A portable flexible photoelectrochemical detector device

Abstract

The application discloses a portable flexible photoelectrochemical detector device, and belongs to the technical field of photoelectrochemical detection. The device is composed of a microfluidic flexible sensing electrode, a darkroom structure, a magnetic field unit, a miniaturized electrochemical workstation and a movable light source. The flexible electrode adopts a PET substrate and a screen-printed three-electrode, the microfluidic channel is made of PDMS and is hydrophilic treated, and the whole is integrated in the darkroom to shield stray light. The magnetic field unit non-contact regulates and controls the electrode interface reaction kinetics, and the signal acquisition is realized by combining light excitation and the miniaturized electrochemical workstation. The device can be connected to a man-machine interaction platform to complete data processing. The device does not need complex nano material modification and enzyme catalytic amplification, and significantly improves the detection sensitivity and stability under the premise of portability. The device is suitable for on-site rapid and instant detection of trace biomarkers, heavy metals and other target objects, and meets the needs of ultra-sensitive rapid screening in bedside diagnosis and resource-limited scenes.

Description

Technical Field

[0001] This invention relates to the field of photoelectrochemical detection technology, and more specifically to a portable flexible photoelectrochemical detector device. Background Technology

[0002] Electrochemical biosensing technology, with its advantages of high sensitivity, rapid response, low cost, and ease of integration, has become an important analytical tool in fields such as precision medicine, environmental monitoring, and food safety. However, when facing the detection needs of ultra-low concentration targets (such as certain early cancer biomarkers, single-cell secretions, and trace heavy metal ions), traditional electrochemistry still faces limitations in sensitivity and detection limits. Traditional solutions typically rely on complex nanomaterial modifications, enzyme-catalyzed amplification, or multi-stage signal conversion strategies. While these methods can improve performance, they also significantly increase the complexity, reproducibility, and manufacturing cost of sensor fabrication, limiting their application in large-scale field detection or resource-constrained environments. It is particularly noteworthy that current high-performance detection often relies on large, non-portable laboratory equipment, making it difficult to meet the urgent needs for point-of-care diagnostics, rapid on-site screening, and real-time detection in resource-limited areas.

[0003] Therefore, developing high-performance portable electrochemical sensing devices is a crucial step in moving technology from the laboratory to practical applications. To address the dual challenges of performance and portability, combining external field manipulation with electrochemical sensing systems has become an emerging trend. In recent years, researchers have actively explored innovative strategies for integrating external field (such as light, sound, magnetism, and heat) manipulation with electrochemical sensing systems. Among these, magnetic modulation technology, as a non-contact, green, and efficient strategy, demonstrates unique application potential and provides innovative ideas for signal amplification on portable platforms.

[0004] Therefore, how to propose a portable flexible photoelectrochemical detector device to overcome the shortcomings of existing technologies is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a portable flexible photoelectrochemical detector device. By optimizing the detection process through magnetic field modulation, it aims to significantly improve the detection sensitivity and stability of the portable system without relying on complex sensitizing materials and processes, thereby promoting breakthroughs in the practical application of ultrasensitive electrochemical detection technology in real-time and field scenarios. To achieve the above objectives, the present invention adopts the following technical solution: A portable flexible photoelectrochemical detector device includes: a microfluidic flexible sensing electrode, a darkroom structure, a magnetic field unit, a miniaturized electrochemical workstation, and a portable light source; The microfluidic flexible sensing electrode, magnetic field unit, and miniaturized electrochemical workstation are all housed inside the darkroom structure; the microfluidic flexible sensing electrode is connected to the miniaturized electrochemical workstation via signal connection. The magnetic field unit is adapted to the microfluidic flexible sensing electrode and is used to regulate the magnetic field of the microfluidic flexible sensing electrode; the movable light source is adapted to the microfluidic flexible sensing electrode and is used to provide optical excitation conditions for the microfluidic flexible sensing electrode.

[0006] Optionally, it also includes a human-computer interaction platform, and the miniaturized electrochemical workstation is signal-connected to the human-computer interaction platform.

[0007] Optionally, the microfluidic flexible sensing electrode includes: a flexible PET substrate, a flexible electrochemical three-electrode, an adhesive layer, and a microfluidic channel connected in sequence.

[0008] Optionally, the flexible electrochemical three electrodes are prepared using a screen printing process: (1) Place the flexible substrate PET on the printing platform and fix the screen A on the printing platform. Add carbon ink to the screen. Use a squeegee to apply force evenly at an angle to the screen so that the carbon ink can be transferred through the mesh to the PET surface. Remove the screen and then heat it to cure the carbon ink. (2) Place the PET with the cured carbon electrode back on the printing platform, align the markings on the screen B with the carbon pattern printed on the PET, and fix the screen B. (3) Add ink to screen B, use a squeegee to apply pressure evenly to the screen at an angle to squeeze the ink, so that the ink passes through the screen and is printed on the PET. After removing the screen, heat it to complete the curing.

[0009] Optionally, stencil A is used to print the working electrode and the counter electrode, and stencil B is used to print the reference electrode and the pin electrode. Both stencils are designed with alignment marks to align the electrode positions during the two printing processes.

[0010] Optionally, the reference electrode and the pin electrode are made of Ag / AgCl ink.

[0011] Optionally, the microfluidic channel includes: an inlet channel, a liquid storage chamber, and an outlet channel; the liquid storage chamber is circular, and the inlet channel and outlet channel are radially symmetrically distributed with the liquid storage chamber as the center; the outlet channel consists of two parts: one part is a semi-circular arc-shaped channel concentric with the liquid storage chamber and with a diameter greater than the length of the inlet channel; the other part is a straight channel connected to it, which together constitute the fluid outlet path.

[0012] Optionally, the fabrication steps of the microfluidic channel are as follows: Import the design into the printing software, select ultraviolet photoresist as the mask material, and use a dispensing needle to perform patterned direct writing on the PET substrate; After printing, the photoresist is completely cured by irradiation with ultraviolet light to obtain a microfluidic channel mask. After the mask template is prepared, the PDMS solution prepared by mixing the curing agent and crosslinking agent in a preset mass ratio is poured onto the surface of the mask template. After the PDMS solution is stirred evenly, it is allowed to stand to eliminate air bubbles in the PDMS solution. The prepared PDMS solution was dropped onto the surface of a photomask. After spin coating, the PDMS solution was evenly distributed on the photomask. Then, the PDMS was heated to completely cure, resulting in a PDMS film with microfluidic channels.

[0013] Optionally, the preparation steps of the adhesive layer are as follows: Using a dispensing 3D printing process, an uncured PDMS film is coated on the non-electrode area of ​​a PET substrate with printed electrodes. The uncured PDMS film is then pre-cured to form an intermediate adhesive layer with moderate viscosity and incomplete cross-linking. The prepared PDMS film is aligned and bonded to the PET substrate coated with the adhesive layer, aligning the liquid reservoir with the working area of ​​the three electrodes. After bonding, the entire assembly is transferred to a heating stage for heating, so that the PDMS is fully cross-linked and bonded to the PET.

[0014] Optionally, this also includes hydrophilic treatment of the inner wall of the microfluidic channel: Treatment with nonionic surfactants: The nonionic surfactants are injected into the microfluidic channels, left to stand at room temperature for a preset time, then the solution is aspirated and dried in air to obtain hydrophilic microfluidic channels.

[0015] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a portable flexible photoelectrochemical detector device, which has the following beneficial effects: The present invention achieves (1) significantly enhanced detection performance, the external magnetic field can non-contactly enhance the interface mass transfer and reaction kinetics, the photocurrent signal intensity is increased by 52.69%, the creatinine detection limit is as low as 7.66pM, and it shows a good linear relationship (R²=0.997) in the concentration range of 10nM~500μM, and can achieve ultrasensitive detection without complex sensitizing materials.

[0016] (2) Portable and applicable to the field, it adopts a miniaturized electrochemical workstation, flexible electrodes and 3D printed darkroom, with small overall size and light weight, freeing it from the limitations of large laboratory equipment, and supporting bedside diagnosis, field site and instant detection in areas with limited resources.

[0017] (3) The preparation process is simple and low-cost. The flexible electrode is screen printed, and the microfluidic channel is formed by 3D dispensing printing and PDMS casting. The process is simple and suitable for large-scale production. The electrode and channel are firmly packaged and have good reproducibility.

[0018] (4) The microfluidic system is highly efficient and stable. The optimized radially symmetrical channel and the gradually expanding conical outlet can quickly exhaust gas and avoid air resistance. A 50μL micro sample can fill the detection chamber within 7 seconds. The channel is hydrophilized, resulting in low fluid resistance, uniform filling, and high detection repeatability and reliability.

[0019] (5) The detection environment is precise and controllable. The black resin darkroom isolates stray light from the environment, the movable light source provides stable light excitation, and the magnetic field unit strength is adjustable, realizing precise control of multiple fields of light, electricity and magnetism, and improving the detection signal-to-noise ratio and stability. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of a portable flexible photoelectrochemical detector device provided by the present invention.

[0022] Figure 2 The flowchart for screen printing to prepare flexible electrodes provided by this invention is shown.

[0023] Figure 3 A flowchart illustrating the fabrication process of the PDMS microfluidic channel provided by this invention.

[0024] Figure 4 This is a schematic diagram of the microfluidic flexible sensing electrode provided by the present invention.

[0025] Figure 5 This is a flowchart illustrating the fabrication process of the microfluidic flexible sensing electrode provided by the present invention.

[0026] Figure 6 This is a schematic diagram illustrating the detection of the flowability of the microfluidic flexible sensing electrode provided by the present invention.

[0027] Figure 7 The diagram shows the changes in photocurrent signal of the sensor provided by the present invention under conditions of magnetic field and no magnetic field.

[0028] Figure 8 The current response curves provided by this invention are within the range of creatinine concentration from 10 nm to 500 μM.

[0029] Figure 9 This is a linear fitting graph of the current change intensity versus the logarithm of concentration in the creatinine concentration range of 10 nm to 500 μM, provided by the present invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] This invention discloses a portable flexible photoelectrochemical detector device, comprising: a microfluidic flexible sensing electrode, a darkroom structure, a magnetic field unit, a miniaturized electrochemical workstation, and a portable light source; The microfluidic flexible sensing electrode, magnetic field unit, and miniaturized electrochemical workstation are all housed inside the darkroom structure; the microfluidic flexible sensing electrode is connected to the miniaturized electrochemical workstation via signal connection. The magnetic field unit is adapted to the microfluidic flexible sensing electrode and is used to regulate the magnetic field of the microfluidic flexible sensing electrode; the movable light source is adapted to the microfluidic flexible sensing electrode and is used to provide optical excitation conditions for the microfluidic flexible sensing electrode.

[0032] In a specific implementation, a portable flexible photoelectrochemical detection device integrating external magnetic field modulation has the following overall architecture: Figure 1 As shown, the device consists of the following five core modules working together: (1) Microfluidic flexible sensing electrode: integrates screen-printed flexible three electrodes and PDMS microfluidic channel, responsible for sample introduction, transport and electrochemical interface reaction.

[0033] (2) Darkroom structure: It is made of black resin 3D printing, which effectively isolates the interference of stray light in the environment and provides the dark field environment required for photoelectrochemical detection.

[0034] (3) External magnetic field: By using non-contact magnetic field regulation to enhance interfacial mass transfer and reaction kinetics, permanent magnets can be used to improve photo / electrochemical sensing and detection performance.

[0035] (4) The miniaturized electrochemical workstation serves as the core of the system's control and measurement, enabling the application of excitation signals and the acquisition of response signals.

[0036] (5) A smartphone-based software platform provides a human-computer interaction interface to enable parameter setting, data visualization, and storage. The modules work together to form an integrated, magnetic field-assisted, and enhanced portable sensing and analysis platform that integrates "sample introduction" and "result output".

[0037] In a specific implementation, the fabrication and integration steps of the microfluidic flexible sensing electrode include: The microfluidic flexible sensing electrode is formed by integrating a flexible electrochemical three-electrode prepared by screen printing with a PDMS microfluidic channel.

[0038] 1) Fabrication of flexible screen-printed electrodes

[0039] This invention uses two stencils with different patterns—stencil A is used to print the working electrode and counter electrode, and stencil B is used to print the reference electrode and pin electrode. Both stencils are designed with "+" shaped alignment marks to ensure precise alignment of the electrode positions during the two printing processes.

[0040] In this invention, the working electrode and counter electrode use low-cost, highly printable carbon ink; the reference electrode and pin electrode use biocompatible, potential-stable Ag / AgCl ink. The ink viscosity is controlled within the range of 500-5000 cP to ensure a smooth printed pattern surface and reduce screen lines. A 280-mesh screen is used to ensure adequate ink deposition while maintaining printing accuracy. The fabrication process for flexible electrodes using screen printing is shown in the figure, mainly consisting of the following three steps: Figure 2 As shown: (1) Printing and curing of working electrode and counter electrode. Place the flexible PET substrate on the printing platform and fix the screen A on the printing platform. Add an appropriate amount of carbon ink to the screen. Use a rubber squeegee with a hardness of 75 to apply force evenly at a 45° angle to the screen, so that the carbon ink is transferred through the mesh to the PET surface. Carefully remove the screen and then heat at 90°C for 30 minutes to cure the carbon ink.

[0041] (2) Electrode alignment. Place the PET with the cured carbon electrode back on the printing platform, and precisely align it with the "+" mark on the screen B and the "+" carbon pattern printed on the PET. Fix the screen B to provide a positioning reference for the next printing step.

[0042] (3) Printing and curing of reference electrode and pin electrode. An appropriate amount of Ag / AgCl ink was added to stencil B. A rubber squeegee with a hardness of 75 was used to apply uniform pressure at a 45° angle to the stencil to press the Ag / AgCl ink through the stencil onto the PET. After removing the stencil, the PET was heated at 90°C for 30 minutes. After curing, each flexible electrode was cut off with scissors and placed in a sealed bag for later integration with the microfluidic channel.

[0043] 2) Fabrication of microfluidic channels

[0044] The fabrication process of microfluidic channels is as follows: Figure 3 As shown, it mainly consists of the following three steps: (1) Microfluidic channel layout design. The microfluidic channel in this invention mainly consists of three parts: an inlet channel, a liquid storage chamber (i.e., a detection chamber), and an outlet channel. The geometric dimensions (length and width) of the channel directly affect the fluid dynamics behavior, and thus affect the detection response speed and stability. The liquid storage chamber needs to have enough space to accommodate the electrochemical three-electrode system and provide it with a stable liquid-phase reaction environment.

[0045] Specifically, the reservoir is a circle with a diameter of 10 mm, a size that ensures a reasonable layout and sufficient contact of the three-electrode system. The inlet and outlet channels are radially symmetrically distributed around the reservoir. The outlet channel is further composed of two parts: a semi-circular arc-shaped channel concentric with the reservoir and a diameter of 30 mm; and a straight channel connected to it with a length of 10 mm, together forming the fluid outlet path. This invention designs the inlet section near the reservoir as a gradually expanding cone. This cone-shaped structure reduces local flow resistance, creates a pressure gradient conducive to gas discharge, thereby effectively alleviating gas retention problems and improving microfluidic filling efficiency and system reliability.

[0046] (2) 3D mask preparation. The microfluidic mask is prepared by 3D dispensing printing. Based on the different structural functions, the printing parameters need to be optimized in different areas: For the liquid storage chamber (detection chamber), in order to reduce the height of the chamber to reduce the required volume of the detected liquid and avoid the collapse of the film, a combination of lower air pressure and higher speed should be used; For the linear inlet and outlet channels, appropriate air pressure and speed need to be matched to ensure the continuity and uniformity of the channel morphology.

[0047] The specific fabrication steps are as follows: First, the design pattern is imported into the printing software. Ultraviolet photoresist is selected as the mask material, and patterning is performed on the PET substrate using a 0.25mm diameter dispensing needle. During printing, the liquid reservoir region uses a pressure of 100kPa and a speed of 0.8mm / s, while the microfluidic channel region maintains a pressure of 100kPa and reduces the speed to 0.25mm / s. The final mask template has the following dimensions: the detection cavity center height is approximately 0.7mm, and the microfluidic channel height is approximately 0.2mm. After printing, the photoresist is completely cured by irradiation with a 5W ultraviolet lamp for 5 minutes, resulting in the microfluidic channel mask template shown in the figure.

[0048] (3) Preparation of PDMS microfluidic channels. After the mask was prepared, a PDMS solution prepared by mixing curing agent and crosslinking agent at a mass ratio of 10:1 was poured onto the mask surface. The PDMS solution was stirred evenly and allowed to stand for 30 minutes to eliminate air bubbles. The prepared PDMS solution was then dropped onto the mask surface and spin-coated at 200 rpm for 30 seconds. The PDMS solution was then evenly distributed on the mask. Subsequently, the mask was heated at 60°C for 1 hour to completely cure the PDMS. Finally, the cured PDMS film was gently peeled off with tweezers to obtain a PDMS film with microfluidic channels.

[0049] 3) Integration of microfluidics and flexible sensing electrodes

[0050] The microfluidic flexible sensing electrode consists of a flexible PET substrate printed with conductive electrodes, an adhesive layer, and a microfluidic channel layer, such as... Figure 4 As shown. The integrated packaging of microfluidic PDMS films and screen-printed electrodes is a key step in realizing functional sensors. The packaging process is as follows: Figure 5 As shown, the process mainly includes the following three steps: (1) Preparation and pre-curing of the adhesive layer. First, an uncured PDMS film with a thickness of about 100µm was precisely coated on the non-electrode area of ​​the PET substrate with printed electrodes using a dispensing 3D printing process. This PDMS layer was pre-cured at 60℃ for 10min to form an intermediate adhesive layer with moderate viscosity and incomplete cross-linking, providing a uniform and firm adhesion interface for the subsequent bonding of the PDMS microfluidic film.

[0051] (2) Alignment, bonding, and thermosetting. Using tweezers, slowly pick up the prepared PDMS microfluidic film from one edge and gradually align and bond it to the PET substrate coated with the adhesive layer. Pay special attention to aligning the liquid reservoir with the working area of ​​the three electrodes to ensure that the liquid completely covers the effective surface of the electrodes during subsequent detection. After bonding, transfer the entire assembly to a heating stage and heat at 60°C for 1 hour to allow the PDMS to fully crosslink and form a strong bond with the PET.

[0052] (3) Hydrophilic treatment of the inner wall of the microfluidic channel. Since PDMS itself is highly hydrophobic, the inner wall of the channel needs to be hydrophilicized to reduce fluid resistance within the microfluidic channel and promote spontaneous filling of the liquid under capillary force. This invention uses the nonionic surfactant Silwet-177 for treatment: a 10wt% Silwet-177 solution is injected into the microfluidic channel and allowed to stand at room temperature for 20 minutes. Utilizing its excellent spreadability and surface tension reduction effect, the PDMS surface is hydrophilized. The solution is then aspirated and dried in air for 1 hour to obtain a microfluidic channel system with good hydrophilicity, providing a stable liquid flow environment for subsequent electrochemical detection.

[0053] 4) Detection of flowability of microfluidic flexible sensing electrodes

[0054] To visualize the flow of liquid in microfluidic channels, black ink was used for detection. For example... Figure 6 As shown, when 50 μL of ink is dropped into the inlet, the ink rapidly flows along the inlet channel into the reservoir and fills it within 7 seconds, fully covering the conductive electrodes inside, demonstrating the system's rapid filling and response capabilities. The fabricated microfluidic flexible sensing electrode requires only a small amount of liquid to completely fill the detection chamber, which is beneficial for the analysis of trace or precious samples. The liquid then enters the outlet channel and is discharged from the outlet, facilitating continuous detection. The detection process takes place within a sealed reservoir, effectively preventing external contamination and improving detection reliability.

[0055] In a specific implementation, a portable photoelectrochemical device with enhanced magnetic field is constructed based on a smartphone. The fabricated microfluidic flexible sensing electrode is connected to a miniaturized electrochemical workstation via a USB adapter and integrated with a portable light source, a darkroom structure, a magnetic field unit, and the smartphone. The portable light source has a light output power of 50W, providing stable light excitation conditions for the photoactive materials at the sensing interface during detection. The darkroom structure (including the outer shell and the magnetic block support platform) is designed and optimized using 3DMax software and 3D printed from black resin material, effectively isolating stray light interference and providing the necessary dark field environment for photoelectrochemical detection. The magnetic field generating unit consists of a cylindrical permanent magnet with a diameter of 12mm and a height of 10mm. Its surface magnetic induction intensity, measured by a gaussmeter, is approximately 80mT, used to achieve non-contact magnetic field control of the electrode interface during detection.

[0056] In a specific embodiment, the sensor detection performance is tested, as follows: (1) Modification of the sensing working electrode First, the flexible electrode prepared by screen printing was treated in an air plasma atmosphere of 50 W for 1 min to remove surface impurities and enhance hydrophilicity. Then, a 1 mg / mL Cu₂O aqueous dispersion was mixed with a 0.5 wt% Nafion solution at a volume ratio of 9:1. 2 μL of this mixture was added dropwise to the sensing electrode area. After the solvent had completely dried, the modification of the sensing electrode was complete. The modified flexible electrode was then stored in a 4°C refrigerator for later use.

[0057] (2) Performance and detection mechanism of creatinine sensor

[0058] The modified flexible electrode was integrated into a microfluidic flexible sensing electrode according to the above steps and connected to a micro electrochemical workstation for detection. Figure 7The changes in photocurrent signal of the sensor under magnetic field and non-magnetic field conditions are shown. Clearly, the photocurrent signal intensity increases by 52.69% under the applied magnetic field. Different concentrations of creatinine were prepared in artificial urine for photoelectrochemical sensing performance testing. Figure 8 The graph shows the change in photocurrent with creatinine concentration. As can be seen, the photocurrent decreases with increasing creatinine concentration. Figure 9 As shown, within the range of 10 nM to 500 μM, the intensity of photocurrent change is directly proportional to creatinine concentration, which can be described by the correlation equation y = 7.67lgC + 18.25, with a correlation coefficient R. 2 =0.997, where y is the photocurrent intensity and C is the concentration of creatinine. The detection limit of creatinine is calculated to be 7.66 pM (S / N=3). The creatinine sensor has a low detection limit, indicating that the portable photo / electrochemical sensing device has excellent sensing performance.

[0059] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0060] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A portable flexible photoelectrochemical detector device, characterized in that, include: Microfluidic flexible sensing electrodes, darkroom structure, magnetic field unit, miniaturized electrochemical workstation, and portable light source; The microfluidic flexible sensing electrode, magnetic field unit, and miniaturized electrochemical workstation are all housed inside the darkroom structure; the microfluidic flexible sensing electrode is connected to the miniaturized electrochemical workstation via signal connection. The magnetic field unit is adapted to the microfluidic flexible sensing electrode and is used to perform magnetic field control on the microfluidic flexible sensing electrode; the movable light source is adapted to the microfluidic flexible sensing electrode and is used to provide optical excitation conditions for the microfluidic flexible sensing electrode. Darkroom structure: Made of black resin 3D printing, it isolates stray light interference from the environment and provides a dark field environment for photoelectrochemical detection; Magnetic field unit: Composed of cylindrical permanent magnets with a diameter of 12mm and a height of 10mm, and a surface magnetic induction intensity of 80mT, used for non-contact magnetic field control to improve the performance of photo / electrochemical sensing. The microfluidic flexible sensing electrode includes: a flexible PET substrate, a flexible electrochemical three-electrode, an adhesive layer, and a microfluidic channel connected in sequence; The microfluidic channel includes an inlet channel, a liquid storage chamber, and an outlet channel. The liquid storage chamber is circular, and the inlet channel and outlet channel are radially symmetrically distributed with the liquid storage chamber as the center. The outlet channel consists of two parts: one part is a semi-circular arc-shaped channel concentric with the liquid storage chamber and with a diameter greater than the length of the inlet channel; the other part is a straight channel connected to it, which together form the fluid outlet path.

2. The portable flexible photoelectrochemical detector device according to claim 1, characterized in that, It also includes a human-computer interaction platform, and the miniaturized electrochemical workstation is signal-connected to the human-computer interaction platform.

3. The portable flexible photoelectrochemical detector device according to claim 1, characterized in that, The flexible electrochemical three electrodes were prepared using a screen printing process. (1) Place the flexible substrate PET on the printing platform and fix the screen A on the printing platform. Add carbon ink to the screen. Use a squeegee to apply force evenly at an angle to the screen so that the carbon ink can be transferred through the mesh to the PET surface. Remove the screen and then heat it to cure the carbon ink. (2) Place the PET with the cured carbon electrode back on the printing platform, align the markings on the screen B with the carbon pattern printed on the PET, and fix the screen B. (3) Add ink to screen B, use a squeegee to apply pressure evenly to the screen at an angle to squeeze the ink, so that the ink passes through the screen and is printed on the PET. After removing the screen, heat it to complete the curing.

4. The portable flexible photoelectrochemical detector device according to claim 3, characterized in that, The stencil A is used to print the working electrode and the counter electrode, and the stencil B is used to print the reference electrode and the pin electrode. Both stencils are designed with alignment marks to ensure that the electrode positions are aligned during the two printing processes.

5. A portable flexible photoelectrochemical detector device according to claim 4, characterized in that, The reference electrode and the pin electrode are made of Ag / AgCl ink.

6. The portable flexible photoelectrochemical detector device according to claim 1, characterized in that, The preparation steps of the microfluidic channel are as follows: Import the design into the printing software, select ultraviolet photoresist as the mask material, and use a dispensing needle to perform patterned direct writing on the PET substrate; After printing, the photoresist is completely cured by irradiation with ultraviolet light to obtain a microfluidic channel mask. After the mask template is prepared, the PDMS solution prepared by mixing the curing agent and crosslinking agent in a preset mass ratio is poured onto the surface of the mask template. After the PDMS solution is stirred evenly, it is allowed to stand to eliminate air bubbles in the PDMS solution. The prepared PDMS solution was dropped onto the surface of a photomask. After spin coating, the PDMS solution was evenly distributed on the photomask. Then, the PDMS was heated to completely cure, resulting in a PDMS film with microfluidic channels.

7. A portable flexible photoelectrochemical detector device according to claim 6, characterized in that, The preparation steps of the adhesive layer are as follows: Using a dispensing 3D printing process, an uncured PDMS film is coated on the non-electrode area of ​​a PET substrate with printed electrodes. The uncured PDMS film is then pre-cured to form an intermediate adhesive layer with moderate viscosity and incomplete cross-linking. The prepared PDMS film is aligned and bonded to the PET substrate coated with the adhesive layer, aligning the liquid reservoir with the working area of ​​the three electrodes. After bonding, the entire assembly is transferred to a heating stage for heating, so that the PDMS is fully cross-linked and bonded to the PET.

8. The portable flexible photoelectrochemical detector device according to claim 1, characterized in that, This also includes hydrophilic treatment of the inner wall of the microfluidic channel: Treatment with nonionic surfactants: The nonionic surfactants are injected into the microfluidic channels, left to stand at room temperature for a preset time, then the solution is aspirated and dried in air to obtain hydrophilic microfluidic channels.

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