A biological tissue electric field feedback control system under the action of low-temperature plasma jet

Abstract

This invention discloses a biological tissue electric field feedback control system under the action of a low-temperature plasma jet, relating to the field of plasma technology. The system includes: a high-voltage reactor generating low-temperature plasma based on a high-frequency voltage; a microfluidic gas pump forming a plasma jet from the low-temperature plasma generated by the high-voltage reactor through a gas flow rate; when the plasma jet acts on biological tissue, a photoelectric effect electric field sensor collects the electric field signal of the biological tissue and sends the electric field signal to a computer core control system; the computer core control system generates a first control signal and a second control signal based on the electric field signal, and adjusts the amplitude and frequency of the high-frequency voltage output by the high-voltage reactor through the first control signal, and adjusts the gas flow rate of the microfluidic gas pump through the second control signal to adjust the output intensity of the plasma jet. This system reduces the safety risk of tissue damage caused by excessively strong electric fields and improves the electrical safety of clinical applications.

Description

Technical Field

[0001] This application relates to the field of plasma technology, and in particular to a biological tissue electric field feedback control system under the action of a low-temperature plasma jet. Background Technology

[0002] Low-temperature plasma jets can generate discharges rich in electrons, ions, and reactive oxygen and nitrogen components under ambient temperature and pressure conditions. As a flexible and dry biomedical treatment method, it has been widely used in the biomedical field for disinfection, sterilization, hemostasis and coagulation, wound repair, and cancer treatment, demonstrating broad clinical application potential. Macroscopically, low-temperature plasma jets are generated by high-voltage alternating current or pulsed ionization breakdown of helium, neon, argon, nitrogen, or air, ejecting columnar or brush-like plumes under the combined action of a flow field and an electric field. Microscopically, the luminous plume of the jet is often formed by the accumulation of a series of periodically repetitive moving ionized waves.

[0003] When a plasma jet acts on the human body, the large number of electrons and ions generated by the discharge are injected into biological tissues. If the flux of these injected charged particles is too high, it can pose an electrical safety risk to the contacting biological tissues and even the human body. Diagnosing and controlling the electrons, ions, and the induced electric field is a prerequisite for ensuring safe contact with the human body. Therefore, when a low-temperature plasma jet acts on biological tissues, it is necessary to diagnose and control the flux of electrons and ions generated and the induced electric field.

[0004] The clinical application of low-temperature plasma jets not only needs to consider the biological effects of active ingredients, but also needs to assess the electrical safety of the jet discharge acting on human tissues in advance. Existing solutions mainly rely on detecting the discharge circuit current and suppressing the discharge current by increasing the equivalent impedance between the plasma and the human body circuit. In fact, this open-loop control method mainly suffers from impedance heating failure and poor applicability to operating conditions, resulting in the safety risk of biological tissue damage when low-temperature plasma jets act on biological tissues. Summary of the Invention

[0005] Therefore, it is necessary to provide a biological tissue electric field feedback control system under the action of low-temperature plasma jet to address the above-mentioned technical problems.

[0006] The following technical solution is adopted in this specification: This specification provides a biological tissue electric field feedback control system under the action of low-temperature plasma jet. The system includes: a microfluidic pump, a photoelectric effect electric field sensor, a high-voltage reactor, and a computer core control system; the photoelectric effect electric field sensor is attached to the surface of the biological tissue. High-voltage reactors are used to generate low-temperature plasma based on high-frequency voltages. A microfluidic gas pump is used to form a plasma jet from the low-temperature plasma generated by a high-voltage reactor by controlling the gas flow rate. The photoelectric effect electric field sensor is used to collect the electric field signal of biological tissue when a plasma jet acts on it, and then send the electric field signal to the core computer control system. The computer core control system is used to generate a first control signal for the high-voltage reactor and a second control signal for the microfluidic gas pump based on the electric field signal. The first control signal is used to adjust the amplitude and frequency of the high-frequency voltage output by the high-voltage reactor, and the second control signal is used to adjust the gas flow rate of the microfluidic gas pump to adjust the output intensity of the plasma jet.

[0007] Optionally, the system also includes an optocoupler isolation drive circuit, a first adjustable DC switching power supply, a full-bridge inverter circuit, and a high-frequency transformer; the first control signal includes a first level control signal and a PMW signal; The computer core control system sends a first-level control signal to the first adjustable DC switching power supply to control the output voltage of the first adjustable DC switching power supply, and sends a PWM signal to the optocoupler isolation drive circuit. The optocoupler-isolated drive circuit is used to receive the electric field signal collected by the photoelectric effect electric field sensor and stop working when the electric field signal is greater than the preset electric field threshold. During normal operation, it outputs the drive signal of the full-bridge inverter circuit according to the received PWM signal to adjust the switching frequency of the full-bridge inverter circuit. The switching frequency range of the full-bridge inverter circuit is 10-50kHz. The full-bridge inverter circuit is used to convert the DC voltage output by the first adjustable DC switching power supply into AC voltage and output the AC voltage at the corresponding switching frequency. The high-frequency transformer is used to boost the AC voltage output from the full-bridge inverter circuit and use the boosted AC high voltage as the power supply voltage for the high-voltage reactor through the high-voltage lead; the AC high voltage range after boosting by the high-frequency transformer is 0-15kV; the high-frequency voltage induces ionization to generate plasma.

[0008] Optionally, the system includes a second adjustable DC switching power supply; the second control signal is a second-level control signal; The computer core control system is used to send a second-level control signal to the second adjustable DC switching power supply to adjust the output voltage of the second adjustable DC switching power supply; the gas flow rate range of the microfluidic air pump is 0-15 L / min.

[0009] The second adjustable DC switching power supply is used to control the gas flow rate of the microfluidic pump through the output voltage.

[0010] Optionally, the system also includes an integrated power supply circuit and a power supply, wherein the power supply is AC power frequency voltage; The power supply is used to supply power to the first adjustable DC switching power supply, the integrated power supply circuit, and the second adjustable DC switching power supply, respectively. An integrated power supply circuit is used to convert AC voltage to DC voltage to power the computer core control system and the optocoupler isolation drive circuit.

[0011] Optionally, the computer core control system includes instruction setting buttons, including instructions for increasing voltage, frequency, switching the jet on and off, and increasing the flow rate; The computer-based core control system is used to receive external input commands via instruction settings buttons, and output control signals for the high-voltage reactor and microfluidic pump based on the external input commands.

[0012] Optionally, the photoelectric effect electric field sensor includes a photoelectric conversion unit and an all-dielectric sensor; The all-dielectric sensor is used to monitor the electric field distribution of biological tissues in the plasma interaction area in real time, and transmits the collected optical signals to the photoelectric conversion unit via optical fiber. The photoelectric conversion unit is used to convert optical signals into electric field signals.

[0013] Optionally, the photoelectric conversion unit includes a laser chip and a photodetector; the all-dielectric sensor includes a polarizer, an 1 / 8 wave plate, an electro-optic crystal, and an analyzer. When the photoelectric effect electric field sensor is working, the laser chip emits a laser beam, which enters the all-dielectric sensor. In the all-dielectric sensor, a polarizer and an 1 / 8 waveplate receive the laser beam to adjust the polarization state of the incident light. A polarization-maintaining fiber transmits the incident light to an electro-optic crystal. The electro-optic crystal forms a ridge waveguide through ultraviolet lithography. This waveguide is in the form of a grid loop. An analyzer is located at the output end of the electro-optic crystal to detect the change in the polarization state of the light after electric field modulation. The photodetector converts the optical signal output by the analyzer into an electrical signal.

[0014] Optionally, the system employs a patch-type photoelectric effect electric field sensor array structure, in which multiple all-dielectric sensors are integrated and arranged in a square array on the surface of biological tissue.

[0015] This specification provides a method for feedback control of the electric field of biological tissue under the action of a low-temperature plasma jet. This method is applied to the aforementioned feedback control system for the electric field of biological tissue under the action of a low-temperature plasma jet. The method includes: Collect the electric field signal generated by the plasma jet acting on biological tissue; Calculate the potential distribution of biological tissues based on the inversion of electric field signals; Based on the potential distribution of biological tissue, a first control signal for the high-voltage reactor and a second control signal for the microfluidic pump are generated. The amplitude and frequency of the high-frequency voltage output by the high-voltage reactor are adjusted by the first control signal, and the gas flow rate of the microfluidic pump is adjusted by the second control signal to adjust the output intensity of the plasma jet.

[0016] Optionally, based on the electrical potential distribution of biological tissue, a first control signal for the high-voltage reactor and a second control signal for the microfluidic pump are generated, including: Calculate the electric field strength on the surface of biological tissue based on the electric potential distribution of biological tissue; The risk index is determined based on the electric field safety threshold corresponding to the electric field strength and frequency of the electric field signal on the surface of biological tissue. The average current is calculated based on the electrical potential distribution of biological tissue and the preset conductivity. Based on the risk index and average current, determine whether there is an electrical safety risk; If an electrical safety risk exists, determine whether it constitutes a high safety risk; if it constitutes a high safety risk, shut down the full-bridge inverter circuit and shut down the microfluidic pump and photoelectric effect electric field sensor; if it does not constitute a high safety risk, generate the first control signal for the high-voltage reactor and the second control signal for the microfluidic pump. If there is no electrical safety risk, the system determines whether to stop the jet based on the completion status of the plasma jet's task and external inputs such as the external signal stop control signal. If the jet is stopped, the full-bridge inverter circuit, microfluidic pump, and photoelectric effect electric field sensor are turned off. If the jet is not stopped, a first control signal for the high-voltage reactor and a second control signal for the microfluidic pump are generated.

[0017] This specification provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for feedback control of the electric field of biological tissue under the action of a low-temperature plasma jet.

[0018] This specification provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the above-described method for feedback control of the electric field of biological tissue under the action of a low-temperature plasma jet.

[0019] The above-mentioned technical solutions adopted in this specification can achieve the following beneficial effects: In the low-temperature plasma jet-induced biological tissue electric field feedback control system provided in this manual, a photoelectric effect electric field sensor placed within the biological tissue measures the electric field distribution within the tissue in real time, without contact. The measured electric field signal is then fed back to the core computer control system to dynamically adjust the amplitude and frequency of the high-frequency voltage output from the high-voltage reactor, as well as the gas flow rate of the microfluidic pump. This allows for real-time adjustment of the plasma jet's electrical parameters, ensuring that the electric field within the tissue remains within a safe threshold. This system effectively avoids the problems of impedance heating, poor adaptability to operating conditions, and inability to respond to changes in the tissue's electric field in real time, as present in existing open-loop control schemes. It achieves real-time adaptive adjustment of the plasma jet's electrical parameters, effectively reducing the safety risk of tissue damage caused by excessively strong electric fields and improving the electrical safety and clinical applicability of plasma medical equipment. Attached Figure Description

[0020] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0021] Figure 1 This specification provides an architecture diagram of a biological tissue electric field feedback control system under the action of a low-temperature plasma jet; Figure 2 This specification provides a schematic diagram of a plasma control principle based on feedback control of biological tissue electric field signals. Figure 3 This specification provides a plasma excitation power supply topology based on biological tissue electric field signal feedback control. Figure 4 This is a structural diagram of a miniature photoelectric effect electric field sensor provided in this specification; Figure 5 This specification provides a schematic diagram of a photoelectric effect electric field sensor used to measure the electric field distribution in biological tissues. Figure 6 This specification provides a schematic diagram of an arrangement for measuring plasma jets using a photoelectric effect electric field sensor. Figure 7 A schematic diagram of a patch-type photoelectric effect electric field sensor array used in this specification is provided. Figure 8 This is a schematic diagram of a method for feedback control of the electric field of biological tissue under the action of a low-temperature plasma jet, as provided in this specification. Figure 9 This is a schematic diagram of another method for feedback control of the electric field of biological tissue under the action of low-temperature plasma jet, as provided in this specification.

[0022] Explanation of reference numerals in the attached figures: 101. Microfluidic air pump; 102. Photoelectric effect electric field sensor; 103. High-voltage reactor; 104. Computer core control system; 105. Optocoupler isolated drive circuit; 106. First adjustable DC switching power supply; 107. Full-bridge inverter circuit; 108. High-frequency transformer; 109. Second adjustable DC switching power supply; 110. Integrated power supply circuit; 201. Photoelectric conversion unit; 202. All-dielectric sensor; 203. Integrated power supply unit; 301. Laser chip; 302. Photodetector; 303. Polarizer; 304. 1 / 8 waveplate; 305. Electro-optic crystal; 306. Analyzer; 307. Polarization-maintaining fiber; 308. Ridge waveguide; 401. Polarizing beam splitter; 501. Plasma jet. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this specification clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments in this specification without creative effort are within the scope of protection of this application.

[0024] Existing methods all calculate the electrical parameters of biological tissues by measuring the current signal in the plasma region. However, due to the strong nonlinearity of gas discharge parameters and the complexity of the equivalent electrical parameters of biological tissues, existing technologies cannot directly reflect the actual charge and electric field in the tissue. There is an urgent need for a non-invasive, in-situ method to measure the electric field characteristics of the interaction between plasma and biological tissues.

[0025] Therefore, this invention provides a biological tissue electric field feedback control system under the action of a low-temperature plasma jet, solving the problems of difficulty in measuring the electrical parameters of biological tissue and poor stability of plasma parameter control in existing technologies. This system can measure the electric field and charge parameters of biological tissue under the action of a plasma jet in situ, in real time, and non-invasively, providing a quantitative reference for assessing electrical safety. Furthermore, it provides a plasma power supply control strategy based on the feedback of the biological tissue electric field signal, offering a solution for the standardization and clinical application of plasma jet medical devices.

[0026] The technical solutions provided by the various embodiments of this application are described in detail below with reference to the accompanying drawings.

[0027] Figure 1This is a schematic diagram of a biological tissue electric field feedback control system under the action of a low-temperature plasma jet, as described in this specification. Specifically, it includes: a microfluidic pump 101, a photoelectric effect electric field sensor 102, a high-voltage reactor 103, and a computer core control system 104. The photoelectric effect electric field sensor 102 is attached to the surface of the biological tissue.

[0028] High-voltage reactor 103 is used to generate low-temperature plasma based on high-frequency voltage.

[0029] The microfluidic gas pump 101 is used to form a plasma jet from the low-temperature plasma generated by the high-voltage reactor 103 by means of gas flow rate.

[0030] The photoelectric effect electric field sensor 102 is used to collect the electric field signal of the biological tissue when the plasma jet acts on the biological tissue, and send the electric field signal to the computer core control system 104.

[0031] The computer core control system 104 is used to generate a first control signal for the high-voltage reactor 103 and a second control signal for the microfluidic pump 101 based on the electric field signal. The first control signal is used to adjust the amplitude and frequency of the high-frequency voltage output by the high-voltage reactor 103, and the second control signal is used to adjust the gas flow rate of the microfluidic pump 101 to adjust the output intensity of the plasma jet.

[0032] Optionally, the computer core control system 104 can have a built-in control strategy model. After receiving the electric field signal, the computer core control system 104 inputs the electric field signal to the control strategy model to obtain a first control signal for the high-voltage reactor 103 and a second control signal for the microfluidic pump 101. The output amplitude of the high-voltage power supply is adjusted by the first control signal, and the output intensity of the plasma jet is updated by the second control signal.

[0033] In one embodiment, such as Figure 2 As shown, Figure 2 This is a schematic diagram of plasma control based on feedback control of biological tissue electric field signals. The system also includes an optocoupler isolation drive circuit 105, a first adjustable DC switching power supply 106, a full-bridge inverter circuit 107, and a high-frequency transformer 108; the first control signal includes a first level control signal and a PMW signal.

[0034] The computer core control system 104 sends a first-level control signal to the first adjustable DC switching power supply 106 to control the output voltage of the first adjustable DC switching power supply 106, and sends a PWM signal to the optocoupler isolation drive circuit 105.

[0035] The optocoupler isolation drive circuit 105 is used to receive the electric field signal collected by the photoelectric effect electric field sensor 102, and to stop working when the electric field signal is greater than the preset electric field threshold; and during normal operation, it outputs the drive signal of the full-bridge inverter circuit 107 according to the received PWM signal to adjust the switching frequency of the full-bridge inverter circuit 107; the switching frequency range of the full-bridge inverter circuit 107 is 10-50 kHz.

[0036] The full-bridge inverter circuit 107 is used to convert the DC voltage output by the first adjustable DC switching power supply 106 into AC voltage, and output the AC voltage at the corresponding switching frequency.

[0037] The high-frequency transformer 108 is used to boost the AC voltage output by the full-bridge inverter circuit 107 and use the boosted AC high voltage as the power supply voltage for the high-voltage reactor 103 through the high-voltage lead; the AC high voltage range after boosting by the high-frequency transformer 108 is 0-15kV; the high-frequency voltage induces ionization to generate plasma.

[0038] Optionally, the first adjustable DC switching power supply 106 outputs an adjustable DC voltage, and the full-bridge inverter circuit 107 converts the first adjustable DC switching power supply 106 into an AC voltage, which is then generated by the high-frequency transformer 108. The AC high voltage can be used as the power supply voltage for the high-voltage reactor 103 through the high-voltage lead, thereby initiating ionization to generate plasma.

[0039] The computer core control system 104 outputs a PWM signal to the optocoupler-isolated drive circuit 105, which outputs a drive signal to the full-bridge inverter circuit 107. This controls the switching frequency of the full-bridge inverter circuit 107, allowing the frequency of the AC voltage output by the full-bridge inverter circuit 107 to be adjustable within the range of 10-50 kHz. The first-level signal output by the computer core control system 104 controls the output voltage of the first adjustable DC switching power supply 106, ultimately controlling the high-voltage amplitude of the high-voltage reactor 103.

[0040] Please continue reading Figure 2 The system also includes a second adjustable DC switching power supply 109; the second control signal is a second level control signal.

[0041] The computer core control system 104 is used to send a second-level control signal to the second adjustable DC switching power supply 109 to adjust the output voltage of the second adjustable DC switching power supply 109. The second adjustable DC switching power supply 109 is used to control the gas flow rate of the microfluidic pump 101 through the output voltage; the gas flow rate range of the microfluidic pump 101 is 0-15 L / min.

[0042] Please continue reading Figure 2 The system also includes an integrated power supply circuit 110 and a power supply, which is powered by AC power frequency voltage.

[0043] The power supply is used to supply power to the first adjustable DC switching power supply 106, the integrated power supply circuit 110, and the second adjustable DC switching power supply 109, respectively.

[0044] The integrated power supply circuit 110 is used to convert AC voltage into DC voltage to power the computer core control system 104 and the optocoupler isolation drive circuit 105, respectively. Optionally, the integrated power supply circuit 110 converts AC voltage into various DC voltages required by the system to power the computer core control system 104 and the optocoupler isolation drive circuit 105, respectively.

[0045] In one embodiment, the computer core control system 104 includes instruction setting buttons, including instructions to increase voltage, frequency, switch the jet, and increase flow rate; the computer core control system 104 is used to receive externally input instructions through the instruction setting buttons, and output control signals for the high-voltage reactor 103 and the microfluidic pump 101 according to the externally input instructions.

[0046] In this system, a plasma jet acts on biological tissue. A photoelectric effect electric field sensor 102 monitors the electric field in real time, and the electric field signal obtained through photoelectric conversion is fed back to an optocoupler-isolated drive circuit 105 and a computer core control system 104. The optocoupler-isolated drive circuit 105 directly adjusts the frequency of the drive signal of the full-bridge inverter circuit 107 based on the feedback signal, controlling the output amplitude and frequency of the full-bridge inverter circuit 107, and indirectly controlling the high-frequency, high-voltage high-voltage high-voltage reactor 103, ensuring that the electric field surrounding the biological tissue remains within a safe range. The computer core control system 104 determines the current electrical safety status based on a preset safety threshold and the real-time electric field value, and adjusts the output control signal to control the high-voltage amplitude and frequency of the high-voltage reactor 103 and the gas flow rate of the microfluidic pump 101, ensuring that the plasma jet environment surrounding the biological tissue remains within a safe range. This achieves real-time monitoring and control of electrical safety, and the entire system constitutes a closed-loop control. This invention, by constructing a closed-loop feedback mechanism, improves the safety and controllability of plasma medical equipment in clinical applications.

[0047] In one embodiment, the photoelectric effect electric field sensor 102 includes a photoelectric conversion unit 201 and an all-dielectric sensor 202; the all-dielectric sensor 202 is used to monitor the electric field distribution of biological tissue in the plasma interaction area in real time and transmit the collected light signal to the photoelectric conversion unit 201 via optical fiber; the photoelectric conversion unit 201 is used to convert the light signal into an electric field signal.

[0048] like Figure 3 As shown, Figure 3The diagram shows a plasma excitation power supply topology based on biological tissue electric field signal feedback control. It includes an integrated power supply unit 203, an optocoupler-isolated drive circuit 105, a first adjustable DC switching power supply 106, a full-bridge inverter circuit 107, a high-frequency transformer 108, a computer core control system 104, a microfluidic pump 101, a photoelectric conversion unit 201, an all-dielectric sensor 202, and a high-voltage reactor 103. This topology uses industrial frequency AC power as input, which is converted by the integrated power supply unit 203 into various DC voltages required by the system, supplying power to the computer core control system 104, the optocoupler-isolated drive circuit 105, and the microfluidic pump 101. It should be noted that, to simplify the power supply circuit, the integrated power supply unit 203 is represented by the integrated power supply circuit 110 and the second adjustable DC switching power supply 109.

[0049] The first adjustable DC switching power supply 106 receives a first-level signal from the computer core control system 104, outputs an adjustable DC voltage, which is converted into AC voltage by the full-bridge inverter circuit 107, and then boosted by the high-frequency transformer 108. The output high-frequency high voltage drives the high-voltage reactor 103 to output a plasma jet. The all-medium sensor 202 monitors the electric field distribution of biological tissue within the plasma interaction area in real time, and the output optical signal is transmitted to the photoelectric conversion unit 201 via optical fiber, converting the optical signal into an electric field signal.

[0050] The output electric field signal is fed back to the optocoupler isolation drive circuit 105 and the computer core control system 104. The optocoupler isolation drive circuit 105 changes the frequency of the drive signal of the switching transistor of the full-bridge inverter circuit 107 according to the electric field signal, and directly controls the output AC voltage of the full-bridge inverter circuit 107. The computer core control system 104 calculates the electric field distribution of biological tissue based on the electric field signal, assesses electrical risks, and dynamically adjusts the voltage and frequency of the power supply output, the flow rate of the gas pump, etc. This topology realizes closed-loop control of the plasma jet.

[0051] In one embodiment, such as Figure 4 As shown, Figure 4 This is a structural diagram of the miniature photoelectric effect electric field sensor in this invention. The photoelectric conversion unit 201 includes a laser chip 301 and a photodetector 302; the all-dielectric sensor 202 includes a polarizer 303, a 1 / 8 wave plate 304, an electro-optic crystal 305, and an analyzer 306.

[0052] In this design, the laser chip 301 and photodetector 302 are placed on the remote data acquisition side, and both are independently powered by a dedicated power module. Optical modulation elements such as the polarizer 303, 1 / 8 wave plate 304, electro-optic crystal 305, and analyzer 306 are integrated into an all-dielectric sensor to further ensure the stability of the polarization state of the optical signal in the electro-optic crystal 305. Optical signals are transmitted between the light source, sensor probe, and photodetector 302 via polarization-maintaining fiber 307, effectively avoiding electromagnetic interference issues during electrical signal transmission.

[0053] When the photoelectric effect electric field sensor 102 is working, the laser chip 301 acts as a light source, emitting a laser beam. The emitted laser beam enters the all-dielectric sensor 202, which outputs different optical signals according to the electric field strength. In the all-dielectric sensor 202, the polarizer 303 and the 1 / 8 waveplate 304 receive the laser beam to adjust the polarization state of the incident light. The polarization-maintaining fiber 307 transmits the incident light to the electro-optic crystal 305. The electro-optic crystal 305 forms a ridge waveguide 308 through ultraviolet lithography. This waveguide is in the form of a grating loop. The analyzer 306 is located at the output end of the electro-optic crystal 305 to detect the change in the polarization state of the light after being modulated by the electric field. The photodetector 302 converts the optical signal output by the analyzer 306 into an electrical signal. The ridge waveguide 308 in the form of a grating loop allows light to propagate through multiple reflections within a finite size, significantly increasing the interaction length between light and the electric field and improving the sensing sensitivity.

[0054] A laser beam enters the all-dielectric sensor 202, and after its polarization state is adjusted by the polarizer 303 and the 1 / 8 wave plate 304, it is incident on the electro-optic crystal 305. When the crystal is in an external electric field, its refractive index changes with the electric field strength, causing the polarization state of the light passing through the crystal to be deflected. This deflected output light is converted by the analyzer 306 and finally converted into a voltage signal by the photodetector 302, realizing the measurement of the target electric field.

[0055] In one embodiment, such as Figure 5 As shown, Figure 5 This is a schematic diagram of the principle of measuring the electric field distribution in biological tissue using the photoelectric effect electric field sensor of this invention. The diagram includes a polarizing beam splitter prism 401, a 1 / 8 wave plate 304, a polarization-maintaining fiber 307, an electro-optic crystal 305, and a photodetector 302.

[0056] The polarization beam splitter 401 (polarizer 303 and analyzer 306) separates the incident and reflected light and adjusts the polarization direction of the incident light. An 8 / 10 waveplate 304 adjusts the polarization state of the incident light. A polarization-maintaining fiber 307 transmits the incident light to the electro-optic crystal 305 and the light emitted from the electro-optic crystal 305 to the optical path. The polarization-maintaining fiber 307 employs a specific geometric design. During the packaging process of the optical electric field sensor, the polarization direction of the analyzer 306 must be precisely aligned with the principal axis of the polarization-maintaining fiber 307 to maintain a stable polarization state of the output light signal, ensuring the accuracy of the final photoelectric conversion signal and the reliability of the system measurement. The electro-optic crystal 305 is relatively thin, effectively reducing the photoelastic effect caused by thermal expansion and improving the crystal's environmental adaptability. The waveguide is designed as a grating loop, allowing light to propagate through multiple reflections within the crystal. The photodetector 302 converts the electric field-modulated reflected light signal into an electrical signal.

[0057] After the laser beam's polarization state is adjusted by a polarization beam splitter 401 and an 8 / 10 wave plate 304, it is incident on an electro-optic crystal 305 through a polarization-maintaining fiber 307. When the electro-optic crystal 305 is placed on the surface of biological tissue, the tissue's electric field causes a change in the crystal's refractive index, resulting in a deflection of the polarization state of the light passing through the crystal. The modulated light signal returns to the polarization beam splitter 401 and finally enters the photodetector 302, where it is converted into an electrical signal, enabling high-precision, real-time measurement of the electric field distribution in biological tissue.

[0058] In one embodiment, such as Figure 6 As shown, Figure 6 This is a schematic diagram of the arrangement of the photoelectric effect electric field sensor for measuring plasma jets according to the present invention. The diagram includes a photodetector 302, a polarization-maintaining fiber 307, an all-dielectric sensor 202, and a plasma jet 501.

[0059] The all-dielectric sensor 202 is placed on the surface of the plasma jet output system housing. The electric field near the crystal causes a change in the crystal's refractive index, resulting in a deflection of the polarization state of the light passing through the crystal. The modulated optical signal is returned to the polarization-maintaining fiber 307 and transmitted to the photodetector 302, where the optical signal is converted into an electrical signal, thus enabling the measurement of the electric field on the surface affected by the plasma jet.

[0060] In one embodiment, the system employs a patch-type photoelectric effect electric field sensor array structure, in which multiple all-dielectric sensors 202 are integrated and arranged in a square array on the surface of biological tissue. Figure 7 As shown, Figure 7This is a schematic diagram of the patch-type photoelectric effect electric field sensor array used in this invention. The diagram includes a plasma jet 501 and four all-dielectric sensors 202. The diagram illustrates the plasma jet 501 generated by the system acting on the surface of biological tissue. The four all-dielectric sensors 202 are integrated in a square array on the surface of the biological tissue to measure the electric field around the surface and output optical signals through a polarization-maintaining fiber 307. This achieves high-resolution, multi-directional, synchronous monitoring of the electric field on the surface of biological tissue.

[0061] The above are one or more embodiments of the biological tissue electric field feedback control system under the action of a low-temperature plasma jet provided in this specification. Based on the same idea, this specification also provides a corresponding biological tissue electric field feedback control method under the action of a low-temperature plasma jet. This method is applied to the above-mentioned biological tissue electric field feedback control system under the action of a low-temperature plasma jet, such as... Figure 8 As shown, the method includes the following steps: S801 collects the electric field signal generated by the plasma jet acting on biological tissue.

[0062] S802, calculates the potential distribution of biological tissues based on the electric field signal inversion.

[0063] S803 generates a first control signal for the high-voltage reactor and a second control signal for the microfluidic pump based on the potential distribution of biological tissue. The amplitude and frequency of the high-frequency voltage output by the high-voltage reactor are adjusted by the first control signal, and the gas flow rate of the microfluidic pump is adjusted by the second control signal to adjust the output intensity of the plasma jet.

[0064] In one embodiment, generating a first control signal for the high-voltage reactor and a second control signal for the microfluidic pump based on the potential distribution of the biological tissue includes: calculating the electric field strength on the surface of the biological tissue based on the potential distribution of the biological tissue; determining a risk index based on the electric field strength on the surface of the biological tissue and the electric field safety threshold corresponding to the frequency of the electric field signal; calculating the average current based on the potential distribution of the biological tissue and a preset conductivity; determining whether there is an electrical safety risk based on the risk index and the average current; if there is an electrical safety risk, determining whether it constitutes a high safety risk; if it constitutes a high safety risk, shutting down the full-bridge inverter circuit and shutting down the microfluidic pump and the photoelectric effect electric field sensor; if it does not constitute a high safety risk, generating the first control signal for the high-voltage reactor and the second control signal for the microfluidic pump; if there is no electrical safety risk, determining whether to stop the jet based on the completion status of the plasma jet's task and external input; if the jet is stopped, shutting down the full-bridge inverter circuit and shutting down the microfluidic pump and the photoelectric effect electric field sensor; if the jet is not stopped, generating the first control signal for the high-voltage reactor and the second control signal for the microfluidic pump.

[0065] In one embodiment, the present invention also provides a method for feedback control of the electric field of biological tissue under the action of a low-temperature plasma jet, such as... Figure 9 As shown, this embodiment includes the following steps: S901, introduce working gas.

[0066] S902, to excite the plasma jet.

[0067] S903, activate the photoelectric effect electric field sensor.

[0068] S904, plasma jet acts on biological tissue.

[0069] S905, a photoelectric effect electric field sensor for measuring the electric field of biological tissues.

[0070] S906, Inversion calculation of electrical potential distribution in biological tissues.

[0071] The electric field intensity vector measurements at multiple spatial locations obtained from the photoelectric effect electric field sensor are used to determine the relationship between electric potential (φ) and electric field (E) according to electrostatic theory. The potential distribution of biological tissues can be solved by inversion from the measured electric field distribution.

[0072] The specific calculation process begins with spatial discretization, dividing the surface area of ​​the biological tissue covered by the sensor array into a grid. An inversion equation is then constructed, assuming no free charges (or a known charge distribution) within the measurement region, and that the electric potential satisfies the Laplace equation. By combining boundary conditions, the continuous partial differential equations are discretized into a system of linear equations. Here, A is the coefficient matrix, determined by the discretization scheme and grid size. Φ is the potential distribution at the grid nodes to be determined, and B is a vector composed of boundary electric field measurements. Finally, the system of equations is solved to calculate the potential values ​​at each node, outputting the potential distribution on the surface of the biological tissue. This potential distribution can then be obtained using the formula... Calculate the electric field strength on the surface of biological tissue. , This indicates the distance between two measurement points.

[0073] S907 combines electric field and frequency to perform electrical risk calculations.

[0074] The electrical risks of biological tissues are related to both the electric field strength and frequency. For specific risk assessment, refer to the electric field versus frequency curves in medical electrical safety standards such as IEC 60601.

[0075] Output the calculated surface electric field strength of biological tissue Given the frequency f of the electric field signal, query the electric field safety threshold corresponding to the preset frequency. Calculate the risk index .

[0076] S908, associated with electric field and frequency, evaluates average current.

[0077] Based on the obtained potential distribution of biological tissue and the equivalent impedance model parameters of biological tissue (preset tissue conductivity σ), and combined with the frequency f of the electric field, the differential form of Ohm's law is used. J is the current density, and the average current is evaluated by integrating the current density over the region of action.

[0078] The specific calculation process begins with calculating the current density distribution. Integrating the current density over the selected area The average current is obtained. The calculation results are compared with the average current that guarantees safety at that electric field frequency as specified in the electrical safety standard. The ratio between this average current and the average current that guarantees safety at that electric field frequency is calculated to determine the current assessment ratio.

[0079] S909, determine whether there is an electrical safety risk.

[0080] If there is an electrical safety risk, execute S910; otherwise, execute S911.

[0081] The risk index and current assessment ratio obtained from the first two steps are compared with preset safety thresholds to determine whether an electrical safety risk exists. Exceeding these thresholds indicates the presence of an electrical safety risk.

[0082] For example, if the risk index is greater than the safety risk threshold, or the current assessment ratio is greater than the safe current ratio threshold, then an electrical safety risk is determined to exist; otherwise, no electrical safety risk exists.

[0083] S910 determines whether it constitutes a high security risk.

[0084] If there is a high security risk, execute S912; otherwise, execute S913.

[0085] If an electrical safety risk has been identified, and the risk index is greater than the emergency threshold for safety risks, or the current assessment ratio is greater than the emergency threshold for safe current ratios, then a high safety risk is identified and immediate intervention is required; otherwise, there is no high safety risk, and the risk is considered general, allowing the system to attempt automatic adjustment.

[0086] Among them, the emergency threshold for safety risk is greater than the safety risk threshold, and the emergency threshold for the safety current ratio is greater than the safety current ratio threshold.

[0087] S911 determines whether to stop the jet.

[0088] The system determines whether to stop the plasma jet based on the completion status of the task and external input. If the jet is stopped, S912 is executed; otherwise, S913 is executed.

[0089] External inputs include stop control signals. If the plasma jet completes its task and / or the external stop control signal is received, the jet stops and S912 is executed; otherwise, S913 is executed.

[0090] S912, shut down the full-bridge inverter circuit, and shut down the microfluidic air pump and photoelectric effect electric field sensor.

[0091] S913, adjust the output amplitude of the high-voltage power supply and update the output intensity of the plasma jet.

[0092] As can be seen from the above process, the process involved in this invention includes gas introduction, plasma excitation, electric field signal acquisition, risk analysis and judgment, power parameter adjustment and system safety shutdown, which constitute a closed-loop control process for the operation of the low-temperature full-bridge inverter circuit.

[0093] After the process begins, a working gas is first introduced to provide a medium for plasma generation. Next, a plasma jet is excited, and plasma is generated through a high-voltage reaction and a gas pump. Simultaneously, a biological tissue electric field sensor is activated, and then the plasma jet is applied to the target biological tissue. During the plasma jet application, a non-invasive electric field optical sensor is used to measure the electric field distribution of the biological tissue in real time.

[0094] The system calculates the potential distribution of biological tissue by inverting the measured electric field signal. It further combines electric field and frequency information to calculate electrical risks and assess the average current. The standard for human safety assessment requires correlation with the average current of the electric field, which generally needs to be below 10mA. The system determines whether an electrical safety risk exists; if so, it further assesses whether it constitutes a high-risk situation. If the risk is high, it will directly enter the safety shutdown procedure, shutting down the full-bridge inverter circuit, the microfluidic pump, and the biological tissue electric field sensor to ensure biological safety. If the risk is controllable, it will calculate and adjust the output amplitude of the high-voltage power supply based on the assessed average current, and then update the plasma jet output intensity, forming a cyclic structure for continuous monitoring of the electric field in the plasma jet. This achieves dynamic closed-loop control of the plasma jet's electrical parameters, ensuring that the electric field intensity remains within a safe range.

[0095] If there are no electrical safety risks, the system determines whether to stop the jet based on the completion status of the plasma jet's task and external inputs such as stop control signals. If the jet stops, the system enters a shutdown procedure, shutting down the full-bridge inverter circuit, the microfluidic pump, and the photoelectric field sensor of the biological tissue, thus ending the process. If the jet does not stop, the output amplitude of the high-voltage power supply is adjusted, the plasma jet output intensity is updated, and the system returns to the main process. The plasma jet acts on the biological tissue, forming a continuous plasma-driven cyclic structure.

[0096] Through the above process, this invention achieves real-time, non-invasive monitoring and closed-loop control of the electric field characteristics of biological tissues under the action of plasma jets, effectively reducing the safety risk of tissue damage caused by excessive electric field, and improving the electrical safety and clinical applicability of plasma medical devices.

[0097] The key point of this invention is: 1. Control system and method for electric field feedback of biological tissue under low-temperature plasma jet action This invention constructs a closed-loop control system that uses the electric field signal on the surface of biological tissue as a feedback variable. The system measures the electric field distribution in the plasma jet's action area in real time and non-contactly by deploying all-dielectric electric field sensors on the surface of the biological tissue. The measured signal is fed back to the computer core control system and drive circuit, dynamically adjusting the output voltage and frequency of the high-voltage power supply and the flow rate of the air pump. This achieves real-time adjustment of the electrical parameters of the plasma jet, ensuring that the electric field around the tissue is always within a safe threshold.

[0098] This system can effectively avoid the problems of impedance heating, poor adaptability to operating conditions, and inability to respond to changes in tissue electric field in real time that exist in existing open-loop control schemes. It realizes real-time adaptive adjustment of the electrical parameters of plasma jet, and improves the controllability, stability and safety of the system in clinical applications.

[0099] 2. Non-invasive biological tissue electric field measurement method based on electro-optic effect This invention employs an electro-optic crystal as the sensing element, utilizing its refractive index to vary with an external electric field. The electric field strength is retrieved by detecting changes in the polarization state of light. This sensor has an all-dielectric structure, requiring no electrode contact with tissue, enabling in-situ, real-time, and non-invasive electric field measurement.

[0100] This system overcomes the problem that traditional current signal detection methods cannot directly and accurately reflect the electric field and charge distribution within biological tissues, providing a more direct and safer means of monitoring electric fields. It achieves high-sensitivity and high-resolution measurement of the electric field on and near the surface of biological tissues.

[0101] 3. Miniaturized, all-dielectric photoelectric effect electric field sensor integrated structure The electro-optic crystal of the photoelectric effect electric field sensor of this invention adopts a ridge-type optical waveguide design. The waveguide has a grid-type loop structure, which significantly increases the interaction length between light and electric field and improves sensitivity. The polarizer, waveplate, analyzer, etc. are integrated into the all-dielectric sensor chip and are remotely connected to the input and output components through polarization-maintaining optical fiber, reducing size and avoiding electromagnetic interference.

[0102] This integrated structure solves the problems of sensors being susceptible to interference in strong electromagnetic fields, having large size, and being difficult to integrate into medical probes. It achieves sensor miniaturization, high anti-interference capability, and easy integration, making it suitable for embedded installation in various plasma medical devices.

[0103] 4. Method for Arranging and Reconstructing Electric Field Distribution of Patch-Type Multi-Sensor Arrays The present invention uses multiple all-dielectric sensors arranged in a square grid array to simultaneously measure the electric field signals at multiple sites and reconstruct the electric field distribution on the tissue surface using an inversion algorithm.

[0104] The array arrangement scheme solves the problem that single-point measurements cannot fully reflect the spatial distribution of the electric field on the tissue surface. It enables high-resolution, multi-directional synchronous monitoring of the electric field distribution on the affected tissue, and provides a more comprehensive assessment of the uniformity and safety of plasma interaction.

[0105] When applying the biological tissue electric field feedback control method under the action of low-temperature plasma jets provided in this manual, it is not necessary to follow the... Figure 8 The steps shown are executed in sequence. The specific execution order of each step can be determined as needed, and this manual does not impose any restrictions on it.

[0106] For specific limitations on the feedback control system for the electric field of biological tissue under the action of low-temperature plasma jet, please refer to the limitations on the feedback control method for the electric field of biological tissue under the action of low-temperature plasma jet mentioned above, which will not be repeated here.

[0107] This specification also provides a computer-readable storage medium storing a computer program that can be used to execute the above-described... Figure 8 A method for feedback control of the electric field of biological tissue under the action of low-temperature plasma jet is provided.

[0108] This specification also provides a schematic diagram of a computer device. At the hardware level, this computer device includes a processor, an internal bus, a network interface, memory, and non-volatile memory, and may also include other hardware required for various operations. The processor reads the corresponding computer program from the non-volatile memory into memory and then executes it to achieve the above-mentioned functions. Figure 8 A method for feedback control of the electric field of biological tissue under the action of low-temperature plasma jet is provided.

[0109] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0110] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A biological tissue electric field feedback control system under the action of a low-temperature plasma jet, characterized in that, The system includes: a microfluidic pump, a photoelectric field sensor, a high-voltage reactor, and a core computer control system; the photoelectric field sensor is attached to the surface of biological tissue. High-voltage reactors are used to generate low-temperature plasma based on high-frequency voltages. A microfluidic gas pump is used to form a plasma jet from the low-temperature plasma generated by a high-voltage reactor by controlling the gas flow rate. The photoelectric effect electric field sensor is used to collect the electric field signal of biological tissue when a plasma jet acts on it, and then send the electric field signal to the core computer control system. The computer core control system is used to generate a first control signal for the high-voltage reactor and a second control signal for the microfluidic gas pump based on the electric field signal. The first control signal is used to adjust the amplitude and frequency of the high-frequency voltage output by the high-voltage reactor, and the second control signal is used to adjust the gas flow rate of the microfluidic gas pump to adjust the output intensity of the plasma jet.

2. The system according to claim 1, characterized in that, The system also includes an optocoupler isolation drive circuit, a first adjustable DC switching power supply, a full-bridge inverter circuit, and a high-frequency transformer; the first control signal includes a first-level control signal and a PWM signal; The computer core control system sends a first-level control signal to the first adjustable DC switching power supply to control the output voltage of the first adjustable DC switching power supply, and sends a PWM signal to the optocoupler isolation drive circuit. The optocoupler-isolated drive circuit is used to receive the electric field signal collected by the photoelectric effect electric field sensor and stop working when the electric field signal is greater than the preset electric field threshold. During normal operation, it outputs the drive signal of the full-bridge inverter circuit according to the received PWM signal to adjust the switching frequency of the full-bridge inverter circuit. The switching frequency range of the full-bridge inverter circuit is 10-50kHz. The full-bridge inverter circuit is used to convert the DC voltage output by the first adjustable DC switching power supply into AC voltage and output the AC voltage at the corresponding switching frequency. The high-frequency transformer is used to boost the AC voltage output from the full-bridge inverter circuit and use the boosted AC high voltage as the power supply voltage for the high-voltage reactor through the high-voltage lead; the AC high voltage range after boosting by the high-frequency transformer is 0-15kV; the high-frequency voltage induces ionization to generate plasma.

3. The system according to claim 2, characterized in that, The system includes a second adjustable DC switching power supply; the second control signal is a second-level control signal; The computer core control system is used to send a second-level control signal to the second adjustable DC switching power supply to adjust the output voltage of the second adjustable DC switching power supply. The second adjustable DC switching power supply is used to control the gas flow rate of the microfluidic pump through the output voltage; the gas flow rate range of the microfluidic pump is 0-15 L / min.

4. The system according to claim 1, characterized in that, The system also includes an integrated power supply circuit and a power supply, which is powered by AC power frequency voltage; The power supply is used to supply power to the first adjustable DC switching power supply, the integrated power supply circuit, and the second adjustable DC switching power supply, respectively. An integrated power supply circuit is used to convert AC voltage to DC voltage to power the computer core control system and the optocoupler isolation drive circuit.

5. The system according to claim 1, characterized in that, The computer core control system includes instruction setting buttons, including instructions to increase voltage, frequency, switch the jet on / off, and increase flow rate; The computer-based core control system is used to receive external input commands via instruction settings buttons, and output control signals for the high-voltage reactor and microfluidic pump based on the external input commands.

6. The system according to claim 1, characterized in that, Photoelectric effect electric field sensors include photoelectric conversion units and all-dielectric sensors; The all-dielectric sensor is used to monitor the electric field distribution of biological tissues in the plasma interaction area in real time, and transmits the collected optical signals to the photoelectric conversion unit via optical fiber. The photoelectric conversion unit is used to convert optical signals into electric field signals.

7. The system according to claim 6, characterized in that, The photoelectric conversion unit includes a laser chip and a photodetector; the all-dielectric sensor includes a polarizer, an 1 / 8 wave plate, an electro-optic crystal, and an analyzer. When the photoelectric effect electric field sensor is working, the laser chip emits a laser beam, which enters the all-dielectric sensor. In the all-dielectric sensor, a polarizer and an 1 / 8 waveplate receive the laser beam to adjust the polarization state of the incident light. A polarization-maintaining fiber transmits the incident light to an electro-optic crystal. The electro-optic crystal forms a ridge waveguide through ultraviolet lithography. This waveguide is in the form of a grid loop. An analyzer is located at the output end of the electro-optic crystal to detect the change in the polarization state of the light after electric field modulation. The photodetector converts the optical signal output by the analyzer into an electrical signal.

8. The system according to claim 6, characterized in that, The system employs a patch-type photoelectric effect electric field sensor array structure, with multiple all-dielectric sensors integrated and arranged in a square array on the surface of biological tissue.

9. A method for feedback control of the electric field of biological tissue under the action of a low-temperature plasma jet, characterized in that, The method is applied to the system according to any one of claims 1-8, and the method includes: Collect the electric field signal generated by the plasma jet acting on biological tissue; Calculate the potential distribution of biological tissues based on the inversion of electric field signals; Based on the potential distribution of biological tissue, a first control signal for the high-voltage reactor and a second control signal for the microfluidic pump are generated. The amplitude and frequency of the high-frequency voltage output by the high-voltage reactor are adjusted by the first control signal, and the gas flow rate of the microfluidic pump is adjusted by the second control signal to adjust the output intensity of the plasma jet.

10. The method according to claim 9, characterized in that, Based on the electrical potential distribution of biological tissue, a first control signal for the high-voltage reactor and a second control signal for the microfluidic pump are generated, including: Calculate the electric field strength on the surface of biological tissue based on the electric potential distribution of biological tissue; The risk index is determined based on the electric field safety threshold corresponding to the electric field strength and frequency of the electric field signal on the surface of biological tissue. The average current is calculated based on the electrical potential distribution of biological tissue and the preset conductivity. Based on the risk index and average current, determine whether there is an electrical safety risk; If an electrical safety risk exists, determine whether it constitutes a high safety risk; if it constitutes a high safety risk, shut down the full-bridge inverter circuit and shut down the microfluidic pump and photoelectric effect electric field sensor; if it does not constitute a high safety risk, generate the first control signal for the high-voltage reactor and the second control signal for the microfluidic pump. If there is no electrical safety risk, the system determines whether to stop the jet based on the completion status of the plasma jet task and external input. If the jet is stopped, the full-bridge inverter circuit, microfluidic pump, and photoelectric effect electric field sensor are turned off. If the jet is not stopped, a first control signal for the high-voltage reactor and a second control signal for the microfluidic pump are generated.

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