Automatic ultrasonic injector and control method thereof

Abstract

The invention discloses an automatic ultrasonic injector and a control method thereof. The automatic ultrasonic injector comprises a driving module, an injection module and a photonic crystal plate module, the driving module is used for providing driving force; the injection module is connected with the driving module and used for emitting ultrasonic waves and injecting liquid medicine; the injection module comprises a needle cylinder, a needle cylinder push rod, a pressure sensor and a transducer, the needle cylinder is integrally fixed on the base, the needle cylinder push rod is inserted into the tail end of the needle cylinder, and a liquid outlet is formed in the front end of the needle cylinder; the needle cylinder push rod is driven by the driving module, the front end of the needle cylinder push rod is connected with the energy converter and the pressure sensor, and the driving module drives the needle cylinder push rod, the energy converter and the pressure sensor to linearly move in the same direction in the needle cylinder; the phononic crystal plate is installed at the liquid outlet end of the needle cylinder and used for modulating the sound field, enhancing the sound radiation force and accelerating the medicine transfer efficiency. According to the invention, the medicine is permeated into the body in an ultrasonic medicine permeation manner, non-invasive in-vitro administration and targeted therapy are realized, the pain of a patient is relieved, the medicine can directly reach a focus quickly, and the infection risk is relieved.

Description

Technical Field

[0001] The invention relates to an automatic ultrasonic injector and a control method thereof, and belongs to the field of ultrasonic transdermal drug delivery. Background Art

[0002] Ultrasound transdermal drug delivery, also known as ultrasound-assisted permeation or phonophoresis, involves the use of ultrasound to propagate drugs through the skin at a constant (or near-constant) rate, promoting transdermal or mucosal absorption. The primary mechanism is the cavitation effect of ultrasound. During ultrasound, ultrasound energy is converted into heat, raising skin temperature and increasing the size of pores, thereby facilitating transdermal drug absorption. Furthermore, the mechanical effects of ultrasound alter skin structure, potentially increasing drug permeability.

[0003] Improving drug transdermal efficiency can improve the efficacy of transdermal drug delivery, allowing for the same therapeutic effect to be achieved with less drug. However, due to the presence of skin barriers, most drugs, even those with low doses and high efficacy, have difficulty achieving therapeutic results through the skin. Therefore, ensuring sufficient drug permeation through the skin to achieve a therapeutic dose and improving transdermal efficiency are key research priorities and crucial to the success of transdermal drug development.

[0004] To address the above issues, we have developed an automatic ultrasonic injector and its control method. This automatic ultrasonic injector can use phononic crystal plates to regulate the sound field, enhance the acoustic radiation force, allow drug particles to quickly approach the skin, induce cavitation effect, and increase drug transdermal efficiency. At the same time, it is simple and convenient to operate, can automatically adjust the propulsion speed, control ultrasonic emission, and reduce drug waste. Summary of the Invention

[0005] The purpose of the present invention is to provide an automatic ultrasonic injector and a control method thereof, so as to solve the problems of inaccurate drug delivery, low drug delivery efficiency and easy waste caused by traditional ultrasonic drug penetration technology.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] An automatic ultrasonic injector comprises a driving module, an injection module and a phononic crystal plate;

[0008] The driving module is used to provide driving force;

[0009] The injection module is connected to the driving module and is used to emit ultrasonic waves and inject liquid medicine; the injection module includes a syringe, a syringe push rod, a pressure sensor and a transducer. The syringe is fixed to the base as a whole, the syringe push rod is inserted into the rear end of the syringe, and the front end is provided with a liquid outlet; the syringe push rod is driven by the driving module, and the front end of the syringe push rod is connected to the transducer and the pressure sensor. The driving module drives the syringe push rod, the transducer and the pressure sensor to perform linear motion in the same direction in the syringe;

[0010] The phononic crystal plate is movably mounted on the liquid outlet end of the syringe and is used to modulate the sound field, enhance the sound radiation force, and accelerate the drug delivery efficiency.

[0011] Furthermore, the driving module includes a base, a driving motor, a coupling, a transmission screw, and a transmission block. The driving motor is connected to the transmission screw through a coupling. The transmission block is mounted on the transmission screw and is connected to the syringe push rod at the same time. The driving motor drives the transmission screw to rotate, and then drives the transmission block to perform a linear reciprocating motion on the transmission screw.

[0012] Furthermore, limit blocks are provided at the front and rear ends of the transmission block to limit the transmission range of the transmission block.

[0013] Furthermore, the transducer is arranged on the central axis of the syringe push rod, and the top of the front end is in direct contact with the liquid medicine, and is connected to the power supply module through a wire.

[0014] Furthermore, the transducer emission frequency f is the resonance frequency of the phononic crystal plate.

[0015] Furthermore, the pressure sensor and the transducer are fixed to the top of the syringe push rod by bonding, and after installation, the top of the front end of the two are on the same horizontal line and in direct contact with the liquid medicine. At the same time, the outer walls of the pressure sensor and the transducer are provided with sealers.

[0016] Furthermore, the liquid outlet end of the syringe is provided with a buckle for a detachable phononic crystal plate, a sealer is contained in the buckle, and the buckle is connected to the syringe via a thread.

[0017] Furthermore, the phononic crystal plate is an artificial periodic structure, which is arranged by a plurality of phononic crystal unit arrays. The artificial periodic structure is a two-dimensional array of perforated metal plates. When the two-dimensional array is a square and the opening shape is a circular hole, the lattice constant is a and the hole radius is r, then 0.05<(πr2) / a2<0.15.

[0018] A control method for an automatic ultrasonic injector, the operating steps of which are as follows:

[0019] First, the user selects the gear, the system automatically initializes, sets the probe parameters, and the initial propulsion speed v;

[0020] Then the pressure sensor detects the pressure Fs in real time, and the system automatically judges whether the injection pressure is greater than the built-in value F1. If Fs < F1, the coupling degree is detected. If Fs > F1, the propulsion speed is slowed down and then the coupling degree is detected;

[0021] The system detects the coupling degree by detecting the current I in real time. The built-in current range of the system is [a, b]. If a < I < b and the coupling is judged to be good, power transmission is carried out, and the syringe plunger starts to advance stably. If I b and the coupling is judged to be poor, the propulsion speed is increased first and then advanced;

[0022] The system detects the remaining amount of the liquid medicine. If it is not 0, the pressure detection and current detection are carried out again until the current value returns to the built-in current range [a, b] of the system; During the whole process, the pressure and current are monitored in real time, and the propulsion speed is adjusted through the numerical changes of the pressure and current until the system detects that the remaining amount of the liquid medicine is 0 and the injection ends.

[0023] Furthermore, the current I is calculated according to the following formula:

[0024] I = U / Z

[0025] U: The voltage applied to the transducer, Z: The impedance of the transducer in the liquid medicine;

[0026] Where:

[0027]

[0028] j: The imaginary unit, representing a complex number, ω: Angular frequency, C0: Static capacitance of the piezoelectric ceramic, ρ P : Density of the piezoelectric ceramic, c: Propagation speed of the longitudinal acoustic wave in the ceramic, A: Area of the piezoelectric ceramic, t: Thickness of the piezoelectric ceramic, ρ f : Density of the liquid medicine, c f : Sound speed of the liquid medicine, φ: Conversion coefficient between the circuit end and the acoustic end;

[0029] The numerical range of the current is [a, b], a = I - I * 20%, b = I + I * 20%.

[0030] The beneficial effects of the present invention are as follows:

[0031] (1) The drug is penetrated into the body by means of ultrasonic transdermal drug delivery, non-invasive external drug administration, targeted therapy, reducing the pain of patients, quickly reaching the lesion, and reducing the infection risk.

[0032] (2) The phonon crystal plate interacts with ultrasonic waves, generating a local sound field on the surface of the phonon crystal plate, strongly enhancing the acoustic radiation force in the micropores, enhancing the cavitation effect, and the surrounding particles move towards the center of the micropores under the action of the acoustic radiation force, which can accelerate the drug transport rate, better perform drug penetration, and improve the treatment efficiency.

[0033] (3) The pressure sensor monitors in real time and automatically adjusts the pushing speed to avoid pressure overload. The drug dosage can be precisely controlled to avoid waste of drug solution.

[0034] (4) Automatic injection after setting parameters, simple and convenient operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the overall structure of the automatic ultrasonic injector of the present invention;

[0036] Figure 2 It is a schematic diagram of the internal structure of the automatic ultrasonic injector of the present invention;

[0037] Figure 3 This is a schematic diagram of the installation of the phononic crystal plate of the automatic ultrasonic injector of the present invention;

[0038] Figure 4 Schematic diagram of the phononic crystal plate of the automatic ultrasonic injector of the present invention;

[0039] Figure 5 Schematic diagram of a single phononic crystal of the automatic ultrasonic injector of the present invention;

[0040] Figure 6 Schematic diagram of the acoustic radiation force exerted on particles by the automatic ultrasonic injector of the present invention;

[0041] Figure 7 It is a flow chart of the automatic ultrasonic injector control method of the present invention.

[0042] Marked in the figure: 1-base, 2-drive motor, 3-coupling, 4-drive screw, 5-drive block, 6-limit block, 7-syringe, 8-syringe push rod, 9-transducer, 10-pressure sensor, 11-phononic crystal plate, 12-clip, 13-seal. DETAILED DESCRIPTION

[0043] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] like Figure 1 and 2 As shown, an automatic ultrasonic injector includes: a driving module, an injection module and a phononic crystal plate.

[0045] The drive module includes a base 1, a drive motor 2, a coupling 3, a transmission screw 4, a transmission block 5, and a limit block 6; the drive motor 2 is connected to the transmission screw 4 through the coupling 3; the drive motor 2 drives the transmission screw 4 to rotate, thereby driving the transmission block 4 to perform a linear reciprocating motion on the transmission screw 4; the transmission range of the transmission block 5 is limited by the limit block 6.

[0046] The injection module includes a syringe 7, a syringe push rod 8, a pressure sensor 10, and a transducer 9. The syringe 7 is fixed to the base 1 as a whole, with the syringe push rod 8 inserted at the end of the syringe 7 and a liquid outlet at the front end. One end of the syringe push rod 8 is connected to the transmission block 5, and the other end is connected to the transducer 9 and pressure sensor 10. When the transmission block 5 performs linear motion, it can drive the syringe push rod 8, transducer 9, and pressure sensor 10 to perform linear motion in the same direction within the syringe. To prevent liquid from leaking into the syringe, a seal 13 is provided between the outer walls of the pressure sensor 10 and transducer 9 and the inner wall of the syringe.

[0047] In this embodiment, the pressure sensor 10 is a miniature high-frequency sensor with a range of 0-100kPa and an accuracy of ±0.25% FS. The top of the pressure sensor 10 is on the same horizontal line as the top of the transducer 9 and is in direct contact with the liquid medicine. The pressure is set to 10kPa during the advancement of the liquid medicine. The sensor continuously monitors the pressure during the advancement process and adjusts the advancement speed through real-time feedback to ensure that the pressure is not too high and causes waste of liquid medicine. The transducer 9 is located on the central axis of the syringe push rod, with the top in direct contact with the liquid medicine. It is connected to the power supply module of the drive motor through a wire. The frequency f of the transducer 9 is 0.85MHz, which is the resonant frequency with the phononic crystal plate 11. The transducer 9 has a good frequency response in the wide frequency range of 0.7MHz-1.3MHz.

[0048] like Figure 3 The phononic crystal plate 11 is detachably mounted on the liquid outlet end by a buckle 12, and a sealer 13 is provided inside the buckle 12. The buckle 12 is connected to the syringe 7 by a thread. The phononic crystal plate 11 is an artificial periodic structure, and the artificial periodic structure is a perforated metal plate with a two-dimensional array. The two-dimensional perforated array can be a square, a triangle, or a polygon. Preferably, the two-dimensional array is a square, the metal plate is a steel plate, and the plate thickness d is 0.4 to 1 mm, preferably 0.6 mm. The mass density of the steel plate ρ = 7670 kg / m 3 , longitudinal wave velocity c l =6010m / s, shear wave speed c t =3230m / s, the perforated steel plate has a circular hole shape, and the hole radius r is 0.1-0.3mm, preferably 0.25mm. When the two-dimensional array is square and the hole shape is circular, the lattice constant is a, and the hole radius is r, then 0.05<(πr 2 ) / a 2 <0.15. Figure 4 、 5 As shown, the filling rate is 0.05<(πr 2 ) / a 2 <0.15, and the preferred lattice constant a is 1.5 mm, which can prevent the drug from leaking freely while allowing drug molecules below 500 μm to pass through.

[0049] In this embodiment, the resonant frequency of the transducer and the phononic crystal plate is the frequency at which the acoustic radiation force is maximum. By analyzing the acoustic pressure field distribution of the phononic crystal plate at the frequency of the transmission peak, the relationship between the acoustic radiation force and frequency in the acoustic pressure field can be obtained. The transmission coefficient τ of the phononic crystal plate in liquid is expressed as:

[0050]

[0051] Where τ is the transmission coefficient of the phononic crystal plate, P t Indicates the sound pressure amplitude of the transmitted wave, P i Represents the sound pressure amplitude of the incident wave, ρ1: density of the liquid, c1: sound velocity of the liquid.

[0052] When the ultrasonic wave is incident from the bottom of the plate, the acoustic radiation force received by a single liquid particle in its sound field can be obtained by integrating the Brillouin radiation stress tensor on the closed surface of the object, that is:

[0053]

[0054] Among them, the differential region dA points to the outer integral tending to the particle surface; T >: time-averaged radiation stress tensor;

[0055]

[0056] Where: u: first-order fluid velocity field, P: first-order fluid pressure field, I: unit tensor, ρ f : Density of the surrounding fluid (drug solution), c f : Speed ​​of sound of the surrounding fluid (drug solution), Re: real part.

[0057] In this embodiment, the acoustic radiation force reaches a maximum value at 0.85 MHz.

[0058] The ability of phononic crystal plates to accelerate drug delivery is based on the transmission characteristics of phononic crystal plates. Through numerical simulation, we further analyze the acoustic pressure field distribution of the phononic crystal plate at the frequency of the transmission peak, and then use the acoustic radiation force in the acoustic pressure field to control particle movement and enhance the cavitation effect on the skin surface. When ultrasound reaches the phononic crystal plate, the sound wave interacts with the artificial periodic structure, generating a localized acoustic field on the surface of the phononic crystal plate. The relationship between the acoustic radiation force and the particle in the xy plane is shown in the figure below. Figure 6 As shown in the figure, the direction and length of the arrows represent the direction and magnitude of the ultrasonic radiation force. The results show that the particles will experience a stable acoustic radiation force directed toward the hole. The acoustic radiation force in the hole is strongly enhanced, and the cavitation effect is also enhanced. That is, the particles located at any position around the hole will move toward the center of the hole under the action of the acoustic radiation force, thereby accelerating the transport of drug molecules and enhancing drug penetration efficiency. ​

[0059] As shown Figure 7 in the figure, the control method of an automatic ultrasonic syringe has the following operation process:

[0060] Rotate the buckle, remove the buckle and then open the phononic crystal plate. Load the liquid medicine to be injected at one time into the syringe barrel, close the phononic crystal plate, and then use the buckle to completely fix the phononic crystal plate to the syringe barrel. The user selects the gear, and the system automatically initializes, sets the probe parameters and the initial propulsion speed v. Then the pressure sensor detects the pressure Fs in real time, and the system automatically judges whether the injection pressure is greater than 10 kPa. If Fs < 10 kPa, it is judged that the pressure is qualified, and then the coupling degree detection is carried out; if Fs > 10 kPa, it is judged that the pressure is too high, and then the propulsion speed is slowed down and the coupling degree detection is carried out. The system judges whether the skin and the transducer are well coupled by detecting the transducer current I in real time. The current I is calculated according to the formula:

[0061] I = U / Z

[0062] U: the voltage loaded on the transducer, Z: the impedance of the transducer in the liquid medicine;

[0063] The impedance of the transducer in the liquid medicine can be calculated according to the KLM model:

[0064]

[0065] j: the imaginary unit, representing a complex number, ω: angular frequency, C0: the static capacitance of the piezoelectric ceramic, ρ P : the density of the piezoelectric ceramic, c: the propagation speed of the longitudinal acoustic wave in the ceramic, A: the area of the piezoelectric ceramic, t: the thickness of the piezoelectric ceramic, ρ f : the density of the liquid medicine, c f : the sound speed of the liquid medicine, φ: the conversion coefficient between the circuit end and the acoustic end.

[0066] The built-in current value range of the system is [a, b], where a = I - I * 20%, b = I + I * 20%; when a < I < b, it means the coupling degree > 80%, and the coupling is good, then power transmission is carried out, and the syringe barrel push rod starts to advance stably. If I b, it means the coupling degree < 80%, and the coupling is poor, then the propulsion speed is increased and then continue to advance stably; the system detects the remaining amount of the liquid medicine. If it is not 0, then the pressure detection and current detection are carried out again until the pressure value and current value return to the range built in the system. Such a cycle is carried out until the system detects that the remaining amount of the liquid medicine is 0, and the driving motor stops running, ending the injection.

[0067] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the scope of protection of the present invention in any form. All technical solutions obtained by equivalent substitution, etc., fall within the scope of protection of the present invention. Parts not covered by the present invention are the same as the existing technology or can be implemented using existing technology.

Claims

1. An automatic ultrasonic injector, characterized in that: It includes a driving module, an injection module and a phononic crystal plate; The driving module is used to provide driving force; The injection module is connected to the driving module and is used to emit ultrasonic waves and inject liquid medicine; the injection module includes a syringe, a syringe push rod, a pressure sensor and a transducer. The syringe is integrally fixed on the base. The tail end of the syringe is inserted with the syringe push rod, and the front end is provided with a liquid outlet; the syringe push rod is driven by the driving module. The front end of the syringe push rod is connected to the transducer and the pressure sensor. The driving module drives the syringe push rod, the transducer and the pressure sensor to move in the same direction linearly in the syringe; The phononic crystal plate is movably installed at the liquid outlet end of the syringe and is used to modulate the sound field, enhance the acoustic radiation force and accelerate the drug delivery efficiency.

2. An automatic ultrasonic injector according to claim 1, characterized in that: The driving module includes a base, a driving motor, a coupling, a transmission screw rod and a transmission block. The driving motor is connected to the transmission screw rod through the coupling. The transmission block is sleeved on the transmission screw rod and is connected to the syringe push rod at the same time. The driving motor drives the transmission screw rod to rotate, and then drives the transmission block to perform linear reciprocating motion on the transmission screw rod.

3. An automatic ultrasonic injector according to claim 2, characterized in that: Limit blocks are provided at the front and rear ends of the transmission block to limit the transmission range of the transmission block.

4. The automatic ultrasonic injector according to claim 1, characterized in that: The transducer is arranged on the central axis of the syringe push rod. The top of its front end is in direct contact with the liquid medicine, and at the same time it is connected to the power supply module through a wire.

5. The automatic ultrasonic injector according to claim 1, characterized in that: The emission frequency f of the transducer is the resonance frequency of the phononic crystal plate.

6. The automatic ultrasonic injector according to claim 1, characterized in that: The pressure sensor and the transducer are fixed at the top end of the syringe push rod in a bonding form, and the top of their front ends are at the same horizontal line after installation and are in direct contact with the liquid medicine. At the same time, seals are provided on the outer walls of the pressure sensor and the transducer.

7. The automatic ultrasonic injector according to claim 1, characterized in that: A buckle for detachable phononic crystal plate is provided at the liquid outlet end of the syringe. There is a seal in the buckle, and the buckle is connected to the syringe by threads.

8. The automatic ultrasonic injector according to claim 1, characterized in that: The phononic crystal plate is an artificial periodic structure, which is arranged by multiple phononic crystal units in an array. This artificial periodic structure is a two-dimensional array of perforated metal plates. When the two-dimensional array is square and the opening shape is a round hole, the lattice constant is a and the hole radius is r, then 0.05 < (πr2) / a2 < 0.

15.

9. A control method for an automatic ultrasonic injector according to claim 1, characterized in that: The operation steps are as follows: First, the user selects a gear, and the system automatically initializes and sets the probe parameters and the initial propulsion speed v; Then the pressure sensor detects the pressure Fs in real time, and the system automatically judges whether the injection pressure is greater than the built-in value F1. If Fs < F1, the coupling degree is detected. If Fs > F1, the propulsion speed is slowed down and then the coupling degree is detected; The system detects the coupling degree by detecting the current I in real time. The built-in current range of the system is [a, b]. If a < I < b and the coupling is judged to be good, power emission is carried out, and the syringe push rod starts to advance stably. If I b, the coupling is judged to be bad, and the propulsion speed is increased first and then advanced; The system detects the remaining amount of liquid medicine. If it is not 0, the pressure detection and current detection are carried out again until the current value returns to the built-in current range [a, b] of the system; during the whole process, the pressure and current are monitored in real time, and the propulsion speed is adjusted through the numerical changes of the pressure and current until the system detects that the remaining amount of liquid medicine is 0 and the injection ends.

10. The control method of an automatic ultrasonic injector according to claim 9, characterized in that: The current I is calculated according to the following formula: I = U / Z U: voltage applied to the transducer, Z: impedance of the transducer in the liquid; in: j: imaginary unit, representing a complex number, ω: angular frequency, C0: static capacitance of piezoelectric ceramics, ρ P : density of piezoelectric ceramics, c: propagation velocity of longitudinal acoustic waves in ceramics, A: area of ​​piezoelectric ceramics, t: thickness of piezoelectric ceramics, ρ f : Density of the drug solution, c f : liquid sound velocity, φ: conversion coefficient between the circuit end and the acoustic end; The current value range is [a, b], a=II*20%, b=I+I*20%.

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