image, a uniform liquid crystal windmill texture is observed, which verifies that the liquid crystal sensor principle can be used to detect target molecules.

[0122] Example 6 Detection of BSA mimetic protein using flexible array microchannel liquid crystal sensor

[0123] Bovine serum albumin (BSA) was used as a simulated protein to test the detection of biological molecules by the liquid crystal sensor. The liquid crystal was 5CB liquid crystal, and the amphiphilic molecule was cetyltrimethylammonium bromide (CTAB). The principle of simulated protein detection is that the alkyl chain of CTAB will stay on the upper interface of the liquid crystal sensor to anchor the vertical interface of the liquid crystal molecules. When the BSA solution is introduced, BSA will electrostatically bind to the alkyl chain of CTAB, and the liquid crystal molecules on the upper interface will change from vertical arrangement to non-vertical arrangement, thereby causing the optical morphology of the liquid crystal to change, achieving the purpose of detection.

[0124] A sensing device not filled with liquid crystal was prepared according to steps (1) to (3) of the method in Example 1. In the sensing device, the microchannel had a height of 50 μm and a length of 2.5 cm; the microstructure grid had a side length of 60 μm and a depth of 25 μm, and the geometric structure was a quadrilateral.

[0125] The sensor device without liquid crystal was placed on the stage of a polarizing microscope, and 5CB liquid crystal, 10μΜ CTAB solution, and 10μg / mL BSA solution were introduced into the sensor device according to the method of Example 2, and the liquid crystal optical pattern was observed under a microscope. The flow rates of 5CB liquid crystal, 10μΜ CTAB solution, and 10μg / mL BSA solution were 80μL·min -1 、150μL·min -1 , 25μL·min -1 10 μΜ CTAB solution and 10 μg / mL BSA solution were prepared using 1 mM PBS (pH=7.4) solution, and the solution was stored in a 4°C refrigerator.

[0126] like Fig.10 As shown, the experimental results are consistent with those of Examples 3-5. Fig.10 On the left is the optical pattern after the liquid crystal is filled; Fig.10 The middle picture shows the dark image after filling with CTAB solution, where CTAB anchors the liquid crystal molecules perpendicular to the plane; Fig.10 The right picture shows that the liquid crystal forms a windmill-shaped texture after the electrostatic binding of BSA and CTAB. The above results prove that this liquid crystal sensor can also be used for the detection of biological molecules, providing a new detection method for biological molecules with certain biological toxicity.

[0127] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A flexible array microchannel liquid crystal sensor, characterized in that: The invention comprises an upper cover plate and a lower substrate based on polydimethylsiloxane (PDMS) flexible material, wherein the upper cover plate has a concave microchannel structure on its surface, and the lower substrate has a microstructure grid on its surface, wherein the non-channel portion of the upper cover plate is sealed with the non-microstructure grid portion of the lower substrate, and the microchannel and the microstructure grid are arranged relative to each other to form a closed channel, wherein the closed channel is provided with a fluid inlet and an outlet and is connected to the outside; liquid crystal forms a liquid crystal film of a specific thickness in the microstructure grid, and an amphiphilic molecule aqueous solution covers the liquid crystal film; The liquid crystal is selected from 5CB or E7; The amphiphilic molecule alkyl chain has more than 8 carbon atoms; including sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, dodecyltrimethylammonium bromide or hexadecyltrimethylammonium bromide; The concentration of the amphiphilic molecule aqueous solution is 10-500 μΜ; The microstructure grid depth is 10-45 μm; The array unit geometric structure of the microstructure grid includes a triangle, a quadrilateral or a hexagon; the side length of the array unit geometric structure is 60-100 μm.

2. The flexible array microchannel liquid crystal sensor according to claim 1, characterized in that: The concentration of the amphiphilic molecule aqueous solution is 10-100 μM.

3. The flexible array microchannel liquid crystal sensor according to claim 1, characterized in that: The microchannel has a height of 25-75 μm, a length of 2-3.5 cm, and a width of 2-4 mm; The microstructure grid depth is 25 μm; The spacing between adjacent array elements is 10-30 μm; The distance between the array and the boundary is 0.1~0.3 mm.

4. The flexible array microchannel liquid crystal sensor according to claim 3, characterized in that: The microchannel height is 50 μm.

5. The flexible array microchannel liquid crystal sensor according to claim 3, characterized in that: The width of the microchannel is 3 mm.

6. The flexible array microchannel liquid crystal sensor according to claim 3, characterized in that: The spacing between adjacent array elements is 20 μm.

7. The flexible array microchannel liquid crystal sensor according to claim 3, characterized in that: The distance between the array and the border is 0.2 mm.

8. The flexible array microchannel liquid crystal sensor according to claim 1, characterized in that: The number of the fluid inlet and the number of the fluid outlet are at least one; the fluid inlet and the outlet are respectively arranged on the same side or different sides of the sensor.

9. The flexible array microchannel liquid crystal sensor according to claim 8, characterized in that: The fluid inlet and the fluid outlet are respectively arranged on opposite sides of the sensor.

10. The flexible array microchannel liquid crystal sensor according to claim 1, characterized in that: The fluid inlet includes a liquid crystal inlet and a target water phase inlet, and the outlet is a mixed fluid outlet; the liquid crystal inlet and the target water phase inlet are located on the same side of the sensor, and the distance between the liquid crystal inlet and the target water phase inlet is greater than 5 mm; Alternatively, the fluid inlet includes a liquid crystal inlet, an amphiphilic molecule aqueous solution inlet, and a target detection object inlet.

11. The flexible array microchannel liquid crystal sensor according to claim 10, characterized in that: The diameters of the fluid inlet and outlet are 1.0-3.0 mm.

12. The flexible array microchannel liquid crystal sensor according to claim 11, characterized in that: The diameter of the fluid inlet and outlet is 1.5 mm.

13. The flexible array microchannel liquid crystal sensor according to claim 1, characterized in that: The non-channel portion of the upper cover plate and the non-microstructure portion of the lower substrate are sealed by chemical bonding.

14. A liquid crystal filling method for a flexible array microchannel liquid crystal sensor according to any one of claims 1 to 13, characterized in that: The method comprises the following steps: (1) Liquid crystal is introduced into the liquid crystal sensor through the fluid inlet at a certain flow rate so that the microstructure grid is filled with liquid crystal; (2) A specific amphiphilic molecule aqueous solution is introduced at a certain flow rate through the same or different fluid inlet as step (1) to remove excess liquid crystal above the microstructure grid in the channel.

15. The liquid crystal filling method according to claim 14, characterized in that: The method of introducing liquid crystal or amphiphilic molecule aqueous solution into the liquid crystal sensor is: connecting the flexible array microchannel liquid crystal sensor to a fluid transport device, and using the fluid transport device to introduce liquid crystal or amphiphilic molecule aqueous solution into the liquid crystal sensor through a fluid inlet.

16. The liquid crystal filling method according to claim 15, characterized in that: The fluid transport device is composed of a syringe injection pump and an injection needle, and the liquid crystal sensor is connected to the fluid transport device through a silicone hose.

17. The liquid crystal filling method according to claim 16, characterized in that: The inner diameter of the silicone hose is 0.5 mm and the outer diameter is 1.5 mm.

18. The liquid crystal filling method according to claim 15, characterized in that: The minimum flow rate into the liquid crystal is 80 μL·min -1 The minimum flow rate of the amphiphilic molecule aqueous solution is 150 μL·min -1 The maximum flow rate of all fluids entering the channel is 500 μL·min -1 .

19. The method for preparing the flexible array microchannel liquid crystal sensor according to any one of claims 1 to 13, characterized in that: The preparation method comprises the following steps: (1) Design the microchannel of the upper cover plate and the microstructure grid pattern of the lower substrate of the microchannel liquid crystal sensor, prepare the pattern into a mask, and use photolithography technology to etch the mask through photoresist onto the silicon wafer; (2) pouring the PDMS precursor onto the silicon wafer prepared in step (1) for thermal curing, transferring the microstructure of the silicon wafer, and cutting the PDMS substrate formed after thermal curing to obtain an upper cover plate containing a microchannel structure and a lower substrate containing a microstructure grid; (3) After masking the microchannel portion of the upper cover plate and the microstructure grid portion of the lower substrate, plasma cleaning is performed on the non-channel portion and the non-microstructure grid portion. After the cleaning is completed, the microchannel portion of the upper cover plate and the microstructure grid portion of the lower substrate are arranged relative to each other, so that the non-channel portion of the upper cover plate and the non-microstructure portion of the lower substrate are chemically bonded to form an irreversible seal, so that the microchannel and the microstructure grid form a closed channel, thereby preparing a microchannel sensor device; (4) using a punch to set at least one fluid inlet and at least one fluid outlet on the microchannel sensing device obtained in step (3), wherein the fluid inlet and the fluid outlet are connected to the outside and the closed channel respectively; (5) Liquid crystal is introduced into the liquid crystal sensor through a fluid inlet at a certain flow rate so that the microstructure grid is filled with liquid crystal; then, a specific amphiphilic molecule aqueous solution is introduced through the same or different fluid inlet as in the previous step at a certain flow rate to remove excess liquid crystal above the microstructure grid in the channel, thereby preparing a flexible array microchannel liquid crystal sensor.

20. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 19, characterized in that: In step (1), the photoresist is selected from the SU-8 3000 series, and the SU-8 3000 series includes SU-8 3005, 3010, 3025, 3035 or 3050 photoresist; The photolithography steps are sequentially coating, pre-baking, ultraviolet exposure, post-baking, developing, hardening, and vapor deposition.

21. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 19, characterized in that: Before photolithography, the silicon wafer was rinsed with deionized water, dried with nitrogen, and then placed on a hot plate for drying at a temperature of 100°C.

22. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 20, characterized in that: The spin coating parameters in the glue coating step are: Step 1: speed 500 rpm, acceleration 500 rpm·s -1 , time 5 s; Step 2: speed 1800~2500 rpm, acceleration 1800~2500 rpm·s -1 , time 60 s.

23. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 20, characterized in that: The temperature settings of the pre-baking and post-baking are: first step, heating from room temperature to 50°C, and keeping at 50°C for 10 min; second step, heating from 50°C to 65°C, and keeping at 65°C for 10 min; third step, heating from 65°C to 80-95°C, and keeping for 10 min; fourth step, cooling from 80-95°C to room temperature.

24. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 20, characterized in that: The UV exposure parameters are: exposure time 25-30 s, UV intensity 126-132 μM·cm -2 .

25. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 24, characterized in that: The exposure time was 25 s and the UV intensity was 126 μM·cm -2 .

26. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 20, characterized in that: In the developing step, the developer is propylene glycol methyl ether acetate, and the developing time is 4 to 7.5 minutes.

27. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 26, characterized in that: The development time was 4 min.

28. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 20, characterized in that: The temperature parameters of the hard mold are heating from room temperature to 120° C., maintaining the temperature at 120° C. for 30 min, and then cooling to room temperature.

29. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 19, characterized in that: In step (2), the PDMS precursor ratio is a monomer: curing agent mass ratio of 5 to 15:1; Alternatively, in step (2), the thermal curing temperature is 70-110° C., and the thermal curing time is 15-45 min.

30. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 29, characterized in that: The PDMS precursor ratio is a monomer: curing agent mass ratio of 10:

1.

31. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 29, characterized in that: The thermal curing temperature is 90°C and the curing time is 30 min.

32. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 19, characterized in that: In step (3), 3M tape is used to mask the microchannel portion of the upper cover plate and the microstructure grid portion of the lower substrate.

33. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 19, characterized in that: In step (3), a plasma cleaning machine is used to clean the non-microchannel portion of the upper cover plate and the non-microstructure grid portion of the lower substrate, wherein the plasma cleaning machine uses air as gas and the use time is 5 to 10 minutes.

34. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 33, characterized in that: The plasma cleaning machine was used for 6 min.

35. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 19, characterized in that: In step (3), the bonding process requires removing the masking materials of the upper cover plate and the lower substrate.

36. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 19, characterized in that: After bonding is completed, wait 30 minutes before proceeding to the next step.

37. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 19, characterized in that: In step (4), the liquid crystal inlet and the target water phase inlet are respectively arranged on the same side or different sides of the liquid crystal sensor.

38. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 37, characterized in that: In step (4), the fluid inlet and outlet are respectively arranged on opposite sides of the sensor.

39. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 19, characterized in that: In step (4), the fluid inlet includes a liquid crystal inlet and a target water phase inlet, and the outlet is a mixed fluid outlet; the liquid crystal inlet and the target water phase inlet are located on the same side of the sensor, and the distance between the liquid crystal inlet and the target water phase inlet is greater than 5 mm; wherein the liquid crystal inlet is used to transport liquid crystals, and the target water phase inlet is used to transport amphiphilic molecule aqueous solution and target detection object; Or, the fluid inlet includes a liquid crystal inlet, an amphiphilic molecule aqueous solution inlet, and a target detection object inlet; The distance between the liquid crystal inlet and the target water phase inlet is greater than 5 mm.

40. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 19, characterized in that: In step (4), the outer diameter of the punch is 1.0-3.0 mm.

41. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 40, characterized in that: The outer diameter of the punch is 1.5 mm.

42. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 19, characterized in that: In step (5), the liquid crystal or amphiphilic molecule aqueous solution is introduced into the liquid crystal sensor by connecting the flexible array microchannel liquid crystal sensor to a fluid transport device, and using the fluid transport device to introduce the liquid crystal or amphiphilic molecule aqueous solution into the liquid crystal sensor through a fluid inlet.

43. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 42, characterized in that: The fluid transport device is composed of a syringe injection pump and an injection needle, and the liquid crystal sensor is connected to the fluid transport device through a silicone hose.

44. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 43, characterized in that: The inner diameter of the silicone hose is 0.5 mm and the outer diameter is 1.5 mm.

45. The method for preparing the flexible array microchannel liquid crystal sensor according to claim 42, characterized in that: The minimum flow rate into the liquid crystal is 80 μL·min -1 The minimum flow rate of the amphiphilic molecule aqueous solution is 150 μL·min -1 The maximum flow rate of all fluids entering the channel is 500 μL·min -1 .

46. ​​Use of the flexible array type microchannel liquid crystal sensor according to any one of claims 1 to 13 or the flexible array type microchannel liquid crystal sensor prepared by the preparation method according to any one of claims 19 to 45 in the detection of toxic and hazardous substances.

47. The use according to claim 46, characterized in that The toxic and harmful substances include toxic and harmful gases and biological toxins.

48. The use according to claim 46, characterized in that The method for detecting toxic and harmful substances is: A flexible array microchannel liquid crystal sensor is placed between two vertically crossed linear polarizers of a polarizing microscope. The target detection molecules are introduced through the fluid inlet. The detection beam is received by one side of the liquid crystal sensor, and the beam passing through the sensor is detected from the other side. The optical signal of the liquid crystal sensor is received by the microscope CCD electronic element.

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