Full-automatic electrochemical luminescence detector based on silicon photomultiplier

Abstract

The full-automatic electrochemical luminescence detector comprises a shell, a touch screen, a first circuit board, a second circuit board and an electrochemical luminescence detection chip, the touch screen is embedded in the shell, the shell is provided with a layer plate, a partition plate and a support, the layer plate and the support are arranged on the two sides of the partition plate, the first circuit board is arranged below the layer plate, and the second circuit board is arranged below the support. The second circuit board is arranged on the laminate, the silicon photomultiplier is arranged on the bracket, and the electrochemical luminescence detection chip is arranged below the bracket; a power supply module, a main control chip, a control circuit and an in-phase amplification circuit are integrated on the first circuit board, a transimpedance amplification circuit and a bias voltage circuit are integrated on the second circuit board, the power supply module is connected with the main control chip, the control circuit and the in-phase amplification circuit, and the main control chip is connected with the control circuit, the transimpedance amplification circuit and the touch screen. The control circuit is connected with the in-phase amplification circuit and the touch screen, the in-phase amplification circuit is connected with the electrochemical luminescence detection chip, and the transimpedance amplification circuit and the bias voltage circuit are connected with the silicon photomultiplier.

Description

Technical Field

[0001] The invention relates to the technical field of electrochemiluminescence analyzers, and in particular to a full-automatic electrochemiluminescence detector based on a silicon photomultiplier tube. Background Art

[0002] Electrochemiluminescence is an analytical detection technology that combines electrochemistry and chemiluminescence. It has the advantages of low background signal, high sensitivity, wide linear range, and easy control. It has been widely used in biochemical immunology, clinical diagnosis, food safety monitoring and other fields. In electrochemiluminescence analysis technology, the detector is an extremely critical component. Generally, the core components of an electrochemiluminescence detector include an electrochemical reaction excitation module, an optical signal acquisition and processing module, and an instrument operation module.

[0003] At present, electrochemical reaction excitation modules are divided into two types: bipolar type and tripolar type. In view of the weak electrochemical luminescence radiation, photoelectric conversion elements with high sensitivity, fast response time and large receiving area are often required. Therefore, optical signal acquisition modules often use single-photon detectors (such as silicon photomultiplier tubes, photodiodes, etc.) and multi-wavelength detectors (such as complementary metal oxide semiconductor (CMOS) cameras, charge coupled device (CCD) cameras, etc.). In addition, the instrument operation module mostly uses desktop computers or laptops.

[0004] At present, electrochemiluminescence detectors are usually composed of an electrochemiluminescence reaction excitation circuit and an optical signal detection unit. They have been applied in specific fields, but still have the following shortcomings: (1) They are bulky and not portable; (2) Instrument operation requires a desktop computer or laptop computer; (3) The integration is low, and the entire detection process requires the participation of multiple devices (such as a large power supply or electrochemical workstation, computer or smart phone), making it difficult to achieve integrated analysis; (4) The degree of automation is low, and supporting analysis software is required to process data, and some images still require manual intervention; (5) The operation is complicated and cannot meet the needs of point-of-care testing (POCT).

[0005] In recent years, the scale of my country's POCT market has continued to grow and has developed into a highly promising emerging industry. POCT technology provides new detection methods for many fields. By deeply combining advanced detection technology with traditional methods (such as fluorescence, electrochemistry, etc.), it not only achieves high-sensitivity detection, but also takes into account low cost and rapid analysis, significantly improving detection efficiency and convenience. At present, POCT detectors based on fluorescence and electrochemical detection have achieved rapid development and are widely used. However, among the existing POCT detectors, fully automatic electrochemiluminescence detectors based on silicon photomultiplier tubes have not yet been applied. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and to provide a fully automatic electrochemical luminescence detector based on silicon photomultiplier tubes, which is automatic and portable, simple to assemble, easy to operate, low in production cost, and can achieve rapid detection.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A fully automatic electrochemical luminescence detector based on silicon photomultiplier tubes, comprising a housing, an intelligent touch screen, a first circuit board, a second circuit board and an electrochemical luminescence detection chip, wherein the intelligent touch screen is embedded in the housing, a partition, a layer plate and a bracket are arranged in the housing, the layer plate and the bracket are arranged on both sides of the partition plate, the first circuit board is arranged below the layer plate, the second circuit board is arranged on the layer plate, the silicon photomultiplier tube is arranged on the bracket, and the electrochemical luminescence detection chip is arranged below the bracket;

[0009] The first circuit board is integrated with a power module, a main control chip, a control circuit and a common-phase amplifier circuit, and the second circuit board is integrated with a transimpedance amplifier circuit and a bias voltage circuit. The power module is respectively connected to the main control chip, the control circuit and the common-phase amplifier circuit, the main control chip is connected to the control circuit, the transimpedance amplifier circuit and the smart touch screen, the control circuit is connected to the common-phase amplifier circuit and the smart touch screen, the common-phase amplifier circuit is connected to the electrochemical luminescence detection chip, and the transimpedance amplifier circuit and the bias voltage circuit are connected to the silicon photomultiplier tube;

[0010] The smart touch screen is used to set the excitation parameters of the electrochemical luminescence reaction. The control circuit is used to output voltage to the in-phase amplifier circuit according to the excitation parameters. The in-phase amplifier circuit is used to amplify the voltage and transmit it to the electrochemical luminescence detection chip to trigger the electrochemical luminescence reaction. The bias voltage circuit is used to provide a bias voltage to the silicon photomultiplier tube to make the silicon photomultiplier tube work. The silicon photomultiplier tube is used to collect the light signal of the electrochemical luminescence reaction and convert it into a current signal. The transimpedance amplifier circuit is used to convert the current signal into a voltage signal. The main control chip is used to convert the voltage signal into a digital signal, and transmit it to the smart touch screen after data processing.

[0011] Furthermore, the power module includes a 5V to 3.3V circuit, a 5V to 15V circuit and a 5V to 24V circuit. The 5V to 3.3V circuit provides power for the main control chip, the 5V to 15V circuit provides power for the control circuit, and the 5V to 24V circuit provides power for the common-mode amplifier circuit.

[0012] Furthermore, the 5V to 3.3V circuit includes a linear regulator, the linear regulator model is AMS1117-3.3, the circuit is connected to a +5V power supply, configured with 2 22μF chip capacitors and 2 100nF chip capacitors for filtering, configured with a 4.7kΩ fixed resistor for current protection, and the circuit is connected with an LED light to indicate whether the circuit is working normally.

[0013] Furthermore, the 5V to 15V circuit includes a DC boost converter, the DC boost converter model is XL6007E1, the circuit is configured with 6 22μF capacitors for filtering, 1 33μH inductor and 4 diodes for protection, and the circuit is connected in parallel with 1 11kΩ fixed resistor and 1 1kΩ fixed resistor to output +15V and -15V voltages.

[0014] Furthermore, the 5V to 24V circuit includes a DC boost converter, the DC boost converter model is XL6007E1, the circuit is configured with 2 22μF chip capacitors, 2 47μF polar capacitors, 1 33μH inductor and 1 diode for filtering, and the circuit is connected in parallel with 1 18.2kΩ fixed resistor and 1 1kΩ fixed resistor.

[0015] Furthermore, the main control chip transmits data to the smart touch screen through serial communication. The main control chip model is STM32F103C8T6, the power supply voltage is 3.3V, and it has a dual-channel 12-bit analog-to-digital conversion chip inside. The analog-to-digital conversion chip is used to convert the voltage signal input by the transimpedance amplifier circuit into a digital signal. The main control chip uses the software keil5 to write the serial communication program and the digital signal acquisition program, and uses ST-LINK to burn the program.

[0016] Furthermore, the control circuit includes a digital-to-analog conversion chip and an operational amplifier. The model of the digital-to-analog conversion chip is DAC8831IDR. The SCI pin, SCLK pin, LDAC# pin and CS# pin of the digital-to-analog conversion chip are respectively connected to a 47Ω chip resistor, the VDD pin is connected to a 5V external voltage, and the VREF pin is connected to a 5V reference voltage;

[0017] The operational amplifier model is OPA277M / TR. The +IN pin of the operational amplifier is connected to the voltage output by the digital-to-analog conversion chip, the V+ pin and the V- pin are connected to the +15V and -15V voltages output by the 5V to 15V circuit respectively, and the VOUT pin outputs the voltage to the common-mode amplifier circuit.

[0018] Furthermore, the common-mode amplifier circuit includes an operational amplifier, the operational amplifier model is LM2904DR, the reference voltage pin of the operational amplifier is connected to a 24V reference voltage, the positive pole of the operational amplifier is connected to a 5kΩ fixed resistor, and the negative pole of the operational amplifier is connected in parallel with a 5kΩ fixed resistor and a 15kΩ fixed resistor.

[0019] Furthermore, the transimpedance amplifier circuit includes two operational amplifiers, the two operational amplifier models are OPA656N / 250, the circuit is configured with 4 100nF chip capacitors, 1 3pF chip capacitor, 1 40pF chip capacitor and 4 6.8μF polar capacitors for filtering, and a 200Ω fixed resistor is connected in parallel between the input and output ends of each operational amplifier.

[0020] Furthermore, the bias voltage circuit includes a DC-to-DC power supply chip, the DC-to-DC power supply chip model is LT1617ES5#PBF, the circuit is configured with 2 1μF capacitors, 1 100nF capacitor and 1 4.7μF capacitor for filtering, 2 Schottky diodes and 1 10uH inductor for protection, the circuit is connected in parallel with a 26.7kΩ fixed resistor and a 470kΩ adjustable resistor, and the output bias voltage range is 0 to 33V.

[0021] Compared with the prior art, the present invention is the first to create a fully automatic electrochemical luminescence detector based on silicon photomultiplier tubes, which has the characteristics of small size, strong portability, and fast analysis speed, and can realize one-button fully automatic detection. Compared with traditional electrochemical luminescence detection instruments, the main control chip STM32F103C8T6 is used as the core for data transmission and processing, replacing an external computer, significantly reducing equipment costs and reducing size, while improving the integration and portability of the detector.

[0022] The present invention can perform bipolar electrochemical luminescence chip detection without the use of expensive constant potentiostat or DC power supply. It integrates silicon photomultiplier tubes and corresponding configuration circuits. The entire process from light signal acquisition to sample analysis only takes about 15 seconds. It is easy to operate and can achieve rapid detection without the need for professionals. The detector shows good application effects in immunoassay and has significant practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the structure of the fully automatic electrochemiluminescence detector.

[0024] Figure 2 It is a side view schematic diagram of a fully automatic electrochemiluminescence detector.

[0025] Figure 3 It is a cross-sectional schematic diagram of a fully automatic electrochemiluminescence detector.

[0026] Figure 4 It is a schematic diagram of the support structure arranged in the shell.

[0027] Figure 5 This is the schematic diagram of the 5V to 3.3V circuit.

[0028] Figure 6 This is the schematic diagram of the 5V to 15V circuit.

[0029] Figure 7 This is the schematic diagram of the 5V to 24V circuit.

[0030] Figure 8 This is the control circuit schematic.

[0031] Fig. 9 This is the schematic diagram of the common-mode amplifier circuit.

[0032] Fig.10 This is the schematic diagram of the transimpedance amplifier circuit.

[0033] Fig.11 This is the schematic diagram of the bias voltage circuit.

[0034] Fig.12 This is a schematic diagram of the results of using a fully automatic electrochemiluminescence detector to detect luteinizing hormone (LH).

[0035] Description of Figure Numbers:

[0036] 1-shell; 11-partition; 12-layer board; 13-bracket; 131-shading plate; 132-accommodating groove; 2-intelligent touch screen; 3-first circuit board; 4-second circuit board; 5-electrochemical luminescence detection chip; 51-upper cover; 52-lower cover; 6-silicon photomultiplier tube; 7-detection electrode contact. DETAILED DESCRIPTION

[0037] The fully automatic electrochemical luminescence detector based on silicon photomultiplier tube of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0038] See also Figure 1 , Figure 2 and Figure 3 The present invention discloses a fully automatic electrochemical luminescence detector based on silicon photomultiplier tubes, comprising a shell 1, an intelligent touch screen 2, a first circuit board 3, a second circuit board 4 and an electrochemical luminescence detection chip 5, wherein the intelligent touch screen 2 is embedded in the shell 1, a partition 11, a layer plate 12 and a bracket 13 are arranged in the shell 1, the layer plate 12 and the bracket 13 are arranged on both sides of the partition plate 11, the first circuit board 3 is arranged below the layer plate 12, the second circuit board 4 is arranged on the layer plate 12, the silicon photomultiplier tube 6 is arranged on the bracket 13, and the electrochemical luminescence detection chip 5 is arranged below the bracket 13.

[0039] The first circuit board 3 integrates a power module, a main control chip, a control circuit and a common-phase amplifier circuit, and the second circuit board 4 integrates a transimpedance amplifier circuit and a bias voltage circuit. The power module is connected to the main control chip, the control circuit and the common-phase amplifier circuit respectively, the main control chip is connected to the control circuit, the transimpedance amplifier circuit and the smart touch screen 2, the control circuit is connected to the common-phase amplifier circuit and the smart touch screen 2, the common-phase amplifier circuit is connected to the electrochemical luminescence detection chip 5, and the transimpedance amplifier circuit and the bias voltage circuit are connected to the silicon photomultiplier tube 6.

[0040] The smart touch screen 2 is used to set the excitation parameters of the electrochemical luminescence reaction. The control circuit is used to output voltage to the in-phase amplifier circuit according to the excitation parameters. The in-phase amplifier circuit is used to amplify the voltage and transmit it to the electrochemical luminescence detection chip 5 to trigger the electrochemical luminescence reaction. The bias voltage circuit is used to provide a bias voltage to the silicon photomultiplier tube 6 to make the silicon photomultiplier tube 6 work. The silicon photomultiplier tube 6 is used to collect the light signal of the electrochemical luminescence reaction and convert it into a current signal. The transimpedance amplifier circuit is used to convert the current signal into a voltage signal. The main control chip is used to convert the voltage signal into a digital signal, and transmit it to the smart touch screen 2 after data processing.

[0041] Specifically, see Figure 4 The bracket 13 is provided with a light shielding plate 131, and receiving grooves 132 are provided on both sides of the light shielding plate 131. Two silicon photomultiplier tubes 6 are respectively fixed in the receiving grooves on both sides of the light shielding plate 131. By adjusting the fixed position of the bracket 13 on the housing 1, the photosensitive area of ​​the silicon photomultiplier tube 6 is directly opposite to the light-emitting area of ​​the electrochemical luminescence detection chip 5 to collect the electrochemical luminescence signal. In this embodiment, the model of the silicon photomultiplier tube 6 is MICROFJ-30035-TSV-TR, and the photosensitive area is 3mm*3mm.

[0042] The shell 1 is printed by Bambu Lab P1S 3D printer with 1.75mm PLA black wire. The left and right sides of the shell 1 are open and separated by a partition 11 in the middle. The outer dimensions of the shell 1 are 108mm long, 64mm wide and 40mm high. The bracket 13 is printed by Bambu Lab P1S 3D printer with 1.75mm PLA black wire.

[0043] Specifically, the model of the smart touch screen 22 is ASTG028, the dimensions are 86.7mm*55.6mm*13.4mm, and it has 16KB of application memory. After writing a program on a computer using the special software HMILite2.2, the written project is downloaded to the smart touch screen 22 using an SD card, thereby realizing the functions of the smart touch screen 22 displaying and storing data and controlling the excitation voltage of the electrochemical luminescence reaction.

[0044] Specifically, see Figure 1 The electrochemiluminescence detection chip 5 also includes an upper cover 51 and a lower cover 52, and a test strip containing the article to be tested is arranged between the upper cover 51 and the lower cover 52. The upper cover 51 and the lower cover 52 are both printed by a Bambu Lab P1S 3D printer. The electrodes of the electrochemiluminescence detection chip 5 are connected to the detection electrode contacts 7, and the detection electrode contacts 7 are connected to the output end of the in-phase amplifier circuit. The excitation voltage is connected to the two detection electrode contacts 7 through the in-phase amplifier circuit, and the two detection electrode contacts 7 are in contact with the electrodes of the electrochemiluminescence detection chip 5, triggering the electrochemiluminescence detection chip 5 to produce an electrochemiluminescence reaction.

[0045] Specifically, a USB interface is also integrated on the first circuit board 3, and the detector as a whole is powered by an external 5V through the USB interface of the first circuit board 3. The power module includes a 5V to 3.3V circuit, a 5V to 15V circuit, and a 5V to 24V circuit. The 5V to 3.3V circuit provides power for the main control chip, the 5V to 15V circuit provides power for the control circuit, and the 5V to 24V circuit provides power for the in-phase amplifier circuit.

[0046] Specifically, see Figure 5 , the 5V to 3.3V circuit includes a linear regulator, the linear regulator model is AMS1117-3.3, and the circuit is directly connected to the +5V power supply. The circuit is configured with two 22μF chip capacitors and two 100nF chip capacitors for filtering to generate a more stable voltage closer to 3.3V, and a 4.7kΩ fixed resistor is configured for current protection. The circuit is also connected to an LED light, which is used to indicate whether the circuit is working properly.

[0047] Specifically, see Figure 6 , the 5V to 15V circuit includes a DC boost converter, the DC boost converter model is XL6007E1, and the circuit is equipped with 6 22μF capacitors for filtering, so that the circuit can output a stable 15V voltage. The circuit is equipped with a 33μH inductor and 4 diodes for protection. The circuit is connected in parallel with a 11kΩ fixed resistor and a 1kΩ fixed resistor. The voltage value output by the circuit can be changed by adjusting the ratio of the two resistors, so that the circuit can output +15V and -15V voltages.

[0048] Specifically, see Figure 7 , the 5V to 24V circuit includes a DC boost converter, the DC boost converter model is XL6007E1. The circuit is configured with 2 22μF chip capacitors, 2 47μF polar capacitors, 1 33μH inductor and 1 diode for filtering. The circuit is connected in parallel with a 18.2kΩ fixed resistor and a 1kΩ fixed resistor. By adjusting the ratio of the two resistors, the output reference voltage can be changed. After repeated tests, the parallel connection of 18.2kΩ and 1kΩ resistors can output 24V voltage.

[0049] Specifically, the main control chip transmits data to the smart touch screen 2 through serial communication. The main control chip model is STM32F103C8T6, which is a core processor based on the ARM architecture. The power supply voltage is 3.3V, and it has a dual-channel 12-bit analog-to-digital conversion chip inside. The analog-to-digital conversion chip is used to convert the voltage signal input by the transimpedance amplifier circuit into a digital signal. The main control chip uses the software keil5 to write the serial communication program and the digital signal acquisition program, and uses ST-LINK to burn the program to realize the function.

[0050] Specifically, see Figure 8 The control circuit includes a digital-to-analog conversion chip and an operational amplifier. The model of the digital-to-analog conversion chip is DAC8831IDR. The SCI pin, SCLK pin, LDAC# pin and CS# pin of the digital-to-analog conversion chip are connected to a 47Ω chip resistor for protection. Then they are connected to the four corresponding pins of the main control chip, so that the digital-to-analog conversion chip can receive the voltage command from the smart touch screen 2 transferred by the main control chip. The VDD pin is connected to a 5V external voltage, and the VREF pin is connected to a 5V reference voltage.

[0051] The operational amplifier model is OPA277M / TR. The +IN pin of the operational amplifier is connected to the voltage output by the digital-to-analog conversion chip (that is, connected to the VOUT pin of the digital-to-analog conversion chip), the V+ pin and the V- pin are respectively connected to the +15V and -15V voltages output by the 5V to 15V circuit, and the VOUT pin outputs the voltage to the common-mode amplifier circuit.

[0052] Specifically, see Fig. 9 The in-phase amplifier circuit includes an operational amplifier, and the operational amplifier model is LM2904DR. The reference voltage pin of the operational amplifier is connected to a 24V reference voltage, and the 24V reference voltage is provided by a 5V to 24V circuit. The positive pole of the operational amplifier is connected to a 5kΩ fixed resistor to limit the current to prevent excessive current from burning the operational amplifier. The negative pole of the operational amplifier is connected in parallel with a 5kΩ fixed resistor and a 15kΩ fixed resistor, and a voltage of 0-15V can be output. The amplification factor can be changed by changing the ratio of the two parallel resistors, and the excitation voltage is connected to the detection electrode contact 7 through a wire. The two detection electrode contacts 7 are in contact with the electrodes of the electrochemical luminescence detection chip 5 to trigger the electrochemical luminescence reaction.

[0053] Specifically, see Fig.10The transimpedance amplifier circuit includes two operational amplifiers, the models of which are OPA656N / 250. The circuit is configured with 4 100nF chip capacitors, 1 3pF chip capacitor, 1 40pF chip capacitor and 4 6.8μF polar capacitors for filtering. A 200Ω fixed resistor is connected in parallel between the input and output of each operational amplifier. The two operational amplifiers divide the circuit into two stages, the first stage converts the weak current signal into a weak voltage signal, and the second stage converts the weak voltage signal into a detectable analog voltage signal. The amplification factor can be changed by changing the size of the parallel resistor.

[0054] Specifically, see Fig.11 The bias voltage circuit includes a DC-DC power supply chip, the model of which is LT1617ES5#PBF. The circuit is configured with two 1μF capacitors, one 100nF capacitor and one 4.7μF capacitor for filtering, and two Schottky diodes and a 10uH inductor for protection. The circuit is connected in parallel with a 26.7kΩ fixed resistor and a 470kΩ adjustable resistor. By changing the resistance value of the adjustable resistor, the bias voltage output by the bias voltage circuit is changed, and the output bias voltage range is 0 to 33V.

[0055] Application Example 1

[0056] This embodiment uses a fully automatic electrochemiluminescence detector for immunoassay, the immunoassay target is luteinizing hormone (LH), and a closed dual-electrode electrochemiluminescence detection chip is used.

[0057] (1) Preparation of sample pad

[0058] Add 200 μL of sample pad treatment solution (0.025% casein, 0.05% polyvinyl pyrrolidone (PVP), 0.25% polysorbate-20 (S19) and 10-fold diluted phosphate buffer solution (PBS)) on a 1×5 cm glass fiber and bake in a 37°C oven for 1 h for later use.

[0059] (2) Preparation of conjugate pad

[0060] 100 μL of conjugate pad treatment solution (0.025% casein, 0.05% PVP, 0.25% S19 and 10-fold diluted PBS) was added dropwise onto a 0.5×5 cm glass fiber and baked in a 37°C oven for 1 h. Next, the prepared T-line and C-line electrochemiluminescent probes were mixed at a volume ratio of 1:1 between the T-line electrochemiluminescent probe and the C-line electrochemiluminescent probe, and the mixture contained 0.05% PVP, 5 mg / mL trehalose, 0.03% proclin-300, 0.025% casein and 0.1% S19 (Tetronic1307). Then, the gold spray film was sprayed onto the conjugate pad at a spray volume of 6 μL / cm and a speed of 50 mm / s (repeat the film twice). Finally, the conjugate pad was baked at 37°C for 1 h for use.

[0061] (3) Processing test pad

[0062] The C-line capture antibody (5 mg / mL trehalose, 0.1% S19, 5 mg / mL sucrose and 0.25 mg / mL antibody dissolved in PBS at pH 7), and the T-line capture antibody (0.1% S19, 15 mg / mL sucrose and 0.5 mg / mL antibody dissolved in PBS at pH 7). Subsequently, the T-line and C-line capture antibodies were coated on a nitrocellulose membrane (NC membrane) using a gold spray film instrument at 50 mm / s and a spray volume of 2 μL / cm. Finally, the NC membrane was baked at 37°C for 2 h and set aside.

[0063] (4) Preparation of electrode pads

[0064] First, a screen printing plate is fixed on a screen printing table. Then, a hydrophobic PET base plate is placed under the screen printing plate. Subsequently, a conductive carbon paste is poured on the screen printing plate. Next, the carbon paste is squeezed onto the PET base plate by a screen printing scraper. Finally, the screen-printed PET base plate is dried overnight at room temperature to obtain a prepared electrode pad for standby use.

[0065] (5) Preparation of connection pads

[0066] Cut out 0.5×1 cm absorbent paper to form the connection pad.

[0067] (6) Preparation of absorption pad

[0068] Cut out 5×0.8 cm absorbent paper to make the absorbent pad.

[0069] (7) Assembling a dry closed bipolar electrode electrochemiluminescent lateral flow immunoassay test strip, the process is as follows:

[0070] First, stick the NC membrane (detection pad) on the PET base plate. Then, stack the absorption pad near the T line, overlapping by about 1mm. Next, stack the binding pad and sample pad in sequence near the C line, overlapping by about 1mm. Subsequently, cut the assembled test strip into strips. Next, turn it upside down on the electrode pad so that the C line and the T line overlap on the two anodes of the electrode respectively, and stick the connection pad on the closed bipolar electrode cathode and the corresponding positive driving electrode. Finally, assemble the closed bipolar electrode electrochemiluminescence lateral flow immunoassay strip with its housing for LH immunoassay.

[0071] (8) The LH sample concentrations used in the experiment were 0, 0.1, 1, and 10 mIU / mL.

[0072] The experimental results are as follows Fig.12 As shown, it can be seen from the test results that: using the fully automatic electrochemiluminescence detector of the present invention, as the LH concentration increases, the ratio of the electrochemiluminescence intensity value on the chip T line to the electrochemiluminescence intensity value on the C line (i.e., T / C) also increases accordingly; and there is a good linear relationship between the logarithm of the LH concentration and T / C, the linear fitting equation is Y=1.192X+2.635, and the correlation coefficient R 2 The value is 0.9829 (5 repetitions). Therefore, the fully automatic electrochemiluminescence analyzer of the present invention can be applied to LH immunoassay, and can also be applied to immunoassay of biomarkers of other diseases and other physiological activities.

[0073] In summary, the present invention is the first to create a fully automatic electrochemical luminescence detector based on silicon photomultiplier tubes, which has the characteristics of small size, strong portability, and fast analysis speed, and can realize one-button fully automatic detection. Compared with traditional electrochemical luminescence detection instruments, the main control chip STM32F103C8T6 is used as the core for data transmission and processing, replacing an external computer, significantly reducing equipment costs and reducing size, while improving the integration and portability of the detector.

[0074] The present invention can perform bipolar electrochemical luminescence chip detection without the use of expensive constant potentiostat or DC power supply. It integrates silicon photomultiplier tubes and corresponding configuration circuits. The entire process from light signal acquisition to sample analysis only takes about 15 seconds. It is easy to operate and can achieve rapid detection without the need for professionals. The detector shows good application effects in immunoassay and has significant practical value.

[0075] The above description is a detailed description of the preferred feasible embodiment, but the embodiment is not intended to limit the scope of the patent application. All equivalent changes or modified changes made under the disclosed technical spirit should fall within the scope of the patent covered.

Claims

1. A fully automatic electrochemical luminescence detector based on silicon photomultiplier tube, characterized in that: It includes a shell, a smart touch screen, a first circuit board, a second circuit board and an electrochemical luminescence detection chip. The smart touch screen is embedded in the shell. A partition, a layer plate and a bracket are arranged in the shell. The layer plate and the bracket are arranged on both sides of the partition plate. The first circuit board is arranged below the layer plate, the second circuit board is arranged on the layer plate, the silicon photomultiplier tube is arranged on the bracket, and the electrochemical luminescence detection chip is arranged below the bracket. The first circuit board is integrated with a power module, a main control chip, a control circuit and a common-phase amplifier circuit, and the second circuit board is integrated with a transimpedance amplifier circuit and a bias voltage circuit. The power module is respectively connected to the main control chip, the control circuit and the common-phase amplifier circuit, the main control chip is connected to the control circuit, the transimpedance amplifier circuit and the smart touch screen, the control circuit is connected to the common-phase amplifier circuit and the smart touch screen, the common-phase amplifier circuit is connected to the electrochemical luminescence detection chip, and the transimpedance amplifier circuit and the bias voltage circuit are connected to the silicon photomultiplier tube; The smart touch screen is used to set the excitation parameters of the electrochemical luminescence reaction. The control circuit is used to output voltage to the in-phase amplifier circuit according to the excitation parameters. The in-phase amplifier circuit is used to amplify the voltage and transmit it to the electrochemical luminescence detection chip to trigger the electrochemical luminescence reaction. The bias voltage circuit is used to provide a bias voltage to the silicon photomultiplier tube to make the silicon photomultiplier tube work. The silicon photomultiplier tube is used to collect the light signal of the electrochemical luminescence reaction and convert it into a current signal. The transimpedance amplifier circuit is used to convert the current signal into a voltage signal. The main control chip is used to convert the voltage signal into a digital signal, and transmit it to the smart touch screen after data processing.

2. The fully automatic electrochemical luminescence detector based on silicon photomultiplier tube according to claim 1, characterized in that: The power module includes a 5V to 3.3V circuit, a 5V to 15V circuit and a 5V to 24V circuit. The 5V to 3.3V circuit provides power for the main control chip, the 5V to 15V circuit provides power for the control circuit, and the 5V to 24V circuit provides power for the in-phase amplifier circuit.

3. The fully automatic electrochemical luminescence detector based on silicon photomultiplier tube according to claim 2, characterized in that: The 5V to 3.3V circuit includes a linear voltage regulator, the linear voltage regulator model is AMS1117-3.3, the circuit is connected to the +5V power supply, configured with 2 22μF chip capacitors and 2 100nF chip capacitors for filtering, configured with a 4.7kΩ fixed resistor for current protection, and the circuit is connected with an LED light to indicate whether the circuit is working normally.

4. The fully automatic electrochemical luminescence detector based on silicon photomultiplier tube according to claim 2, characterized in that: The 5V to 15V circuit includes a DC boost converter, the DC boost converter model is XL6007E1, the circuit is equipped with 6 22μF capacitors for filtering, 1 33μH inductor and 4 diodes for protection, and the circuit is connected in parallel with 1 11kΩ fixed resistor and 1 1kΩ fixed resistor to output +15V and -15V voltages.

5. The fully automatic electrochemical luminescence detector based on silicon photomultiplier tube according to claim 2, characterized in that: The 5V to 24V circuit includes a DC boost converter, the DC boost converter model is XL6007E1, the circuit is configured with 2 22μF chip capacitors, 2 47μF polar capacitors, 1 33μH inductor and 1 diode for filtering, and the circuit is connected in parallel with 1 18.2kΩ fixed resistor and 1 1kΩ fixed resistor.

6. The fully automatic electrochemical luminescence detector based on silicon photomultiplier tube according to claim 1, characterized in that: The main control chip transmits data to the smart touch screen through serial communication. The main control chip model is STM32F103C8T6, the power supply voltage is 3.3V, and it has a dual-channel 12-bit analog-to-digital conversion chip inside. The analog-to-digital conversion chip is used to convert the voltage signal input by the transimpedance amplifier circuit into a digital signal. The main control chip uses the software keil5 to write the serial communication program and the digital signal acquisition program, and uses ST-LINK to burn the program.

7. The fully automatic electrochemical luminescence detector based on silicon photomultiplier tube according to claim 1, characterized in that: The control circuit includes a digital-to-analog conversion chip and an operational amplifier. The model of the digital-to-analog conversion chip is DAC8831IDR. The SCI pin, SCLK pin, LDAC# pin and CS# pin of the digital-to-analog conversion chip are respectively connected to a 47Ω chip resistor, the VDD pin is connected to a 5V external voltage, and the VREF pin is connected to a 5V reference voltage; The operational amplifier model is OPA277M / TR. The +IN pin of the operational amplifier is connected to the voltage output by the digital-to-analog conversion chip, the V+ pin and the V- pin are connected to the +15V and -15V voltages output by the 5V to 15V circuit respectively, and the VOUT pin outputs the voltage to the common-mode amplifier circuit.

8. The fully automatic electrochemical luminescence detector based on silicon photomultiplier tube according to claim 1, characterized in that: The common-mode amplifier circuit includes an operational amplifier, the operational amplifier model is LM2904DR, the reference voltage pin of the operational amplifier is connected to a 24V reference voltage, the positive electrode of the operational amplifier is connected to a 5kΩ fixed-value resistor, and the negative electrode of the operational amplifier is connected in parallel with a 5kΩ fixed-value resistor and a 15kΩ fixed-value resistor.

9. The fully automatic electrochemical luminescence detector based on silicon photomultiplier tube according to claim 1, characterized in that: The transimpedance amplifier circuit includes two operational amplifiers, the models of which are OPA656N / 250. The circuit is configured with four 100nF chip capacitors, one 3pF chip capacitor, one 40pF chip capacitor and four 6.8μF polar capacitors for filtering. A 200Ω fixed resistor is connected in parallel between the input and output of each operational amplifier.

10. The fully automatic electrochemical luminescence detector based on silicon photomultiplier tube according to claim 1, characterized in that: The bias voltage circuit includes a DC-to-DC power supply chip, the model of which is LT1617ES5#PBF. The circuit is configured with 2 1μF capacitors, 1 100nF capacitor and 1 4.7μF capacitor for filtering, 2 Schottky diodes and 1 10uH inductor for protection, and a 26.7kΩ fixed resistor and a 470kΩ adjustable resistor in parallel in the circuit. The output bias voltage range is 0 to 33V.

Images