Surface acoustic wave device

Abstract

The invention provides a surface acoustic wave device, which is characterized in that the surface acoustic wave device is used for opening a blood brain barrier, and comprises a piezoelectric crystal; the two interdigital transducers are arranged on the surface of the piezoelectric crystal; the transfer chamber is arranged on the surface of the piezoelectric crystal and is positioned between the two interdigital transducers; wherein the transfer chamber is used for placing a blood-brain barrier model or a blood-brain barrier part, the two interdigital transducers are used for driving the piezoelectric crystal to vibrate so as to transmit surface acoustic waves in the blood-brain barrier model or the blood-brain barrier part, and the surface acoustic waves act on a blood-brain barrier so as to open the blood-brain barrier. The device provided by the invention can realize reversible opening of the blood-brain barrier and promote the application prospect of drug delivery of the central nervous system.

Description

Technical Field

[0001] This application relates to the technical field of blood-brain barrier, and more specifically, to a surface acoustic wave device. Background Art

[0002] The blood-brain barrier (BBB) is a physical and physiological barrier that separates the blood from the central nervous system. The blood-brain barrier can block the penetration of most macromolecules, small molecules, and ions in the blood, thereby maintaining the homeostasis of the central nervous system. The cells that make up the blood-brain barrier mainly include brain microvascular endothelial cells, pericytes, and astrocytes. Brain microvascular endothelial cells form the blood vessel wall, and there are dense tight junction proteins cross-linked between cells, ensuring the barrier function of the blood-brain barrier. Pericytes are the smooth muscle cells of blood vessels, which can regulate the contraction and relaxation of blood vessels and promote the formation of tight junctions. The end feet of astrocytes provide biochemical support for brain microvascular endothelial cells and regulate the function of the blood-brain barrier by releasing some signals. Under normal circumstances, the existence of the blood-brain barrier can protect the central nervous system from the invasion of toxic substances; however, in the case of central nervous system diseases, it is usually necessary to moderately open or bypass the blood-brain barrier for drug delivery in order to achieve the ideal therapeutic concentration of the drug.

[0003] How to safely open the blood-brain barrier has become a key issue in central nervous system drug delivery. Currently, the methods for opening the blood-brain barrier can be divided into biological and physical categories. Biological methods mainly include receptor / vector-mediated endocytosis, virus vector-mediated delivery, nanoparticle systems, exosomes, and cell-mediated delivery and cell-penetrating peptides. Physical methods are mainly ultrasound-mediated blood-brain barrier opening. These methods all have their own advantages and disadvantages. For example, biological methods usually require fine design or modification of drugs. Ultrasound is a type of pressure wave with a frequency greater than 20 kHz. Research has shown that ultrasound can transiently change the integrity of the blood-brain barrier and improve the symptoms of Parkinson's syndrome patients. However, the blood-brain barrier disruption mediated by ultrasound is usually caused by microvesicles, and the blood-brain barrier and brain tissue damage caused by these microvesicles are difficult to predict. Therefore, how to safely and reversibly open the blood-brain barrier is the key to effective central nervous system drug delivery.

[0004] Surface acoustic wave is a sound wave that propagates along the surface of a material. In recent years, it has been found that surface acoustic wave can change the biological characteristics of cells, manipulate the movement of cells, particles, and liquids. Surface acoustic wave treatment can cause cell stretching and can also remove cells from the culture surface. There is currently no report on surface acoustic wave-mediated blood-brain barrier disruption. Summary of the Invention

[0005] The purpose of the embodiments of the present application is to provide a surface acoustic wave device, which solves the irreversible defect of opening the blood-brain barrier in the prior art, so as to provide a better solution for controllable drug delivery to the central nervous system.

[0006] In view of this, the technical solution of the embodiments of the present application is as follows:

[0007] In a first aspect, the embodiments of the present application provide a surface acoustic wave device for opening the blood-brain barrier. The surface acoustic wave device includes:

[0008] A piezoelectric crystal;

[0009] Two interdigital transducers, which are arranged on the surface of the piezoelectric crystal;

[0010] A transfer chamber, which is arranged on the surface of the piezoelectric crystal and is located between the two interdigital transducers;

[0011] Wherein, the transfer chamber is used to place a blood-brain barrier model or a blood-brain barrier site, and the interdigital transducer is used to generate surface acoustic waves, and the surface acoustic waves act on the blood-brain barrier to open the blood-brain barrier.

[0012] In a second aspect, the embodiments of the present application provide a medical device, including the surface acoustic wave device provided in any embodiment of the present application and a blood-brain barrier model or a blood-brain barrier site, and the surface acoustic wave device is used to open the blood-brain barrier of the blood-brain barrier model or the blood-brain barrier site.

[0013] The embodiments of the present application provide a surface acoustic wave device for opening the blood-brain barrier. The surface acoustic wave device includes: a piezoelectric crystal; two interdigital transducers, which are arranged on the surface of the piezoelectric crystal; a transfer chamber, which is arranged on the surface of the piezoelectric crystal and is located between the two interdigital transducers; wherein, the transfer chamber is used to place a blood-brain barrier model or a blood-brain barrier site, and the interdigital transducer is used to generate surface acoustic waves, and the surface acoustic waves act on the blood-brain barrier to open the blood-brain barrier.

[0014] Compared with the prior art, the beneficial effects of the present invention include but are not limited to: 1. The surface acoustic wave provided by the present invention is applied to open the blood-brain barrier, and the reversibility of opening the blood-brain barrier can be realized, which promotes the application prospect of drug delivery to the central nervous system. 2. The method of using surface acoustic waves to open the blood-brain barrier provided by the present invention, because the surface acoustic wave energy is concentrated on the surface of the medium, the manipulation is strong; by using the characteristics of surface acoustic waves, the opening of the blood-brain barrier can be judged by controlling the parameters of the surface acoustic wave and detecting the change of the transcutaneous resistance of brain microvascular endothelial cells, with good safety and strong reliability. 3. When the surface acoustic wave provided by the present invention is applied to open the blood-brain barrier of zebrafish brain, it is found through a blood-brain barrier tracer indicator that the indicator penetrates into the zebrafish brain tissue and is distributed in dots in the brain tissue, which provides a reliable basis for the application of opening the blood-brain barrier to drug delivery to the central nervous system.

[0015] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and should not limit this application. Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 Structural schematic diagram of a surface acoustic wave device provided by an embodiment of this application;

[0018] Figure 2 Structural schematic diagram of another surface acoustic wave device provided by an embodiment of this application;

[0019] Figure 3 Structural schematic diagram of yet another surface acoustic wave device provided by an embodiment of this application;

[0020] Figure 4 Relationship between the surface acoustic wave density and frequency of the device described in an embodiment of this application;

[0021] Figure 5 Change results of the transendothelial electrical resistance of human brain microvascular endothelial cells after the surface acoustic wave and the control group respectively treat the transfer chamber in Embodiment 2 of this application;

[0022] Figure 6 Relationship between the blood-brain barrier integrity and frequency under 35 decibels milliwatt of this invention;

[0023] Figure 7 Effect results of surface acoustic wave stimulation on the cell viability of human brain microvascular endothelial cells in Embodiment 3 of this application;

[0024] Figure 8 Effect results of surface acoustic wave stimulation on the transendothelial electrical resistance of human brain microvascular endothelial cells in Embodiment 3 of this application;

[0025] Figure 9 Effect results of the paracellular permeability of human brain microvascular endothelial cells to sodium fluorescein and fluorescein isothiocyanate-labeled dextran after surface acoustic wave stimulation in Embodiment 4 of this application;

[0026] Figure 10 Fluorescence distribution results of surface acoustic wave stimulation on the hindbrain tissue of zebrafish in Embodiment 5 of this application;

[0027] Figure 11Schematic structural diagram of a medical device provided by an embodiment of the present application.

[0028] Description of main components and symbols:

[0029] 100, medical device; 10, surface acoustic wave device; 11, piezoelectric crystal; 111, sample placement area; 1111, first chamber; 1112, second chamber; 12, interdigital transducer; 121, interdigital unit; 122, printed circuit board; 1221, hollowed-out part; 13, transfer chamber; 20, blood-brain barrier model / blood-brain barrier site.

[0030] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. Specific embodiments

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. The flowcharts shown in the drawings are only illustrative examples, and do not necessarily include all contents and operations / steps, nor do they necessarily need to be executed in the described order. For example, some operations / steps can be decomposed, combined or partially merged, so the actual execution order may be changed according to the actual situation.

[0032] It should be understood that the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification of the present application and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0033] It should be understood that in order to clearly describe the technical solutions of the embodiments of the present application, in the embodiments of the present application, terms such as "first" and "second" are used to distinguish the same items or similar items with basically the same functions and effects. For example, the first chamber and the second chamber are only used to distinguish different chambers, and do not limit their sequence. Those skilled in the art can understand that the terms "first" and "second" do not limit the quantity and execution order, and the terms "first" and "second" do not necessarily mean different.

[0034] It should also be understood that the term " / and" used in the specification of the present application and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0035] To facilitate the understanding of the embodiments of the present application, some terms involved in the embodiments of the present application are briefly described below.

[0036] 1. Piezoelectric crystal: A piezoelectric crystal is a functional material characterized by the direct piezoelectric effect and the inverse piezoelectric effect. Under the action of mechanical force, the centers of positive and negative charges of the piezoelectric material will shift, resulting in polarization; while under the action of an electric field, the piezoelectric material will generate deformation. Based on this principle, when a regular voltage is applied, the piezoelectric material will generate a regular deformation motion, thereby generating vibration. During this process, the acoustic waves generated by the piezoelectric crystal include surface acoustic waves (SAW) and bulk acoustic waves (BAW), but for the vibration of the material, surface acoustic waves play a key role.

[0037] 2. Interdigital Transducer (IDT): The interdigital transducer is a metal pattern in the shape of crossed fingers formed on the surface of a piezoelectric substrate. Its function is to realize acoustic-electric conversion. Interdigital transducers are mainly used in pairs in surface acoustic wave devices. When an alternating electrical signal is applied to the input end of a group of interdigital transducers on the piezoelectric substrate, a periodically distributed electric field will be generated. Due to the inverse piezoelectric effect, corresponding elastic deformations will be excited near the surface of the piezoelectric medium, thereby causing the vibration of solid particles and forming surface acoustic waves propagating along the surface of the substrate. When the surface acoustic wave reaches the other end of the piezoelectric medium, charges will be generated at both ends of the metal electrode due to the direct piezoelectric effect, and thus an alternating electrical signal can be output using another group of interdigital transducers.

[0038] 3. Standing wave: Two waves with opposite propagation directions, the same vibration direction, the same amplitude, and the same frequency. In terms of waveform, the positions of the nodes and antinodes of the standing wave are always unchanged, giving the impression of "standing still", but its instantaneous value changes with time. If the amplitudes of these two waves are equal, the amplitude of the node is zero. Any point on the synthesized wave performs simple harmonic vibration with the same period.

[0039] Since the horizontal distance between two adjacent nodes is still half a wavelength, the wave surface of the standing wave contains a series of antinodes and nodes. Although the levels of the wave surface at the antinodes and nodes of the standing wave change periodically, the horizontal position of this cross-section is fixed, so the position of the nodes of the standing wave is also fixed.

[0040] The following will describe in detail some embodiments of the present application with reference to the accompanying drawings. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0041] Please refer to Figure 1 , Figure 1Schematic structural diagram of a surface acoustic wave device provided by an embodiment of the present application. As Figure 1 shown, the provided surface acoustic wave device 10 includes a piezoelectric crystal 11, two interdigital transducers 12, and a transfer chamber 13. The interdigital transducers 12 are disposed on the surface of the piezoelectric crystal, and the transfer chamber 13 is disposed on the surface of the piezoelectric crystal and located between the two interdigital transducers 12. Among them, the transfer chamber 13 is used to place a blood-brain barrier model / blood-brain barrier site 20, and the two interdigital transducers 12 are used to drive the piezoelectric crystal 11 to vibrate to generate and propagate surface acoustic waves in the blood-brain barrier model 20 or the blood-brain barrier site 20, and the surface acoustic waves act on the blood-brain barrier to open the blood-brain barrier.

[0042] In order to realize opening the blood-brain barrier by surface acoustic waves, in an embodiment of the present invention, based on the basic principle of a surface acoustic wave generator known to those skilled in the art, an interdigital transducer 12 device capable of exciting surface acoustic waves is designed based on a signal generator and a power amplifier, and then the piezoelectric crystal 11 can be driven to vibrate through the inverse piezoelectric effect of the piezoelectric crystal 11, and then two surface acoustic waves with opposite vibration directions, the same amplitude, and the same frequency as Figure 1 shown are propagated in the cell fluid in the transfer chamber 13. A standing wave formed by the superposition of two surface acoustic waves propagating in opposite directions can act in the transfer chamber 13 to open the blood-brain barrier. This device can well apply the surface acoustic waves to the transfer chamber 13 (Transwell) of the in vitro blood-brain barrier. Using the transfer chamber 13, the parameters of the change in blood-brain barrier permeability caused by surface acoustic waves are evaluated, and it is confirmed that surface acoustic waves are a practical and new optional method for safely opening the blood-brain barrier.

[0043] In one embodiment, please refer to Figure 1 , the piezoelectric crystal 11 includes a sample placement chamber 111, and a culture medium, such as RMPI 1640 culture medium, is stored in the sample placement chamber 111. The sample placement chamber 111 includes a first chamber 1111 and a second chamber 1112, and the first chamber 1111 of the sample placement chamber 111 is used to place the transfer chamber 13.

[0044] Exemplarily, the housing material of the sample placement chamber 111 is any one of plastic, metal, or polydimethylsiloxane material. For example, the housing material of the sample placement chamber 111 is plastic; and / or, the shape of the housing of the sample placement chamber 111 is any one of a circular ring shape, an elliptical ring shape, a square ring shape, or a rhombic ring shape. For example, when the shape of the transfer chamber 14 is a circular ring shape, the shape of the sample placement chamber 111 is also a circular ring shape.

[0045] In one embodiment, the ratio of the wavelength of the surface acoustic wave to the barrier width of the blood-brain barrier model / blood-brain barrier site 20 in the transfer chamber is within a preset magnification range to ensure that the vibration of the piezoelectric crystal driven by the surface acoustic wave can open the blood-brain barrier. The barrier width is the width of the blood-brain barrier model / blood-brain barrier site 20 along the propagation direction of the surface acoustic wave.

[0046] It should be noted that the barrier width corresponding to the blood-brain barrier model / blood-brain barrier site 20 in the transfer chamber 13 is related to the wavelength of the surface acoustic wave. Specifically, the barrier width can be n times the wavelength of the surface acoustic wave, where n is an integer greater than or equal to 1. Thus, the vibration of the piezoelectric crystal is driven to drive the liquid vibration in the transfer chamber 13. Further, the surface acoustic wave can form antinodes and nodes in the blood-brain barrier model / blood-brain barrier site 20, and the nodes can form a strong acting force on the blood-brain barrier. The barrier width is the width of the blood-brain barrier model / blood-brain barrier site 20 along the propagation direction of the surface acoustic wave, thereby realizing the reversibility of opening the blood-brain barrier.

[0047] It should also be noted that the barrier width is n times the wavelength of the surface acoustic wave, and n can also be a decimal greater than 1, such as 100.5, 100.6, etc.

[0048] The barrier width corresponding to the blood-brain barrier model / blood-brain barrier site 20 in the transfer chamber 13 is related to the wavelength of the surface acoustic wave. It can also be understood that the difference between the barrier width and the wavelength of n times the surface acoustic wave is within a preset difference range. Mathematically, the relationship between the barrier width and the wavelength of the surface acoustic wave is as follows:

[0049] Δ = n×λ - a

[0050] In the formula, Δ is used to represent the preset difference. For example, any number selected from -10 μm to 10 μm is used as the preset difference. n is the multiple of the barrier width to the surface acoustic wave, λ is the wavelength of the surface acoustic wave, and a is the barrier width. Through the surface acoustic wave device 10 provided by the embodiments of the present application, the wavelength of the surface acoustic wave can be adjusted according to the barrier width of the blood-brain barrier model / blood-brain barrier site 20 to be opened, thereby realizing the reversibility of opening the blood-brain barrier.

[0051] It can also be understood that the ratio of the barrier width to the wavelength of the surface acoustic wave is within a preset magnification range. For example, when the preset magnification n is equal to 95, 100, 105, etc., the piezoelectric crystal 11 can be driven to vibrate to open the blood-brain barrier. The relationship between the barrier width and the wavelength of the surface acoustic wave is as follows:

[0052]

[0053] In the formula, n is used to represent a preset ratio. For example, any number selected from the preset magnification range of 90 to 110 is used as the preset ratio. λ is the wavelength of the surface acoustic wave, and a is the barrier width. Through the cytometer 10 provided by the embodiments of the present application, the wavelength of the surface acoustic wave can be adjusted according to the barrier width corresponding to the blood-brain barrier to be opened, so as to realize the reversibility of the opening of the blood-brain barrier.

[0054] Exemplarily, the preset magnification range is 90 to 110. For example, when the barrier width is 2 cm, the wavelength of the surface acoustic wave in this area is 200 μm at this time. Further, it can be ensured that the surface acoustic wave can drive the piezoelectric crystal 11 to vibrate and open the blood-brain barrier.

[0055] It should be noted that in one embodiment, the wavelength range of the surface acoustic wave is 190 μm to 210 μm, and the barrier width of the blood-brain barrier model / blood-brain barrier part 20 in the transfer chamber 13 is 1.8 cm to 2.2 cm. The barrier width is the width of the blood-brain barrier model or blood-brain barrier part along the propagation direction of the surface acoustic wave.

[0056] In one embodiment, the surface acoustic wave device 10 further includes: a signal generator, which is respectively connected to the two interdigital transducers 12. The signal generator is used to control the two interdigital transducers 12 to drive the piezoelectric crystal 11 to vibrate towards the transfer chamber direction respectively, so as to form a superimposed and enhanced surface acoustic wave in the transfer chamber 13.

[0057] Exemplarily, the signal generator can be any one of a magnetoelectric signal generator, a Hall signal generator, and an optoelectronic signal generator. By adjusting the parameters of the excitation electrical signal emitted by the signal generator, it is possible to control the two interdigital transducers 12 to cooperate to drive the piezoelectric crystal 11 to vibrate and propagate the surface acoustic wave towards the blood-brain barrier model / blood-brain barrier part 20 in the transfer chamber 13. Therefore, the embodiments of the present application do not limit the type of the signal generator.

[0058] The interdigital transducer 12 based on the surface acoustic wave applicable to the analysis in the transfer chamber 13 is designed as follows:

[0059] Please also refer to Figure 1 and Figure 2 , Figure 2 is a schematic structural diagram of another surface acoustic wave device provided by the embodiments of the present application. The surface acoustic wave device 10 of this solution is based on the interdigital transducer 12 coupled to the printed circuit board. Using the printed circuit board can reduce the volume of the device and enhance the stability of the instrument. The interdigital transducer 12 is tightly pressed on the surface of the piezoelectric crystal 11 by a mechanical fixing method, so as to generate a stable and adjustable surface acoustic wave interdigital transducer 12. In the center of the piezoelectric crystal 11, a ring-shaped plastic is inlaid as the housing of the sample placement chamber 111, which can store a small amount of culture medium for the surface acoustic wave to stimulate the transfer chamber 13. In some embodiments, please refer to Figure 3 ,Figure 3 This is a schematic structural diagram of another surface acoustic wave device provided by an embodiment of the present application. In Figure 3 , each interdigital transducer 12 includes: an interdigital unit 121 and a printed circuit board 122. The interdigital unit 121 is disposed on the first side surface of the printed circuit board 122. Among them, the printed circuit boards 122 of the two interdigital transducers 12 are both disposed on the piezoelectric crystal 11, and the first side surfaces of the printed circuit boards 122 are both in contact with the piezoelectric crystal 11.

[0060] As Figure 3 shown, the interdigital transducer 12 is composed of two rows of busbars (bus lines), and each row of busbars has multiple electrodes. These electrodes are distributed at intervals from each other, thus forming an interdigital transducer 12. The surface acoustic wave device 10 provided by the present application can generate a surface acoustic wave to open the blood-brain barrier by adding two interdigital units 121 into the printed circuit board 122 and then driving the piezoelectric crystal 11 jointly after aligning the two interdigital units 121.

[0061] It should be noted that, in some embodiments, as Figure 3 shown, the two printed circuit boards 122 are integrally formed. The integrally formed circuit board body includes a hollowed-out portion 1221 located between the two interdigital units 121, and the hollowed-out portion 1221 corresponds to the transfer chamber 13. Furthermore, the two interdigital units 121 do not need to be aligned every time they are used, which improves the usage efficiency of the provided surface acoustic wave device 10.

[0062] It should be noted that, in some embodiments, the finger pitch of the interdigital transducer 12 is negatively correlated with the operating frequency of the interdigital transducer 12. The finger pitch of the interdigital transducer refers to the distance between two adjacent electrodes up and down. By restricting the finger pitch of the two interdigital transducers 12 according to the operating frequency, the interdigital transducer 12 can be designed to have an operating frequency of MHz to GHz. As Figure 4 shown, the present application also explores the relationship between the operating frequency and the acoustic wave density per unit area, and it can be confirmed that the higher the operating frequency, the greater the acoustic wave density per unit area.

[0063] It should be noted that the usage method of the provided surface acoustic wave device 10 is as follows: Place the transfer chamber 13 into a plastic ring, turn on the signal generator, and then the cells in the transfer chamber 13 can be stimulated. Subsequently, the change in the blood-brain barrier permeability can be evaluated by measuring the transendothelial electrical resistance of the transfer chamber 13. By adjusting the input signal of the surface acoustic wave of the device, surface acoustic waves with different powers from 0 - 40 dBm (decibel milliwatt) can be used to stimulate the transfer chamber 13.

[0064] In some embodiments, the provided piezoelectric crystal 11 is made of any one of lithium niobate crystal, lead zinc niobate-lead titanate crystal, lead magnesium zirconate titanate niobate crystal, lead zinc titanate niobate crystal, lead nickel titanate niobate crystal, or polyvinylidene fluoride crystal. Thus, due to the piezoelectric properties of the piezoelectric crystal, the piezoelectric crystal 11 can cooperate with two interdigital transducers 12 to achieve the transmission of surface acoustic waves.

[0065] Exemplarily, the provided piezoelectric crystal 11 is made of lithium niobate crystal. Since lithium niobate has excellent piezoelectric properties, such as lithium niobate with a 128-degree Y-cut, it can cooperate well with two interdigital transducers 12 to achieve the transmission of surface acoustic waves. At the same time, lithium niobate has good light transmittance, which is also convenient for the provided surface acoustic wave device 10 to observe the open state of the blood-brain barrier.

[0066] In one embodiment of the present invention, the opening of the blood-brain barrier is judged by detecting the change in the transendothelial electrical resistance of brain microvascular endothelial cells; and during the opening of the blood-brain barrier, when the transcutaneous electrical resistance of brain microvascular endothelial cells decreases to a threshold value and then recovers, it can be judged that the opening of the blood-brain barrier is reversible.

[0067] In one embodiment of the present invention, through the detection and observation means mastered by those skilled in the art, it is found that the morphology and activity of brain microvascular endothelial cells remain unchanged or the changes are within the normal range. It can be judged that the morphology and activity of brain microvascular endothelial cells are not changed during the stimulation of hBMECs by surface acoustic waves, further confirming that the opening process of the blood-brain barrier is reversible.

[0068] In one embodiment of the present invention, the blood-brain barrier model includes, but is not limited to, a human blood-brain barrier model or other animal models. The human blood-brain barrier model can be obtained by in vitro culture of human brain microvascular endothelial cells.

[0069] In a preferred embodiment, a model chamber is pre-constructed on the surface of the piezoelectric crystal, and human brain microvascular endothelial cells are placed in the chamber for culture, so that the blood-brain barrier model is close to the surface of the piezoelectric crystal, and the surface acoustic wave energy is concentrated on the medium surface, thus being easy to control.

[0070] In one embodiment, the period when the blood-brain barrier model or the blood-brain barrier site is formed in vitro is positively correlated with the frequency of the surface acoustic wave; and / or, the period when the blood-brain barrier model or the blood-brain barrier site is formed in vitro is positively correlated with the power of the surface acoustic wave.

[0071] Exemplarily, if the period range when the blood-brain barrier model or the blood-brain barrier site is formed in vitro is 20 hours to 50 hours, the frequency of the surface acoustic wave is 10 MHz to 100 MHz, and / or, the power of the surface acoustic wave is 20 dBm to 40 dBm.

[0072] It should be noted that in one embodiment, when opening the blood-brain barrier model of the human brain, the frequency of the surface acoustic wave is 10-100 MHz, and the power is 20-40 dBm; for blood-brain barrier models in different formation periods, the surface acoustic wave can reduce the trans-epithelial resistance value of human brain microvascular endothelial cells when the power is 20 dBm, 25 dBm, 30 dBm, 35 dBm or 37.8 dBm, and can recover after several minutes, which can be regarded as reversibly opening the blood-brain barrier.

[0073] It should be noted that in one embodiment, if the formation period range of the blood-brain barrier model or the blood-brain barrier site in vitro is 20 hours to 35 hours, the power range of the surface acoustic wave is 20 dBm to 30 dBm, and the time range for the surface acoustic wave to act on the blood-brain barrier is 1 to 5 minutes.

[0074] It should be noted that in one embodiment, if the formation period range of the blood-brain barrier model or the blood-brain barrier site in vitro is 36 hours to 50 hours, the power range of the surface acoustic wave is 30 dBm to 40 dBm, and the time range for the surface acoustic wave to act on the blood-brain barrier is 4 to 10 minutes.

[0075] Based on the above parameters for opening the blood-brain barrier model of the human brain, those skilled in the art can adjust the frequency and power through the surface acoustic wave generator provided by the present invention according to the blood-brain barrier conditions of different brain objects, and can open the blood-brain barrier through a limited number of experiments. By detecting the change in the trans-endothelial resistance value of brain microvascular endothelial cells, the parameters of frequency and power can be obtained, which are all within the scope of the embodiments of the present invention.

[0076] In particular, the opening of the blood-brain barrier described in the present invention is to provide a biological state of temporary disruption of the blood-brain barrier, aiming to provide a channel for central nervous system drug delivery, rather than a direct way to diagnose or treat diseases. Therefore, it does not belong to the category of diagnosing or treating diseases.

[0077] The following are the preferred embodiments provided by this solution, which are used to illustrate the above solution and verify the technical effects.

[0078] Example 1. Cultivation of human brain microvascular endothelial cells (Human Brain Microvascular Endothelial Cells, hBMECs) and construction of the transfer chamber 13 model.

[0079] In order to stimulate the blood-brain barrier using two interdigital transducers 12, it is also necessary to construct an in vitro blood-brain barrier (BBB) model. A transwell 14 model is constructed using hBMECs. The hBMECs are cultured in RPMI 1640 medium and passaged every three to four days. To construct the transwell 14 model, the transwell 14 is first coated with collagen, then washed with phosphate buffer saline (PBS), and placed in a 37 °C carbon dioxide incubator. In a 6.5 mm transwell 14, 8×10⁴ cells are added to each well for culturing in 100 μL, as Figure 1 shown, the second chamber of the transwell 14 is a 24-well plate, and 1.5 mL of medium is added to each well. The culture plate containing the transwell 14 is then placed in a 37 °C carbon dioxide incubator for culturing, and an in vitro blood-brain barrier model can be formed after a period of time.

[0080] Example 2. Opening of the in vitro blood-brain barrier induced by surface acoustic waves.

[0081] In some embodiments, when the blood-brain barrier is opened, the trans-epithelial electrical resistance value of the blood-brain barrier is lower than a threshold value.

[0082] Exemplarily, the surface acoustic wave device 10 further includes: a resistivity meter, the resistivity meter includes a first measurement electrode and a second measurement electrode, and the length of the first measurement electrode is greater than the length of the second measurement electrode; wherein, by inserting the first measurement electrode into the second chamber 1112 of the sample placement chamber 111 and inserting the second measurement electrode of the resistivity meter into the first chamber 1111 of the sample placement chamber 111, the trans-epithelial electrical resistance value is measured.

[0083] To analyze the effect of surface acoustic waves on the in vitro blood-brain barrier, we adjusted the frequency of the signal generator to the operating frequency of the interdigital transducer 12 and used surface acoustic waves with different powers and for different durations to stimulate the transfer chamber 14 in the interdigital transducer 12 device. By detecting the transendothelial electrical resistance of hBMECs, we reflected the change in the integrity of the blood-brain barrier. There are literature reports that the disruption of the blood-brain barrier is accompanied by a decrease in transendothelial electrical resistance. Therefore, the change in transendothelial electrical resistance is usually used to evaluate the integrity of the blood-brain barrier. For the early blood-brain barrier at 24 h, the transfer chamber 14 was treated with surface acoustic waves at powers of 20 dBm, 25 dBm, and 30 dBm for 5 min, and then the transendothelial electrical resistance of the blood-brain barrier was immediately detected. The experimental results showed that 20 dBm, 25 dBm, and 30 dBm could all effectively reduce the transendothelial electrical resistance of hBMECs, confirming the opening of the blood-brain barrier. Further observation found that after hBMECs were cultured for a period of time, the transendothelial electrical resistance could return to the normal level and even increase slightly, confirming that the opening of the blood-brain barrier induced by the transfer chamber 14 was reversible. Subsequently, we fixed the surface wave power at 30 dBm (power of 1 W) and used different treatment times to stimulate the transfer chamber 14. The test situation is as Figure 5 shown, Figure 5 The results showed that for the early-formed blood-brain barrier at 24 h, surface acoustic waves at 30 dBm for 1 min, 3 min, and 5 min could all effectively reduce the transendothelial electrical resistance of hBMECs. However, for the firmly formed blood-brain barrier at 48 h, surface acoustic waves at 30 dBm were not sufficient to reduce the transendothelial electrical resistance of hBMECs. At this time, the function of the surface acoustic waves had to reach 35 dBm to reduce the transendothelial electrical resistance of hBMECs. In addition, after culturing for a period of time after the blood-brain barrier was opened, the transendothelial electrical resistance increased somewhat, indicating the recovery of the function of the blood-brain barrier. Through these experiments, it was confirmed that the interdigital transducer 12 based on the surface acoustic wave device 10 could open the in vitro blood-brain barrier and had a certain dose dependence. 30 dBm was sufficient to open the early blood-brain barrier, while for the late blood-brain barrier, 35 dBm or higher power was required to open it.

[0084] The principle of surface acoustic wave manipulation of cells is the acoustic radiation force generated by sound waves, and the formula is:

[0085]

[0086] where F r is the acoustic radiation force, P0 is the pressure amplitude, V P is the particle volume, λ is the surface acoustic wave wavelength, Φ(,) is the contrast factor, x is the distance from the pressure node, β m is the medium compressibility, β p is the cell compressibility, ρ m is the medium density, ρ p is the cell density.

[0087] When the frequency is higher, the wavelength is shorter, the acoustic radiation force is greater, and it is more effective to manipulate cells. Through modeling and analysis of the integrity of the blood-brain barrier and frequency at 35 dBm, as Figure 6 shown. Figure 6 As can be seen from the results, in the range of 10 to 100 MHz, the integrity of the blood-brain barrier under the stimulation of surface acoustic waves at 35 dBm decreases with the increase of frequency. For other frequencies to induce blood-brain barrier disruption, the power of the surface acoustic waves needs to be changed to achieve the best effect.

[0088] Example 3. Surface acoustic wave stimulation does not change the cell viability of hBMECs.

[0089] Traditional ultrasonic waves are prone to generate microvesicles during the treatment process, thus easily causing tissue damage. To analyze the effect of surface acoustic wave treatment on hBMECs, we analyzed the growth state of hBMECs after surface acoustic wave stimulation. First, hBMECs in the transfer chamber 14 were stimulated with surface acoustic waves at 35 dBm and 37.8 dBm respectively. Experiments found that surface acoustic wave stimulation at 35 dBm and 37.8 dBm can both open the blood-brain barrier ( Figure 7 A). Using the CCK8 kit for cell viability detection and analysis, it was observed that even under the stimulation of high-power surface acoustic waves at 35 dBm and 37.8 dBm, the cell viability of hBMECs could still remain at 93% and 85% ( Figure 7 B). In addition, cell morphology observation confirmed that surface acoustic wave stimulation did not change the cell morphology of hBMECs. This result indicates that surface acoustic wave treatment does not change the cell viability of hBMECs. In addition, by detecting the transendothelial electrical resistance of hBMECs, as Figure 8 shown, under the stimulation of surface acoustic waves with a power of 37.8 dBm, the change in the transendothelial electrical resistance of hBMECs showed a trend of decreasing first and then increasing, further confirming that the opening of the blood-brain barrier induced by surface acoustic waves is reversible. Based on the fact that high-power surface acoustic wave stimulation can achieve reversible opening of the blood-brain barrier, it can also be achieved at low power.

[0090] Example 4. Surface acoustic wave stimulation increases the paracellular permeability of hBMECs to substances with different molecular weights.

[0091] In one embodiment, the first chamber of the sample placement chamber includes a marker with a preset molecular weight, and when the blood-brain barrier is opened, the marker can be detected at the second chamber of the sample placement chamber.

[0092] Paracellular permeability is another indicator for evaluating the integrity of the blood-brain barrier. To confirm that the destruction of the blood-brain barrier mediated by surface acoustic wave stimulation can indeed promote drug delivery, we selected sodium fluorescein (NaF, 376 Da), fluorescein isothiocyanate (FITC)-labeled dextran (FITC-dextran 10 kD), and FITC-dextran 70 kD as markers to represent small and large molecules respectively. After surface acoustic wave stimulation, the fluorescence intensity of these substances passing through the hBMECs gap and reaching the lower chamber (paracellular permeability) was detected. The detection results are as Figure 9 shown. The results showed that surface acoustic wave stimulation increased the permeability of hBMECs to NaF and FITC-dextran, confirming that surface acoustic wave is an effective method to open the blood-brain barrier and deliver drugs.

[0093] In some embodiments, when the blood-brain barrier is opened, arrangement information of tight junction proteins corresponding to the brain microvascular endothelial cells is obtained according to the blood-brain barrier model or the brain microvascular endothelial cells within the blood-brain barrier site, and the arrangement information of the tight junction proteins conforms to the preset arrangement information corresponding to the opening of the blood-brain barrier.

[0094] When the tight junction proteins corresponding to the brain microvascular endothelial cells are arranged orderly and tightly and there is co-localization of different proteins, it can be considered that the blood-brain barrier is opened. When the tight junction proteins are arranged chaotically and incompletely, it is inferred that the integrity of the blood-brain barrier is damaged at this time.

[0095] Example 5. Surface acoustic wave stimulation promotes the penetration of NaF into zebrafish brain tissue.

[0096] In some embodiments, the blood-brain barrier model 20 is a zebrafish, and the transfer chamber 14 includes an indicator. Surface acoustic waves act on the brain tissue of the zebrafish to enable the indicator to penetrate into the brain tissue of the zebrafish, opening the blood-brain barrier of the zebrafish and the blood-retinal barrier at the eyes of the zebrafish.

[0097] To confirm that surface acoustic waves can promote drug penetration in vivo, we selected zebrafish with transparent bodies (10 days post-fertilization, 10 dpf) as the in vivo model and used NaF (376 Da) as the blood-brain barrier tracer indicator. In the experiment, the zebrafish were placed in an aqueous solution containing 1 mg / ml NaF, and then treated with or without surface acoustic waves. After the treatment, they were immediately washed with clean water, and the fluorescence distribution of the fish body was observed under a fluorescence microscope. The results are as Figure 10 (A-D) shown. The experimental results showed that surface acoustic wave stimulation promoted the penetration of NaF into zebrafish brain tissue and showed a punctate distribution in the brain tissue ( Figure 10D, as indicated by the arrow). In addition, we also found that in the fish body stimulated by surface acoustic waves, the fluorescence intensity at the eyes was higher than that of the control group ( Figure 10 A, Figure 10 B). These results indicate that surface acoustic wave stimulation can indeed open the blood-brain barrier and promote the penetration of NaF; moreover, the barrier affected by surface acoustic waves is not limited to the blood-brain barrier. For example, the blood-retinal barrier at the eyes can also be opened by surface acoustic waves.

[0098] Please refer to Figure 11 , Figure 11 which is a schematic block diagram of a medical device provided by this application. In Figure 11 , the medical device 100 includes the surface acoustic wave device 10 and the blood-brain barrier model / blood-brain barrier site 20 provided by the embodiments of this application. The surface acoustic wave device 10 is used to open the blood-brain barrier of the blood-brain barrier model / blood-brain barrier site 20.

[0099] In some embodiments, the surface acoustic wave device 10 can be set with reference to the example of Figures 1 to 3 . For example, the surface acoustic wave device 10 includes a piezoelectric crystal 11, two interdigital transducers 12, and a transfer chamber 13. The specific setting method of the surface acoustic wave device 10 can refer to the corresponding embodiments described in the specification of this application, and will not be elaborated here. Finally, it should be noted that although the present invention has been described in detail with general descriptions and specific embodiments above, based on the present invention, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A surface acoustic wave device, characterized in that, For opening the blood-brain barrier, the surface acoustic wave device includes: A piezoelectric crystal; Two interdigital transducers disposed on the surface of the piezoelectric crystal; A transfer chamber disposed on the surface of the piezoelectric crystal and located between the two interdigital transducers; Wherein, the transfer chamber is used to place a blood-brain barrier model or a blood-brain barrier site, and the two interdigital transducers are used to drive the piezoelectric crystal to vibrate to propagate surface acoustic waves in the blood-brain barrier model or the blood-brain barrier site, and the surface acoustic waves act on the blood-brain barrier to open the blood-brain barrier.

2. The surface acoustic wave device according to claim 1, characterized in that, The ratio of the wavelength of the surface acoustic wave to the barrier width of the blood-brain barrier model or the blood-brain barrier site in the transfer chamber is within a preset magnification range to ensure that the vibration of the piezoelectric crystal driven by the surface acoustic wave can open the blood-brain barrier, and the barrier width is the width of the blood-brain barrier model or the blood-brain barrier site along the propagation direction of the surface acoustic wave.

3. The surface acoustic wave device according to claim 2, wherein The preset magnification range is from 90 to 110.

4. The surface acoustic wave device according to claim 2, wherein The wavelength range of the surface acoustic wave is from 190 μm to 210 μm, and the barrier width of the blood-brain barrier model or the blood-brain barrier site in the transfer chamber is from 1.8 cm to 2.2 cm.

5. The surface acoustic wave device according to claim 1, characterized in that, The surface acoustic wave device further includes: A signal generator respectively connected to the two interdigital transducers, and the signal generator is used to control the two interdigital transducers to respectively drive the piezoelectric crystal to vibrate towards the transfer chamber direction to form a superimposed and enhanced surface acoustic wave in the transfer chamber.

6. The surface acoustic wave device according to claim 1, wherein The period of formation of the blood-brain barrier model or the blood-brain barrier site in vitro is positively correlated with the frequency of the surface acoustic wave; and / or, the period of formation of the blood-brain barrier model or the blood-brain barrier site in vitro is positively correlated with the power of the surface acoustic wave.

7. The surface acoustic wave device according to claim 6, wherein If the period range of formation of the blood-brain barrier model or the blood-brain barrier site in vitro is from 20 hours to 50 hours, the frequency of the surface acoustic wave is from 10 MHz to 100 MHz, and / or, the power of the surface acoustic wave is from 20 dBm to 40 dBm.

8. The surface acoustic wave device according to claim 1, wherein The piezoelectric crystal includes a sample placement chamber storing a culture medium, the sample placement chamber includes a first chamber and a second chamber, and the first chamber of the sample placement chamber is used to place the transfer chamber.

9. The surface acoustic wave device according to claim 8, wherein, The housing material of the sample placement chamber is any one of plastic, metal or polydimethylsiloxane material; and / or, the shape of the housing of the sample placement chamber is any one of circular ring, elliptical ring, square ring or rhombic ring.

10. The surface acoustic wave device according to claim 8, characterized in that, When the blood-brain barrier is opened, the transcutaneous resistance value of the blood-brain barrier is lower than the threshold.

11. The surface acoustic wave device according to claim 10, characterized in that, The surface acoustic wave device further includes: A resistance meter including a first measurement electrode and a second measurement electrode, and the length of the first measurement electrode is greater than the length of the second measurement electrode; wherein, by inserting the first measurement electrode into the second chamber of the sample placement chamber and inserting the second measurement electrode of the resistance meter into the first chamber of the sample placement chamber, the transcutaneous resistance value is measured.

12. The surface acoustic wave device according to claim 8, wherein, The first chamber of the sample placement chamber includes a marker with a preset molecular weight, and when the blood-brain barrier is opened, the marker can be detected at the second chamber of the sample placement chamber.

13. The surface acoustic wave device according to claim 1, wherein Each of the interdigital transducers includes: a printed circuit board and an interdigital unit disposed on a first side of the printed circuit board; Wherein, the printed circuit boards of the two interdigital transducers are both disposed on the piezoelectric crystal, and the first sides of the printed circuit boards are in contact with the piezoelectric crystal.

14. The surface acoustic wave device according to claim 13, wherein, The printed circuit boards of the two interdigital transducers are integrally formed. The integrally formed circuit board body includes a hollow portion located between the interdigital units of the two interdigital transducers, and the hollow portion corresponds to the transfer chamber.

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