Wireless implantable ph sensor for monitoring of anastomotic stoma after gastrointestinal reconstruction surgery

Abstract

The application provides a wireless implantable pH sensor for monitoring anastomotic stoma after gastrointestinal reconstruction surgery, which comprises a piezoelectric transducer, a circuit module, a pH detection bin and a packaging layer. The application can continuously monitor in real time, reduce the impact on patients, and avoid the risks that may be caused by traditional invasive methods. In terms of biocompatibility, the sensor is specially designed to be more suitable for long-term use in the body, reducing the risk of immune response and other physiological rejection. Compared with traditional pH measurement technology, this wireless implantable pH sensor can detect gastrointestinal fluid leakage in real time, faster and at a lower cost. In addition, the device can transmit monitoring data directly to external devices, facilitating remote monitoring by doctors, and avoiding subjective judgment of pH. This technology not only improves the accuracy of detection, but also significantly reduces the burden on patients and medical staff.

Description

Technical Field

[0001] This invention pertains to biomedical engineering devices for monitoring the pH of fluid accumulation near the anastomosis after gastrointestinal reconstruction surgery. The system utilizes ultrasound for wireless power supply and combines machine learning to monitor the pH of the fluid near the anastomosis to determine if leakage has occurred at the anastomosis. Background Technology

[0002] In recent years, homeostasis disruption has been proven to be a core component of the pathogenesis of many diseases, especially gastrointestinal diseases. Effective monitoring of physiological homeostasis is crucial for understanding pathophysiological processes and guiding clinical treatment. Particularly after gastric surgery, timely detection of changes in intraperitoneal pH can serve as an early indicator of potentially life-threatening leakage events.

[0003] To accurately and promptly assess pH changes in deep tissues, existing techniques typically rely on expensive imaging equipment such as computed tomography (CT) and magnetic resonance imaging (MRI), or invasive biopsies. However, these methods are not only costly but also require specialized equipment and technical support, limiting their widespread use and feasibility in routine clinical practice. Traditional diagnostic methods, such as abdominal radiography, are often performed only after patients present with obvious symptoms (such as abdominal pain or inflammation), potentially missing opportunities for early diagnosis and timely intervention. Especially after gastric surgery, leakage problems are often not detected promptly, increasing patient risk.

[0004] Meanwhile, current clinical practice often only intervenes when leakage causes significant inflammation or abdominal pain, thus missing the optimal intervention window. Traditional screening methods mainly rely on abdominal radiology, including upper gastrointestinal contrast radiography and computed tomography, to assess the quality or output changes of drainage fluid. Because these methods are time-delayed, they cannot accurately monitor early postoperative leakage. Therefore, there is an urgent need to develop new technologies that can promptly and accurately detect changes in gastric pH. Considering the high hydrogen ion concentration in gastric juice, the leakage fluid inside the gastric cavity exhibits higher acidity than other peritoneal fluids. Therefore, timely monitoring of gastric pH changes is crucial for medical personnel to implement early intervention and help prevent clinical sequelae.

[0005] Most current pH monitoring technologies rely on laboratory analysis; however, results often take a long time to return, ranging from at least half an hour to as long as half a day, making it difficult to take effective measures in emergency situations. Furthermore, in vitro pH detection technologies, such as electrochemical sensors (e.g., pH meters), suffer from low accuracy and large errors due to the complexity of the in vivo environment and numerous interfering factors. Their biocompatibility is also poor; materials like rigid glass or reference electrodes are unsuitable for long-term use in vivo. While some technologies use color sensors, such as pH test strips, they cannot be directly applied in the in vivo environment. Moreover, these test strips rely on visual color readings and comparison with color charts, which is highly subjective, especially for visually impaired individuals, whose color interpretation varies depending on individual differences.

[0006] Reports in authoritative journals such as *Science* indicate that pH can serve as an important indicator of gastrointestinal anastomotic leakage; monitoring the pH value of fluid accumulated near the anastomosis can assess whether leakage has occurred. However, the limitations of current pH detection technologies cannot be ignored: ① Long testing times in laboratories can lead to missed opportunities for optimal treatment. ② Specialized and expensive testing equipment. ③ The complex microenvironment in the body makes electrochemical sensing technology prone to errors, unsuitable for implantation. ④ Colorimetric strips rely on subjective readings. Furthermore, these technologies all have poor biocompatibility, making them unsuitable for implantation. Summary of the Invention

[0007] To address the above issues, this invention provides a wireless implantable pH sensor specifically developed for monitoring the pH value of fluids near the anastomosis site after gastrointestinal reconstruction surgery. Unlike existing technologies, this device enables continuous real-time monitoring, reducing the impact on patients and avoiding the risks associated with traditional invasive methods. Regarding biocompatibility, the sensor is specially designed for long-term use in vivo, reducing the risk of immune reactions and other physiological rejections. Compared to traditional pH measurement technologies, this wireless implantable pH sensor can detect gastrointestinal fluid leakage in real time, faster and at a lower cost. Furthermore, the device can directly transmit monitoring data to external devices, facilitating remote monitoring by doctors and eliminating subjective pH judgments. This technology not only improves detection accuracy but also significantly reduces the burden on patients and medical staff.

[0008] To solve the above-mentioned technical problems, the specific technical solution of the wireless implantable pH sensor for anastomotic monitoring after gastrointestinal reconstruction surgery of the present invention is as follows:

[0009] A wireless implantable pH sensor for monitoring anastomosis after gastrointestinal reconstruction surgery includes a piezoelectric transducer, a circuit module, a pH detection chamber, and an encapsulation layer.

[0010] The pH sensor is cylindrical in shape, with the pH detection chamber being annular. The circuit module and piezoelectric transducer are located in the annular chamber, and the encapsulation layer is on the upper and lower surfaces of the pH detection chamber, encapsulating the circuit module and piezoelectric transducer inside the annular chamber.

[0011] The circuit module includes a flexible substrate 1-2, a capacitor 1-3, a monitoring module 1-4, a Bluetooth module 1-5, and a control module 1-7. The capacitor, monitoring module, Bluetooth module, and their connecting circuits are integrated on the upper surface of the flexible substrate. A piezoelectric transducer 1-1 is connected to the lower surface of the flexible substrate. Silver electrodes are provided at both ends of the piezoelectric transducer 1-1. One side of the silver electrode of the piezoelectric transducer is integrated onto the flexible substrate using reflow soldering technology. Electrical connection between the silver electrode of the piezoelectric transducer and the flexible substrate is achieved through flying wires. The piezoelectric transducer receives ultrasonic signals from the outside to charge the capacitor, which in turn powers the circuit module.

[0012] The pH detection chamber consists of multiple arc-shaped chambers, each with two through holes on its surface, serving as an inlet and an outlet. The through holes are superhydrophobic-hydrophilic liquid diodes; liquid flows in through the inlet and out through the outlet, with no flow possible in the opposite direction. A control module is fixed to the inlet and sealed with lanolin; each arc-shaped chamber contains a pH-sensitive hydrogel.

[0013] The control module specifically includes a resistance wire 2-1, a Bluetooth module that controls the heating of the resistance wire, and the controlled heating of the resistance wire melts the lanolin, opening the drainage inlet 2-2 of the arc-shaped compartment.

[0014] After the control module is activated, the monitoring module detects the color of the pH-sensitive hydrogel and then sends the data to the terminal via Bluetooth. The terminal then converts the data into a pH value through program calculation.

[0015] Furthermore, the liquid diode includes an inlet end and an outlet end. The inlet end has a superhydrophobic coating with a contact angle ≥150°, and the outlet end has a hydrophobic coating with a contact angle ≤10°. The two ends form a wetting gradient interface with a contact angle difference ≥120°.

[0016] Furthermore, the pH-sensitive hydrogel is specifically a bromothymol blue-polyvinyl alcohol hydrogel.

[0017] Furthermore, the piezoelectric transducer is a lead zirconate titanate piezoelectric ceramic.

[0018] Furthermore, the monitoring module includes a white light-emitting diode and a three-color sensor. The pH detection chamber has a light transmittance of over 85%. When the control module completes its operation and the pH-sensitive hydrogel develops its color, the white light-emitting diode illuminates the pH-sensitive hydrogel. The three-color sensor reads the color of the pH-sensitive hydrogel and sends the data to the mobile phone via Bluetooth. If the measured pH of the peritoneal fluid is less than 6.5 and the pH of the intestinal fluid is less than 7.0, it indicates that the anastomosis has leaked.

[0019] Furthermore, the arc-shaped chamber of the pH detection chamber is opened sequentially in a controlled manner, and measurements are taken every 2 hours after the operation.

[0020] Furthermore, the entire circuit module is encapsulated using polydimethylsiloxane.

[0021] Furthermore, the pH sensor also includes an abdominal drainage tube, in which the pH sensor is placed and implanted near the gastric anastomosis.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. The implantable pH sensor provided by this invention has a very small overall shape, and its accuracy has been proven while ensuring biosafety, thus verifying the effectiveness of real-time monitoring.

[0024] 2. This invention can be implanted deep into the tissues of a living organism to collect ultrasonic energy, which is then converted into electrical signals based on the piezoelectric effect, thus achieving wireless power supply.

[0025] 3. This invention uses a self-made pH-sensitive hydrogel for colorimetric detection, and combined with machine learning, it can quickly process sensor data and calculate the real-time pH value.

[0026] 4. The pH sensor provided by this invention has a simple structure and uses an inexpensive pH hydrogel, which has a significant cost advantage over pH sensors in the prior art. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of a wireless implantable pH sensor according to an embodiment of the present invention;

[0028] Figure 2 This is an enlarged view of the control module of the wireless implantable pH sensor according to an embodiment of the present invention;

[0029] Figure 3 This is an enlarged view of the monitoring module of the wireless implantable pH sensor according to an embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram illustrating the application of the wireless implantable pH sensor according to an embodiment of the present invention.

[0031] Figure 5 This is a schematic diagram illustrating the working process of the wireless implantable pH sensor according to an embodiment of the present invention.

[0032] Figure 6 This is a comparison chart of data from in vitro detection of gastric and intestinal fluid in rat models using an implanted sensor.

[0033] Figure 7 This is a graph showing the pH changes in ascites fluid in a rat gastric wound leakage model. Detailed Implementation

[0034] To better understand the purpose, structure, and function of this invention, the following detailed description, in conjunction with the accompanying drawings, provides an example of a wireless implantable pH sensor for monitoring anastomotic sites after gastrointestinal reconstruction surgery.

[0035] This embodiment provides a wireless implantable sensor for monitoring the pH value of fluid accumulation near the anastomosis after gastrointestinal reconstruction surgery, the structure of which is as follows. Figure 1 As shown, it includes a piezoelectric transducer 1-1, a polyimide substrate 1-2, a capacitor 1-3, a monitoring module 1-4, a Bluetooth module 1-5, a pH detection chamber 1-6, a control module 1-7, and a flexible encapsulation layer 1-8.

[0036] Specifically, the overall device has a diameter of approximately 1.2 cm and a height of 0.7 cm, and is cylindrical in shape. The flexible substrate is a polyimide film, on which a flexible circuit is integrated. The flexible circuit includes capacitors 1-3, a monitoring module 1-4, and a Bluetooth module 1-5. A piezoelectric transducer 1-1 is connected to the lower surface of the flexible substrate. Silver electrodes are provided at both ends of the piezoelectric transducer 1-1. One side of the silver electrode of the piezoelectric transducer is integrated onto the flexible substrate using reflow soldering technology. The electrical connection between the silver electrode of the piezoelectric transducer and the flexible substrate is achieved through flying wires. The pH detection chamber is a ring chamber composed of multiple arc chambers. A flexible encapsulation layer is located on the upper and lower surfaces of the pH detection chamber, encapsulating the circuit module and the piezoelectric transducer within the ring.

[0037] Each arc-shaped chamber has two through-holes on its surface, including a drainage inlet 2-2 and a drainage outlet 2-4. A control module is fixed at the drainage inlet and sealed with lanolin, while the drainage outlet is not treated in this way. Each arc-shaped chamber contains a pH-sensitive hydrogel 2-3, which is water-soluble. The entire device is encapsulated on both the upper and lower surfaces using a flexible encapsulation layer. The drainage inlet can be opened in a controlled manner; after the hydrogel completes the detection, it liquefies and flows out from the drainage outlet to avoid affecting subsequent detections. The entire device is encapsulated on both the upper and lower surfaces using a flexible encapsulation layer. The arc-shaped chambers are opened sequentially in a controlled manner, and measurements are taken every 2 hours after surgery.

[0038] The through-hole is a superhydrophobic-hydrophilic liquid diode. The inflow end of the liquid diode is treated with superhydrophobicity, and the outflow end is treated with hydrophilicity, so the liquid can only flow from the inflow end to the outflow end, and cannot flow in the opposite direction. During testing, ascites fluid flows in from the inflow end of the drainage inlet and flows into the arc chamber from the outflow end. After passing through the pH hydrogel, the hydrogel melts into liquid and flows from the inflow end of the drainage outlet to the outflow end. This liquid diode utilizes the wetting gradient interface with a contact angle difference of ≥120° between the inflow and outflow ends, and relies on the capillary driving force at the outlet end to the resistance at the inflow end reaching a ratio of ≥5 to achieve directional fluid transport.

[0039] The pH-sensitive hydrogel uses polydimethylsiloxane (PDMS) as a substrate, on which a layer of polyvinyl alcohol (PVA) hydrogel containing bromothymol blue is fixed. The resulting hydrogel exhibits a color change range of pH 5.0-7.5, appearing yellow at pH 5.0 and turning blue at pH 7.5.

[0040] The PVA hydrogel dissolves in water and flows out as a liquid after the test is completed, without affecting subsequent tests in other circular chambers. Furthermore, the hydrogel material is harmless to the human body. This pH sensor is reusable; after all circular chamber tests are completed, simply replace the hydrogel inside the device.

[0041] The piezoelectric transducer 1-1 is a cylindrical lead zirconate titanate (PZT) piezoelectric ceramic with a diameter of 3 mm and a thickness of 2 mm. This piezoelectric material has excellent electrical properties and, through combination with silver electrodes, can effectively convert mechanical energy into electrical energy. Based on the piezoelectric effect, this invention can receive ultrasonic signals from an external source and use the ultrasonic energy to charge a capacitor, enabling real-time wireless power supply for monitoring. The capacitor powers the monitoring module, control module, and Bluetooth module.

[0042] like Figure 2 As shown, the control module specifically includes a micro-resistance wire, completely sealed with lanolin. The resistance wire is controlled to heat the lanolin, which melts at 40°C, opening the channel. The micro-resistance wire, controlled by a Bluetooth module, heats the lanolin, opening the channel and allowing the ascites fluid to come into contact with the pH hydrogel in the circular chamber at a 2-3° angle, causing the pH hydrogel to develop color.

[0043] like Figure 3As shown, the monitoring module consists of a white LED and a tri-color sensor to observe the color of the pH hydrogel. When the control module completes its operation and the pH hydrogel develops its color, the white LED 3-1 illuminates the hydrogel, and the tri-color sensor 3-2 reads the value and transmits the data to the mobile phone via Bluetooth. After processing, the data is converted into a directly readable pH value. The data measured by the sensors can be transmitted to the mobile phone via Bluetooth, processed on the phone, and directly converted into a pH value for viewing. If the measured pH of the peritoneal fluid is less than 6.5, or the pH of the intestinal fluid is less than 7.0, it indicates a leak at the anastomosis. The pH detection chamber is made using a negative mold method, and the material is PDMS, which has good flexibility and light transmittance, maintaining more than 85% light transmittance within the visible light range.

[0044] The flexible circuit consists of several key components, including a piezoelectric transducer, a capacitor, a tri-color sensor, and a light-emitting diode (LED). These components are encapsulated in polydimethylsiloxane (PDMS) to ensure good mechanical protection and electrical insulation. The entire flexible circuit is integrated on a polyimide substrate, providing excellent thermal stability and flexibility.

[0045] Furthermore, the flexible circuit is electrically connected to the miniature resistance wire via a reflow soldering process. This soldering process ensures smooth current flow throughout the system, improving the overall reliability of the circuit. The miniature resistance wire is sealed within a controlled channel using lanolin, and the opening of the channel is controlled by the circuitry.

[0046] In flexible circuits, piezoelectric transducers can effectively receive ultrasonic signals from external sources. Through the piezoelectric effect, the mechanical energy carried by these ultrasonic waves is converted into a piezoelectric signal. This signal is then sent to a rectifier bridge in the flexible circuit, which processes the piezoelectric signal into a square-wave DC signal. After rectification, this DC signal is used to charge the capacitor, thus providing a stable energy source for the system. This process not only improves energy utilization but also provides a reliable power supply for subsequent signal processing.

[0047] The device's flexible encapsulation layer uses polydimethylsiloxane (PDMS) material, a design that effectively isolates the device from the external environment after encapsulation. PDMS has excellent water resistance, enabling the device to operate stably in humid environments. Furthermore, this material exhibits excellent acid and alkali resistance, withstanding the corrosion of both strong acids and weak bases. More importantly, PDMS demonstrates good biocompatibility, making this encapsulation material particularly suitable for biomedical applications and effectively reducing the risk of interactions with living organisms.

[0048] In this embodiment, the external ultrasonic transmitter used is a cylindrical lead zirconate titanate piezoelectric ceramic with a diameter of 25 mm and a height of 4 mm. The device has an acoustic frequency of 0.5 MHz and an output power of 2 W. Ultrasonic waves are converted into piezoelectric signals by the ultrasonic transducer of the implanted ultrasonic patch, and the frequency of the piezoelectric signal matches the frequency of the received ultrasonic waves. This means that the system can efficiently capture and convert acoustic signals. After conversion, the voltage amplitude of the piezoelectric signal is approximately 30 V, and the short-circuit current is approximately 2.5 mA. These parameters indicate that the present invention has strong signal processing capabilities and energy conversion efficiency in practical applications, providing sufficient power support for actual tasks.

[0049] Figure 5 The flowchart of this system is shown. When the piezoelectric transducer receives ultrasound, it converts the ultrasound energy into electrical energy, which is stored in a capacitor to power the entire system. When a command is sent from the mobile phone, the Bluetooth module receives the command, the control module opens the controlled channel, and the monitoring module transmits the measured data back to the mobile phone via the Bluetooth module.

[0050] In the operating mode of an external ultrasonic transducer, the duty cycle is adjustable. This feature allows the ultrasonic transducer of an implantable ultrasonic patch to be matched with a modulated ultrasonic signal, thereby achieving the same period and duty cycle.

[0051] Figure 4 This is a schematic diagram of the operation of this embodiment, consisting of three parts: an abdominal drainage tube 4-1 and a wireless implantable pH sensor 4-2. The wireless implantable pH sensor is placed in the drainage tube and surgically implanted near the gastric anastomosis.

[0052] This embodiment also provides a method for preparing an implantable sensor for monitoring anastomotic pH after gastrointestinal reconstruction surgery:

[0053] Step 1: Fabrication of the flexible substrate. First, computer-aided design (CAD) is used for structural design, and then the polyimide film is patterned to fabricate the flexible substrate and conductive circuit.

[0054] Step 2: Integration of Flexible Circuits. Silver electrodes are located at both ends of the piezoelectric transducer. First, reflow soldering is used to integrate one side of the silver electrode of the piezoelectric transducer with components on the flexible substrate. Then, flying wires are used to electrically connect the silver electrode of the piezoelectric transducer to the flexible substrate. A similar method is used to solder the capacitor, monitoring module, and Bluetooth module into place. Finally, miniature resistance wires are connected to the flexible substrate using flying wires.

[0055] Step 3: Preparation of pH hydrogel: Add 10g of polyvinyl alcohol (PVA) to 55ml of pure water and rotate at 100 rpm for 90 minutes at 80℃ to completely dissolve the PVA in the pure water, obtaining a PVA solution. Dissolve 1ml of pentanediol and 0.3g of bromothymol blue in 5ml of methanol, and add them together with 5g of polyvinylpyrrolidone to the PVA solution, rotating at 100 rpm for 30 minutes. Select a circular PDMS film with a diameter of 5mm, a thickness of 0.2mm, and high light transmittance as a substrate, place it in the solution prepared above, and dry it in an oven at 45℃ for 1 day to obtain the pH hydrogel.

[0056] Step 4: Fabrication of the pH detection chamber. The negative molds for the upper and lower parts of the arc-shaped chamber are drawn using CAD and then manufactured using 3D printing technology. Next, polydimethylsiloxane (PDMS) is used for casting at 80°C for 2 hours. After drying, the chamber is demolded; the surface of the arc-shaped chamber has two through holes.

[0057] Step 5: Fabrication of the liquid diode; First, 100nm hydrophobic nanoparticles are uniformly sprayed onto the surfaces of the inlet and outlet ends of the via to form a superhydrophobic coating with a thickness of 10μm and a contact angle ≥150°; then, a blue photoresist film is used to fully protect the inlet end, with a 200μm safety margin reserved at the edges. At the outlet end, an annular mask is constructed to expose the central channel region, maintaining the ratio of the aperture diameter to the original channel diameter at 1.0; the system with the mask assembled is placed in a plasma processing chamber and processed for 90 seconds at 150W RF power in a 100Pa oxygen or air environment. This process reduces the contact angle of the exposed area at the outlet end to ≤10°, while the inlet end remains hydrophobic under the protection of the mask. Finally, by forming a wetting gradient interface with a contact angle difference ≥120° at both ends, the directional transport of fluid is achieved by relying on the ratio of capillary driving force at the outlet end to resistance at the inlet end reaching ≥5.

[0058] Step 6: Encapsulation of the entire device. The pH hydrogel is placed inside the arc-shaped chamber, and finally, the upper and lower parts of the arc-shaped chamber are bonded together using PDMS.

[0059] PDMS films were fabricated using spin coating, and the entire device was encapsulated in small batches multiple times. The final device had a diameter of approximately 1.2 cm and a height of 0.7 cm, and was cylindrical in shape.

[0060] This embodiment also provides an implantable sensor model for in vitro detection of rat gastric and intestinal fluids.

[0061] Step 1: Prepare, disinfect, and drape the abdomen of three anesthetized rats, placing them in a prone position. Inject 20 ml of buffered saline solutions with different pH values ​​(pH = 5.5, 7.2, 8.0) into the gastrointestinal anastomosis site to create fluid accumulation at the anastomosis. Half an hour later, aspirate the fluid from the rats using a syringe.

[0062] Step 3: Control the sensor to open the arc-shaped compartment, inject a small amount of gastrointestinal anastomosis fluid into the compartment to react with the pH hydrogel, measure the data and send it to the mobile phone for recording.

[0063] Step 4: Prepare solutions with pH values ​​of 5.5, 7.2, and 8.0 in vitro using hydrochloric acid, sodium hydroxide, and water. React these solutions with the hydrogel and then use this system to detect the reaction. The measured data is then sent to the mobile device for recording.

[0064] The pH hydrogel was placed inside the circular chamber beforehand. During testing, the drainage inlet of the circular chamber was opened, and the collected gastrointestinal fluid was reacted with the hydrogel. The results were then read and transmitted to a mobile phone via Bluetooth for viewing. We compared the two sets of measured data, and the results are as follows: Figure 6 As shown, the triaxial data X1, Y1, Z1 obtained from rat gastrointestinal fluid and the triaxial data X2, Y2, Z2 obtained from an in vitro prepared solution were compared. The results showed that the errors of the three sets of data were 0.188, 0.114, and 0.122, respectively. These two data indicate that the sensor has good accuracy and application potential.

[0065] Subsequently, triaxial data (X, Y, Z) at different pH values ​​were measured, and a linear regression model was used to fit these data. The triaxial data obtained in this invention are XYZ. These data models conform to the standard human eye response curve and reflect the response of long, medium, and short light cone cells in the retina to the spectral power distribution. The final fitting result has a determination coefficient (R²) greater than 0.95, indicating a good fitting effect. Based on this fitting function, corresponding software was developed, and machine learning technology was combined to import a large amount of X, Y, Z data at different pH values ​​into a database. When the triaxial values ​​X, Y, and Z acquired by the sensor are input, the system can calculate and output the corresponding pH value in real time.

[0066] This embodiment also provides an in vivo sensor model for monitoring leakage from gastric wounds in rats.

[0067] Step 1: Immerse the packaged sensor in a 70% ethanol solution for 30 minutes. Then, place the sensor in a laminar flow cell culture incubator and expose it to ultraviolet light for sterilization for 30 minutes. Finally, install the sensor in the drainage tube.

[0068] Step 2: Prepare and disinfect the abdomen of anesthetized rats that have been fasted for 12 hours, and drape it with surgical towels. Place the rats in a prone position. Then, make a longitudinal incision in the rat's abdomen, cutting through the skin, subcutaneous tissue, and muscle to fully expose the stomach. Ligate the duodenum for two hours to allow sufficient accumulation of the rat's gastric contents. Create a wound approximately 2 mm long at the pylorus of the stomach to allow the gastric contents to leak out.

[0069] Step 3: Place the drainage tube near the wound and suture the surgical site in the order of muscle, subcutaneous tissue, and skin.

[0070] Step 4: Inject phosphate-buffered saline (PBS) with a pH of 7.2 into the peritoneal cavity using a syringe.

[0071] Step 5: Apply sufficient ultrasound gel to the skin above the surgical area and use the ultrasound probe to charge the sensor through the piezoelectric transducer.

[0072] Step 6: Take readings at 0, 0.5, and 1 hour, and convert the data to pH values ​​using software. Plot the pH change curve of rat ascites fluid. The results are shown below. Figure 7 As shown.

[0073] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A wireless implantable pH sensor for monitoring of anastomotic leaks after gastrointestinal reconstruction surgery, characterized in that, The pH sensor comprises a piezoelectric transducer, a circuit module, a pH detection chamber and a packaging layer. The pH sensor is in a cylindrical shape as a whole, the pH detection chamber is in a circular ring shape, the circuit module and the piezoelectric transducer are located in the circular ring, and the packaging layer is arranged on the upper and lower surfaces of the pH detection chamber to encapsulate the circuit module and the piezoelectric transducer in the circular ring. The circuit module comprises a flexible substrate 1-2, a capacitor 1-3, a monitoring module 1-4, a Bluetooth module 1-5 and a control module 1-7, wherein the capacitor, the monitoring module, the Bluetooth module and the connecting circuit thereof are integrated on the upper surface of the flexible substrate, the lower surface of the flexible substrate is connected with the piezoelectric transducer 1-1, the piezoelectric transducer receives an ultrasonic signal from the outside to charge the capacitor, and the capacitor supplies power to the circuit module. The pH detection chamber is composed of a plurality of circular arc chambers, each of which has two through holes, which are a drainage inlet and a drainage outlet, respectively; the through holes are super-hydrophobic-hydrophilic liquid diodes, liquid flows into the drainage inlet and flows out of the drainage outlet, and the reverse direction is not available; the drainage inlet is fixed with the control module and is sealed with lanolin; each circular arc chamber is internally fixed with a pH-sensitive hydrogel. The control module specifically comprises a resistance wire 2-1, the Bluetooth module controls the control module to heat the resistance wire, the resistance wire is controlled to melt the lanolin, and the drainage inlet 2-2 of the circular arc chamber is opened. The monitoring module detects the color of the pH-sensitive hydrogel after the control module acts, then sends the data to the terminal through the Bluetooth module, and the terminal converts the data into a pH value after program operation.

2. A wireless implantable pH sensor for monitoring anastomotic site after gastrointestinal reconstruction surgery according to claim 1, characterized in that, The liquid diode comprises an inlet end and an outlet end, the inlet end has a super-hydrophobic coating with a contact angle ≥150°, the outlet end has a hydrophobic coating with a contact angle ≤10°, and the two ends form a wetting gradient interface with a contact angle difference ≥120°.

3. A wireless implantable pH sensor for monitoring anastomotic connections after gastrointestinal reconstruction surgery according to claim 2, characterized in that The pH-sensitive hydrogel is specifically bromothymol blue-polyvinyl alcohol hydrogel.

4. A wireless implantable pH sensor for monitoring anastomotic connections after gastrointestinal reconstruction surgery according to claim 3, characterized in that The piezoelectric transducer is a lead zirconate titanate piezoelectric ceramic, silver electrodes are arranged on the upper and lower ends of the piezoelectric transducer, one side of the silver electrode of the piezoelectric transducer is integrated on the flexible substrate by reflow soldering technology, and the electrical connection between the silver electrode of the piezoelectric transducer and the flexible substrate is realized by a flying wire.

5. A wireless implantable pH sensor for monitoring anastomotic connections after gastrointestinal reconstruction surgery according to claim 4, characterized in that The monitoring module comprises a white light-emitting diode and a three-color sensor, the pH detection chamber has a light transmittance of more than 85%, the white light-emitting diode illuminates the pH-sensitive hydrogel after the control module works and the pH-sensitive hydrogel develops color, the three-color sensor reads the color of the pH-sensitive hydrogel and sends the data to the mobile phone terminal through the Bluetooth module, and if the measured pH of the abdominal effusion is less than 6.5 and the pH of the intestinal effusion is less than 7.0, it indicates that the anastomotic leakage occurs.

6. A wireless implantable pH sensor for monitoring anastomotic connections after gastrointestinal reconstruction surgery according to claim 5, characterized in that The through holes of the circular arc chambers of the pH detection chamber are controlled to be opened in turn, and each measurement is performed every 2 hours after the operation.

7. A wireless implantable pH sensor for monitoring anastomotic connections after gastrointestinal reconstruction surgery according to claim 6, characterized in that The whole circuit module is packaged by polydimethylsiloxane.

8. A wireless implantable pH sensor for monitoring anastomotic connections after gastrointestinal reconstruction surgery according to claim 7, characterized in that The pH sensor further comprises an abdominal drainage tube, the pH sensor is placed in the abdominal drainage tube and is implanted near the gastric anastomotic stoma.

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