Microfluidic automated sample injection field effect transistor biosensor and method of sample injection

Abstract

The application relates to a micro-fluid automatic sampling field effect transistor biosensor and a sampling method, which are composed of elastic materials and include a substrate, a semiconductor material layer, a first elastic material layer and a second elastic material layer; the semiconductor material layer is located on the substrate, the first elastic material layer is located on the semiconductor material layer, and the second elastic material layer is located on the first elastic material layer; a central flow channel groove and two electrode channel grooves which are symmetrically arranged with the central flow channel groove are arranged on a first surface of the first elastic material layer; the first surface is a surface where the first elastic material layer is connected with the semiconductor material layer; a plurality of independent liquid inlet flow channels which are connected with the central flow channel groove are arranged in the first elastic material layer; a plurality of independent gas channels which correspond to the plurality of liquid inlet flow channels are arranged in the second elastic material layer; one end of each gas channel is provided with a longitudinally deformable stop valve; and each stop valve is located above the corresponding liquid inlet flow channel.

Description

Technical Field

[0001] This specification relates to the fields of semiconductor technology and microfluidics technology, and in particular to a field-effect transistor biosensor and sample introduction method for automated microfluidic sample introduction. Background Technology

[0002] Graphene field-effect transistor (GFET) biosensors have attracted widespread attention due to their low power consumption, high precision, low cost, label-free characteristics, and ease of surface functionalization. This novel nucleic acid biosensor, based on two-dimensional monolayer graphene, is highly sensitive to the charge near the graphene channels. The charge strongly influences the position of the Dirac peak, which provides a measure of the amount of charge carried by the analyte. Since most biomolecules, such as antibodies, DNA, peptides, proteins, and lipids, are inherently charged, their detection using field-effect sensors is essentially label-free. Compared to other field-effect transistor (FET) sensors (such as silicon nanowires), GFETs offer similar charge sensitivity but with a larger functionalized surface area, higher chemical stability, and greater manufacturing tolerance. Therefore, graphene-based FETs (GFETs) are demonstrating unique advantages in the rapid detection of biomarkers.

[0003] Microfluidic chip analysis systems are low-power, easily integrated, rapid, and high-throughput miniature analytical experimental devices. Utilizing micro- and nanofabrication technologies, they maximize the integration of sample introduction, detection, and other analytical functions onto biosensors. Microfluidic technology is low-cost and low-pollution, making it an essential tool for achieving high-throughput, highly sensitive biological detection. The organic combination of microfluidic technology and GFET biosensing technology realizes potential advantages such as device portability, high-throughput analysis, and intelligent real-time detection. Therefore, the novel sensing technology combining graphene field-effect transistor biosensors with microfluidic systems can further amplify the advantages of both, thus attracting widespread attention.

[0004] In existing technologies, although biosensors based on different principles and applications have incorporated microfluidic technology to assist in sample introduction and detection processes, they still face many technical challenges. For example, the microfluidic sample introduction system in Chinese patent application CN11929460B is typically complex in structure and has high processing and manufacturing costs. Its large size does not meet the goals of miniaturization and easy integration of point-of-care biosensors, making it difficult to integrate with flexible and portable biosensors. Furthermore, there are similar application cases based on microfluidic systems and field-effect transistor biosensors, such as Chinese patent application CN202410114455.X, but these applications still have many shortcomings: 1. The open liquid tank for biochemical reactions is in direct contact with the external environment, requiring large sample volumes and easily leading to cross-contamination of biological samples and mutual interference of response signals; 2. Sample retention and evaporation problems caused by open reaction chambers or simple flow channel encapsulation systems can damage the structure of the substrate response material and affect the results of biosensing; 3. The simple microfluidic flow channel design and encapsulation still require manual intervention for sample delivery, which may interfere with the detection signal and result in a need to improve the automation level of the overall sensing system.

[0005] Therefore, the core problems of traditional GFET biosensors lie in the design flaws of open liquid baths (low reaction efficiency, easy contamination) and the shortcomings of microfluidic technology (manual dependence, structural fragility, poor sealing). These problems together limit the detection accuracy, stability, and practical application value of GFETs. Summary of the Invention

[0006] To address the problems in existing technologies, this paper presents a microfluidic automated sample introduction field-effect transistor (FET) biosensor and its introduction method. This method combines the features of a FET with those of a microfluidic chip, allowing biological solution samples to be directly introduced into the reaction channel via a suction needle under negative pressure using a sample pump. This eliminates the need for manual sample addition and improves the automation level of nucleic acid detection. Furthermore, a channel structure is designed to completely encapsulate graphene, isolating it from the external environment and effectively isolating the liquid gate and source / drain electrodes. Simultaneously, the flow and cutoff of the liquid sample are controlled through the synergistic action of the gas valve and the flow channel. This enables the automated introduction of biological samples into the sensor and the modification of graphene in a flowing state. It avoids disturbances to the detection signal caused by manual sample introduction and reduces the risk of cross-contamination.

[0007] On one hand, embodiments of this specification provide a microfluidic automated sample delivery field-effect transistor biosensor, comprising:

[0008] Substrate, semiconductor material layer, first elastic material layer and second elastic material layer;

[0009] The semiconductor material layer is located on the substrate, the first elastic material layer is located on the semiconductor material layer, and the second elastic material layer is located on the first elastic material layer;

[0010] The first surface of the first elastic material layer is provided with a central flow channel groove and two electrode channel grooves arranged symmetrically with the central flow channel groove as the axis. The first surface is the surface where the first elastic material layer and the semiconductor material layer are connected. The first elastic material layer is provided with multiple independent liquid inlet channels connected to the central flow channel groove.

[0011] The second elastic material layer has multiple independent gas channels corresponding to multiple liquid inlet channels. Each gas channel has a longitudinally deformable shut-off valve at one end, and each shut-off valve is located above the corresponding liquid inlet channel.

[0012] Furthermore, the other end of each inlet channel is connected to its respective biological sample storage tube.

[0013] Furthermore, each gas channel is connected to its respective gas pump at the other end.

[0014] Furthermore, the shut-off valve is a hollow structure opened inside the second elastic material layer, the hollow structure is connected to the corresponding gas channel, and the longitudinal deformation of the shut-off valve is the volume deformation of the hollow structure along the longitudinal direction.

[0015] Furthermore, a hollow gold needle is provided at the entrance of the central flow channel, which is the connection point between the central flow channel and the multiple liquid inlet channels.

[0016] Furthermore, the first elastic material layer is provided with a first through hole and a second through hole respectively connected to both ends of each electrode channel groove. The first through hole is used to insert an electrode wire, and the second through hole is used to inject liquid metal.

[0017] Furthermore, the first surface of the first elastic material layer is provided with multiple sets of two electrode channel grooves arranged symmetrically about the central flow channel groove.

[0018] Furthermore, the first elastic material layer is provided with a third through hole connected to the central flow channel groove, and the other end of the third through hole is connected to a vacuum pump.

[0019] Furthermore, the material of the first elastic material layer or the second elastic material layer is polydimethylsiloxane.

[0020] On the other hand, embodiments of this specification also provide a sample introduction method for a microfluidic automated sample introduction field-effect transistor biosensor, applied to the aforementioned microfluidic automated sample introduction field-effect transistor biosensor, the method comprising:

[0021] The longitudinal deformation of the corresponding shut-off valve is controlled by the gas channel, thereby controlling the opening or closing of the liquid inlet channel corresponding to the gas channel;

[0022] The controlled liquid inlet channel introduces the corresponding biological sample into the central flow channel, thereby enabling the detection of the biological sample within the central flow channel.

[0023] In this embodiment, multiple independent liquid inlet channels are formed within the first elastic material layer. One end of each channel is connected to its respective biological sample storage tube, thereby reducing the risk of cross-contamination. Furthermore, because the liquid inlet channels are located inside the first elastic material layer, they effectively isolate the biological sample from the external environment, preventing contamination. In addition, a central flow channel and an electrode channel are formed on the surface of the first elastic material layer connected to the semiconductor material layer. Both the central flow channel and the electrode channel are sealed spaces composed of the first elastic material layer and the semiconductor material layer. The biological sample flows into the central flow channel through the liquid inlet channels for detection, thus creating a closed space for the biological reaction, effectively isolating the external environment, improving the reaction rate, and reducing contamination. Furthermore, to achieve microfluidics, this embodiment of the specification provides a second elastic material layer above the first elastic material layer. The interior of the second elastic material layer contains multiple independent gas channels corresponding to multiple liquid inlet channels. Each gas channel has a longitudinally deformable shut-off valve at one end, and each shut-off valve is located above its corresponding liquid inlet channel. Therefore, when a liquid inlet channel needs to be opened, negative pressure is applied to the shut-off valve through the corresponding gas channel, causing the valve's longitudinal volume to shrink, thus opening the liquid inlet channel. Conversely, when a liquid inlet channel needs to be closed, positive pressure is applied to the shut-off valve through the corresponding gas channel, causing the valve's longitudinal volume to increase, thus squeezing the liquid inlet channel and closing it. Through the synergistic effect of the gas valve and the channels, the flow and shut-off of the liquid sample are controlled, achieving precise microfluidics and reducing reliance on manual intervention. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments or prior art described herein, the accompanying drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this article. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of a microfluidic automated sample delivery field-effect transistor biosensor in the embodiments of this specification;

[0026] Figure 2This is a schematic diagram of the structure of the first elastic material layer in the embodiments of this specification;

[0027] Figure 3 This is a schematic diagram of the structure of the central flow channel groove and the electrode channel groove in the embodiments of this specification;

[0028] Figure 4 This is a schematic diagram of the structure of the first elastic material layer including multiple sets of electrode channel grooves in the embodiments of this specification;

[0029] Figure 5 This is a schematic diagram of the structure of the first elastic material layer in the embodiments of this specification;

[0030] Figure 6 This is a schematic diagram of the structure of the second elastic material layer in the embodiments of this specification;

[0031] Figure 7 This is a schematic diagram of the first and second elastic material layers after installation in the embodiments of this specification;

[0032] Figure 8 This is a schematic flowchart of a microfluidic automated sample introduction method for a field-effect transistor biosensor, as described in the embodiments of this specification.

[0033] Figure 9a and Figure 9b This is a schematic diagram of the chip cover plate fixture structure in the embodiments of this specification;

[0034] Figure 10 This is a schematic diagram of the operation of the inlet flow channel and the shut-off valve in the embodiments of this specification;

[0035] Figure 11 These are specific detection results from the examples in this specification.

[0036] [Explanation of Markings in the Attached Images]

[0037] 1. Substrate;

[0038] 2. Semiconductor material layer;

[0039] 3. First elastic material layer;

[0040] 4. Second elastic material layer;

[0041] 31. Central flow channel;

[0042] 32. Electrode channel groove;

[0043] 33. Liquid inlet channel;

[0044] 34. First through hole;

[0045] 35. Second through hole;

[0046] 36. Third through hole;

[0047] 41. Gas passage;

[0048] 42. Stop valve. Detailed Implementation

[0049] The technical solutions in the embodiments described below will be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments described herein, and not all of the embodiments. Based on the embodiments described herein, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this document.

[0050] Figure 1 The diagram shown is a schematic diagram of the structure of a microfluidic automated sample delivery field-effect transistor biosensor according to an embodiment of this specification, including a substrate 1, a semiconductor material layer 2, a first elastic material layer 3, and a second elastic material layer 4;

[0051] like Figure 1 As shown, the semiconductor material layer 2 is located on the substrate 1, the first elastic material layer 3 is located on the semiconductor material layer 2, and the second elastic material layer 4 is located on the first elastic material layer 3.

[0052] Among them, a tight contact interface is formed between the substrate 1 and the semiconductor material layer 2, between the semiconductor material layer 2 and the first elastic material layer 3, and between the first elastic material layer 3 and the second elastic material layer 4. The interface is airtight and watertight.

[0053] Optionally, the substrate 1 is a two-inch Si / SiO2 wafer with a 300nm thick layer of silicon dioxide on the front side.

[0054] The semiconductor material layer 2 can be graphene film, black phosphorus, carbon nanotubes, molybdenum disulfide, organic thin film semiconductors, etc. Taking graphene film as an example, the size of the graphene film is 0.5cm×1.5cm, which is laid flat in the center of the silicon dioxide substrate.

[0055] The material of the first elastic material layer 3 or the second elastic material layer 4 is polydimethylsiloxane (PDMS).

[0056] like Figure 2 and Figure 3As shown, the first surface of the first elastic material layer 3 is provided with a central flow channel 31 and two electrode channel grooves 32 arranged symmetrically with the central flow channel 31 as the axis. The first surface is the surface where the first elastic material layer 3 is connected to the semiconductor material layer 2. The first elastic material layer 3 is provided with multiple independent liquid inlet channels 33 connected to the central flow channel 31. The other end of each liquid inlet channel 33 is connected to its respective biological sample storage tube (not shown in the figure), so that the biological sample in the biological sample storage tube is introduced into the central flow channel 31 for detection through the liquid inlet channel 33.

[0057] Furthermore, a hollow gold needle (not shown in the figure) is provided at the inlet of the central flow channel 31, which is the connection point between the central flow channel 31 and the multiple liquid inlet channels 33. The first elastic material layer 3 is provided with a first through hole 34 and a second through hole 35 respectively connected to both ends of each electrode channel 32. The first through hole 34 is used to insert an electrode wire, and the second through hole 35 is used to inject liquid metal. Optionally, the liquid metal can be a gallium-indium alloy. Without heating, the liquid metal can contact the graphene through the electrode channel and flow to another port to contact the external electrode wire, forming the source and drain of the field-effect transistor. The hollow gold needle inserted at the inlet of the central flow channel serves two purposes: firstly, as a conductive electrode of the gate, and secondly, as a liquid gate, the biological sample is directly injected into the reaction zone of the central flow channel via the gold needle.

[0058] It should be noted that the reaction process of biological samples is common knowledge in this field and will not be elaborated here.

[0059] Furthermore, in order to improve the success rate of testing, such as Figure 4 As shown, the first surface of the first elastic material layer 3 is provided with multiple sets of two electrode channel grooves 32 arranged symmetrically with the central flow channel groove 31 as the axis. It can be understood that the two electrode channel grooves 32 arranged symmetrically with the central flow channel groove 31 form a set of electrode channel grooves. In this embodiment, multiple sets of electrode channel grooves are provided on the first elastic material layer 3, and the area corresponding to each set of electrode channel grooves and the central flow channel groove 31 is a reaction zone. Therefore, multiple reaction zones are formed within the central flow channel groove 31 in this embodiment, thereby improving the detection success rate.

[0060] Furthermore, such as Figure 5 As shown, the first elastic material layer 3 is provided with a third through hole 36 connected to the central flow channel 31, and the other end of the third through hole 36 is connected to a vacuum pump (not shown in the figure). It can be understood that when it is necessary to introduce a biological sample into the central flow channel 31 through the liquid inlet channel 33, the vacuum pump is activated to reduce the pressure in the central flow channel 31, and the biological sample is introduced into the central flow channel 31 by using atmospheric pressure.

[0061] To achieve microfluidics, such as Figure 6 and Figure 7 As shown, the second elastic material layer 4 has multiple independent gas channels 41 corresponding to multiple liquid inlet channels 33. Each gas channel 41 has a longitudinally deformable shut-off valve 42 at one end, and each shut-off valve 42 is located above the corresponding liquid inlet channel 33.

[0062] The other end of each gas channel 41 is connected to its respective gas pump (not shown in the figure).

[0063] The shut-off valve 42 is a hollow structure opened inside the second elastic material layer 4. The hollow structure is connected to the corresponding gas channel 41. The longitudinal deformation of the shut-off valve 42 is the volume deformation of the hollow structure along the longitudinal direction.

[0064] In this embodiment, multiple independent liquid inlet channels are formed within the first elastic material layer. One end of each channel is connected to its respective biological sample storage tube, thereby reducing the risk of cross-contamination. Furthermore, because the liquid inlet channels are located inside the first elastic material layer, they effectively isolate the biological sample from the external environment, preventing contamination. In addition, a central flow channel and an electrode channel are formed on the surface of the first elastic material layer connected to the semiconductor material layer. Both the central flow channel and the electrode channel are sealed spaces composed of the first elastic material layer and the semiconductor material layer. The biological sample flows into the central flow channel through the liquid inlet channels for detection, thus creating a closed space for the biological reaction, effectively isolating the external environment, improving the reaction rate, and reducing contamination. Furthermore, to achieve microfluidics, this embodiment of the specification provides a second elastic material layer above the first elastic material layer. The interior of the second elastic material layer contains multiple independent gas channels corresponding to multiple liquid inlet channels. Each gas channel has a longitudinally deformable shut-off valve at one end, and each shut-off valve is located above its corresponding liquid inlet channel. Therefore, when a liquid inlet channel needs to be opened, negative pressure is applied to the shut-off valve through the corresponding gas channel, causing the valve's longitudinal volume to shrink, thus opening the liquid inlet channel. Conversely, when a liquid inlet channel needs to be closed, positive pressure is applied to the shut-off valve through the corresponding gas channel, causing the valve's longitudinal volume to increase, thus squeezing the liquid inlet channel and closing it. Through the synergistic effect of the gas valve and the channels, the flow and shut-off of the liquid sample are controlled, achieving precise microfluidics and reducing reliance on manual intervention.

[0065] Based on the same inventive concept, embodiments of this specification also provide a sample introduction method for a microfluidic automated sample introduction field-effect transistor biosensor, applicable to... Figures 1-7 The field-effect transistor biosensor shown is a microfluidic automated sample delivery system. (Example:) Figure 8 As shown, the method includes:

[0066] Step 801: Control the longitudinal deformation of the corresponding shut-off valve through the gas channel, thereby controlling the opening or closing of the liquid inlet channel corresponding to the gas channel;

[0067] Step 802: Control the opening of the liquid inlet channel to introduce the corresponding biological sample into the central flow channel, thereby detecting the biological sample in the central flow channel.

[0068] In the embodiments of this specification, the fabrication of a microfluidic automated sample delivery field-effect transistor biosensor may include the following steps:

[0069] 1) Use CAD to draw the layout of the required structure and make it into a mask.

[0070] 2) Clean the 8-inch silicon wafer sequentially with acetone, isopropanol, and deionized water using ultrasonication for 15 minutes. Fix it in the center of a spin coater. Spin coat the SU-8 3050 photoresist onto the silicon wafer surface using a two-step method (first step: spin coat at 500 rbm for 20 seconds, second step: spin coat at 3000 rbm for 30 seconds).

[0071] 3) Place the spin-coated silicon wafer on a hot plate and bake at 95°C for 25 minutes to complete the pre-baking step;

[0072] 4) First, place the photomask in the fixed position of the lithography machine, then place the pre-baked silicon wafer in the corresponding position, set the lithography machine to direct contact lithography mode, and expose the pre-baked silicon wafer under ultraviolet light for 12 seconds.

[0073] 5) Place the exposed silicon wafer on a hot plate and heat it at 95°C for 30 minutes to complete the baking step.

[0074] 6) Place the finished silicon wafer in the negative photoresist developer for 20 seconds.

[0075] 7) Place the developed silicon wafer on a hot plate and heat it at 150°C for 30 minutes to achieve the modeling goal.

[0076] The above operations completed the fabrication of the microfluidic automated sample introduction field-effect transistor biosensor mold, resulting in a silicon wafer with a raised structure, the average height of which is 50 μm. This mold can be reused, avoiding the need for photolithography for each field-effect transistor fabrication. Next, PDMS casting and curing are required to complete the fabrication of the PDMS flow channel module with a concave structure for use in the graphene field-effect transistor biosensor. (Specific questions follow.)

[0077] 8) Mixing the PDMS adhesive: The PDMS adhesive consists of two parts, A (polymer) and B (curing agent), which should be mixed in a 10:1 ratio. Use a transparent disposable plastic cup as the container and a disposable plastic dropper as the mixing tool to thoroughly mix the adhesive and ensure it is evenly mixed. Then pour the mixture evenly and smoothly onto the surface of the male mold.

[0078] 9) Defoaming: Place the prepared PDMS adhesive in a vacuum pump, turn on the pump until the air inside the chamber reaches the ultimate vacuum level, and evacuate for 30 minutes to ensure that the bubbles are completely eliminated. Then, place the defoamed PDMS adhesive in an 80℃ oven and bake for 30 minutes to allow it to cure and set.

[0079] 10) Demolding: Gently make an opening at the edge with a blade, first lift the PDMS colloid at the edge of the silicon wafer, then slowly peel it off, being careful to avoid damaging the PDMS colloid to ensure the accuracy of the flow channels. Then use a spatula to cut the microchannel module along the dividing line with a blade for later use, ensuring the bottom surface is flat to prevent the PDMS colloid from sticking.

[0080] 11) Cleaning: Rinse the PDMS with alcohol, then rinse with purified water. Finally, use nitrogen or a high-speed blower to remove surface water droplets and place it in an oven to dry. This removes dust and marks from the PDMS surface.

[0081] 12) Bonding: Start the vacuum pump and plasma cleaner, set the relevant parameters, place the first and second elastic material layers into the chamber, wait for the vacuum level in the chamber to recover, remove the two PDMS channel modules, and quickly bond the two PDMS layers according to... Figure 7 Align and press the surfaces as shown to ensure no air bubbles remain, thus completing the bonding process.

[0082] 13) Drilling: Use a 0.8mm drill bit to make through holes for the central flow channel groove and multiple liquid inlet channels, and through holes for multiple gas channels; use a 1.1mm drill bit to make through holes for two pairs of electrode channels; during the drilling process, ensure that there are no residual cores in each hole and that the holes are as vertical as possible to ensure unobstructed fluid flow.

[0083] Then proceed with the assembly:

[0084] 14) The first surface of the first elastic material layer of the microfluidic channel system is attached to the graphene surface, so that the central channel groove covers the graphene and is fixed with a custom fixture, exposing only the through holes of the electrode, liquid and gas channel passages.

[0085] 15) Insert the external electrode wire into the first through hole of the electrode channel slot, and then inject liquid tin-indium alloy through the second through hole to complete the assembly of each module. Simultaneously, according to the chip cover plate fixture structure shown in the CAD diagram ( Figure 9a and Figure 9bAfter the fixture is processed, the substrate, graphene, first elastic material layer and second elastic material layer are sandwiched together to ensure the airtightness of the structure and the stability of the test.

[0086] 16) An ionic solution containing biomarkers flows in from the inlet channel of the first elastic material layer. Simultaneously, a hollow gold needle is inserted at the inlet of the central channel groove as a gate conductive metal to apply an electric field for modulation.

[0087] Finally, the fabricated microfluidic automated sample introduction field-effect transistor biosensor was used for sample introduction validation in biological detection:

[0088] 17) First, the biological sample to be injected is stored in the biological sample reservoir tube, which is connected to the first elastic material layer through a conduit and then connected to the graphene field-effect transistor biosensor. The structure is designed with multiple inlet channels to meet the needs of cleaning solution, modification solution, sealing reagent, target analyte, and control reagent that need to be introduced during the test. It ensures that each reagent enters the central channel through an independent through hole, which greatly avoids mutual interference between analytes.

[0089] 18) Multiple pathways in the second elastic material layer are connected to multiple external gas channels. The switching of the shut-off valve is controlled by adjusting the gas pump. Specifically, when positive pressure is applied to a gas channel, the shut-off valve at the connected end will expand longitudinally, compressing the corresponding liquid inlet channel, thereby closing the sample inlet of that channel. Figure 10 ); Figure 10 In the middle, the liquid inlet passage is the liquid inlet flow channel 33.

[0090] 19) A hollow gold needle is inserted at the inlet corresponding to the central flow channel as a conductive electrode for the grid. It is also connected to a vacuum pump via a conduit to control the inlet and outlet of the liquid. The vacuum pump controls the extraction of biological samples. If the biological sample needs to be replaced, negative pressure is applied to the corresponding gas channel. The shut-off valve at the connected end will shrink longitudinally, and the corresponding liquid inlet channel will open.

[0091] The above operations enable automated sample introduction of biological samples. This microfluidic automated sample introduction method using a field-effect transistor biosensor avoids frequent manual liquid changes. Sample replacement is achieved by adjusting the air pump, which controls the opening and closing of a shut-off valve in the second elastic material layer using pressure. Because PDMS is an elastomer, the deformation and recovery of the shut-off valve compresses the inlet channel in the first elastic material layer, thereby controlling the opening or closing of the inlet flow channel.

[0092] Using the method described above, a microfluidic automated sample delivery field-effect transistor biosensor was applied to the nucleic acid detection of a certain virus. The virus-positive sample contained a complementary strand, which was a single strand of RNA that could pair complementaryly with a DNA probe. When nucleic acid molecules hybridize, it causes a change in charge doping on the graphene surface, which is reflected in a change in the Dirac point voltage value of the electrical signal. Therefore, monitoring the change in this signal can achieve the sensing and identification of the virus.

[0093] Specific test results such as Figure 11 As shown, Figure 11 The horizontal axis, Concentration, represents the concentration, and the vertical axis, ΔV, represents the concentration. CNP The electrochemical signal changes associated with C-type natriuretic peptide were analyzed. Using a non-complementary viral sequence as a negative control, multiple tests demonstrated the feasibility of the automated sample introduction structure without affecting the device's stability or detection capability, maintaining a detection limit of 10 fM. In summary, the microfluidic automated sample introduction field-effect transistor biosensor of the embodiments in this specification effectively improves the automation level of biological detection.

[0094] It should be understood that in the various embodiments of this document, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this document.

[0095] It should also be understood that, in the embodiments herein, the term "and / or" is merely a description of the relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following associated objects have an "or" relationship.

[0096] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this document.

[0097] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0098] In the embodiments provided herein, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the couplings or direct couplings or communication connections shown or discussed may be indirect couplings or communication connections through some interfaces, devices, or units, or they may be electrical, mechanical, or other forms of connection.

[0099] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments described herein, depending on actual needs.

[0100] Furthermore, the functional units in the various embodiments of this document can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0101] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this paper, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this paper. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0102] This document uses specific embodiments to illustrate the principles and implementation methods of this document. The descriptions of the embodiments above are only for the purpose of helping to understand the methods and core ideas of this document. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this document. Therefore, the content of this specification should not be construed as a limitation of this document.

Claims

1. A microfluidic automated sample introduction field-effect transistor biosensor, characterized in that, include: Substrate (1), semiconductor material layer (2), first elastic material layer (3), and second elastic material layer (4); The semiconductor material layer (2) is located on the substrate (1), the first elastic material layer (3) is located on the semiconductor material layer (2), and the second elastic material layer (4) is located on the first elastic material layer (3). The first elastic material layer (3) has a central flow channel groove (31) and two electrode channel grooves (32) arranged symmetrically with the central flow channel groove (31) as the axis. The first surface is the surface where the first elastic material layer (3) connects with the semiconductor material layer (2). The first elastic material layer (3) has multiple independent liquid inlet channels (33) connected to the central flow channel groove (31) inside. The second elastic material layer (4) has multiple independent gas channels (41) corresponding to multiple liquid inlet channels (33). Each gas channel (41) has a longitudinally deformable shut-off valve (42) at one end, and each shut-off valve (42) is located above the corresponding liquid inlet channel (33).

2. The field-effect transistor biosensor with microfluidic automated sample delivery according to claim 1, characterized in that, The other end of each liquid inlet channel (33) is connected to its respective biological sample storage tube.

3. The field-effect transistor biosensor with microfluidic automated sample delivery according to claim 1, characterized in that, Each gas channel (41) is connected to its respective gas pump at the other end.

4. The field-effect transistor biosensor with microfluidic automated sample delivery according to claim 1, characterized in that, The shut-off valve (42) is a hollow structure opened inside the second elastic material layer (4). The hollow structure is connected to the corresponding gas channel (41). The longitudinal deformation of the shut-off valve (42) is the volume deformation of the hollow structure along the longitudinal direction.

5. The field-effect transistor biosensor with microfluidic automated sample delivery according to claim 1, characterized in that, A hollow gold needle is provided at the entrance of the central flow channel (31), which is the connection point between the central flow channel (31) and the multiple liquid inlet channels (33).

6. The field-effect transistor biosensor with microfluidic automated sample delivery according to claim 1, characterized in that, The first elastic material layer (3) is provided with a first through hole (34) and a second through hole (35) respectively connected to both ends of each electrode channel groove (32). The first through hole (34) is used to insert an electrode wire, and the second through hole (35) is used to inject liquid metal.

7. The field-effect transistor biosensor with microfluidic automated sample delivery according to claim 1, characterized in that, The first surface of the first elastic material layer (3) is provided with multiple sets of two electrode channel grooves (32) arranged symmetrically about the central flow channel groove (31).

8. The field-effect transistor biosensor with microfluidic automated sample delivery according to claim 1, characterized in that, The first elastic material layer (3) is provided with a third through hole (36) connected to the central flow channel groove (31), and the other end of the third through hole (36) is connected to a vacuum pump.

9. The field-effect transistor biosensor with microfluidic automated sample delivery according to claim 1, characterized in that, The material of the first elastic material layer (3) or the second elastic material layer (4) is polydimethylsiloxane.

10. A sample introduction method for a microfluidic automated sample introduction field-effect transistor biosensor, applied to the microfluidic automated sample introduction field-effect transistor biosensor according to any one of claims 1-9, characterized in that, The method includes: The longitudinal deformation of the corresponding shut-off valve is controlled by the gas channel, thereby controlling the opening or closing of the liquid inlet channel corresponding to the gas channel; The controlled liquid inlet channel introduces the corresponding biological sample into the central flow channel, thereby enabling the detection of the biological sample within the central flow channel.

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