A low-adhesion magnetic soft composite antibacterial coating, its preparation method and application

Abstract

This invention belongs to the field of antibacterial coating manufacturing, specifically relating to a low-adhesion magnetic soft composite antibacterial coating, its preparation method, and its application. The method involves curing a magnetic soft composite material, then subjecting it to directional saturation magnetization and saturation swelling treatment on its surface to obtain the low-adhesion magnetic soft composite antibacterial coating. The magnetic soft composite material, by weight, comprises 20-40 parts silicone rubber, 40-80 parts silicone oil, and 20-40 parts neodymium iron boron nanoparticles. The low-adhesion magnetic soft composite antibacterial coating removes bacterial adhesion by being driven by a periodically moving magnet array. Compared with existing technologies, the low-adhesion magnetic soft composite antibacterial coating proposed in this invention removes bacterial adhesion under the drive of a periodically moving magnet array, exhibiting good biocompatibility and durable magnetic sterilization.

Description

Technical Field

[0001] This invention belongs to the field of antibacterial coating manufacturing, specifically relating to an antibacterial coating of low-adhesion magnetic soft composite material, its preparation method and application. Background Technology

[0002] Biofouling refers to the microbial deposits or biofilms formed on artificial surfaces in an aquatic environment, where proteins, bacteria, and other microorganisms have infiltrated. For most medical devices, large ships, and industrial equipment, biofouling is undesirable because it can cause significant harm. For example, bacterial adhesion to medical devices can lead to serious medical consequences such as surgical infections and implant rejection. Marine microorganisms adhering to the surfaces of large ships not only corrode the hull but also increase drag and cause additional energy consumption. In water cooling systems, biofilm adhesion to pipes reduces heat transfer rates and significantly increases fluid flow resistance and the energy required to pump the fluid.

[0003] To address the issue of antibacterial / antimicrobial properties on artificial surfaces, antibacterial / antimicrobial coating design strategies involve controlling the chemical properties of the coating surface or designing micro / nano structures to make it difficult for bacteria to survive on the coating surface. This typically utilizes the hydration properties of hydrophilic coatings and the low surface energy of superhydrophobic coatings to prevent bacterial adhesion to the material surface. Such antibacterial coating designs do not harm bacteria. For example, Chinese patent CN117815463A discloses a hydrophilic antibacterial coating and its preparation method. This method involves contacting a thiol-containing polydopamine coating with a mixed aqueous solution of double-bond functionalized polyethylene glycol and a zwitterionic organic compound with double bonds, reacting under ultraviolet light to form the hydrophilic antibacterial coating. Chinese patent CN118557809A discloses a highly stable superhydrophilic and superlubricating antibacterial coating, its preparation method, and its application. This method synthesizes a quaternized polyethyleneimine polymer containing a polyamino-type antibacterial agent. Based on the strong hydration induced by the electrostatic interaction of the zwitterionic components, a robust and stable hydrated layer is formed, achieving the coating's superhydrophilic and superlubricating functions and excellent antibacterial properties. Chinese patent CN118557809A discloses a superhydrophilic antibacterial coating sol, its preparation method, and its application. This method utilizes the synergistic effect of crosslinking agents and carboxyl-containing compounds to easily, conveniently, and stably construct hydrophilic antibacterial polymers on the surfaces of various substrates. Chinese patent CN115851071A discloses an environmentally friendly method for preparing a superhydrophobic, biofouling-resistant, self-healing coating. This method involves modifying carbon nanotube silane and nano-copper silane, bonding the modified nano-copper to the modified carbon nanotubes, loading 2-mercaptobenzimidazole onto the nano-copper hybrid, and then mixing and spraying with epoxy resin to obtain a superhydrophobic, biofouling-resistant, self-healing coating. Chinese patent CN114231127A discloses a superhydrophobic antibacterial coating loaded with antibacterial nanocomposite microspheres and its preparation method. The method first soaks silica nanospheres in dopamine solution, silver nitrate solution and D-cysteine ​​solution in sequence to prepare multilayer antibacterial nanocomposite microspheres functionalized with silver nanoparticles and D-cysteine. Then, bisphenol A diglycidyl ether epoxy resin and hydrophobically modified silica nanoparticles are sprayed onto the metal surface to prepare a superhydrophobic coating substrate. Finally, the antibacterial nanocomposite microspheres are sprayed onto the superhydrophobic substrate to prepare a superhydrophobic antibacterial coating.

[0004] On the other hand, methods involve introducing bactericidal heavy metals and oxides onto the coating surface to kill bacteria. For example, Chinese patent CN112451748A discloses a method for preparing a silk fibroin-based bimetallic antibacterial coating. This method uses ultraviolet radiation to reduce silk fibroin in situ, lowering the concentration of nano-silver and nano-gold particles. Furthermore, by introducing a polydopamine auxiliary layer onto the metal substrate surface, the binding performance between the metal and the silk fibroin-based bimetallic antibacterial coating is greatly enhanced, achieving a long-term, highly efficient, synergistic bactericidal function. Chinese patent CN101073434A discloses a long-lasting, fixed, slow-release silver nano-metal antibacterial coating and its preparation method. This method synthesizes nano-silver particles of different sizes and morphologies through process control and uses chemical bonding technology to fix the nano-metal particles onto different substrate surfaces to obtain a nano-antibacterial coating.

[0005] However, antibacterial coatings based on surface modification and surface microstructure design have not yet overcome the problem of antibacterial durability. Antibacterial coatings based on bactericides such as heavy metals and oxides can pollute the environment and produce serious side effects, limiting their application scope. Summary of the Invention

[0006] The purpose of this invention is to provide a low-adhesion magnetic soft composite antibacterial coating, its preparation method, and its application in order to solve at least one of the above-mentioned problems. This solves the problems of low durability and toxic substances in the formulation of existing antibacterial coatings, and achieves good durability and sterilization effect.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] One technical solution of the present invention is to provide a low-adhesion magnetic soft composite material antibacterial coating. The magnetic soft composite material is cured and then directionally saturated magnetized, followed by a saturation swelling treatment on its surface to obtain the low-adhesion magnetic soft composite material antibacterial coating. The magnetic soft composite material, by weight, comprises 20-40 parts silicone rubber, 40-80 parts silicone oil, and 20-40 parts neodymium iron boron nanoparticles.

[0009] Furthermore, by weight, the magnetic soft composite material comprises 20 parts silicone rubber, 40 parts silicone oil, and 40 parts neodymium iron boron nanoparticles.

[0010] Furthermore, the silicone oil has a viscosity of 100 cst-5000 cst, and the NdFeB nanoparticles have a size of 200 nm-20 μm.

[0011] Furthermore, the viscosity of the silicone oil is preferably 1000 cst.

[0012] Furthermore, the elastic modulus, curing time, curing temperature, and magnetically driven deformation amplitude of the composite material can be designed by adjusting the silicone oil content, silicone oil viscosity, and NdFeB nanoparticle content.

[0013] Furthermore, the composite material is preferably an NdFeB / Ecoflex composite material.

[0014] The second technical solution of the present invention provides a method for preparing the antibacterial coating of the low-adhesion magnetic soft composite material as described above, characterized in that it includes: coating and curing the magnetic soft composite material, then subjecting it to directional saturation magnetization by a directional magnetization magnetic field, and spraying a swelling agent onto its surface for saturation swelling treatment to prepare the antibacterial coating of the low-adhesion magnetic soft composite material.

[0015] Furthermore, the strength of the directional magnetizing magnetic field is 1.0T-3.5T, preferably 2T.

[0016] Furthermore, the swelling agent is silicone oil, and the viscosity of the silicone oil is 0.65 cst-1000 cst, preferably 10 cst.

[0017] Furthermore, the coating method includes any one of spin coating, spray coating, and printing.

[0018] Furthermore, after the composite material is coated, it is allowed to stand and level naturally before being cured.

[0019] Furthermore, the curing is performed by heating under vacuum, preferably at 80°C for 2 hours.

[0020] Furthermore, the preparation method of the composite material includes: mixing silicone rubber with silicone oil, adding neodymium iron boron nanoparticles, and stirring to obtain the composite material.

[0021] Furthermore, the preparation method of the composite material includes: stirring and vacuum degassing silicone rubber to prepare a uniform silicone rubber precursor solution, adding silicone oil to it, stirring and vacuum degassing to obtain a silicone oil-silicone rubber precursor solution, adding neodymium iron boron nanoparticles to it, stirring and vacuum degassing to obtain the composite material.

[0022] Furthermore, the composite material is a magnetic soft composite coating material solution.

[0023] The third technical solution of the present invention is to provide an application of the low-adhesion magnetic soft composite antibacterial coating as described above, characterized in that the low-adhesion magnetic soft composite antibacterial coating is driven by a periodically moving magnet array to remove bacterial adhesion.

[0024] Furthermore, the periodically moving magnet array drives the low-adhesion magnetic soft composite antibacterial coating to produce periodic dynamic deformation, causing eddies to form on the coating surface to remove bacterial adhesion.

[0025] Furthermore, the magnet array generates a periodic motion driving magnetic field to drive the low-adhesion magnetic soft composite antibacterial coating to produce periodic dynamic deformation, causing eddies to form on the coating surface to remove bacterial adhesion.

[0026] Furthermore, the magnet array is mounted on an XY two-dimensional motion platform.

[0027] Furthermore, the magnet array is programmed and controlled on an XY two-dimensional motion platform according to the sterilization requirements, thereby controlling the magnet array to perform periodic motion and generate the required periodic motion driving magnetic field.

[0028] Furthermore, the speed range of the driving magnetic field in the X direction is 0-30 mm / s, and the speed range in the Y direction is 0-30 mm / s.

[0029] The area of ​​a single magnet unit in the magnet array used is 1 mm². 2 -125 mm 2 The maximum magnetic field strength on the surface of the magnet array is 100mT-500mT. The controllable driving magnetic field of 0-300mT can be adjusted by changing the distance between the magnet array and the antibacterial coating of the magnetic soft composite material.

[0030] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] 1. This invention uses a silicone oil-saturated swelling magnetic soft composite material coating, which forms a nano-oil film on the surface of the magnetic soft composite material. This causes the interface between the coating and the bacterial biofilm to change from a solid-solid interface to a solid-liquid interface, greatly reducing the adhesion strength between the coating and the bacterial biofilm. Under the action of a magnetic field, some of the silicone oil on the surface of the saturated swelling magnetic soft composite material coating is squeezed out, which can continuously replenish the oil film on the surface of the coating, thereby significantly improving the antibacterial durability of the magnetic soft composite material coating. By using a directional strong magnetic field to directionally saturate magnetize the magnetic soft composite material coating, the internal magnetization profile of the normal direction of the magnetic soft composite material coating is given. Under the same external driving magnetic field, the magnetic soft composite material after saturation magnetization experiences a greater magnetic force and magnetic moment, thereby achieving a greater amplitude of magnetically driven deformation to generate higher intensity eddy currents and having a better sterilization effect.

[0033] 2. This invention proposes a magnetic response periodic eddy current sterilization method based on a low-adhesion magnetic soft composite antibacterial coating. By designing a periodic moving magnet array, the low-adhesion magnetic soft composite antibacterial coating is driven to produce periodic dynamic deformation, which causes eddy currents to form on the coating surface in a fluid environment to remove bacterial adhesion. Experimental results show that increasing the magnetic field strength, motor speed, and magnet unit area can effectively remove bacteria, resulting in good sterilization effect.

[0034] 3. This invention utilizes modular magnet units to form a magnet array, which is then installed on an XY two-dimensional motion platform to create a programmable, patterned motion-driven magnetic field. The size of the magnet units, their spacing, magnetic field strength, and the speed and trajectory of the XY two-dimensional motion platform can be customized according to sterilization requirements to achieve the desired patterned driving magnetic field, thereby enhancing the sterilization effect.

[0035] 4. The low-adhesion magnetic soft composite antibacterial coating proposed in this invention does not require surface modification or surface micro / nano structure design of the coating, nor does it require the introduction of bactericides such as toxic heavy metals and oxides. It relies on the long-term effective magnetic field response deformation of the coating to induce eddy currents to remove bacteria, and has good biocompatibility and magnetic sterilization durability. Attached Figure Description

[0036] Figure 1 A schematic diagram of the preparation process for an antibacterial coating on a low-adhesion magnetic soft composite material.

[0037] Figure 2 A schematic diagram of the indentation deformation of the antibacterial coating of the magnetic soft composite material driven by the magnet array.

[0038] Figure 3 A schematic diagram of the experimental results of the indentation deformation of the antibacterial coating of the magnetic soft composite material in Example 1, driven by the magnet array.

[0039] Figure 4 This is a schematic diagram showing the movement of the concave deformation area of ​​the antibacterial coating of the magnetic soft composite material in Example 1 along the X direction with the magnet array.

[0040] Figure 5 A schematic diagram of the deformation-induced eddy current removal of bacterial adhesion by the antibacterial coating of the magnetic soft composite material in Example 1, driven by a magnet array.

[0041] Figure 6This diagram illustrates the quantitative characterization of magnetically driven deformation of the antibacterial coating of the magnetic soft composite material. A represents the magnetic soft composite material deformation in Example 1 driven by a magnetic field; B represents the laser confocal morphology of the magnetically driven deformation of the NdFeB / Ecoflex composite material in Example 1; C represents the magnetically driven deformation depth of the NdFeB / Ecoflex composite material and the Fe3O4 / Ecoflex composite material under the same driving magnetic field and material content parameters; D represents the relationship between the magnetically driven deformation depth of the NdFeB / Ecoflex composite material and the driving magnetic field strength; E represents the relationship between the magnetically driven deformation depth of the NdFeB / Ecoflex composite material and the NdFeB nanoparticle content; and F represents the relationship between the magnetically driven deformation depth of the NdFeB / Ecoflex composite material and the ratio of Ecoflex to silicone oil.

[0042] Figure 7 This is a schematic diagram of the wettability characterization of the antibacterial coating of the magnetic soft composite material in Example 1. A is a contact angle diagram of the magnetic soft composite material before and after silicone oil swelling; B is a schematic diagram of the droplet sliding test of the magnetic soft composite material before and after silicone oil swelling; C is a schematic diagram comparing the contact angle hysteresis of aluminum plate, Ecoflex, and magnetic soft composite material before and after silicone oil swelling.

[0043] Figure 8 This is a schematic diagram of the surface adhesion test of the antibacterial coating of the magnetic soft composite material in Example 1. In this diagram, A is a schematic diagram of the adhesion between the magnetic soft composite material and the aluminum plate before and after the silicone oil swelling; B is a schematic diagram of the adhesion between the magnetic soft composite material and Ecoflex before and after the silicone oil swelling; and C is a schematic diagram of the adhesion between the magnetic soft composite material and PDMS before and after the silicone oil swelling.

[0044] Figure 9 This is a schematic diagram of particle image velocimetry (PIV) for deformation-induced eddies generated by the antibacterial coating of the magnetically driven soft composite material in Example 1. A is a schematic diagram of the experimental setup for PIV, where an arrayed magnetic field drives the magnetically soft composite material to generate eddies. B is a schematic diagram of the PIV results for one reciprocating cycle under the action of an arrayed magnetic field of 300 mT (motor speed is 30 mm / s). C is a schematic diagram of the flow velocity in the x and y directions within 10 reciprocating cycles (reciprocating frequency is approximately 0.5 Hz). D is a schematic diagram of the local flow velocity changes between two reciprocating cycles. E is a schematic diagram comparing the flow velocity amplitude changes under different magnetic field intensities. F is a schematic diagram comparing the flow velocity amplitude changes under different motor speeds.

[0045] Figure 10The diagrams show the fluorescent area coverage of bacteria on the surface of the antibacterial coating of the magnetic soft composite material in Example 1 under different parameters such as magnetic field strength, motor speed, and magnet unit area. A represents the fluorescent area coverage of bacteria on the surface of the antibacterial coating of the magnetic soft composite material in a static state; BD represents the fluorescent area coverage of bacteria on the surface of the antibacterial coating of the magnetic soft composite material under different magnetic field strengths; EF represents the fluorescent area coverage of bacteria on the surface of the antibacterial coating of the magnetic soft composite material under different motor speeds; and GH represents the fluorescent area coverage of bacteria on the surface of the antibacterial coating of the magnetic soft composite material under different magnet unit areas.

[0046] Figure 11 The diagrams show the colony-forming unit (CFU) counts of the antibacterial coating of the magnetic soft composite material in Example 1 under different magnetic field strengths, motor speeds, and magnet unit areas. A represents the CFU counts of the antibacterial coating of the magnetic soft composite material under different magnetic field strengths; B represents the CFU counts of the antibacterial coating of the magnetic soft composite material under different motor speeds; and C represents the CFU counts of the antibacterial coating of the magnetic soft composite material under different magnet unit areas. Detailed Implementation

[0047] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0048] Unless otherwise specified, all experimental reagents and raw materials used in this invention are commercially available. The silicone rubber (Ecoflex 30-polybutylene adipate terephthalate) used in the examples was purchased from Smooth-on, Inc., USA; the silicone oil (viscosity 0.65 cst-5000 cst) was purchased from Dow Corning, Inc., USA; and the neodymium iron boron nanoparticles (average particle size 500 nm) were purchased from Foshan Xin Nuode Materials Co., Ltd.

[0049] Unless otherwise specified, the experimental methods described below follow conventional methods and conditions, or are selected according to the product instructions. Unless otherwise specified, all experimental instruments used in this invention are standard laboratory instruments.

[0050] Example 1

[0051] This embodiment provides an antibacterial coating for magnetic soft composite materials, its preparation method, and its application:

[0052] Firstly, the preparation of the antibacterial material from the magnetic soft composite material is as follows: By weight, the magnetic soft composite material comprises 20 parts silicone rubber, 40 parts silicone oil, and 40 parts neodymium iron boron nanoparticles. The preparation method of the magnetic soft composite material includes:

[0053] Add 10g of Ecoflex 30 Part A and 10g of Ecoflex 30 Part B to a 50ml beaker, stir at 2000 rpm for 30 seconds using a mechanical stirrer, and then perform vacuum degassing to prepare a homogeneous Ecoflex 30 precursor solution. Then add 40g of silicone oil with a viscosity of 1000cst to the Ecoflex 30 precursor solution, stir at 2000 rpm for 5 minutes using a mechanical stirrer, and then perform vacuum degassing to prepare a silicone oil-Ecoflex 30 precursor solution. Finally, add 40g of NdFeB nanoparticles to the silicone oil-Ecoflex 30 precursor solution, stir at 2000 rpm for 10 minutes using a mechanical stirrer, and then perform vacuum degassing to obtain the magnetic soft composite material solution, i.e., the NdFeB / Ecoflex composite material solution, and store it in a 4°C medical refrigerator for later use.

[0054] Next, a low-adhesion antibacterial coating of magnetic soft composite material was prepared using a magnetic soft composite material solution, such as... Figure 1 As shown, the magnetic soft composite material solution was first uniformly spin-coated onto the substrate surface using a spin-coating method and allowed to stand at room temperature for 5 minutes. After the magnetic soft composite material solution naturally leveled, the entire sample was transferred to a vacuum drying oven for vacuum treatment and cured at 80°C for 2 hours under vacuum. After the magnetic soft composite coating material solution was completely cured, a magnetizing magnetic soft composite material coating was magnetized to saturation using a magnetizing magnetic field of 2T±0.2T, and then a silicone oil with a viscosity of 10cst was sprayed onto its surface to perform interfacial saturation swelling, thus preparing a low-adhesion magnetic soft composite antibacterial coating.

[0055] Next, a periodically moving magnet array is designed to drive the low-adhesion magnetic soft composite antibacterial coating to remove bacterial adhesion. For example... Figure 2 As shown, a magnet array is composed of modular magnet units (each magnet unit has an area of ​​25 mm²). 2 This drives the formation of arrayed indentations in the antibacterial coating of low-adhesion magnetic soft composite materials. For example... Figure 3 As shown, when the magnet array approaches the antibacterial coating of the low-adhesion magnetic soft composite material, an array of indentations and deformations will form on the coating surface, as demonstrated in the experimental results. Figure 4 As shown, when the magnet array moves along the X direction, an array of recessed deformation regions will form on the coating surface as it moves along the X direction. Figure 5As shown, a magnet array is installed on an XY two-dimensional motion platform. By programming and controlling the patterned motion of the magnet array, a periodic moving driving magnetic field is formed, which drives the antibacterial coating of the low-adhesion magnetic soft composite material to produce periodic dynamic deformation, causing eddies to form on the surface of the coating in a fluid environment to remove bacterial adhesion.

[0056] Example 2

[0057] This embodiment provides an antibacterial coating for magnetic soft composite materials, its preparation method and application. Except that the content of neodymium iron boron nanoparticles added during the preparation process is 20wt%, the rest is the same as in Example 1.

[0058] Example 3

[0059] This embodiment provides an antibacterial coating of magnetic soft composite material, its preparation method and application. Except that the content ratio of silicone rubber Ecoflex to silicone oil is 1:1.5 and the content of neodymium iron boron nanoparticles is kept at 40wt%, the rest is the same as in Example 1.

[0060] Comparative Example 1

[0061] This comparative example provides an antibacterial coating for a magnetic soft composite material, its preparation method, and its application. Except that the neodymium iron boron nanoparticles added during the preparation process are replaced with an equal amount of iron tetroxide, the rest is the same as in Example 1.

[0062] Comparative Example 2

[0063] This comparative example provides an antibacterial coating of magnetic soft composite material, its preparation method and application. Except that the content of neodymium iron boron nanoparticles added during the preparation process is 60 wt%, the rest is the same as in Example 1.

[0064] Comparative Example 3

[0065] This comparative example provides an antibacterial coating of magnetic soft composite material, its preparation method and application. Except that the content ratio of silicone rubber Ecoflex to silicone oil is 2:1 and the content of neodymium iron boron nanoparticles is kept at 40wt%, the rest is the same as in Example 1.

[0066] Test Example 1

[0067] like Figure 6 As shown, this test example quantitatively characterizes the magnetically driven deformation by the content of silicone oil, the content of neodymium iron boron nanoparticles, and the driving magnetic field strength added during the preparation of the antibacterial coating of the magnetic soft composite material. Figure 6 As shown in -A, after the NdFeB / Ecoflex (neodymium iron boron magnetic soft composite material) of Example 1 is directionally saturated magnetized, it will impart remanence to the internal magnetic particles parallel to the magnetization direction. For example... Figure 6As shown in Figure -B, under the action of a magnet array of 300mT±10mT, the NdFeB / Ecoflex composite material can produce a conical pit deformation with a diameter of approximately 1.5mm and a depth of approximately 1066.9μm.

[0068] (1) Influence of magnetic particle materials on the magnetically driven deformation depth of the antibacterial coating of the magnetic soft composite material: By performing directional saturation magnetization and magnetic driving on Example 1 and Comparative Example 1, as... Figure 6 As shown in Figure C, under the same magnetic particle content (40 wt%) and driving magnetic field (300 mT), the deformation depth of Fe3O4 / Ecoflex (Fe3O4 / Ecoflex magnetic soft composite material) is 226.5 μm, which is only 20% of the deformation depth of NdFeB / Ecoflex composite material. This demonstrates that NdFeB / Ecoflex composite material can achieve greater deformation and generate higher intensity eddy currents under the same driving magnetic field, thus being more effective in removing bacterial adhesion.

[0069] (2) Effect of driving magnetic field strength on the magnetically driven deformation depth of the antibacterial coating of the magnetic soft composite material: By conducting magnetic driving under different magnetic field strengths in Example 1, such as... Figure 6 As shown in Figure -D, when the NdFeB content is 40wt% and the ratio of Ecoflex to silicone oil (Ecoflex:silicone oil) is 1:2, the magnetically driven deformation depth of the NdFeB / Ecoflex composite material increases with the increase of magnetic field strength.

[0070] (3) The effect of NdFeB nanoparticle content on the magnetically driven deformation depth of the antibacterial coating of the magnetic soft composite material: This was achieved by magnetically driving Example 1, Example 2, and Comparative Example 2 under different magnetic field intensities. Figure 6 As shown in Figure -E, when the driving magnetic field strength is 300mT and the ratio of Ecoflex to silicone oil (Ecoflex:silicone oil) is 1:2, the magnetically driven deformation depth of the NdFeB / Ecoflex composite material increases with the increase of NdFeB nanoparticle material content.

[0071] (4) The elastic modulus of NdFeB / Ecoflex composite material also increases with the increase of NdFeB content. Under the same driving magnetic field, the higher the NdFeB content, the smaller the deformation of NdFeB / Ecoflex composite material under magnetic drive. Moreover, the higher the NdFeB content, the more difficult it is to cure NdFeB / Ecoflex composite material.

[0072] (5) The effect of the ratio of Ecoflex to silicone oil on the magnetically driven deformation depth of the antibacterial coating of the magnetic soft composite material: By conducting magnetic driving tests on Examples 1 and 3, and Comparative Example 3 under different magnetic field strengths, such as... Figure 6As shown in Figure -F, when the driving magnetic field strength is 300 mT and the NdFeB content is 40 wt%, the magnetically driven deformation depth of the NdFeB / Ecoflex composite increases with the ratio of Ecoflex to silicone oil. This is because a higher Ecoflex to silicone oil ratio results in a softer NdFeB / Ecoflex composite, leading to greater deformation under the same driving magnetic field. It is important to note that if the Ecoflex to silicone oil ratio is too high, the NdFeB / Ecoflex composite may not fully recover after magnetically driven deformation, or the recovery response time may be long, which is detrimental to inducing eddy currents in the magnetic field response to remove bacterial adhesion.

[0073] Test Example 2

[0074] like Figure 7 As shown, this test example characterizes the wettability of the antibacterial coating of the magnetic soft composite material in Example 1: (as shown) Figure 7 As shown in Figure -A, the contact angles of the magnetic soft composite material before and after silicone oil swelling are 97.4° and 76.8°, respectively. Figure 7 As shown in Figure -B, the experimental results demonstrate that the antibacterial coating of the magnetic soft composite material exhibits better liquid repellency after being saturated and swollen with silicone oil. Figure 7 As shown in Figure -C, the contact angle hysteresis of the aluminum plate, Ecoflex, and magnetic soft composite (MSC) is 35°, 25°, and 20°, respectively, while the contact angle hysteresis of the saturated swollen magnetic soft composite (SMSC) is only 4°. Therefore, the liquid repellency and low contact angle hysteresis indicate that the magnetic soft composite antibacterial coating has good anti-solid adhesion properties.

[0075] Test Example 3

[0076] like Figure 8 As shown, this test example focuses on the surface adhesion test of the antibacterial coating of the magnetic soft composite material in Example 1: To further verify the adhesion performance of the antibacterial coating of the magnetic soft composite material, the adhesion of the magnetic soft composite material to the aluminum plate, Ecoflex, and PDMS before and after silicone oil swelling was tested. Figure 8 As shown in Figure -A, the experimental results show that the adhesion force between the magnetic soft composite material and the aluminum plate is 6.62 N, and after saturation swelling with silicone oil, the adhesion force is 0.98 N, a reduction of 6.8 times. Figure 8 As shown in Figure -B, the adhesion force between the magnetic soft composite material and Ecoflex is 7.35 N. After saturation swelling with silicone oil, the adhesion force with Ecoflex is 1.43 N, a decrease of 5.1 times. Figure 8 As shown in -C, the adhesion force between the magnetic soft composite material and PDMS is 8.51N, and after saturation swelling with silicone oil, the adhesion force between the composite material and PDMS is 1.65N, a decrease of 5.2 times.

[0077] Test Example 4

[0078] like Figure 9 As shown, this test example focuses on the magnetic soft composite antibacterial coating of Example 1, using magnetic drive, and then analyzes the deformation-induced eddy currents generated by the magnetic soft composite antibacterial coating: as follows Figure 9 As shown in -A, this test case designs a particle image velocimetry (PIV) experimental setup to analyze the eddy current field generated by the deformation of a magnetic soft composite material driven by a periodically moving magnetic field. The reciprocating speed of the motor is set to 30 mm / s, one reciprocating stroke is 60 mm, and the magnetic field strength of the arrayed magnets on the surface of the magnetic soft composite material is 300 mT. Figure 9 As shown in Figure -B, the PIV experiment results for one reciprocating cycle demonstrate that deformation of the magnetic soft composite material leads to a significant eddy current flow field in the surface fluid. The velocity variation of the fluid on the surface of the magnetic soft composite material is as follows: Figure 9 As shown in -C, the flow velocity in the X and Y directions exhibits periodic changes, such as... Figure 9 As shown in Figure -D, the PIV results for the first two motion cycles indicate a peak flow velocity of approximately 605.7 μm / s in the Y direction and approximately 454.5 μm / s in the X direction. The magnetic field strength can be controlled by varying the distance between the arrayed magnet group and the magnetic soft composite material. Figure 9 -E presents a comparison of the amplitude changes in fluid velocity on the surface of the composite material under magnetic fields of 100mT, 200mT, and 300mT. The experimental results show that the greater the magnetic field strength, the greater the deformation depth of the magnetic soft composite material, and the greater the amplitude of the fluid velocity on its surface. Further investigation is needed to examine the effect of the motor speed on the fluid velocity on the surface of the composite material under a magnetic field. Figure 9 -F presents a comparison of the changes in fluid velocity amplitude on the surface of the composite material at motor speeds of 10 mm / s, 20 mm / s, and 30 mm / s. The experimental results show that the greater the motor speed, the greater the fluid velocity amplitude on the surface of the magnetic soft composite material.

[0079] Test Example 5

[0080] like Figure 10-11 As shown, this test example uses magnetic drive to perform antibacterial experiments on the magnetic soft composite antibacterial coating of Example 1:

[0081] To verify the antibacterial performance of the magnetic soft composite antibacterial coating, *E. coli* was first cultured in 5 ml of LB medium at 200 rpm and 37°C in a shaking incubator for 12 hours. Then, the antibacterial properties were measured at 600 nm wavelength (OD) using a spectrophotometer. 600The bacterial concentration was measured to be 0.3. Subsequently, the suspension culture medium was centrifuged at 5000 rpm for 15 minutes, with the medium replaced, and the bacteria were cultured at 37°C for 10 hours, then the bacterial concentration was diluted to 0.1. Next, the antibacterial coating sample of the magnetic soft composite material was sprayed with ethanol (70 vol%) and disinfected by irradiation with a UV lamp for 2 minutes. The sample was then immersed in the bacterial suspension, and the effects of magnetic field strength, motor speed, and magnet unit area on the deformation-induced eddy currents of the magnetically driven magnetic soft composite antibacterial coating on bacterial adhesion removal were investigated.

[0082] (1) To quantify the bacterial coverage of the coating surface, multiple groups of coating samples were prepared and cultured simultaneously under identical conditions. After culturing, the samples were rinsed three times with phosphate-buffered saline (PBS), stained with a fluorescently labeled reagent, and then placed in the dark at room temperature for 20 minutes, followed by rinsing twice with PBS solution. The samples were observed using a multiphoton confocal microscope, and the bacterial coverage was subsequently analyzed using ImageJ software. Figure 10 As shown in -A, the bacterial coverage of the coated sample surface in a static state was 24.66%. Figure 10 As shown in -B~10-D, when the motor speed V x =30mm / s and magnet unit area a=25mm² 2 At that time, the bacterial coverage area on the surface of the coated sample decreased with increasing magnetic field strength, indicating that the greater the applied magnetic field strength, the better the antibacterial performance of the magnetic soft composite antibacterial coating. Figure 10 As shown in -E and 10-F, when the magnetic field strength B = 300mT and the magnet unit area a = 25mm² 2 At that time, the bacterial coverage area on the surface of the coated sample decreased with the increase of motor speed, indicating that the higher the motor speed, the better the antibacterial performance of the magnetic soft composite antibacterial coating. This is because the greater the applied magnetic field strength and motor speed, the greater the induced eddy current velocity and vorticity on the surface of the magnetic soft composite antibacterial coating, which is more conducive to removing bacterial adhesion. This is consistent with the PIV experiment results in Example 6. Figure 10 As shown in -G and 10-H, when the magnetic field strength B = 300mT and the motor speed V... x When the speed is 30 mm / s, the area coverage of bacteria on the surface of the coated sample increases with the increase of the area of ​​the magnet unit. This indicates that the larger the area of ​​the magnet unit, the less conducive it is to removing bacterial adhesion.

[0083] (2) To further investigate the antibacterial properties of the magnetic soft composite antibacterial coating, the colony-forming unit count (CFU) of the magnetic soft composite antibacterial coating under different parameters such as magnetic field strength, motor speed, and magnet unit area was also analyzed, as follows:

[0084] First, the coated sample, rinsed with PBS, was transferred to a beaker containing 5 ml of sterile PBS and sonicated in a water bath for 2 minutes at a frequency of 350 Hz to remove all bacteria from the surface of the coated sample. The serially diluted bacterial solution was then evenly spread onto an LB agar surface and incubated for 20 hours, after which the grown bacteria were counted. Figure 11 As shown, the CFU on the surface of the coated sample in a static state is 147.92 × 10⁻⁶. 3 / ml. For example... Figure 11 As shown in -A, when the motor speed V x =30mm / s and magnet unit area a=25mm² 2 At that time, the CFU on the surface of the coated sample decreased with the increase of magnetic field strength, indicating that the greater the applied magnetic field strength, the better the antibacterial performance of the magnetic soft composite antibacterial coating. Figure 11 As shown in Figure B, when the magnetic field strength B = 300 mT and the magnet unit area a = 25 mm² 2 At that time, the CFU on the surface of the coated sample decreased with the increase of motor speed, indicating that the higher the motor speed, the better the antibacterial performance of the magnetic soft composite antibacterial coating. Figure 11 As shown in -C, when the magnetic field strength B = 300mT and the motor speed V x When the speed is 30 mm / s, the CFU on the surface of the coated sample increases with the increase of the area of ​​the magnet unit, which further proves that the larger the area of ​​the magnet unit, the less conducive it is to removing bacterial adhesion.

[0085] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A low-adhesion magnetic soft composite material antibacterial coating, characterized in that, After the magnetic soft composite material is cured, it is directionally saturated magnetized and its surface is subjected to saturated swelling treatment to obtain the low-adhesion magnetic soft composite material antibacterial coating. The magnetic soft composite material includes, by weight, 20-40 parts of silicone rubber, 40-80 parts of silicone oil and 20-40 parts of neodymium iron boron nanoparticles. The swelling agent used in the saturated swelling treatment is silicone oil.

2. A method for preparing an antibacterial coating of a low-adhesion magnetic soft composite material as described in claim 1, characterized in that, include: The magnetic soft composite material is coated and cured, then directionally saturated magnetized by a directional magnetizing magnetic field, and a swelling agent is sprayed on its surface for saturation swelling treatment to prepare the low-adhesion magnetic soft composite material antibacterial coating.

3. The method for preparing a low-adhesion magnetic soft composite antibacterial coating according to claim 2, characterized in that, The strength of the directional magnetizing magnetic field is 1.0T-3.5T.

4. The method for preparing a low-adhesion magnetic soft composite antibacterial coating according to claim 2, characterized in that, The curing process involves heating and curing under vacuum conditions.

5. The method for preparing a low-adhesion magnetic soft composite antibacterial coating according to claim 2, characterized in that, The preparation method of the magnetic soft composite material includes: mixing silicone rubber and silicone oil, adding neodymium iron boron nanoparticles, and stirring to obtain the composite material.

6. The application of the low-adhesion magnetic soft composite antibacterial coating as described in claim 1, characterized in that, The antibacterial coating of the low-adhesion magnetic soft composite material is driven by a periodically moving magnet array to remove bacterial adhesion.

7. The application of the low-adhesion magnetic soft composite antibacterial coating according to claim 6, characterized in that, The magnet array generates a periodic motion driving magnetic field, which in turn drives the low-adhesion magnetic soft composite antibacterial coating to produce periodic dynamic deformation, causing eddies to form on the coating surface to remove bacterial adhesion.

8. The application of the low-adhesion magnetic soft composite antibacterial coating according to claim 6, characterized in that, The magnet array is mounted on the XY two-dimensional motion platform.

9. The application of the low-adhesion magnetic soft composite antibacterial coating according to claim 6, characterized in that, The area of ​​a single magnet unit in the magnet array used is 1 mm². 2 -125 mm 2 The maximum magnetic field strength on the surface of the magnet array is 100mT-500mT. The controllable driving magnetic field of 0-300mT can be adjusted by changing the distance between the magnet array and the antibacterial coating of the magnetic soft composite material.

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