A method for controlling multiphase particles by regulating meniscus with magnetic field responsive microneedles

Abstract

This invention belongs to the field of open surface manipulation technology, specifically relating to a method for multiphase particle manipulation using magnetically responsive microneedles to control menisci. This invention utilizes changes in the magnetic field to alter the orientation of a magnetically controlled microneedle, generating an asymmetric meniscus deformation at a fluid interface. This asymmetric meniscus deformation provides a horizontal component difference in interfacial tension to the controlled object, which may include solid, liquid, or gaseous particles. This horizontal component difference in interfacial tension drives the controlled object to perform multifunctional motions, including one or more of the following: capture, rotation, transmission, and in-situ release. This invention utilizes tilted microneedles to generate an asymmetric meniscus, and by adjusting the meniscus morphology, achieves multiphase and multifunctional control. It enables flexible, non-destructive, multi-material, and multifunctional manipulation on open surfaces, broadening the range of controllable materials and control environments, enriching motion control modes, and possessing wider application and development prospects.

Description

Technical Field

[0001] This invention belongs to the field of open surface manipulation technology, specifically relating to a method for manipulating multiphase particles on a meniscus using magnetic field-responsive microneedles. Background Technology

[0002] Open droplet microfluidics refers to the manipulation of discrete droplets with tiny volumes on open surfaces. It integrates traditional laboratory sample preparation, screening, and detection functions onto a microchip with a surface area of ​​only a few square centimeters. Open droplet microfluidics not only possesses the advantages of traditional microfluidics, such as small reagent volume, precise manipulation, large specific surface area, and high integration, but also offers unique advantages such as ease of online analysis, good compatibility, and avoidance of cross-contamination. It shows great application prospects and development potential in fields such as biomedicine, fine chemicals, materials science, and detection.

[0003] Currently, various external fields, including light, electrostatics, and heat, have been studied in open surface manipulation techniques, enabling non-contact manipulation through attraction and movement by generating polarized charges or directional flow fields. However, these strategies primarily focus on specific materials, and high-energy inputs can cause damage due to thermal damage or electrostatic breakdown. Magnetic fields, with their long-distance, fast-response, high-penetration, and low-energy impact, offer a versatile and flexible approach. However, the difficulty in confining and precisely controlling magnetic fields, or limitations imposed by structural constraints or material properties, makes it challenging to simultaneously meet the requirements of non-destructive, flexible, and non-contact manipulation. This hinders the realization of non-destructive, multi-functional control on open surfaces, limiting the practical application of manipulation methods. Summary of the Invention

[0004] The purpose of this invention is to provide a method for manipulating multiphase particles on a meniscus using magnetic field-responsive microneedles. The method provided by this invention enables flexible, non-destructive, multi-material, and multi-functional operation on open surfaces.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for manipulating multiphase particles on a meniscus using magnetic field-responsive microneedles, comprising the following steps:

[0007] The magnetic field changes the position of the magnetically controlled microneedle, generating an asymmetric meniscus deformation at the fluid interface; the deformation of the asymmetric meniscus provides a horizontal component difference of interfacial tension to the controlled object, which includes solid particles, liquid particles, or gaseous particles.

[0008] The control object is driven to perform multi-functional motion by utilizing the difference in the horizontal component of the interfacial tension. The multi-functional motion includes one or more of the following: the control object is captured, rotated, transmitted, and released in situ.

[0009] Preferably, the application of the magnetically controlled microneedles includes a single magnetically controlled microneedle or an array of magnetically controlled microneedles.

[0010] Preferably, the length of the single magnetron microneedle is 1-5 mm and the bottom radius is 0.15-0.5 mm; the single magnetron microneedle is a free single magnetron microneedle.

[0011] Preferably, the length of any single magnetically controlled microneedle in the magnetically controlled microneedle array is 1 to 5 mm, and the bottom radius is 0.15 to 0.5 mm;

[0012] The spacing between any two adjacent magnetically controlled microneedles in the magnetically controlled microneedle array is 1 to 2 times the length of a single magnetically controlled microneedle.

[0013] Preferably, the pose of the single magnetically controlled microneedle includes swinging and translation.

[0014] Preferably, when the magnetically controlled microneedle is a magnetically controlled microneedle array, the multifunctional motion is directional transmission; the directional transmission means that the controlled object is transmitted along the arrangement direction of the magnetically controlled microneedles in the magnetically controlled microneedle array.

[0015] Preferably, the controlled object includes bubbles, droplets, hydrogel particles, or hard particles; the radius of the controlled object is >0.5mm.

[0016] Preferably, the fluid interface includes a gas-liquid interface or a liquid-liquid interface.

[0017] This invention provides a method for manipulating multiphase particles on a meniscus using a magnetically responsive microneedle, comprising the following steps: altering the orientation of a magnetically controlled microneedle by utilizing a change in a magnetic field to generate an asymmetric meniscus deformation at a fluid interface; the deformation of the asymmetric meniscus provides a horizontal component difference in interfacial tension to a controlled object, the controlled object including solid particles, liquid particles, or gaseous particles; and driving the controlled object to perform multifunctional motion using the horizontal component difference in interfacial tension, the multifunctional motion including one or more of the following: the controlled object being captured, rotated, transported, and released in situ. Compared with existing technologies, this invention has the following technical advantages: This invention utilizes a magnetically controlled microneedle to generate an asymmetric meniscus. By controlling the pose (including oscillation and translation) of the magnetically controlled microneedle through magnetic field changes, the deformation (including rise height and position) of the asymmetric meniscus is controlled. This provides a horizontal component difference in interfacial tension to drive the controlled object in the interfacial environment. Thus, this invention achieves precise control of the asymmetric meniscus morphology of the fluid interface by controlling the pose of the magnetically controlled microneedle through magnetic field changes, thereby achieving flexible, non-destructive, and precise motion control of the controlled object (i.e., multiphase particles), overcoming the limitation of precise control by magnetic field control. The controlled object provided by this invention covers solid, liquid, and gaseous three-phase particles, significantly broadening the range of controlled objects and control environments, and is not limited to magnetically responsive materials. Finally, this invention achieves multifunctional operation of capturing, rotating, transmitting, and releasing the controlled object in situ, enriching motion control modes, enhancing the universality of the control method in applications, improving the practicality and application prospects of multiphase particle manipulation methods, and is applicable to a wider range of functional materials and particle manipulation in complex environments.

[0018] Furthermore, in this invention, when the magnetically controlled microneedles are a magnetically controlled microneedle array, the multifunctional motion is the directional transmission of the controlled object by the magnetically controlled microneedle array; the directional transmission occurs along the direction of the magnetically controlled microneedle array. In the magnetically controlled microneedle array, the transmission motion of the controlled object between the magnetically controlled microneedles is achieved by changing the liquid surface balance state through the positional relationship between the two needles. As the microneedle positional relationship changes, the liquid level changes accordingly, resulting in a difference in liquid level near the two needles. This difference is used to achieve the directional transmission function of the controlled object.

[0019] In summary, the multiphase particle manipulation method for controlling menisci with magnetic field-responsive microneedles provided by this invention utilizes tilted microneedles to generate an asymmetric meniscus. By adjusting the shape of the meniscus, multiphase and multifunctional control can be achieved, such as the capture, rotation, transport, and in-situ release of bubbles, droplets, and solid particles. This expands the range of controllable materials and control environments, enriches motion control modes, and has broader application and development prospects. Attached Figure Description

[0020] Figure 1A flowchart illustrating the method for controlling multiphase particles on a meniscus using magnetic field-responsive microneedles, as provided by this invention.

[0021] Figure 2 This is a schematic diagram illustrating the manipulation of a free, single magnetically controlled microneedle in this invention.

[0022] Figure 3 A schematic diagram illustrating how to control the position and movement of a single free magnetically controlled microneedle to alter its motion.

[0023] Figure 4 This is a top view schematic diagram of the rotation control of the present invention;

[0024] Figure 5 This describes the basic process of particle transfer within a magnetically controlled microneedle array composed of three magnetically controlled microneedles.

[0025] Figure 6 This is a schematic diagram illustrating the process of meniscus changes.

[0026] Figure 7 The diagram shows the force analysis of the controlled object under the influence of the meniscus. Figure 7 (1) in the diagram is the resting state diagram. Figure 7 (2) and (3) in the text refer to the capture and transmission process. Figure 7 (4) in the diagram represents the in-situ release process;

[0027] Figure 8 The process of attracting particles of different materials is illustrated in the figure, where the scale bar is 1 mm in length.

[0028] Figure 9 The image shows a physical object obtained by controlling the angle to change the morphology of the interface, as captured by a confocal microscope.

[0029] Figure 10 The magnetically controlled microneedle array is used to control the movement of droplets, where the scale bar has a length of 1 mm.

[0030] Figure 11 To enable continuous, staged microchemical reactions by controlling droplets of different solutions with magnetically controlled microneedles, where the scale bar is 1 mm long;

[0031] Figure 12 This is a graph showing the relationship between the radius of the controlled object in this invention, the ratio of the distance between any two adjacent magnetically controlled microneedles in the magnetically controlled microneedle array, and the directional transmission speed.

[0032] Figure 13 This is a graph showing the relationship between the volume of the controlled object, the length of the magnetically controlled microneedles, the spacing between any two adjacent magnetically controlled microneedles in the array, and the actual driving effect in this invention. Detailed Implementation

[0033] This invention provides a method for manipulating multiphase particles on a meniscus using magnetic field-responsive microneedles, comprising the following steps:

[0034] The magnetic field changes the position of the magnetically controlled microneedle, generating an asymmetric meniscus deformation at the fluid interface; the deformation of the asymmetric meniscus provides a horizontal component difference of interfacial tension to the controlled object, which includes solid particles, liquid particles, or gaseous particles.

[0035] The controlled object is driven to perform multi-functional motion by utilizing the horizontal component difference of the interfacial tension. The multi-functional motion includes one or more of the following: the controlled object is captured, rotated, transmitted, and released in situ.

[0036] In this invention, unless otherwise specified, all raw materials / components used in the preparation are commercially available products well known to those skilled in the art.

[0037] Figure 1 This is a flowchart illustrating the magnetic field-responsive microneedle-based method for manipulating multiphase particles on a meniscus, as provided by the present invention. Figure 1 It can be seen that the present invention mainly uses magnetically controlled microneedles to generate an asymmetric meniscus on the fluid interface to perform multifunctional motion control on the controlled object.

[0038] The following is combined Figure 1 The present invention provides a detailed description of the method for controlling multiphase particles on a meniscus using magnetic field-responsive microneedles.

[0039] This invention utilizes changes in the magnetic field to alter the orientation of a magnetically controlled microneedle, generating an asymmetric meniscus at the fluid interface. The asymmetric meniscus generated around the microneedle exhibits differences in height and morphology, causing the controlled object to be driven by the difference in the horizontal component of the interfacial tension resulting from the interface changes. Due to this asymmetric difference, it exhibits tracking ability towards the tilted side of the microneedle's meniscus, thereby achieving multifunctional motion.

[0040] In this invention, the definition of a meniscus is as follows: A liquid meniscus is a curved surface formed near the contact area when a liquid comes into contact with a solid surface or another medium (such as a gas or another liquid). The shape of the meniscus is determined by factors such as surface tension, contact angle, and gravity, and it typically presents as a curved interface. (e.g.) Figure 6The asymmetry arises from the tilt angle. A detailed explanation is as follows: Based on the Young-Laplace equation, interfacial tension exists tangentially at the highest point of the meniscus, balancing the meniscus's own weight in the vertical direction. Changing the angle between this tangential and vertical direction alters the mass of the lifting fluid, thus changing the height of the meniscus. For magnetically controlled microneedles, this angle differs on both sides due to the tilt, resulting in asymmetry. It is noteworthy that the fundamental principle, the Young-Laplace equation, is a well-established principle in fluid mechanics, commonly manifested in capillary action. This invention emphasizes an interfacial morphology control method based on the Young-Laplace equation theory.

[0041] In this invention, Figure 6 The process of controlling the magnetically controlled microneedle to swing from a horizontal, stationary state to a vertical state and change the meniscus on the tilted side is demonstrated. Figure 6 (1) and Figure 6 In (2), during the process of the increase of the inclination angle α, the meniscus is fixed at the end of the microneedle and does not migrate. Only the angle φ between the interface tangential direction and the vertical direction in the Young-Laplace equation changes, which increases the height of the meniscus. Figure 6 (3) and Figure 6 The process in (4) is a breakthrough. Figure 6 In state (2), after edge pinning, the included angle φ changes with the inclination angle α and contact angle θ, resulting in a change in the meniscus. Specifically, as the inclination angle α increases, the meniscus height h decreases. In summary, in... Figure 6 In (2) of the equation (when φ=α+θ-π / 2), the maximum height of the meniscus is obtained. This is the result of the combined effect of the interface pinning effect under the influence of the length of the magnetically controlled microneedle and the Young-Laplace equation. Figure 6 The parameters appearing in the text are: φ is the angle between the liquid surface and the vertical direction, θ is the contact angle, and α is the tilt angle of the magnetron-controlled microneedle.

[0042] In this invention, the pinning effect is a phenomenon where the liquid boundary (typically a three-phase contact line) is "pinned" due to surface inhomogeneities (such as roughness or chemical heterogeneity). Intuitively, the three-phase contact line remains at the tip of the magnetron-controlled microneedle until the aforementioned boundary value is reached.

[0043] This invention utilizes changes in a magnetic field to alter the orientation of a magnetically controlled microneedle, generating an asymmetric meniscus deformation at a fluid interface. In this invention, the magnetically controlled microneedle is controlled by changes in the magnetic field, continuously and dynamically altering the morphology of the asymmetric meniscus. The fluid interface is a two-phase fluid interface, preferably a slippery liquid-infused porous surface (SLIPS). The fluid interface preferably includes a gas-liquid interface or a liquid-liquid interface. The gas-liquid interface can be an air-water interface, an air-silicone oil interface, or an air-other fluid-flowing organic liquid interface. The liquid-liquid interface can be any two immiscible liquids.

[0044] In this invention, the shape of the magnetically controlled microneedle preferably includes cylindrical, cilia-like, cone-shaped, mushroom-shaped, or variant structures with longitudinal and / or transverse textured surface modifications. The magnetically controlled microneedle possesses magnetic responsiveness and can function as an independent unit or as a basic unit for collective control. In this invention, the material of the magnetically controlled microneedle is preferably stainless steel, shape memory polymer, or alloy. In this invention, when the real-time responsiveness and flexibility of the controlled object's multifunctional motion are not critical but long-term durability is required, the material of the magnetically controlled microneedle can be a shape memory polymer or alloy.

[0045] In this invention, the magnetically controlled microneedle comprises a single magnetically controlled microneedle or an array of magnetically controlled microneedles. The single magnetically controlled microneedle is a free single magnetically controlled microneedle. The position of the free single magnetically controlled microneedle can change freely, i.e., it can translate. This invention utilizes changes in the magnetic field to alter the pose of the magnetically controlled microneedle; the pose of the single magnetically controlled microneedle includes oscillation and translation. The pose of the magnetically controlled microneedle array is the change in the pose relationship between any two adjacent magnetically controlled microneedles.

[0046] In this invention, the magnetically controlled microneedles can preferably be modified by changing their contact angle with water and oil.

[0047] In an embodiment of the present invention, the preferred method for preparing the free single magnetically controlled microneedle manipulation environment includes: spin-coating a polytetrafluoroethylene suspension onto a glass substrate, heating and sintering it, and then injecting dimethyl silicone oil.

[0048] In an embodiment of the present invention, the substrate of the magnetically controlled microneedle array manipulation environment is preferably first cast and cured with Ecoflex material, and then formed by injecting dimethyl silicone oil.

[0049] In this invention, the method of generating the magnetic field preferably relies on external magnet induction and triaxial electromagnetic coil dependent signal generator control.

[0050] In this invention, the deformation of the asymmetric meniscus includes changes in both height and position. This invention utilizes changes in the magnetic field to alter the orientation of a magnetically controlled microneedle, generating asymmetric meniscus deformation at the fluid interface. This achieves precise control of the fluid interface morphology by the magnetic field. In this invention, the fluid interface morphology is characterized by the deformation of the asymmetric meniscus.

[0051] In this invention, since the asymmetric meniscus change is affected by both the radius and length of the magnetically controlled microneedle (i.e., the height of the asymmetric meniscus is proportional to the changes in both the radius and length of the magnetically controlled microneedle), and in order not to affect the operational capability of the magnetically controlled microneedle, the length of the single magnetically controlled microneedle is preferably 1 to 5 mm, and the bottom radius is preferably 0.15 to 0.5 mm.

[0052] In this invention, the magnetically controlled microneedle array is formed by arranging two or more individual magnetically controlled microneedles, and each individual microneedle in the array is a non-free individual magnetically controlled microneedle. That is, the position of any individual magnetically controlled microneedle in the array cannot be changed.

[0053] In this invention, the length of any single magnetically controlled microneedle in the magnetically controlled microneedle array is preferably 1–5 mm, and the bottom radius is preferably 0.15–0.5 mm. The spacing between any two adjacent magnetically controlled microneedles in the magnetically controlled microneedle array is related to the length of the controlled object, such as… Figure 12 As shown, given a fixed size of the magnetically controlled microneedles, the smaller the ratio of the radius of the controlled particle to the distance between any two adjacent magnetically controlled microneedles in the array, the greater the average velocity of the controlled particle and the better the control effect. Simultaneously, due to... Figure 13 It is known that the smaller the particle size of the controlled object and the better the match between the spacing between the microneedles and the length of the microneedles in the magnetically controlled microneedle array, the better the control effect. In this invention, the spacing between any two adjacent magnetically controlled microneedles in the magnetically controlled microneedle array is preferably 1 to 2 times the length of a single magnetically controlled microneedle.

[0054] After obtaining the deformation of the asymmetric meniscus, the deformation provides a horizontal component difference in interfacial tension. This invention utilizes this horizontal component difference to drive a controlled object to perform multifunctional motion. The controlled object includes solid particles, liquid particles, or gaseous particles. The multifunctional motion includes one or more of the following: capture, rotation, transport, and in-situ release of the controlled object. In this invention, the horizontal component difference in interfacial tension provided by the asymmetric meniscus also exhibits asymmetry. This drives the controlled object to always follow the tilted side of the meniscus, achieving multifunctional motion.

[0055] In this invention, the controlled object preferably includes bubbles, droplets, hydrogel particles, or hard particles. The radius of the controlled object is preferably greater than 0.5 mm.

[0056] In this invention, when the magnetically controlled microneedle is a free single magnetically controlled microneedle, the pose of the single magnetically controlled microneedle includes swinging and translation, and the multifunctional motion includes one or more of the controlled object being captured, rotated, transmitted and released in situ.

[0057] In this invention, Figure 2 This is a schematic diagram illustrating the motion and process achievable by a single, freely movable magnetically controlled microneedle.

[0058] In this invention, when the magnetron-controlled microneedle is a free single magnetron-controlled microneedle, the invention utilizes the tilting of the free single magnetron-controlled microneedle to alter the morphology of the two-phase fluid interface. Specifically, this manifests as a higher rise in the interface on the tilted side (e.g., ...). Figure 6 On the other side, the rising height is lower and the angle between the three-phase contact line and the vertical direction is larger. This morphological change leads to differences in the ability to control particles in different directions, meaning that a higher liquid level has a stronger attraction.

[0059] Therefore, the controlled object has the following multi-functional motion forms:

[0060] Capture process: The liquid level is raised on one side of the controlled object by using a magnetically controlled microneedle to increase its height, causing a change in the horizontal force and moving it towards the magnetically controlled microneedle (e.g., Figure 7 The magnetic control method for controlling the swing angle and direction is as described above. Figure 3 As shown in the left figure.

[0061] Transmission and rotation processes: Due to the above reasons, the force state of the controlled object (e.g., Figure 7 (3) shows the basic state during the transmission and rotation process. The controlled object will be continuously pulled to follow the real-time changing meniscus position of the magnetically controlled microneedle and move with it, translating the magnetic field (such as...). Figure 3 The right image in the diagram will enable transmission, while changing the position of the magnetic field (such as...) Figure 3 (Left image) By changing the swing angle and direction, the needle can be rotated, the meniscus can be rotated, and even the rotation of the object can be controlled (e.g., Figure 4 (As shown).

[0062] In-situ release process: Using the same principle, the magnetically controlled microneedle is swung in the opposite direction, which reduces the attraction and manipulation ability on the controlled object. The same method is employed. Figure 3 The magnetic field manipulation method shown in the left figure.

[0063] Figure 7 The diagram shows the force analysis of the controlled object under the influence of the meniscus. Figure 7 (1) in the diagram is the resting state diagram. Figure 7 (2) and (3) in the text refer to the capture and transmission process. Figure 7(4) in the text is the in-situ release process. Figure 7 (1) represents the resting state of a particle when it is out of control, and the angle between the interfacial tension on either side of the central interface and the horizontal direction is the same. Figure 7 (2) and (3) in the text represent a progressive process. Figure 7 (2) indicates that the presence of the asymmetric meniscus causes the liquid level to rise, breaking the quiescent state; Figure 7 (3) represents the final state of the capture process and the force state during the transmission process; Figure 7 (4) in the diagram represents the in-situ release process of the controlled object. When the magnetically controlled microneedle swings to the opposite direction, the angle between the interface tension on both sides of the controlled object and the horizontal direction is approximately the same again, causing the magnetically controlled microneedle and the controlled object to disengage from the control relationship.

[0064] In this invention, when the magnetically controlled microneedles are a magnetically controlled microneedle array, the multifunctional motion is the directional transmission of the controlled object by the magnetically controlled microneedle array; the directional transmission occurs along the direction of the magnetically controlled microneedle array. For the magnetically controlled microneedle array, the transmission motion of the controlled object between the magnetically controlled microneedles is achieved by changing the liquid surface balance state through the positional relationship between the two needles. As the positional relationship of the magnetically controlled microneedles changes, the liquid level changes accordingly, resulting in a difference in liquid level near the two needles. This difference is used to achieve directional control of the controlled object. The magnetic field changes during the operation are as follows: Figure 5 As shown, Figure 5 The four steps (1), (2), (3) and (4) are repeated in a loop. Figure 5 The basic process of directional transmission of the controlled object within a magnetically controlled microneedle array formed by three magnetically controlled microneedles (from...) Figure 5 (From left to right in the middle), the directional transmission includes two basic processes in the control of a free single magnetically controlled microneedle: capture and rotation.

[0065] In this invention, the control principle for the multi-functional motion of the controlled object is as follows: The control of the multi-functional motion of the controlled object is based on the fundamental property of interfacial tension. Due to the difference in surface energy, there exists a contact angle at the solid-liquid-gas / liquid three-phase interface. When the contact angle is not 90°, interfacial deformation occurs. This deformation manifests as the liquid level rising or falling in the vertical direction, a typical phenomenon being capillary action. Utilizing this fundamental property, under the condition that other factors remain unchanged, changing the tilt angle of the microneedle can obtain different meniscus heights on the tilted side and the opposite side, achieving asymmetric differential control.

[0066] On the other hand, for the controlled object (i.e., multiphase particles) at the interface, a meniscus also exists. In a static state, the resultant force provided by the interfacial tensions around the particles is zero, and the particles do not move. When the meniscus provided by the magnetically controlled microneedle overlaps with the meniscus of the particles, the rising liquid level changes the morphology of the liquid surface on one side of the particles, making the sum of the interfacial tensions on the particles in that plane non-zero, thereby driving the particles to follow the asymmetric meniscus.

[0067] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0068] Example 1

[0069] This embodiment provides a method for manipulating multiphase particles using a magnetically responsive microneedle to control a meniscus. The invention utilizes changes in the magnetic field to alter the orientation of the magnetically controlled microneedle, generating an asymmetric meniscus deformation at the fluid interface. After obtaining the asymmetric meniscus deformation, the deformation provides a horizontal component difference in interfacial tension. This horizontal component difference is then used to drive a controlled object to perform multifunctional motion. The controlled object includes solid particles, liquid particles, or gaseous particles. The multifunctional motion includes one or more of the following: capture, rotation, transport, and in-situ release of the controlled object by the magnetically controlled microneedle.

[0070] The magnetically controlled microneedles used in this embodiment are made of stainless steel. The magnetic field is generated by external magnet induction and a triaxial electromagnetic coil controlled by a signal generator.

[0071] In this embodiment, the preparation method of the slippery liquid-infused porous surface (SLIPS) for the application of free single magnetically controlled microneedles includes: spin-coating a polytetrafluoroethylene suspension (60 wt%) onto a glass slide (the size of the glass slide is not required), sintering it at 380°C, and then injecting dimethyl silicone oil. The main purpose of this preparation is to retain the dimethyl silicone oil to facilitate the formation of the two-fluid interface required in this embodiment.

[0072] In this embodiment, the preparation method of the slippery liquid-infused porous surface (SLIPS) for the application of the magneto-controlled microneedle array includes: arranging microneedles under a parallel magnetic field, casting the surface with Ecoflex, heating at 120°C for 30 minutes, and then injecting dimethyl silicone oil to form a functional surface.

[0073] Figure 8 This embodiment describes the process of preparing a free single magnetically controlled microneedle to attract controlled objects of different materials, including bubbles, droplets, and nylon particles. Figure 8 The medium-scale bar is 1 mm long.

[0074] Figure 9 This is a photograph taken with a confocal microscope, showing how the morphology of an interface can be altered by controlling the tilt angle of a single, freely movable, magnetically controlled microneedle. Figure 9 The specific experimental procedure included: mixing fluorescent dye into Ecoflex, controlling the angle of the magnetically controlled microneedles in an inclined magnetic field and casting the stained Ecoflex, then heating at 120℃ for 30 minutes to cure. After curing, the microneedles were removed and a cross-section was cut using a medical blade. The cross-section was fixed to the edge of a glass slide and photographed facing the light source of a laser confocal microscope. Different fluorescent dyes with their corresponding laser wavelengths (not specifically required, 488nm in this experiment) were selected, and images were taken at different tilt angles α. Figure 9 The content of the upper and lower images in the image corresponds to... Figure 6 (2) and (3) in the figure are the results of qualitative shooting for theoretical verification.

[0075] Figure 10 To control droplet movement using a magnetically controlled microneedle array. Figure 10 The medium-scale bar is 1 mm long. Figure 10 The magnetically controlled microneedles in the array are polished stainless steel needles with a length of 2 mm and a spacing of 4 mm between any two adjacent magnetically controlled microneedles. The particles are droplets stained with aniline blue (no specific ratio or size requirement). The oscillation and rotation of the microneedles are achieved by controlling the local magnetic field, thereby realizing the directional transport of the droplets.

[0076] Figure 11 To enable continuous, staged microchemical reactions by controlling droplets of different solutions with microneedles, Figure 11 The medium scale is 1 mm long. Figure 11 The specific experimental method involved placing 10 μL of sodium bicarbonate aqueous solution, 10 μL of calcium chloride aqueous solution, and a small amount of anhydrous copper sulfate powder on a SLIPS substrate. A tilted microneedle, modulated by a magnetic field, was used to transport the sodium bicarbonate solution to merge with the calcium chloride solution, forming a white calcium carbonate precipitate. Then, the reaction product was transported to contact with the anhydrous copper sulfate powder, initiating a hydration reaction.

[0077] As demonstrated by the above embodiments, this invention utilizes an asymmetric meniscus generated by tilted magnetically controlled microneedles. By adjusting the height of the meniscus, it achieves controllable, directional, flexible, and precise manipulation of the controlled object at the fluid interface. Secondly, the interfacial tension effect places no special requirements on the material properties of the controlled object itself, enabling the capture, transfer, rotation, and release of various particles such as bubbles, droplets, and solid particles. This significantly broadens the range of controllable materials and control environments, extending beyond just magnetically responsive materials. Finally, this invention enriches motion control modes, providing more diverse and efficient manipulation methods, greatly enhancing its practicality and application prospects. It is applicable to a wider range of functional materials and particle manipulation in complex environments.

[0078] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative intent, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for manipulating multiphase particles on a meniscus using magnetic field-responsive microneedles, characterized in that, Includes the following steps: The magnetic field changes alter the orientation of the magnetically controlled microneedles, generating an asymmetric meniscus deformation at the fluid interface. This asymmetric meniscus deformation provides a horizontal component difference in interfacial tension to a controlled object, which may include solid particles, liquid particles, or gaseous particles. The radius of the controlled object is greater than 0.5 mm. The magnetically controlled microneedles can be used as a single microneedle or an array of microneedles. The length of a single microneedle is 1–5 mm, the length of any single microneedle in the array is 1–5 mm, and the spacing between any two adjacent microneedles in the array is 1–2 times the length of a single microneedle. The controlled object is driven to perform multi-functional motion by utilizing the horizontal component difference of the interfacial tension. The multi-functional motion includes one or more of the following: the controlled object is captured, rotated, transmitted, and released in situ.

2. The method for multiphase particle manipulation of the meniscus using magnetic field-responsive microneedles according to claim 1, characterized in that, The bottom radius of the single magnetically controlled microneedle is 0.15~0.5mm; the single magnetically controlled microneedle is a free single magnetically controlled microneedle.

3. The method for multiphase particle manipulation of the meniscus using magnetic field-responsive microneedles according to claim 1, characterized in that, The bottom radius of any single magnetically controlled microneedle in the magnetically controlled microneedle array is 0.15~0.5mm.

4. The method for multiphase particle manipulation of the meniscus using magnetic field-responsive microneedles according to claim 1 or 2, characterized in that, The position of the single magnetically controlled microneedle includes swinging and translation.

5. The method for controlling multiphase particles on a meniscus using magnetic field-responsive microneedles according to claim 1 or 3, characterized in that, When the magnetically controlled microneedle is a magnetically controlled microneedle array, the multifunctional motion is directional transmission; the directional transmission means that the controlled object is transmitted along the arrangement direction of the magnetically controlled microneedles in the magnetically controlled microneedle array.

6. The method for multiphase particle manipulation of the meniscus using magnetic field-responsive microneedles according to claim 1, characterized in that, The controlled objects include bubbles, droplets, hydrogel particles, or hard particles.

7. The method for multiphase particle manipulation of the meniscus using magnetic field-responsive microneedles according to claim 1, characterized in that, The fluid interface includes a gas-liquid interface or a liquid-liquid interface.

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