Ferrofluid magnetic transportation adhesion testing device and adhesion testing method

Abstract

The invention discloses a ferromagnetic fluid magnetic transportation adhesion testing device and an adhesion testing method. The device comprises a mounting table; the fixing support is mounted on the mounting table, the fixing support extends downwards to form a cantilever beam, and a hydrophilic circular groove is formed in the tail end of the cantilever beam; the test board is mounted on the mounting table, a test substrate is arranged on the test board and used for placing ferrofluid droplets, and the hydrophilic circular groove is located on a moving path of the ferrofluid droplets; the detection center of the displacement sensor and the circle center of the hydrophilic circular groove coincide on the same horizontal line, and the cantilever beam is located between the displacement sensor and the ferrofluid droplet; the moving mechanism is mounted on the mounting table, the moving mechanism is provided with a movable table capable of moving back and forth, and a magnetic block is arranged on the movable table and located below the test table. The technology has the advantages of high repeatability and low test cost, can simulate the adhesive force characteristics of the ferrofluid in a high-precision manner when the human body carries the medicine, and provides quantitative adhesive force data support for medicine carrier optimization.

Description

Technical Field

[0001] The present invention relates to the technical field of biotechnology, and in particular to a ferrofluid magnetic transport adhesion test device and an adhesion test method. Background Art

[0002] The adhesion behavior of ferrofluids in biological tissues is currently unclear, and this adhesion behavior directly affects their targeted delivery efficiency. However, existing research has mostly focused on magnetic responsiveness, lacking quantitative measurements of solid-liquid interfacial interactions. Existing measurement techniques, such as atomic force microscopy (AFM), are prohibitively expensive, unsuitable for large-scale droplet experiments, and unable to simulate realistic magnetically controlled drug delivery scenarios. Summary of the Invention

[0003] The present invention aims to provide a ferrofluid magnetic transport adhesion testing device to solve one or more technical problems existing in the prior art and at least provide a beneficial option or create conditions.

[0004] A ferrofluid magnetic transport adhesion testing device according to an embodiment of the first aspect of the present invention comprises:

[0005] Mounting table;

[0006] A fixed bracket is mounted on the mounting platform, wherein a cantilever beam extends downward from the fixed bracket, and a hydrophilic circular groove is provided at the end of the cantilever beam;

[0007] A test platform, which is mounted on the mounting platform, wherein a test substrate is provided on the test platform, wherein the test substrate is used to place ferrofluid droplets, wherein the relative position between the ferrofluid droplets and the mounting platform is adjustable, and wherein the hydrophilic circular groove is located on the moving path of the ferrofluid droplets;

[0008] A displacement sensor, wherein the detection center thereof and the center of the hydrophilic circular groove coincide with each other on the same horizontal line, and the cantilever beam is located between the displacement sensor and the ferrofluid droplet;

[0009] A moving mechanism is installed on the mounting table. The moving mechanism is provided with a movable table that can move back and forth. A magnetic block is provided on the movable table. The magnetic block is located below the test table and is used to drive the ferrofluid droplets to move on the test substrate.

[0010] According to the ferrofluid magnetic transport adhesion test device of the embodiment of the present invention, there are at least the following beneficial effects: during the test, the ferrofluid droplet is first brought into contact with the hydrophilic circular groove of the cantilever beam, and then the moving mechanism drives the movable table to move, and the ferrofluid droplet is driven away from the cantilever beam by magnetic force. Under the action of surface tension, the adhesion force generated by the ferrofluid droplet and the test substrate directly acts on the cantilever beam to force the cantilever beam to undergo elastic deformation. The offset of the cantilever beam is detected by the displacement sensor, and combined with the cantilever beam's own parameters, the adhesion force between the ferrofluid droplet and the test substrate during magnetic transport can be calculated; compared with the existing technology, the present technology has high repeatability and low testing cost, and can simulate the adhesion characteristics of ferrofluid when transporting drugs in the human body with high precision, providing quantitative adhesion data support for drug carrier optimization, and filling the technical gap in how to study the interfacial behavior of ferrofluid during drug delivery.

[0011] According to some embodiments of the present invention, the cantilever beam is a metal component, and a hydrophobic layer is provided on the surface of the cantilever beam. The hydrophilic circular groove destroys the hydrophobic layer during processing. Although some metals naturally have a certain degree of hydrophilicity, a hydrophobic layer is required to prevent ferrofluid droplets from binding to other parts of the cantilever beam. Since the hydrophilic circular groove is processed later, its processing inevitably destroys the hydrophobic layer, thereby making the cantilever beam hydrophilic.

[0012] According to some embodiments of the present invention, specifically, the hydrophobic layer is formed on the cantilever beam by a chemical vapor deposition process.

[0013] According to some embodiments of the present invention, in order to control variables, when the ferrofluid droplet contacts the hydrophilic circular groove, the length of the contact line between the ferrofluid droplet and the test substrate remains unchanged.

[0014] According to some embodiments of the present invention, the displacement sensor is a laser displacement sensor, and the cantilever beam is provided with a positioning mark on the side facing the laser displacement sensor. The position of the positioning mark corresponds to the center of the hydrophilic circular groove. During positioning, the laser displacement sensor and the hydrophilic circular groove can be aligned by simply aligning the laser beam of the laser displacement sensor with the positioning mark.

[0015] According to some embodiments of the present invention, the relative position of the cantilever beam and the laser displacement sensor is adjustable, and the laser displacement sensor leaves a light shadow on the test substrate while the cantilever beam avoids it. The cantilever beam can be translated or rotated relative to the laser displacement sensor, with the ultimate goal of allowing the laser beam of the laser displacement sensor to leave a light shadow on the test substrate. Since a ferrofluid droplet is placed on the test substrate, the center of the ferrofluid droplet can be aligned with the light shadow of the laser beam by moving the position of the test substrate or the position of the ferrofluid droplet, thereby achieving positioning of the laser displacement sensor and the ferrofluid droplet. Combined with the previous embodiment, the center of the hydrophilic circular groove and the center of the ferrofluid droplet can be aligned on the same vertical plane.

[0016] According to some embodiments of the present invention, the test substrate is a polydimethylsiloxane substrate, and the ratio of polydimethylsiloxane to curing agent is 10:0.8 to 10:1.2, so as to produce a substrate material that is closer to the softness of human skin.

[0017] According to some embodiments of the present invention, the mounting platform is a vibration-damping platform, which can reduce the impact of the ferrofluid droplets being affected by the shaking of the working environment during the test process, so as to improve the measurement accuracy.

[0018] According to the second embodiment of the present invention, the adhesion test method using the above-mentioned ferrofluid magnetic transport adhesion test device includes the following steps:

[0019] A cantilever beam with a certain length is selected, with a width of W, a thickness of T, an elastic modulus of E, and a force arm length of the hydrophilic circular groove of L. An appropriate amount of ferrofluid droplets is dripped onto the test substrate.

[0020] Keeping the detection center of the displacement sensor and the center of the hydrophilic circular groove coincident with the same horizontal line, and keeping the center of the hydrophilic circular groove and the center of the ferrofluid droplet on the same vertical plane, then moving the ferrofluid droplet until it contacts the hydrophilic circular groove, and then zeroing the displacement sensor so that the magnetic block is directly below the ferrofluid droplet;

[0021] The moving mechanism drives the movable platform to move in a direction away from the cantilever beam, and the ferrofluid droplet moves away from the cantilever beam under the magnetic induction of the magnetic block. Under the action of surface tension, the adhesion force generated by the ferrofluid droplet and the test substrate directly acts on the cantilever beam, forcing the cantilever beam to undergo elastic deformation;

[0022] The displacement sensor detects the offset X of the cantilever beam and uses the formula calculating the instantaneous adhesion force between the ferrofluid droplet and the test substrate;

[0023] After the ferrofluid droplet is separated from the cantilever beam, the test is terminated.

[0024] The adhesion testing method according to an embodiment of the present invention has at least the following beneficial effects: this technology can quantify the adhesion characteristics of ferrofluids to different tissues, helps to understand their wetting, spreading and separation behaviors in vivo, provides theoretical support for biomedical applications, and provides an experimental basis for regulating magnetic field parameters to ensure the efficient release of ferrofluid-encapsulated drugs at the target location of cancer cells.

[0025] According to some embodiments of the present invention, in the thermal treatment scheme for cancer cells by achieving targeted drug transport in vivo through an in vitro magnetic field, ferromagnetic fluid is used as a transport carrier, which is subject to multiple restrictions such as magnetic field strength, fluid viscosity and biological environment and exhibits a slow movement speed. Therefore, the movable table moves at a uniform speed of no more than 0.05 mm / s, thereby simulating the real situation.

[0026] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0028] Figure 1 3 is a schematic structural diagram of a ferrofluid magnetic transport adhesion test device provided in an embodiment of the present invention before the test begins;

[0029] Figure 2 1 is a schematic structural diagram of the ferrofluid magnetic transport adhesion test device provided by an embodiment of the present invention after the test is completed;

[0030] Figure 3 is a schematic diagram of the offset of the cantilever beam provided in an embodiment of the present invention;

[0031] Figure 4 4 is a flow chart of the adhesion testing method provided by an embodiment of the present invention.

[0032] In the accompanying drawings: 100-mounting table, 200-fixed bracket, 300-test table, 400-moving mechanism, 210-support body, 220-cantilever clamp, 230-connecting block, 500-cantilever beam, 510-hydrophilic circular groove, 310-pillar, 320-test base, 330-ferrofluid droplet, 410-movable table, 420-magnetic block, 421-magnetic flux line, 600-laser displacement sensor, 231-limiting table, 700-controller. DETAILED DESCRIPTION

[0033] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0034] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0035] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0036] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0037] like Figure 1 and Figure 2 As shown, a ferrofluid magnetic transport adhesion test device according to the first embodiment of the present invention includes a mounting platform 100, a fixed bracket 200, a test platform 300, a movable mechanism 400, and a displacement sensor. The mounting platform 100 serves as the mounting base for all components, and its surface is flat and has no obvious undulations. The fixed bracket 200, the test platform 300, and the movable mechanism 400 are all fixedly connected to the mounting platform 100 via a base, while the displacement sensor is fixedly connected to the mounting platform 100 via a support rod, which is used to raise the height of the displacement sensor so that it can be installed in an elevated position. Since the adhesion test of the ferrofluid droplet 330 requires high precision, any vibration generated on the mounting platform 100 will have a significant impact on the test results. In order to reduce the impact of the working environment shaking on the ferrofluid droplet 330 during the test and improve measurement accuracy, in this embodiment, the mounting platform 100 can be optionally used as a shock-absorbing platform.

[0038] A shock-absorbing platform is a type of experimental equipment specifically designed to isolate or reduce external vibration interference. It is widely used in high-precision measurements and precision instrument operation. Through passive or active control technologies, the platform effectively isolates ground vibration, equipment vibration, and ambient noise, ensuring the stability and accuracy of experimental data. Shock-absorbing platforms are primarily categorized as passive and active. Passive shock absorption utilizes elastic materials such as rubber pads and springs, or negative stiffness structures, to absorb vibration energy, reducing resonant frequency through the damping effect. Active shock absorption, on the other hand, uses sensors to detect vibration in real time, driving piezoelectric elements to generate a counterforce to offset interference, making it suitable for dynamic environments.

[0039] Furthermore, the fixing bracket 200 includes a support body 210 and a cantilever clamp 220. The support body 210 is fixedly connected to the mounting platform 100 via a base. The support body 210 extends vertically upward and has a connecting block 230 connected horizontally at its top. The connecting block 230 is connected to the cantilever clamp 220 toward the mounting platform 100. The cantilever clamp 220 consists of two parallel and movable clamps, forming a clamping space between the two clamps. When the size of the clamping space needs to be adjusted, the distance between the two clamps can be adjusted by rotating a screw running through the two clamps, thereby achieving assembly and disassembly of the cantilever beam 500.

[0040] The cantilever beam 500 is detachably connected via the cantilever clamp 220. Although one end of the cantilever beam 500 is secured by the cantilever clamp 220, the rest of the cantilever beam 500 is suspended, extending downward. For ease of description, this embodiment uses the front of the cantilever beam 500 as the rear direction and the back of the cantilever beam 500 as the front direction. The support body 210 is located in front of the cantilever beam 500. In this embodiment, the cantilever beam 500 can be made of metal, such as copper, to ensure good hydrophilicity.

[0041] For this experiment, a copper cantilever beam 500 with a length of 40 mm, a width (W) of 3 mm, and a thickness (T) of 0.1 mm was selected. A hydrophobic layer was formed on the surface of the cantilever beam 500 using a chemical vapor deposition process. Chemical vapor deposition primarily utilizes one or more vapor-phase compounds or single substances containing the film element to chemically react on the substrate surface to form a thin film. For example, using a copper sheet as the cathode and platinum as the anode, electrolysis is performed in a nickel ion solution to produce a rough nickel nanowire structure. The electrodeposited copper sheet is then placed in a parylene coating system, where a low-surface-energy material is vapor-deposited to form the hydrophobic layer.

[0042] After constructing the hydrophobic layer, a hydrophilic circular groove 510 needs to be machined on the end of the cantilever beam 500 away from the cantilever fixture 220. The hydrophilic circular groove 510 is a blind hole and is located on the front of the cantilever beam 500. Since the processing of the hydrophilic circular groove 510 is a subtractive process, it will inevitably destroy the hydrophobic layer during processing. After the hydrophobic layer is lost, a copper oxide layer will form on the surface of the hydrophilic circular groove 510. Because the copper oxide layer contains hydroxyl groups, it has good hydrophilicity. However, the cantilever beam 500 has a hydrophobic layer at locations other than the hydrophilic circular groove 510, so the droplet mainly binds to the hydrophilic circular groove 510, thereby limiting the droplet's testing position.

[0043] Furthermore, the test bench 300 is supported by support posts 310, which are fixedly connected to the mounting platform 100 via a base. Although in this embodiment, the support posts 310 and the mounting platform 100 have a fixed relative position, making the position of the test bench 300 non-adjustable, the present invention is not limited to this embodiment. In other embodiments, the test bench 300 can also be configured as a movable type, not limited to the above embodiment.

[0044] Taking the fixed test bench 300 as an example, a test substrate 320 is provided on the test bench 300 for placing droplets. Since both the test substrate 320 and the droplets are the objects to be tested, a variety of materials can be selected for testing. Taking this experiment as an example, since this experiment is to test a treatment plan for targeted drug transport to cancer cells in vivo, a polydimethylsiloxane base is selected for the test substrate 320, and a ferrofluid droplet 330 is selected for the droplet. To make the test substrate 320 more similar to the softness of human skin, the ratio of polydimethylsiloxane to curing agent is 10:0.8 to 10:1.2, preferably 10:1.

[0045] Although the position of the test platform 300 cannot be changed, the relative position of the ferrofluid droplet 330 and the mounting platform 100 can be adjusted by adjusting the position of the test substrate 320 on the test platform 300 or adjusting the position of the ferrofluid droplet 330 on the test substrate 320. The ferrofluid droplet 330 is located behind the cantilever beam 500, and the hydrophilic circular groove 510 is located in the movement path of the ferrofluid droplet 330, so that the ferrofluid droplet 330 and the hydrophilic circular groove 510 have the possibility of contact. In other words, the setting height of the hydrophilic circular groove 510 must be adapted to the setting height of the ferrofluid droplet 330, and the central axis of the hydrophilic circular groove 510 must intersect with the ferrofluid droplet 330.

[0046] Before the test, the cantilever beam 500 is kept vertically downward, and the test substrate 320 or the position of the ferrofluid droplet 330 is adjusted so that the ferrofluid droplet 330 can contact the hydrophilic circular groove 510 of the cantilever beam 500. After the two are in contact, they are left to stand still for about 3 seconds to achieve sufficient wetting of the ferrofluid droplet 330 and the hydrophilic circular groove 510 before the next step can be performed.

[0047] In addition, the moving mechanism 400 includes but is not limited to a screw moving mechanism, a gear rack moving mechanism, a cylinder moving mechanism or an oil cylinder moving mechanism. In this embodiment, since the moving mechanism 400 needs to be controlled with high precision, it is preferably a screw moving mechanism. The screw moving mechanism mainly includes a structure, a motor, a screw and a nut block. The structure is fixedly connected to the mounting platform 100 through a base. The screw is arranged in the structure along the front-back direction. The main shaft of the motor is rigidly connected to the screw. The nut block is threadedly connected to the screw, and the nut block and the structure have a degree of freedom of movement, so that when the motor is started, the nut block can move forward or backward with the forward and reverse rotation of the motor under the drive of the screw. A movable platform 410 is connected to the end of the nut block. The movable platform 410 is located below the test bench 300. The movable platform 410 is movably connected to the structure through a guide rail.

[0048] Next, a magnetic block 420 is fixedly attached to the movable platform 410. Because the movable platform 410 is located below the test platform 300, the magnetic block 420 is also located below the test platform 300. The magnetic flux lines 421 of the magnetic block 420 can pass through the test platform 300 and the test substrate 320, affecting the ferrofluid droplet 330. When the magnetic block 420 is moved directly below the ferrofluid droplet 330 via the moving mechanism 400, the ferrofluid droplet 330 is subjected to the maximum magnetic field of the magnetic block 420. The magnetic block 420 drives the ferrofluid droplet 330 in a predetermined direction through magnetic induction, simulating the actual situation in which an in vitro magnetic field controls magnetically controlled drugs in vivo.

[0049] Ferrofluids are composed of nanoscale magnetic particles suspended in a carrier fluid, and their viscosity is affected by the particle volume fraction and surfactant. Experiments have shown that for every 1% increase in the volume fraction of solid particles, the viscosity of the ferrofluid increases significantly. In vivo, high viscosity significantly increases the resistance to fluid movement. The movement of ferrofluids relies on the magnetic force generated by an external magnetic field gradient. This magnetic force not only overcomes the viscous resistance of the fluid, but in in vivo applications, the magnetic field gradient is typically set relatively weakly to avoid tissue damage, resulting in a limited net driving force for the ferrofluid. Compounding these factors, in cancer cell thermal therapy protocols using an in vitro magnetic field to achieve targeted drug transport within the body, the ferrofluid, as a transport vehicle, moves at a slow speed, typically no higher than 0.05 m / s, with a typical range of 0.01 m / s. As a comparison test, in this embodiment, the movable stage 410 is moved at a constant speed of 0.01 mm / s to simulate real-world conditions. To achieve high-precision movement of the movable stage 410 in this situation, the motor of the movable mechanism 400 is preferably a servo motor.

[0050] Specifically, the displacement sensor can be a laser displacement sensor 600. Its laser emits a beam of red laser light with a wavelength of 670 nm, illuminating the surface of the object being measured at a fixed angle. The reflected light is focused by a receiving lens onto a CCD camera. Object displacement causes the position of the light spot on the CCD camera to change, and the object's displacement is calculated based on geometric relationships. Laser displacement sensor 600 is positioned in front of cantilever beam 500, with its laser beam directly directed at cantilever beam 500 to detect the displacement of cantilever beam 500.

[0051] It is understandable that the displacement sensor may also be other sensors, such as an inductive displacement sensor or a Hall-type displacement sensor, and is not limited to the above embodiments.

[0052] For the laser displacement sensor 600, the cantilever beam 500 is provided with a positioning mark on the side facing the laser displacement sensor 600. The positioning mark can be a cross mark, and the position of the positioning mark corresponds to the center of the hydrophilic circular groove 510. When the laser of the laser displacement sensor 600 is aligned with the positioning mark, it means that the detection center of the laser displacement sensor 600 and the center of the hydrophilic circular groove 510 coincide with the same horizontal line. Figure 3 As shown, when the cantilever beam 500 is displaced due to the force applied to the hydrophilic circular groove 510, the laser displacement sensor 600 can detect the offset X of the hydrophilic circular groove 510. At this time, the length of the force arm of the hydrophilic circular groove 510 is L. If the laser displacement sensor 600 is not aligned with the center of the hydrophilic circular groove 510, the difference in L value will cause the X value to deviate, resulting in an error.

[0053] During testing, the ferrofluid droplet 330 must be in contact with the hydrophilic groove 510 to generate the applied force. Experiments have shown that when the center of the ferrofluid droplet 330 and the center of the hydrophilic groove 510 are not aligned in the same vertical plane, that is, when the ferrofluid droplet 330 and the hydrophilic groove 510 are not aligned in the left-right direction, the applied force will appear in different directions, resulting in poor repeatability and error. To improve accuracy, the center of the ferrofluid droplet 330 and the center of the hydrophilic groove 510 must be aligned in the same vertical plane.

[0054] Although the positions of the laser displacement sensor 600 and the hydrophilic circular groove 510 can be aligned through positioning marks, due to the lack of obvious alignment reference between the ferrofluid droplet 330 and the hydrophilic circular groove 510, the traditional method is to achieve the alignment of the ferrofluid droplet 330 and the hydrophilic circular groove 510 through multiple repeated experiments, which is cumbersome and inefficient.

[0055] To address the aforementioned technical issues, in this embodiment, the cantilever fixture 220 is configured as a movable fixture, movably connected to the connecting block 230 of the fixed bracket 200. This allows the relative position of the cantilever beam 500 and the laser displacement sensor 600 to be adjusted. The laser displacement sensor 600, while avoiding the cantilever beam 500, illuminates the test platform 300, leaving a shadow on the test substrate 320. The operator can use the shadow to guide the position of the test substrate 320 or the ferrofluid droplet 330, thereby achieving alignment between the laser displacement sensor 600 and the ferrofluid droplet 330. Afterwards, the cantilever beam 500 is reset under the guidance of the cantilever fixture 220. Because the detection center of the laser displacement sensor 600 is aligned with the center of the hydrophilic groove 510, and the detection center of the laser displacement sensor 600 and the center of the ferrofluid droplet 330 are in the same vertical plane, the center of the hydrophilic groove and the center of the ferrofluid droplet are in the same vertical plane.

[0056] To ensure the most distinct light and shadow cast by the laser on the test substrate 320, the laser emitter must emit laser light stably and accurately, ensuring both the intensity and stability of the light. This ensures a clear, stable light and shadow are formed on the reference surface. Furthermore, the visibility of the light and shadow can be affected by ambient lighting. In overly bright environments, the light and shadow may be blurred with the surrounding light, making it difficult to distinguish. In overly dark environments, the light and shadow, while more distinct, may be limited by factors such as the brightness of the laser device itself. Therefore, this experiment should be conducted in an environment with uniform, but not overly bright, lighting to achieve optimal results.

[0057] like Figure 1As shown, one side of the cantilever fixture 220 is rotatably connected to the connecting block 230 via a rotating shaft. The connecting block 230 is provided with a limit stop 231 on the other side of the cantilever fixture 220. The limit stop 231 and the cantilever fixture 220 are detachably connected via magnetic force. When the cantilever fixture 220 and the limit stop 231 abut and are magnetically attracted to each other, the cantilever fixture 220 returns to its initial position. In other words, the range of motion of the cantilever beam 500 has an origin. Even if the cantilever beam 500 and the laser displacement sensor 600 are aligned and their relative positions change after alignment, the alignment between the cantilever beam 500 and the laser displacement sensor 600 remains as long as the cantilever beam 500 is returned to its origin. On an implementation level, aligning the laser displacement sensor 600 with the hydrophilic circular groove 510 or with the ferrofluid droplet 330 first does not affect the final test results.

[0058] Using the above structure, during testing, the ferrofluid droplet 330 contacts the hydrophilic circular groove 510 of the cantilever beam 500, with the magnetic block 420 positioned directly below the ferrofluid droplet 330. The moving mechanism 400 then drives the movable platform 410 backward, and the magnetic block 420 uses magnetic force to pull the ferrofluid droplet 330 away from the cantilever beam 500. Under the influence of surface tension, the adhesive force generated between the ferrofluid droplet 330 and the test substrate 320 directly acts on the cantilever beam 500, forcing it to undergo elastic deformation. The displacement sensor detects the deflection of the cantilever beam 500, and combined with the cantilever beam 500's own parameters, the adhesive force between the ferrofluid droplet 330 and the test substrate 320 during magnetic transport can be calculated. Compared with existing technologies, this technology has high repeatability and low testing cost. It can simulate the adhesion characteristics of ferrofluids when transporting drugs in the human body with high precision, providing quantitative adhesion data support for drug carrier optimization, and filling the technical gap in how to study the interfacial behavior of ferrofluids during drug delivery.

[0059] In some embodiments of the present invention, to control variables, the contact line length between the ferrofluid droplet 330 and the test substrate 320 must remain constant when the ferrofluid droplet 330 contacts the hydrophilic groove 510. The contact line length refers to the longest straight line between the ferrofluid droplet 330 and the test substrate 320. This length can generally be simply represented by the diameter of the ferrofluid droplet 330. Since the adhesion force is related to the contact line length, maintaining the contact line length before and after the test can eliminate its impact on the test results. As for how to maintain the contact line length before and after the test, the following method can be used: Experimental results show that if the ferrofluid droplet 330 is taken in a 6 μl amount, the diameter of the ferrofluid droplet 330 is approximately 2.5 mm to 2.6 mm. Therefore, the diameter of the hydrophilic groove 510 should be set to 1.8 mm. The hydrophilic groove 510 should be located in the path of the ferrofluid droplet 330, and the center of the ferrofluid droplet 330 should be in the same vertical plane as the center of the hydrophilic groove 510.

[0060] It should be noted that, prior to testing, the ferrofluid droplet 330 must contact the hydrophilic circular groove 510 of the cantilever beam 500. While this process can be achieved by manually moving the test substrate 320 or the ferrofluid droplet 330, it can also be driven by the magnetic block 420. In other words, before the test, the magnetic block 420 is already directly below the ferrofluid droplet 330. Driven by the moving mechanism 400, the magnetic block 420 moves forward, thereby driving the ferrofluid droplet 330 toward the cantilever beam 500, thus meeting the technical requirements of automation.

[0061] Furthermore, the forward and backward movement of the movable platform 410 can be controlled by an automated program. This requires a visual camera (not shown) positioned adjacent to the cantilever beam 500. During the movement of the movable platform 410, if the visual camera detects contact between the ferrofluid droplet 330 and the hydrophilic circular groove 510, causing deformation of the ferrofluid droplet 330, the visual camera feeds this information back to the controller 700, which in turn controls the movement mechanism 400 to pause. If the visual camera detects complete separation of the ferrofluid droplet 330 from the cantilever beam 500, the visual camera feeds this information back to the controller 700, which in turn controls the laser displacement sensor 600 to cease detection.

[0062] like Figure 4 As shown, the adhesion test method according to the second embodiment of the present invention uses the ferrofluid magnetic transport adhesion test device according to the first embodiment of the present invention, including the following steps:

[0063] S100. Select a cantilever beam 500 of a certain length, with a width of W, a thickness of T, an elastic modulus of E, and a force arm length of the hydrophilic circular groove 510 of L. Fix the cantilever beam 500 on the cantilever fixture 220, and drip an appropriate amount of ferrofluid droplets 330 onto the test substrate 320.

[0064] S200 . According to the positioning mark on the cantilever beam 500 , adjust the detection position of the laser displacement sensor 600 so that its laser is aligned with the positioning mark to achieve alignment between the laser displacement sensor 600 and the hydrophilic circular groove 510 .

[0065] S300. Rotate the position of the cantilever fixture 220 so that the cantilever beam 500 avoids the laser of the laser displacement sensor 600. The laser displacement sensor 600 irradiates in the direction of the test bench 300 and leaves a light and shadow on the test substrate 320. The position of the test substrate 320 or the ferrofluid droplet 330 is adjusted by the guidance of the light and shadow to achieve alignment of the laser displacement sensor 600 and the ferrofluid droplet 330.

[0066] S400. Move the ferrofluid droplet 330 until it contacts the hydrophilic groove 510, then zero the displacement sensor. At this point, the magnetic block 420 is directly below the ferrofluid droplet 330. If manually adjusting the position of the ferrofluid droplet 330, it is recommended to do so by moving the test substrate 320, which is connected to the test platform 300 via a slide in a forward and backward direction, rather than directly adjusting the position of the ferrofluid droplet 330 to avoid disrupting the alignment between the ferrofluid droplet 330 and the hydrophilic groove 510. Prior to this, the magnetic block 420 must be moved forward to its limit position to prevent displacement of the ferrofluid droplet 330 due to the forward movement of the magnetic block 420 after the ferrofluid droplet 330 contacts the hydrophilic groove 510. If the position of the ferrofluid droplet 330 is adjusted automatically, before the test, the magnetic block 420 is already directly below the ferrofluid droplet 330. Driven by the moving mechanism 400, the magnetic block 420 moves forward, thereby driving the ferrofluid droplet 330 to move toward the cantilever beam 500. When the ferrofluid droplet 330 moves to contact the hydrophilic circular groove 510, the moving mechanism 400 stops working.

[0067] S500. The moving mechanism 400 drives the movable stage 410 to move backward at a constant speed of 0.01 mm / s. The ferrofluid droplet 330 is magnetically induced by the magnet 420 and moves away from the cantilever beam 500. Under the action of surface tension, the adhesive force generated between the ferrofluid droplet 330 and the test substrate 320 acts directly on the cantilever beam 500, forcing the cantilever beam 500 to undergo elastic deformation.

[0068] S600. The laser displacement sensor 600 detects the offset X of the cantilever beam 500 and calculates the offset X by the formula Calculating the instantaneous adhesion force between the ferrofluid droplet 330 and the test substrate 320;

[0069] S700. After the ferrofluid droplet 330 is separated from the cantilever beam 500, stop recording data and save the data.

[0070] It is understandable that the order of step S200 and step S300 can be interchanged, and the present invention does not limit the order of the two.

[0071] The above operation steps can simulate the adhesion of ferrofluid in transporting drugs in the human body. The adhesion of different ferrofluid droplets 330 on the surface of the test substrate 320 can be measured using the cantilever beam 500 measurement method, and the change pattern of the adhesion of different ferrofluid droplets 330 over time can be obtained.

[0072] This invention, through cantilever measurement technology, can quantify the adhesion properties of ferrofluids to different tissues (such as the vascular endothelium and the tumor microenvironment), helping to understand their wetting, spreading, and separation behaviors in vivo, and providing theoretical support for biomedical applications. Subsequent magnetic field guidance can achieve precise targeted drug delivery to cancer cells. This invention provides an experimental basis for regulating magnetic field parameters to ensure the efficient release of ferrofluid-encapsulated drugs at the target cancer cell location.

[0073] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the technical field without departing from the scope of the present invention.

Claims

1. Ferrofluid magnetic transport adhesion test device, characterized in that: include: Mounting table; A fixed bracket is mounted on the mounting platform, wherein a cantilever beam extends downward from the fixed bracket, and a hydrophilic circular groove is provided at the end of the cantilever beam; A test platform, which is mounted on the mounting platform, wherein a test substrate is provided on the test platform, wherein the test substrate is used to place ferrofluid droplets, wherein the relative position between the ferrofluid droplets and the mounting platform is adjustable, and wherein the hydrophilic circular groove is located on the moving path of the ferrofluid droplets; A displacement sensor, wherein the detection center thereof and the center of the hydrophilic circular groove coincide with each other on the same horizontal line, and the cantilever beam is located between the displacement sensor and the ferrofluid droplet; A moving mechanism is installed on the mounting table. The moving mechanism is provided with a movable table that can move back and forth. A magnetic block is provided on the movable table. The magnetic block is located below the test table and is used to drive the ferrofluid droplets to move on the test substrate.

2. The ferrofluid magnetic transport adhesion test device according to claim 1, characterized in that: The cantilever beam is a metal component. A hydrophobic layer is provided on the surface of the cantilever beam. The hydrophilic circular groove destroys the hydrophobic layer during processing.

3. The ferrofluid magnetic transport adhesion test device according to claim 2, characterized in that: The hydrophobic layer is formed on the cantilever beam through a chemical vapor deposition process.

4. The ferrofluid magnetic transport adhesion test device according to claim 1, characterized in that: When the ferrofluid droplet contacts the hydrophilic circular groove, the length of the contact line between the ferrofluid droplet and the test substrate remains unchanged.

5. The ferrofluid magnetic transport adhesion testing device according to claim 1, characterized in that: The displacement sensor is a laser displacement sensor. The cantilever beam is provided with a positioning mark on a side facing the laser displacement sensor. The position of the positioning mark corresponds to the center of the hydrophilic circular groove.

6. The ferrofluid magnetic transport adhesion testing device according to claim 5, characterized in that: The relative positions of the cantilever beam and the laser displacement sensor are adjustable, and the laser displacement sensor leaves a light shadow on the test substrate when the cantilever beam avoids the sensor.

7. The ferrofluid magnetic transport adhesion testing device according to claim 1, characterized in that: The test substrate is a polydimethylsiloxane substrate, and the ratio of polydimethylsiloxane to curing agent is 10:0.8 to 10:1.

2.

8. The ferrofluid magnetic transport adhesion testing device according to claim 1, characterized in that: The mounting platform is a vibration-damping platform.

9. Adhesion testing method, characterized in that, The ferrofluid magnetic transport adhesion test device according to any one of claims 1 to 8 is used, comprising the following steps: A cantilever beam with a certain length is selected, with a width of W, a thickness of T, an elastic modulus of E, and a force arm length of the hydrophilic circular groove of L. An appropriate amount of ferrofluid droplets is dripped onto the test substrate. Keeping the detection center of the displacement sensor and the center of the hydrophilic circular groove coincident with the same horizontal line, and keeping the center of the hydrophilic circular groove and the center of the ferrofluid droplet on the same vertical plane, then moving the ferrofluid droplet until it contacts the hydrophilic circular groove, and then zeroing the displacement sensor so that the magnetic block is directly below the ferrofluid droplet; The moving mechanism drives the movable platform to move in a direction away from the cantilever beam, and the ferrofluid droplet moves away from the cantilever beam under the magnetic induction of the magnetic block. Under the action of surface tension, the adhesion force generated by the ferrofluid droplet and the test substrate directly acts on the cantilever beam, forcing the cantilever beam to undergo elastic deformation; The displacement sensor detects the offset X of the cantilever beam and uses the formula calculating the instantaneous adhesion force between the ferrofluid droplet and the test substrate; After the ferrofluid droplet is separated from the cantilever beam, the test is terminated.

10. The adhesion testing method according to claim 9, wherein: The movable platform moves at a constant speed of no more than 0.05 mm / s.

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