Self-assembled single-layer anchored hybrid lipid-copolymer mask as well as forming method and application thereof

Abstract

The invention discloses a self-assembled single-layer anchored hybrid lipid-copolymer mask as well as a forming method and application thereof, and belongs to the field of electrochemical processing. The mask comprises a metal-hydroxyl anchoring single layer combined to the surface of a workpiece anode through a covalent bond and a hybrid bimolecular layer fixed through the anchoring single layer; the hybrid bilayer is formed by synergistically self-assembling a lipid amphiphilic monomer and a block copolymer amphiphilic monomer, wherein the length of a block copolymer hydrophobic block is matched with the length of a lipid hydrophobic tail and the thickness of a target ion channel protein transmembrane hydrophobic region. The forming method comprises the steps of constructing an anchoring single layer through surface chemical modification, preparing a self-assembly solution, carrying out synergistic self-assembly on an oil-water interface and the like. The method improves the breakdown voltage of the mask and the bonding strength of the substrate, and is suitable for atomic-scale electrochemical machining of high-potential materials such as copper, gold, platinum and semiconductors.

Description

Technical Field

[0001] This invention relates to the field of electrochemical processing, and more particularly to a self-assembled monolayer anchored hybrid lipid-copolymer mask, its forming method, and its application. Technical Background

[0002] Electrolytic machining (ECM) is a specialized machining technique that removes materials through anodic dissolution. Its basic unit of material removal is metal ions, thus possessing the potential to achieve atomic-level precision machining. The key to realizing this potential lies in the ability to stably and precisely confine the electrochemical reaction within an atomic-scale space. Traditional phospholipid bilayers, formed by the self-assembly of natural or single synthetic phospholipids, typically have a breakdown voltage below 400 mV. For Fe, Ni, Ti, Al, and their alloys, this voltage window is usually sufficient to drive anodic dissolution. However, for Cu, Au, Pt, and most semiconductor materials, the minimum required electrolytic voltage may exceed this range, causing the mask to break down before the metal begins to dissolve effectively, thus rendering the insulating shielding of non-processed areas ineffective and preventing machining from proceeding.

[0003] To improve the stability of biomimetic membranes, numerous studies have been conducted in related fields. For example, in the field of nanopore gene sequencing, to improve the mechanical strength and stability of supporting lipid bilayer membranes, Chinese inventions CN113416344B, CN114106329B, and CN113402768A have disclosed methods such as introducing polymerizable phospholipids, in-situ polymerization using photocrosslinking or click chemistry, or hybridization polymerization with hydrophobic monomers containing double bonds. While these methods can significantly improve the breakdown voltage and lifetime of the membrane, their application scenarios are gene sequencing pools where both sides are solution environments, and the self-assembly and stabilization of the membrane are relatively easy. However, in electrolytic processing scenarios, one side of the biomimetic mask is a solid metal electrode, and the other side is an electrolyte, making the interface environment more complex and demanding. To construct a robust biomimetic membrane on a metal surface, an additional surface hydration step is usually required to introduce hydroxyl groups (-OH) as anchoring points. However, the hydroxyl groups introduced by conventional plasma or ultraviolet treatment often have low coverage and are mostly physically adsorbed with weak binding forces (Tang H, Shen Z, Shen Y, et al. Reinforcing self-assembly of hole transport molecules for stable inverted perovskite solar cells[J]. Science, 2024, 383(6688): 1236-1240.). They are prone to detachment under electrochemical and fluid disturbances during processing, leading to mask failure. Furthermore, the introduction of hydroxyl groups in plasma requires oxygen or water vapor as a gas source, which will cause unnecessary oxidation of the metal. The surface oxide layer requires a higher breakdown voltage to dissolve the metal in the electrochemical environment, which places high demands on the mechanical strength and stability of the biomimetic membrane.

[0004] On the other hand, besides biogenic phospholipids, amphiphilic block copolymers can also self-assemble in solution to form lipid bilayer structures (Zhang X, Fu W, Palivan CG, et al. Natural channel protein inserts and functions in a completely artificial, solid-supported bilayer membrane[J]. Scientific Reports, 2013, 3(1): 2196.), and usually have higher mechanical and chemical stability. However, when using them as electrolytic processing masks, a key matching problem must be solved: the length of the hydrophobic region of the block copolymer must be precisely matched with the transmembrane hydrophobic region scale of the target ion channel protein (for example, the degree of polymerization m and n values ​​of the PBD-PEO copolymer commonly used in gene sequencing need to be carefully selected). Excessively long hydrophobic chains may cause ion channel proteins to fail to insert correctly or malfunction, preventing electrolyte ions from reaching the metal surface through their channels.

[0005] In addition, traditional strategies to enhance membrane stability by adding components such as cholesterol or polyethylene glycol (PEG) also have limitations in electrolytic processing environments: cholesterol is easily oxidized in electrochemical environments, which may damage the structure of ion channel proteins and cause membrane phase separation; while high-purity functional PEG is expensive and not conducive to large-scale applications. Summary of the Invention

[0006] Technical problem to be solved: Therefore, in order to overcome the shortcomings of the above-mentioned prior art, especially to solve the problems of low breakdown voltage, weak binding with metal substrate and poor compatibility with ion channel proteins of traditional phospholipid masks, and thus expand the applicability of near-atomic scale electrochemical processing to high-potential materials such as Cu, Au, Pt and semiconductors, this invention proposes a self-assembled monolayer anchored hybrid lipid-copolymer mask, its forming method and application.

[0007] Technical Solution: A self-assembled monolayer anchored hybrid lipid-copolymer mask, the mask being formed on the anode surface of a workpiece, and comprising: a metal-hydroxyl anchoring monolayer covalently bonded to the anode surface of the workpiece; and a hybrid bilayer fixed by the anchoring monolayer, the hybrid bilayer being formed by the synergistic self-assembly of a lipid amphiphilic monomer and a block copolymer amphiphilic monomer; wherein the length of the hydrophobic block of the block copolymer amphiphilic monomer is matched with the length of the hydrophobic tail of the lipid amphiphilic monomer and the thickness of the transmembrane hydrophobic region of the target ion channel protein.

[0008] The aforementioned metal-hydroxyl anchored monolayer is formed through a surface chemical modification process that includes inert and reducing plasma treatment followed by water vapor dissociation.

[0009] The amphiphilic monomer of the above block copolymer is poly(1,2-butadiene)-b-poly(ethylene oxide) block copolymer (PBD). 11 PEO8, PBD 22 PEO 14 Purchased from Polymer Source.

[0010] The aforementioned amphiphilic monomer of lipids is diaphytylphosphatidylcholine (DPhPC), which was purchased from Sigma-Aldrich.

[0011] A method for forming a self-assembled monolayer anchored hybrid lipid-copolymer mask includes the following steps: S1, chemically modifying the anode surface of a workpiece to construct a covalently bonded metal-hydroxyl anchoring monolayer in situ; S2, dissolving the amphiphilic lipid monomer and the amphiphilic block copolymer monomer in an oily organic solvent to obtain a self-assembly solution; wherein the length of the hydrophobic block of the amphiphilic block copolymer monomer matches the length of the hydrophobic tail of the amphiphilic lipid monomer and the thickness of the transmembrane hydrophobic region of the target ion channel protein; S3, introducing the self-assembly solution to the interface between the anode surface of the workpiece treated in step S1 and an aqueous solution, so that the hydrophilic head groups of the amphiphilic lipid monomer and the amphiphilic block copolymer monomer bind to the anchoring monolayer, and their hydrophobic portions synergistically self-assemble in the oily organic solvent to form the hybrid lipid-copolymer mask.

[0012] In step S1, the chemical modification specifically includes: placing the workpiece anode in a plasma atmosphere of inert and reducing mixed gas to remove surface oxides and expose metal active sites; subsequently introducing water vapor onto the surface of the workpiece anode to dissociate water molecules and form the metal-hydroxyl anchored monolayer.

[0013] In step S2, the oily organic solvent is squalene.

[0014] In step S2, the concentrations of the lipid amphiphilic monomer and the block copolymer amphiphilic monomer in the oily organic solvent are both 5-10 mg / mL.

[0015] After forming the hybrid mask in step S3, the method further includes step S4: introducing the target ion channel protein into the system so that it is inserted into the hybrid mask; then applying a DC pre-bias voltage to adjust the conformation and orientation of the ion channel protein in the mask.

[0016] The above-mentioned self-assembled monolayer anchored hybrid lipid-copolymer mask is used in atomic-scale electrochemical processing of metal or semiconductor material surfaces with standard electrode potentials higher than 0.5 V (relative to the standard hydrogen electrode).

[0017] Technical Principles: 1. In-situ Construction of High-Strength Covalently Anchored Monolayer: This step aims to solve the core problem of weak adhesion between the mask and the metal substrate. Unlike conventional physical adsorption or weakly bonded hydroxylation treatments, this invention employs a powerful modification method to treat the anode surface of the workpiece. The clean workpiece is placed in an inert and reducing plasma atmosphere (such as an argon-hydrogen mixture). Under controlled conditions, the physical bombardment of inert molecules and the reducing properties of reducing molecules can natively remove oxides from the workpiece surface, exposing high-energy metal dangling bonds. Subsequently, while shutting off the plasma source, a trace amount of water vapor is introduced into the plasma cavity. The chemical bonds of water molecules are dissociated by the high-energy metal surface, directly and uniformly generating high-density metal-hydroxyl (M-OH) bonds in situ on the surface. These M-OH bonds are firmly anchored to the substrate in covalent form, forming a dense and stable self-assembled monolayer (SAM) anchoring layer. This layer not only provides the hydrophilic sites necessary for subsequent molecular assembly, but its strong covalent bonding fundamentally ensures the substrate adhesion of the entire biomimetic mask in the subsequent electrochemical processing environment.

[0018] 2. Hybrid mask self-assembly with precise molecular structure design: After forming a strong anchoring layer, the hybrid mask is self-assembled. This is the core innovation of the present invention, which includes two levels of design: (1) Monomer molecular design, which selects two complementary amphiphilic monomers - lipid amphiphilic monomers (providing biocompatibility) and block copolymer amphiphilic monomers (providing mechanical strength). The key is to precisely design the molecular structure of the block copolymer, especially the chain length of its hydrophobic block. This length must be optimized to achieve triple matching: scale matching with the hydrophobic tail of the lipid monomer, scale matching with the transmembrane hydrophobic region of the target ion channel protein, so as to jointly form a thermodynamically stable hydrophobic core; its hydrophilic block provides compatibility with the anchoring layer and the aqueous electrolyte. (2) Cooperative self-assembly process, the designed lipid monomer and block copolymer monomer are dissolved in a low surface tension, chemically inert oily organic solvent at a preset ratio and concentration. This solution system is introduced to the surface of the modified workpiece and the aqueous interface. Driven by intermolecular forces, the hydrophilic head groups of the two monomers bind to the hydroxyl sites of the anchoring layer. Their scale-matched hydrophobic tails then spontaneously aggregate and align within the organic phase, ultimately assembling at the interface to form a transversely continuous, dense hybrid lipid-copolymer bilayer. The rigid polymer chains significantly enhance the membrane's mechanical strength and thermal stability, thereby substantially increasing its breakdown voltage.

[0019] 3. Functional Insertion of Ion Channel Proteins and Post-Mask Processing: After the hybrid mask is formed, the target ion channel protein (or its biomimetic analogue) is introduced into the system. Due to the precise matching of the hydrophobic core, the ion channel protein can spontaneously and functionally insert into the hybrid mask. To further optimize its functional orientation, a low-amplitude DC pre-bias voltage can be applied after insertion, allowing the protein to complete the correct conformational adjustment under the influence of the electric field. Finally, the formed hybrid mask can be selectively subjected to stability enhancement treatments (such as mild photocrosslinking or thermal annealing) to further enhance the overall stability of the mask without affecting protein activity, enabling it to withstand higher voltage electrolytic processing.

[0020] Beneficial effects: (1) Significantly improved mask stability and applicability. Compared with traditional single phospholipid bilayer masks, the hybrid lipid-copolymer mask formed in this invention achieves a breakthrough in structural rigidity and chemical stability. The introduction of copolymer segments enhances the mechanical strength and thermal stability of the mask, giving it higher voltage tolerance (breakdown voltage). This characteristic fundamentally expands the material processing range of the technology, making it not only suitable for active metals such as aluminum, but also applicable to metals with more positive electrode potentials that are traditionally difficult to process precisely (such as Cu, Au, Pt) and even some semiconductor materials, providing a new and reliable interface basis for realizing atomic-scale processing of these materials.

[0021] (2) Robust interfacial anchoring and simplified process. A high-density, covalently bonded M-OH anchoring monolayer is generated in situ on the anode surface of the workpiece using a reducing plasma and water molecule dissociation strategy. This method produces a high hydroxyl coverage and strong bonding, providing uniform and robust binding sites for subsequent self-assembly of lipids and copolymer monomers, significantly reducing film defects caused by weak anchoring. This process can be efficiently completed under conventional chemical laboratory conditions, greatly simplifying the process flow and lowering equipment requirements and preparation costs.

[0022] (3) In-situ cleaning and activation are completed in one step. During the generation of the anchored hydroxyl monolayer, the trace oxide layer and organic contaminants inherent on the anode surface of the workpiece are also removed, exposing a fresh and active metal atom interface. This integrated "cleaning-activation-anchoring" process ensures that the subsequent self-assembly interface has the best chemical purity and reactivity while building a strong anchoring layer, laying a solid foundation for the formation of a highly ordered, low-defect hybrid mask.

[0023] (4) The hydrophobic microenvironment is precisely controllable, ensuring protein function. By rationally designing the length of the copolymer hydrophobic block (such as PBD), it is precisely matched with the thickness of the transmembrane hydrophobic area (approximately 2.7-3 nm) of the natural lipid hydrophobic tail chain and the target ion channel protein. This scale-matched hybrid structure provides a near-natural, thermodynamically stable hydrophobic microenvironment for the insertion and folding of ion channel proteins. It not only promotes the correct insertion of proteins but also effectively maintains their natural conformation and biological function after insertion, ensuring the stable conduction and confinement efficiency of nanopores during electrochemical processing.

[0024] (5) Strong process compatibility and high reliability. The entire method is based on the principles of physicochemistry and self-assembly, with clear steps and controllable parameters (such as processing time, water vapor concentration, and gas ratio), exhibiting good process repeatability and reliability. The resulting hybrid mask structure is dense, effectively blocking the penetration of harmful components in the electrolyte and ensuring the integrity of the mask itself during long-term or multiple pulse processing, thereby improving the stability and yield of the entire atomic-scale electrolytic processing process. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the formation of a hybrid lipid-polymer mask for electrolytic machining.

[0026] Figure 2 This is a schematic diagram of hydroxyl monolayer anchoring.

[0027] Figure 3 These are schematic diagrams and simplified molecular structures of lipid monomers and copolymer monomers.

[0028] Figure 4 This is a schematic diagram illustrating the formation principle of hybrid lipid-copolymer masks.

[0029] Figure 5 It is the ratio of surface oxidation to hydroxyl content in traditional surface modification methods.

[0030] Figure 6 It is the detection of surface hydroxyl groups after dissociation of water vapor in an inert / reducing plasma atmosphere.

[0031] Figure 7 It is PBD 22 PEO 14 The It curve of ion channel insertion detected after forming a hybrid lipid-copolymer mask with DPhPC.

[0032] Figure 8 It is PBD 11 The It curve of ion channel insertion detected after PEO8 and DPhPC form a hybrid lipid-copolymer mask.

[0033] Figure 9These are TEM images of nanopores obtained through electrolytic processing.

[0034] Labels and names in the figure: 1. Workpiece anode; 2. Electrolyte droplet; 3. Pipette cathode; 4. Oily organic solvent; 5. Lipid-copolymer bilayer; 6. Inert / reducing plasma atmosphere; 7. High-energy metal surface; 8. Anchored monolayer; 9. Lipid hydrophilic head; 10. Lipid hydrophobic tail; 11. Copolymer hydrophobic tail; 12. Copolymer hydrophilic head. Detailed Implementation

[0035] The following is combined Figure 1-4 The implementation of this invention patent will be further described.

[0036] A method for forming a self-assembled monolayer anchored hybrid lipid-polymer mask mainly includes the following steps:

[0037] S1: The sputtered Cu workpiece anode 1 is placed in an inert / reducing plasma atmosphere 6 and surface modified in a water vapor atmosphere, and finally a dense hydroxyl anchoring monolayer 8 is formed on the high-energy metal surface 7 of the Cu workpiece anode 1.

[0038] S2: Immediately immerse the treated Cu workpiece anode 1 into a solution containing DPhPC lipid monomer and PBD. 11 In squalene oily organic solvent 4, PEO8 copolymer monomers, DPhPC and PBD 11 The concentration of PEO8 is 5 mg / mL. The hydrophilic head of lipid 9 and the hydrophilic head of copolymer 12 are covalently anchored to the anchored monolayer 8. The hydrophobic tail of lipid 10 and the hydrophobic tail of copolymer 11 self-assemble through hydrophobic interaction to form a lipid-copolymer monolayer on the high-energy metal surface 7.

[0039] S3: At the beginning of step S2, 10 μL of electrolyte droplet 2 is squeezed out through the cathode 3 of the pipette and immediately immersed in squalene oily organic solvent 4. After the hydrophobic tail of lipid 10 and the hydrophobic tail of copolymer 11 are fully self-assembled at the interface between squalene oily organic solvent 4 and electrolyte droplet 2, another lipid-copolymer monolayer is formed. The cathode 2 of the pipette is moved to contact the lipid-copolymer monolayer in S2 to form a lipid-copolymer bilayer 5.

[0040] Example 1:

[0041] This embodiment aims to clarify the key role of inert / reducing plasma atmosphere and water vapor dissociation in constructing a high-density covalently bonded hydroxyl-anchored monolayer, and to compare it with traditional oxygen plasma treatment; a high-purity copper sheet is used as the workpiece anode, which is ultrasonically cleaned and then placed in a radio frequency plasma reaction chamber. The chamber is first evacuated to a base pressure ≤1×10. -2Pa, then an argon-hydrogen mixed gas (Ar:H2 volume ratio 95:5, total flow rate 50 sccm) was introduced, maintaining a pressure of 10 Pa. A reducing plasma treatment with 100W radio frequency power was applied for 5 minutes. Adsorbates were removed by argon ion bombardment, and surface copper oxide was reduced by hydrogen free radicals, exposing highly active metal atom dangling bonds. The plasma source was then turned off, and 0.1 vol% water vapor was introduced under vacuum conditions and exposed for 60 seconds, causing water molecules to dissociate on the active metal surface to form a covalently bonded Cu-OH anchored monolayer. X-ray photoelectron spectroscopy showed high hydroxyl coverage density and no significant oxide layer formation. Figure 6 As shown, no O1s characteristic peak was detected at the binding energy of 529 eV, indicating that a layer of hydroxyl groups was formed in situ on the anode surface of the workpiece, rather than occurring simultaneously with oxidation. In contrast, while conventional argon-oxygen plasma and UV treatment of copper sheets under the same process parameters can introduce hydroxyl groups, it also results in the simultaneous formation of a 2–3 nm thick copper oxide layer. Figure 5 The bonding mechanism is mainly physical adsorption. The formation of oxides hinders the binding of metal active sites and hydroxyl groups, thus affecting the spreading of lipid-copolymer hybrid masks on the workpiece anode. This embodiment confirms that the synergistic effect of reducing plasma and water vapor dissociation can realize an integrated "cleaning-activation-anchoring" process. While inhibiting substrate oxidation, it forms high-density, strongly bonded hydroxyl anchoring sites, providing a foundation for the subsequent lipid-copolymer hybrid mask with significantly better adhesion and stability than traditional oxygen plasma treatment.

[0042] Example 2

[0043] This embodiment specifically implements a method for forming a self-assembled monolayer anchored hybrid lipid-copolymer mask, using a high-purity copper sheet as the workpiece anode, and elaborates on the formation process and performance advantages of the hybrid mask. First, the surface of the copper sheet is subjected to reducing plasma treatment and water vapor dissociation (0.5 vol%, 60 seconds) according to the method of Example 1 to form a high-density Cu-OH anchored monolayer. Then, the workpiece is immediately immersed in a mixture containing DPhPC lipid monomer and PBD. 11 In a squalene solution of PEO8 (i.e., m=11, n=8) block copolymer monomers (all at a concentration of 5 mg / mL), self-assembly was carried out at room temperature for 30 minutes, allowing the hydrophilic head of the lipid to covalently connect with the hydrophilic head of the copolymer to the anchored monolayer. This was followed by a scale-matched hydrophobic tail (DPhPC hydrophobic chain length approximately 2.4 nm, PBD...). 11Hydrophobic chains (approximately 2.8 nm in length) synergistically arrange to form a dense lower hybrid monolayer in the oil phase; simultaneously, 10 μL of electrolyte droplets are injected into the squalene solvent through a pipette cathode, self-assembling at the liquid-liquid interface to form the upper monolayer. After contact between the two layers, a complete hybrid mask is formed. To verify performance, a conventional pure DPhPC lipid mask was prepared under the same conditions as a comparison. The results show that the hybrid mask has a breakdown voltage ≥800 mV, significantly higher than the ≤400 mV of the pure lipid membrane; at 1 M… The membrane lifetime in KCl solution exceeded 48 hours (pure lipid membrane < 8 hours); after insertion of α-hemolysin ion channel protein, the protein functional insertion success rate in the hybrid mask was >90% (pure lipid membrane about 60%), and the mask remained intact and undamaged after multiple electrical pulses; this embodiment demonstrates that by precisely matching the length of the hydrophobic chain with the hybridization of the copolymer and the lipid monomer, a mask with high mechanical strength, excellent insulation and biocompatibility can be formed, and its comprehensive performance is significantly better than that of traditional pure lipid masks, providing a reliable interface basis for the atomic-scale electrolytic processing of high-potential materials.

[0044] Example 3

[0045] This embodiment aims to systematically compare block copolymers with different hydrophobic chain lengths (such as PBD). 11 PEO8 and PBD 22 PEO 14 The study examines the performance differences in forming hybrid lipid-copolymer masks and inserting ion channel proteins, focusing on verifying the crucial impact of hydrophobic region thickness matching on protein functional insertion. Comparative experiments clarify the role of PBD in this process. 22 PEO 14 The mechanism by which excessively long hydrophobic blocks prevent ion channel proteins from properly inserting provides empirical evidence for the design of hybrid mask molecules. Experimental method: Using high-purity copper sheets as the workpiece anode, the workpieces were first subjected to reducing plasma treatment (argon-hydrogen mixed gas, volume ratio 95:5, pressure 10 Pa, 100 W RF power for 5 minutes) and water vapor dissociation (0.1 vol% water vapor exposure for 60 seconds) as described in Example 1, forming a high-density Cu-OH anchored monolayer. Subsequently, the workpieces were divided into two groups: Group A: using PBD... 11 PEO8 block copolymer (hydrophobic PBD block polymerization degree m=11, chain length approximately 2.8 nm) and DPhPC lipid monomer (hydrophobic tail chain length approximately 2.4 nm) synergistically self-assembled at a concentration of 5 mg / mL in squalene solvent. Group B: Using PBD 22 PEO 14Block copolymers (m=22, hydrophobic PBD block chain length approximately 6.6 nm) and the same DPhPC lipid monomers were used in group A at the same concentrations and solvent conditions. In both groups, 10 μL of electrolyte (0.1 M NaCl) was injected into squalene via a pipette cathode, and a hybrid mask was formed at the interface through self-assembly. After mask formation, α-hemolysin ion channel protein (transmembrane hydrophobic region thickness approximately 2.7-3 nm) was introduced, and a 50 mV DC pre-bias voltage was applied to optimize protein orientation. Group A (PBD...) 11 The hybrid mask structure formed by PEO8 is dense, with a breakdown voltage exceeding 800mV and a membrane lifetime exceeding 48 hours. After insertion of ion channel proteins, a step signal of current will appear (e.g., ...). Figure 8 As shown in the figure, it conforms to the characteristics of a natural protein. This indicates that PBD 11 The hydrophobic chain length (approximately 2.8 nm) is highly matched with the hydrophobic tail of DPhPC (approximately 2.4 nm) and the transmembrane region of the protein (approximately 2.7-3 nm), forming a thermodynamically stable hydrophobic core that ensures the correct folding and function of the protein. In contrast, group B (PBD) 22 PEO 14 Although it can form a macroscopically complete hybrid mask (with a relatively high breakdown voltage of approximately 850 mV), the ion channel protein insertion process is abnormal: only sporadic and stable current signals (current magnitude between 12-15 pA) are observed in conductivity tests. These signals are characteristic of phospholipid bilayer signals and are not generated by α-hemolysin ion channel proteins (such as...). Figure 7 (As shown). This indicates a significant spatial mismatch between the protein's hydrophobic region and the mask's hydrophobic core—PBD. 22 The chain length (approximately 6.6 nm) far exceeds the thickness of the protein's transmembrane region (approximately 3 nm), causing the protein to be unable to fully embed itself in the hydrophobic environment. Its transmembrane helix becomes twisted or partially exposed to the hydrophilic interface, thus disrupting the integrity of the pore structure.

[0046] Example 4

[0047] This embodiment aims to demonstrate the application of the self-assembled monolayer anchored hybrid lipid-copolymer mask in the atomic-scale electrolytic machining of high-potential metallic materials (taking copper as an example). By fully simulating a real-world machining scenario, the stability, insulation, and confinement capability of the mask under high-voltage electrolytic conditions are verified, highlighting its superiority over traditional phospholipid masks. Implementation process reference. Figure 1The mask forming schematic diagram shown ensures process repeatability and reliability. Processing preparation and method: A high-purity copper sheet (0.1 mm thickness, 99.99% purity) was used as the workpiece anode 1, a typical high-potential material. First, the copper sheet surface was pretreated according to the method in Example 1: it was placed in an inert / reducing plasma atmosphere 6 of argon-hydrogen mixed gas (volume ratio 95:5) (pressure 10 Pa, 100 W RF power for 5 minutes) to remove surface oxides and expose active metal sites; subsequently, 0.1 vol% water vapor was introduced for 60 seconds to form a covalently bonded Cu-OH anchored monolayer 8. Figure 2 Next, the workpiece is immersed in a mixture of DPhPC lipid monomers and PBD. 11 PEO8 block copolymer monomers (all at a concentration of 5 mg / mL) were placed in a squalene-based oily organic solvent 4 and allowed to self-assemble for 30 minutes. This allowed the hydrophilic head 9 of the lipid and the hydrophilic head 12 of the copolymer to be fixed through hydroxyl anchoring sites. The hydrophobic tail (DPhPC chain length approximately 2.4 nm, PBD) was then observed. 11 The chains (approximately 2.8 nm in length) synergistically arrange themselves in the oil phase to form the lower hybrid monolayer. Simultaneously, 10 μL of electrolyte droplet 2 (0.1 M NaCl solution) is injected into squalene through the cathode 3 via a pipette, causing self-assembly at the liquid-liquid interface to form the upper monolayer. After contact between the two layers, a complete hybrid lipid-copolymer bilayer 5 mask is formed. Figure 4 After mask formation, α-hemolysin ion channel protein (with a transmembrane hydrophobic region thickness of approximately 2.7-3 nm) is introduced and inserted into the hydrophobic core of the mask. A 50 mV DC pre-bias voltage is applied to optimize protein orientation. Electrolytic machining process: The above system is placed under the control of a potentiostat, with the pipette cathode 3 (tip diameter 1 μm) as the tool electrode and the workpiece anode 1 as the machining target. A pulsed voltage (amplitude 600 mV, pulse width 100 μs, interval 500 μs) is applied to simulate atomic-scale electrolytic machining conditions. Due to the high breakdown voltage (≥800 mV) and dense structure of the hybrid mask, the electrolytic reaction is strictly confined to the nanopore region of the ion channel protein: ions migrate directionally through the protein pores to the copper surface, driving anodic dissolution of copper atoms (Cu → Cu). 2+ + 2e - The non-processed area remains intact due to the mask insulation, and the processing result is as follows: Figure 9 As shown.

Claims

1. A self-assembled monolayer anchored hybrid lipid-copolymer mask, characterized in that, The mask is formed on the anode surface of the workpiece and includes: a metal-hydroxyl anchoring monolayer covalently bonded to the anode surface of the workpiece; and a hybrid bilayer fixed by the anchoring monolayer, the hybrid bilayer being formed by the synergistic self-assembly of a lipid amphiphilic monomer and a block copolymer amphiphilic monomer; wherein the length of the hydrophobic block of the block copolymer amphiphilic monomer is matched with the length of the hydrophobic tail of the lipid amphiphilic monomer and the thickness of the transmembrane hydrophobic region of the target ion channel protein.

2. The self-assembled monolayer anchored hybrid lipid-copolymer mask according to claim 1, characterized in that, The metal-hydroxy anchored monolayer is formed through a surface chemical modification process that includes inert and reducing plasma treatment followed by water vapor dissociation.

3. The self-assembled monolayer anchored hybrid lipid-copolymer mask according to claim 1, characterized in that, The copolymer amphiphilic monomer is a block copolymer lipid containing hydrophobic and hydrophilic blocks.

4. A method for forming a self-assembled monolayer anchored hybrid lipid-copolymer mask according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1. Chemically modify the anode surface of the workpiece to construct a covalently bonded metal-hydroxyl anchored monolayer in situ on it; S2. Dissolve the amphiphilic monomer of the lipid and the amphiphilic monomer of the block copolymer in an oily organic solvent to obtain a self-assembly solution; wherein the length of the hydrophobic block of the amphiphilic monomer of the block copolymer is matched with the length of the hydrophobic tail of the lipid amphiphilic monomer and the thickness of the transmembrane hydrophobic region of the target ion channel protein; S3. Apply the self-assembly solution to the interface between the anode surface of the workpiece treated in step S1 and an aqueous solution, so that the hydrophilic head groups of the amphiphilic monomer of the lipid and the amphiphilic monomer of the block copolymer bind to the anchoring monolayer, and their hydrophobic portions synergistically self-assemble in the oily organic solvent to form the hybrid lipid-copolymer mask.

5. The forming method according to claim 4, characterized in that, In step S1, the chemical modification specifically includes: placing the workpiece anode in a plasma atmosphere of inert and reducing mixed gas to remove surface oxides and expose metal active sites; subsequently introducing water vapor onto the surface of the workpiece anode to dissociate water molecules and form the metal-hydroxyl anchored monolayer.

6. The forming method according to claim 4, characterized in that, In step S2, the oily organic solvent is a non-polar solvent with low surface tension, high boiling point and chemical inertness, used to stabilize the structure of the hybrid mask during self-assembly and subsequent processing.

7. The forming method according to claim 4, characterized in that, After forming the hybrid mask in step S3, the method further includes step S4: introducing the target ion channel protein into the system so that it is inserted into the hybrid mask; A DC pre-bias voltage is then applied to adjust the conformation and orientation of the ion channel protein in the mask.

8. The application of the self-assembled monolayer anchored hybrid lipid-copolymer mask according to any one of claims 1 to 3 in atomic-scale electrochemical processing of metal or semiconductor material surfaces with standard electrode potentials higher than 0.5 V.

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