A multi-parameter integrated bionic odor sensing chip and a preparation method and application thereof

Abstract

The application discloses a multi-parameter integrated bionic smell sensing chip and a preparation method and application thereof, and has the characteristics of high flux, small size, high integration and low energy consumption by integrating tens of human olfactory receptor proteins and field effect transistors on the same chip by combining MEMS technology and bionic sensing technology. When gas molecules are combined with the olfactory receptor proteins on the chip, the protein conformation changes, the gate current of the field effect transistor is changed, the current signal is normalized, the response spectrum of different gas molecules is constructed to form a smell database, the cross-sensitivity of the olfactory receptor proteins is utilized, and a pattern recognition algorithm is combined to realize high-dimensional detection and accurate identification of a large number of different smells. The smell sensing chip has wide application prospects in the fields of air quality monitoring, food safety and hazardous product detection.

Description

Technical Field

[0001] This invention relates to the field of biomimetic odor detection technology, and in particular to an odor sensing chip based on human olfactory receptor proteins and a FET sensor array. Background Technology

[0002] Gas detection technology has significant economic and social benefits in food safety, industrial production, national defense, and healthcare. Its core component is the gas sensor chip. Traditional gas sensors include semiconductor, electrochemical, catalytic combustion, thermal conductivity, and infrared gas sensors. Existing gas sensors suffer from limitations such as a limited variety of sensitive elements, high energy consumption, poor selectivity, and low integration, restricting their widespread application in industrial IoT, security, military, and food industries.

[0003] Human olfactory receptor proteins are chemoreceptors expressed on the cell membranes of olfactory receptor neurons, responsible for detecting odors that produce a sense of smell. The human olfactory system is composed of more than 400 olfactory receptor proteins, and thanks to the cross-specificity of these proteins, it can recognize millions of odors. Using human olfactory receptor proteins as the sensitive elements of a biomimetic odor-sensing chip allows for a near-perfect replication of the human olfactory system in vitro. By covalently coupling dozens of olfactory receptor proteins with field-effect transistor arrays to construct a biomimetic odor-sensing chip, the detection range, accuracy, and sensitivity of traditional gas sensors can be effectively improved. This enables high-dimensional detection and accurate identification of complex odors, further simulating the realistic human olfactory experience. Summary of the Invention

[0004] The technical problem to be solved by the present invention is how to provide a gas sensor array based on human olfactory receptor proteins and a method for manufacturing the same. The gas sensor array has many detection parameters, high integration, high sensitivity, and can be mass-produced.

[0005] The technical problem proposed by this invention is solved by the following technology: Firstly, this invention provides a multi-parameter integrated biomimetic odor sensing chip, which includes: several independent graphene FET sensors, each graphene FET sensor including a silicon oxide substrate, a source electrode, a drain electrode, a graphene gate electrode, a source lead, a drain lead, a gate lead, an olfactory receptor protein, and a pad; wherein the source electrode, drain electrode, and graphene gate electrode are attached to the silicon oxide substrate; the graphene gate electrode is located between the source electrode and the drain electrode, and the three electrodes are respectively connected to the pad through corresponding source leads, drain leads, and gate leads; the olfactory receptor protein is fixed on the surface of the graphene gate electrode; the olfactory receptor protein, as the sensitive material of the graphene FET sensor, undergoes a conformational change after binding with gas molecules, causing a change in the leakage current of the FET sensor. Since each FET device has a different current response, the chip has different response heatmaps for different gases, and the detection of different types of gases is achieved by combining with a pattern recognition algorithm.

[0006] Furthermore, the source electrode and drain electrode are made of gold, and the gate electrode is made of graphene.

[0007] Furthermore, the olfactory receptor protein is a human olfactory receptor protein, which is modified onto the independent graphene gate electrodes of the FET sensor.

[0008] Secondly, the present invention also provides a method for fabricating a biomimetic odor-sensing chip based on multi-parameter integration, comprising the following steps:

[0009] S1. A silicon wafer is used as a substrate, and the silicon wafer is organically cleaned.

[0010] S2. Prepare a silicon oxide layer on the surface of a silicon wafer;

[0011] S3. Transfer the graphene film onto the silicon oxide substrate;

[0012] S4. Etch a gate pattern on the graphene film to serve as the graphene gate for the FET device.

[0013] S5. Fabricate source electrodes, drain electrodes, source electrode wires, drain electrode wires, and pads on the silicon oxide layer;

[0014] S6. A silicon oxide insulating layer is formed on the source electrode wire and the drain electrode wire;

[0015] S7. Divide and package the silicon wafer;

[0016] S8. Human olfactory receptor protein was expressed using a cell-free system method;

[0017] S9. Use a protein purification device to purify olfactory receptor proteins;

[0018] S10. Phospholipid vesicles were constructed using a micro extruder. The olfactory receptor protein, phospholipid vesicles and Brij35 were mixed and transferred to a dialysis membrane and dialyzed for 3-4 days. The three-dimensionally reconstructed olfactory receptor protein was collected by centrifugation for 60 minutes.

[0019] S11. The recombinant olfactory receptor protein is drop-coated onto the graphene gate electrode 5 of the FET array treated with poly-L-lysine. The interface coupling between the olfactory receptor protein and the graphene FET chip is completed through electrostatic adsorption.

[0020] Thirdly, the present invention also provides an application of a biomimetic odor sensing chip based on multi-parameter integration in odor detection.

[0021] Furthermore, odor detection includes the following steps:

[0022] (1) Signal detection: The graphene FET sensor was cleaned with ultrapure water and dried with N2. 20 μL of the odor buffer solution to be tested was dropped on the surface of each individual graphene FET sensor, and the pads were connected to the source meter with wires. The voltage-current characteristic curve was recorded by Keithley2636A source meter.

[0023] (2) Odor response heatmap construction: Hundreds of known odors were tested, and the signal features [I, n] of each FET sensitive unit after different types of odor processing were extracted, where I is the peak current signal value and n is the number of the FET sensitive unit, which includes the spatial location information of the graphene FET sensor. The peak current signal was converted into a visual response heatmap to form an odor response spectrum database.

[0024] (3) Odor recognition: When an unknown gas reacts, the signal features [I, n] of each FET sensitive unit are extracted, the signal features are converted into a one-dimensional array, and the Euclidean distance between the array and the odor response database is calculated. The Euclidean distance is compared and the closest value is selected to realize odor recognition.

[0025] The present invention has the following beneficial effects:

[0026] (1) This invention provides a multi-parameter integrated biomimetic odor sensing chip, whose sensitive element is 16 kinds of human olfactory receptor proteins and graphene FET array, which can generate specific response heatmaps for different odors. Theoretically, it can generate 65,536 response heatmaps. Combined with pattern recognition algorithm, it greatly improves the resolution and detection capability of gas sensor.

[0027] (2) Compared with traditional gas sensors, the present invention uses human olfactory receptor protein as the sensor sensitive element and graphene FET as the transducer. It does not require heating of the sensor and has the advantages of high accuracy, low energy consumption and fast response.

[0028] Based on the above advantages, this invention opens up new avenues for the research and application of biomimetic gas sensors. Attached Figure Description

[0029] Figure 1 This is an overall structural diagram of a multi-parameter integrated biomimetic odor-sensing chip according to the present invention.

[0030] Figure 2 This is a schematic diagram of the coupling between the olfactory receptor protein and a single FET device in this invention;

[0031] Figure 3 This is a graph showing the change in the conductivity characteristic curve of a single-channel FET device after odor testing according to the present invention.

[0032] Figure 4 This is a schematic diagram of the odor response heatmap of the present invention;

[0033] In the figure, pad 1, source electrode wire 2, source electrode 3, drain electrode 4, graphene gate 5, drain electrode wire 6, olfactory receptor protein 7, graphene layer 8, silicon oxide layer 9. Detailed Implementation

[0034] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but this is not intended to limit the invention.

[0035] like Figure 1 , 2 As shown, Figure 1 This is a top view of the electrode structure of a graphene FET sensor array, with each FET unit modified with a different olfactory receptor protein; Figure 2 This is a schematic diagram of the structure of a single graphene FET sensor.

[0036] Example 1:

[0037] like Figure 1 As shown, the present invention discloses a multi-parameter integrated biomimetic odor sensing chip, which includes pads 1, source electrode wires 2, source electrode 3, drain electrode 4, graphene gate 5, drain electrode wires 6, olfactory receptor protein 7, and graphene layer 8; wherein the pads 1, source electrode wires 2, source electrode 3, drain electrode 4, graphene gate 5, and drain electrode wires 6 are attached to a silicon oxide layer 9; the graphene gate 5 is located between the source electrode 3 and the drain electrode 4; the source electrode 3 is connected to the pads 1 around the chip in sequence through the source electrode wires 2 and the drain electrode 4 is connected to the drain electrode wires 6 in sequence.

[0038] like Figure 2As shown, olfactory receptor protein 7 is immobilized on graphene layer 8 on graphene gate 5; the source electrode 3, drain electrode 4, source electrode wire 2, and drain electrode wire are micrometer-sized and made of gold; the olfactory receptor proteins are of the following types: OR1A1, OR1A2, OR1A3, OR1D2, OR1G1, OR2B11, OR2C1, OR2J2, OR2J3, OR2M4, OR2W1, OR3A1, OR5B17, OR10A6, OR10G7, and OR52D1. As the sensitive material of the graphene FET sensor, the olfactory receptor protein binds to odor molecules and undergoes conformational changes, causing changes in conductivity and thus altering the leakage current of the FET sensor. Different proteins have different response characteristics and cross-specific recognition capabilities. Each FET device has a different current response, and the chip exhibits different response heatmaps for different gases. Combined with pattern recognition algorithms, different types of gases can be detected.

[0039] Example 2:

[0040] This invention discloses a method for fabricating the aforementioned multi-parameter integrated biomimetic odor-sensing chip, comprising the following steps:

[0041] S1. A 4-inch silicon wafer (100) is used as the substrate, and the silicon wafer is organically cleaned.

[0042] S2. A silicon oxide layer 9 is prepared on the surface of a silicon wafer using a thermal oxidation process; the thickness of the silicon oxide layer is 200 nm.

[0043] S3. Graphene films are transferred onto silicon oxide substrate 9 using photolithography and PMMA wet transfer techniques.

[0044] S4. Using oxygen plasma etching technology, a gate pattern is etched on the graphene film to serve as the graphene gate 5 of the FET device; the width of the graphene gate electrode is 40-60 μm; S5. Using magnetron sputtering, photolithography and lift-off technology, a source electrode 3, a drain electrode 4, a source electrode wire 2, a drain electrode wire 6 and a pad 1 are fabricated on the silicon oxide layer 9. The electrode materials are gold (Au) and titanium (Ti); the gold (Au) is 100 nm and the titanium (Ti) is 10 nm.

[0045] S6. Using PECVD technology, photolithography technology, and lift-off technology, a silicon oxide insulating layer is formed on the source electrode wire 2 and the drain electrode wire 6; the thickness of the insulating layer is 200nm.

[0046] S7. Divide and package the silicon wafer;

[0047] S8. Human olfactory receptor protein was expressed using a cell-free system method;

[0048] S9. Use a protein purification device to purify olfactory receptor proteins;

[0049] S10. Phospholipid vesicles were constructed using a micro extruder. The olfactory receptor protein, phospholipid vesicles and Brij35 were mixed and transferred to a dialysis membrane and dialyzed for 3-4 days. The three-dimensionally reconstructed olfactory receptor protein was collected by centrifugation for 60 minutes.

[0050] S11. The recombinant olfactory receptor protein droplet 7 is coated onto the graphene gate electrode 5 of the FET array treated with poly-L-lysine. The interface coupling between the olfactory receptor protein and the graphene FET chip is completed through electrostatic adsorption.

[0051] Example 3:

[0052] This invention discloses an application of the aforementioned biomimetic odor sensing chip based on multi-parameter integration in odor detection. The odor detection process includes the following steps:

[0053] (1) Signal Detection: The sensors were cleaned with ultrapure water and dried with N2. 20 μL of methyl cinnamaldehyde buffer solution was dropped onto the surface of each individual FET device, and the pads were connected to a source meter with wires. The voltage-current characteristic curves were recorded using a Keithley 2636A source meter, such as... Figure 3 As shown, the leakage current signal change rate of one of the graphene FET channels gradually increased as the concentration of methyl cinnamaldehyde increased from 10 pM to 1 μM.

[0054] (2) Odor response heatmap construction: such as Figure 4 As shown, the signal characteristics [I, n] of 16 FET sensitive units on the multi-parameter integrated biomimetic odor sensing chip after methyl cinnamaldehyde treatment are extracted, where I is the peak current signal value and n is the number of the FET sensitive unit. It contains the spatial location information of the graphene FET sensor. The peak current signal is converted to construct a 16-channel visual response heatmap to form an odor response spectrum database.

[0055] (3) Unknown odor recognition: When an unknown gas reacts, the signal features [I, n] of each FET sensitive unit are extracted, and the signal features are converted into a one-dimensional array. The Euclidean distance between the one-dimensional array and the one-dimensional array of the odor response database is calculated. The Euclidean distance is compared and the closest value is selected to group the odors, thereby achieving accurate recognition of multiple odors.

[0056] The above embodiments are used to explain and illustrate the present invention, but not to limit the present invention. Any modifications and changes made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A multi-parameter integrated biomimetic odor-sensing chip, characterized in that, The chip includes several independent graphene FET sensors. Each graphene FET sensor includes a silicon oxide substrate, a source electrode, a drain electrode, a graphene gate electrode, source leads, drain leads, a gate lead, an olfactory receptor protein, and pads. The source electrode, drain electrode, and graphene gate electrode are attached to the silicon oxide substrate. The graphene gate electrode is located between the source electrode and the drain electrode, and the three electrodes are connected to the pads through corresponding source leads, drain leads, and gate leads, respectively. The olfactory receptor protein, which is a human olfactory receptor protein, is fixed on the surface of the graphene gate electrode and is modified on the independent graphene gate electrodes of the FET sensors. The olfactory receptor protein is of type OR1A.

1. OR1A2, OR1A3, OR1D2, OR1G1, OR2B11, OR2C1, OR2J2, OR2J3, OR2M4, OR2W1, OR3A1, OR5B17, OR10A6, OR10G7, OR52D1; Olfactory receptor proteins, used as the sensitive material in graphene FET sensors, undergo conformational changes upon binding with gas molecules, causing variations in the leakage current of the FET sensor. Different proteins exhibit different response characteristics and cross-specific recognition capabilities. Since each FET device has a different current response, the chip displays distinct response heatmaps for different gases. Combined with pattern recognition algorithms, different types of gases can be detected. Specifically: Odor response heatmap construction: Hundreds of known odors were tested, and the signal features [I, n] of each FET sensitive unit after different types of odor processing were extracted, where I is the peak current signal value and n is the number of the FET sensitive unit, which includes the spatial location information of the graphene FET sensor. The peak current signal was converted into a visual response heatmap to form an odor response spectrum database. Odor Recognition: When an unknown gas reacts, the signal features [I, n] of each FET sensitive cell are extracted, the signal features are converted into a one-dimensional array, and the Euclidean distance between this array and the odor response database is calculated. The Euclidean distance is compared and the closest value is selected to achieve odor recognition.

2. The multi-parameter integrated bionic odor-sensing chip according to claim 1, characterized in that, The source and drain electrodes are made of gold, and the gate electrode is made of graphene.

3. A method for fabricating a biomimetic odor-sensing chip based on the multi-parameter integration described in any one of claims 1-2, characterized in that, Includes the following steps: S1. A silicon wafer is used as a substrate, and the silicon wafer is organically cleaned. S2. Prepare a silicon oxide layer on the surface of a silicon wafer; S3. Transfer the graphene film onto the silicon oxide substrate; S4. Etch a gate pattern on the graphene film to serve as the graphene gate for the FET device. S5. Fabricate source electrodes, drain electrodes, source electrode wires, drain electrode wires, and pads on the silicon oxide layer; S6. A silicon oxide insulating layer is formed on the source electrode wire and the drain electrode wire; S7. Divide and package the silicon wafer; S8. Human olfactory receptor protein was expressed using a cell-free system method; S9. Use a protein purification device to purify olfactory receptor proteins; S10. Phospholipid vesicles were constructed using a micro extruder. The olfactory receptor protein, phospholipid vesicles and Brij35 were mixed and transferred to a dialysis membrane and dialyzed for 3-4 days. The three-dimensionally reconstructed olfactory receptor protein was collected by centrifugation for 60 minutes. S11. The recombinant olfactory receptor protein is drop-coated onto the graphene gate electrode 5 of the FET array treated with poly-L-lysine. The interface coupling between the olfactory receptor protein and the graphene FET chip is completed through electrostatic adsorption.

4. An application of the multi-parameter integrated bionic odor sensing chip according to any one of claims 1-2 in odor detection; odor detection includes the following steps: (1) Signal detection: The graphene FET sensor was cleaned with ultrapure water and dried with N2. 20 μL of the odor buffer solution to be tested was dropped on the surface of each individual graphene FET sensor, and the pads were connected to the source meter with wires. The voltage-current characteristic curve was recorded by Keithley 2636A source meter. (2) Odor response heatmap construction: Hundreds of known odors were tested, and the signal features [I, n] of each FET sensitive unit after different types of odor processing were extracted, where I is the peak current signal value and n is the number of the FET sensitive unit, which includes the spatial location information of the graphene FET sensor. The peak current signal was converted into a visual response heatmap to form an odor response spectrum database. (3) Odor recognition: When an unknown gas reacts, the signal features [I, n] of each FET sensitive unit are extracted, the signal features are converted into a one-dimensional array, and the Euclidean distance between the array and the odor response database is calculated. The Euclidean distance is compared and the closest value is selected to realize odor recognition.

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