Stainless steel pipe with tissue low-resistance puncture and self-lubricating functions and machining method

Abstract

The invention discloses a stainless steel pipe with tissue low-resistance puncture and self-lubricating functions and a machining method, and relates to the field of medical instruments. Comprising a pipe base body, a bionic microstructure tip is arranged at the puncture end of the pipe base body, and an in-situ activation lubricating layer is arranged on the outer surface of the pipe base body; the bionic microstructure tip comprises a first-stage skin breaking area and a second-stage expanding area which are sequentially arranged in the puncture direction. The first-stage skin breaking area is a nanoscale sharp cutting edge; the second-stage expansion area is a spiral or stepped micro-groove array arranged on the outer surface of the pipe; the in-situ activation lubricating layer is a hydrophilic polymer composite gel coating which can be rapidly hydrated when encountering tissue fluid or blood. The method has the advantages that puncture resistance is remarkably reduced, tissue damage is reduced, instant self-lubrication is achieved, and the coating is stable and controllable.

Description

Technical Field

[0001] This invention relates to the field of medical devices, and more particularly to stainless steel tubing with low-resistance tissue puncture and self-lubricating functions, and its processing method. Background Technology

[0002] Puncture-type medical devices are crucial tools in clinical diagnosis and treatment. Traditional stainless steel puncture needles rely primarily on their sharp edges to cut through skin and tissue, resulting in significant puncture resistance. This can easily cause tissue deformation, compression, and tearing, leading to increased patient pain, greater tissue damage, and potentially affecting the accuracy and stability of the puncture. Furthermore, the dry friction between the needle and tissue further increases the resistance to advancement and may cause complications due to frictional heat or tissue adhesion.

[0003] In existing technologies, some methods improve puncture performance by designing special geometric shapes at the needle tip (such as triangular needle tips or reverse-angle needle tips), but the expansion of the tissue channel remains relatively rigid, resulting in limited drag reduction. Other methods involve coating the needle surface with a lubricating coating (such as polytetrafluoroethylene or silicone oil), but these coatings are mostly passive lubricants with limited lubrication effect and poor durability, or their lubrication performance decreases significantly after contact with blood, failing to achieve the immediate strong lubrication effect of "on-demand activation."

[0004] Therefore, there is an urgent need for a new type of stainless steel pipe and processing method that can work synergistically from both structural design and surface functionalization to significantly reduce tissue penetration resistance at the moment of puncture, thereby achieving smooth, precise, and low-damage puncture.

[0005] Therefore, this invention proposes a stainless steel tube with low resistance puncture and self-lubricating function, as well as a processing method thereof. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a stainless steel tube with low resistance puncture and self-lubricating function, as well as a processing method thereon.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A stainless steel tube with low resistance puncture and self-lubricating function includes a tube substrate, wherein the puncture end of the tube substrate is provided with a biomimetic microstructure tip, and the outer surface of the tube substrate is provided with an in-situ activated lubrication layer. The biomimetic microstructure tip includes a primary skin-breaking zone and a secondary expansion zone arranged sequentially along the puncture direction; the primary skin-breaking zone is a nanoscale sharp cutting edge with a cutting edge angle of 7°-13°; the secondary expansion zone is a spiral or stepped microgroove array on the outer surface of the tube, the width of the microgroove is 20-100μm, the depth is 10-50μm, and the ridge width between adjacent microgrooves is 10-30μm; The in-situ activated lubricating layer is a hydrophilic polymer composite gel coating that can be rapidly hydrated upon contact with tissue fluid or blood.

[0008] Preferably, when the secondary extension region is a spiral microgroove array, its spiral angle is 15°-45°.

[0009] Preferably, the in-situ activated lubricating layer is composed of the following components by weight percentage: 85-95% hydrophilic polymer matrix, 5-10% lubricating enhancer, 0.5-2% crosslinking agent, 0.5-1.5% photoinitiator, and the balance being solvent; The hydrophilic polymer matrix is ​​composed of polyvinylpyrrolidone and carboxymethyl chitosan, wherein the weight ratio of polyvinylpyrrolidone to carboxymethyl chitosan is (50-70):(20-35). The lubricant enhancer is composed of polyethylene glycol and sodium alginate; The crosslinking agent is genipin or 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride.

[0010] Preferably, the polyvinylpyrrolidone has a K value of 90; the carboxymethyl chitosan has a degree of substitution ≥0.8; and the polyethylene glycol has a molecular weight of 1000-10000.

[0011] A method for processing stainless steel pipes includes the following steps: S1: Pretreatment of the stainless steel pipe substrate; S2: The biomimetic microstructure tip is fabricated at the puncture end of the pipe substrate using ultrashort pulse laser micro-engraving technology or mask electrochemical micromachining technology. S3: Prepare a coating solution for forming the in-situ activated lubricating layer; S4: The coating solution is applied to the outer surface of the tube substrate with the processed biomimetic microstructure tip, and then cured to form the in-situ activated lubricating layer.

[0012] Preferably, in S2, the parameters of the ultrashort pulse laser micro-engraving process are: using a femtosecond or picosecond laser, with a wavelength of 1064nm or 355nm, a pulse width of <10ps, a single pulse energy of 10-100μJ, a repetition frequency of 100-500kHz, a scanning speed of 100-1000mm / s, and a focused spot diameter of 5-20μm.

[0013] Preferably, in step S2, the parameters of the mask electrochemical micromachining process are as follows: using the tube as the anode, employing a specially designed microstructure mask, using a 10-20 wt% NaNO3 solution as the electrolyte, a processing voltage of 8-15 V, and a current density of 5-20 A / dm³. 2 Processing time is 1-5 minutes.

[0014] Preferably, in step S3, the coating solution is prepared as follows: polyvinylpyrrolidone and carboxymethyl chitosan are dissolved in a mixed solvent of deionized water and ethanol according to the specified ratio to obtain solution A; then polyethylene glycol, sodium alginate, crosslinking agent, and photoinitiator are added to solution A, stirred and ultrasonically dispersed for 2-4 hours to obtain coating solution B; wherein, the volume ratio of deionized water to ethanol is 7:3.

[0015] Preferably, in step S4, the coating is performed using either a dip-coating method or a precision spraying method; the dip-coating method involves a dip time of 30-60 seconds and a coating speed of 1-5 mm / s.

[0016] Preferably, in step S4, the curing process includes: first, preheating and curing at 50-70°C for 5-10 minutes, and then curing under inert gas protection using ultraviolet light with a wavelength of 365nm and a light intensity of 20-50mW / cm². 2 Irradiation time is 30-120 seconds, and finally post-curing heat treatment is carried out at 80-100℃ for 10-30 minutes.

[0017] The beneficial effects of this invention are as follows: Significantly reduced puncture resistance: The biomimetic microstructure tip effectively reduces the initial peak force of puncture and the continuous resistance during the advancement process by "sharp cutting first and then gradual expansion", thus achieving smooth puncture.

[0018] Reduced tissue damage: The progressive expansion pattern avoids tearing and compression injuries caused by forcibly stretching tissue, which is beneficial for postoperative tissue recovery.

[0019] Instant self-lubrication: The intelligent responsive coating rapidly forms an ultra-slippery interface upon contact with bodily fluids, dynamically reducing friction and allowing the needle to move more smoothly within tissues, improving control precision and patient comfort.

[0020] The coating is stable and controllable: the coating formulation and process are well-defined, it is stable in the dry state, has a fast activation response, and provides significant and reliable lubrication. Attached Figure Description

[0021] Figure 1 This is a flowchart of the processing method for stainless steel pipes with low resistance puncture and self-lubricating function proposed in this invention. Detailed Implementation

[0022] The technical solution of the present invention will be further described in detail below with reference to specific embodiments.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection or setting, a detachable connection or setting, or an integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] Example 1: Substrate: 316L stainless steel pipe with an outer diameter of 0.8mm and an inner diameter of 0.6mm is selected, cut to the required length, cleaned and activated.

[0025] Microstructure fabrication: Picosecond laser (8ps pulse width, 355nm wavelength) was used to process one end of the tube. First, a focused laser spot was used to finely etch a nano-cutting edge with a tip angle of approximately 12°. Then, with parameters of a helix angle of 30°, a linewidth of 40μm, a line depth of 25μm, and a ridge width of 15μm, a 3mm long helical microgroove region was etched by laser scanning.

[0026] Coating preparation: Weigh 6.5g of PVPK90 and 2.5g of CMCS and dissolve them in 80g of deionized water / ethanol (7:3) mixed solvent. Add 0.7g of PEG-4000, 0.3g of sodium alginate, 0.08g of genipin, and 1840.1g of photoinitiator. Stir and sonicate for 3 hours to obtain the coating solution.

[0027] Coating and curing: The pipe (with the non-puncture end sealed and protected) is immersed and pulled out of the coating solution at a speed of 2 mm / s, ensuring a uniform wet film. Preheat in a 60℃ oven for 8 minutes, then apply under nitrogen at 40 mW / cm². 2 Expose to UV light for 60 seconds, then cure at 90°C for 20 minutes.

[0028] Performance testing: Tests showed that the initial puncture force of the prepared needle-based simulated tissue puncture (gelatin-PVA composite material) was reduced by approximately 45% compared to a traditional bevel needle of the same specifications, and the propulsion friction was reduced by approximately 60%. After the coating came into contact with physiological saline, the surface water contact angle decreased from approximately 60° to <10° within 100ms, and the coefficient of friction decreased to 0.03.

[0029] Example 2: The microstructure was modified to a stepped axial microgroove array (groove width 50 μm, depth 20 μm, step spacing 100 μm), and the coating crosslinking agent was changed to EDC (0.1 g). Precision spraying was used for coating (spray gun air pressure 0.2 MPa, moving speed 10 mm / s). The resulting pipe also exhibited excellent low-resistance puncture and self-lubricating properties.

[0030] Example 3: This embodiment focuses on using a more precise femtosecond laser process to prepare finer microstructures and optimize coating formulations to improve lubrication response speed and durability.

[0031] Substrate and pretreatment: Same as in Example 1, but 316L stainless steel pipe with an outer diameter of 1.2mm was selected and cleaned and activated.

[0032] High-precision microstructure fabrication: Femtosecond laser (300 fs pulse width, 1030 nm wavelength) was used for processing. To obtain a sharper initial cutting edge, the cutting edge angle in the primary skin-breaking zone was controlled at approximately 8°, and fine sharpening was achieved through a high energy density (80 μJ per pulse) and low scanning speed (150 mm / s) circular scanning strategy. The secondary extension zone was designed as a variable helix angle microgroove: the initial section (1 mm from the tip) had a helix angle of 15°, a groove width of 30 μm, and a depth of 15 μm; the subsequent section (2 mm) gradually increased the helix angle to 30°, the groove width to 50 μm, and the depth to 25 μm. This design aimed to achieve a smoother resistance transition. Laser parameters were: repetition frequency 200 kHz, focused spot diameter approximately 8 μm.

[0033] Optimize coating formulation: This embodiment aims to achieve faster swelling rate and stronger lubricating film strength. The formulation is adjusted as follows (by weight percentage): PVPK90: 60% CMCS: 25% PEG-2000 (lower molecular weight, facilitating rapid hydration): 8% Sodium alginate: 4% Composite crosslinking agent: Genipin 0.4% + EDC 0.6% (total 1.0%) Photoinitiator 184: 1.0% The remainder is a mixture of deionized water and ethanol (7:3).

[0034] The addition of a composite crosslinking agent aims to form a denser and more resilient interpenetrating network, thereby improving the mechanical strength and adhesion of the coating in the swollen state.

[0035] Coating and Curing: Precision spraying is used, with uniform spraying at a speed of 8 mm / s under a pressure of 0.15 MPa, resulting in a wet film thickness of approximately 15 μm. Curing Process: Preheating at 65℃ for 5 minutes, under nitrogen protection, at 40 mW / cm². 2 Expose to UV light for 90 seconds, then cure at 95°C for 15 minutes.

[0036] Performance testing: Microstructure characterization: Scanning electron microscopy shows that the cutting edge is sharp, the microgroove edge is clear, and the dimensional accuracy is ±2μm.

[0037] Lubrication performance: When the coating comes into contact with bovine serum, the hydration response time is shortened to about 80 milliseconds. The formed lubricating layer has a stable coefficient of friction of 0.02 in the reciprocating friction test (on pig skin tissue), and after 20 puncture cycles, the coefficient of friction only rises to 0.035, showing excellent durability.

[0038] Puncture test: In the puncture of ex vivo porcine liver tissue, the peak puncture force was reduced by more than 50% compared with the traditional puncture needle of the same specification, and the straightness evaluation of the puncture trajectory (puncture deviation angle) was significantly improved.

[0039] Example 4: This embodiment demonstrates a processing path suitable for medium to high volume and more cost-sensitive applications, and adjusts the coating for puncture applications that may be exposed to high-fat environments.

[0040] Substrate and pretreatment: Same as above.

[0041] Microstructure machining using a mask-based electrochemical process: A pre-prepared flexible polymer mask was tightly wrapped around the puncture end of the tube (5 mm in length). Electrochemical machining was performed in a 15 wt% NaNO3 electrolyte, using the tube as the anode and a platinum electrode as the cathode. Parameters: DC voltage 12 V, initial current density approximately 15 A / dm³. 2 The processing time is 3 minutes. After processing, a stepped axial microgroove array is obtained, with a groove width of approximately 60 μm, a depth of approximately 30 μm, and a step spacing of 150 μm. This method is highly efficient and suitable for batch processing of microstructures with a certain degree of pattern consistency.

[0042] Formulation of anti-biofouling lubricating coating: Considering certain intervention scenarios, a certain degree of resistance to non-specific protein adsorption is introduced into the lubrication system. The formulation is adjusted as follows: PVPK90: 55% CMCS: 30% Introducing a zwitterionic polymer: poly(sulfobetaine methacrylate) (PSBMA, molecular weight approximately 5000): 5% PEG-6000: 5% Sodium alginate: 3% Crosslinking agent EDC: 1.2% Photoinitiator: 0.8% Solvent: Balance.

[0043] The introduction of PSBMA helps to further enhance the hydrophilicity and anti-protein adsorption of the coating surface, reduce the adhesion of tissue debris or protein to the needle surface, and maintain long-term lubrication.

[0044] Coating and curing: Dip-and-coat method is used, with a coating speed of 3 mm / s. Curing process: Preheat at 60℃ for 8 minutes, then UV light (30 mW / cm²).2 Irradiate for 80 seconds, then cure at 90°C for 25 minutes.

[0045] Performance testing: Coating stability: After immersing the coated syringe in PBS buffer for 7 days, the coating showed no bubbling or peeling, and the adhesion test (100-grid test) achieved a grade of 0.

[0046] Anti-contamination test: After repeated punctures in a solution rich in fetal bovine serum albumin, the amount of protein adhering to the needle surface in this embodiment was significantly lower than that in the control group without added PSBMA.

[0047] Puncture force: When puncturing in simulated adipose tissue, the advance resistance is about 40% lower than that of conventional silicone oil-lubricated puncture needles, and the withdrawal resistance is even lower, indicating that the lubricating layer is still effective in a lipid environment.

[0048] Example 5: This embodiment demonstrates the feasibility of applying the present invention to smaller tubing (such as fine needles for minimally invasive surgery) and addresses the challenge of achieving uniform coating on small-diameter tubing.

[0049] Substrate: 304VS ultra-fine stainless steel tubing with an outer diameter of 0.3mm is selected, which has extremely high requirements for cleanliness.

[0050] Microstructure fabrication: Due to the extremely thin tubing, a high-precision picosecond laser (355nm) is used for processing. The primary ablation zone is precisely ablated by laser to form a conical tip of approximately 10°. The secondary expansion zone is fabricated with a set of shallow, axially straight microgrooves (non-spiral), 15μm wide, 8μm deep, and 1.5mm long, totaling six circumferentially distributed grooves. This design ensures drag reduction while avoiding excessively deep microgrooves that could affect the torsional stiffness of the micro-tubing. Laser parameters require fine-tuning to lower energy (15μJ per pulse) and higher scanning speed (800mm / s).

[0051] Coating optimization for fine needles: The goal is to create an ultra-thin and uniform coating on extremely fine tubing. Adjustments are made to achieve lower viscosity and faster curing. PVPK90: 70% (higher percentage to provide film-forming properties and rapid hydration) CMCS: 20% PEG-1000: 6% (low molecular weight, reduces viscosity, facilitates spreading) Sodium alginate: 2% Crosslinking agent genipin: 0.5% Low-viscosity photoinitiator: Phenylenol bis(2,4,6-trimethylbenzoyl)phosphine oxide: 1.5% Solvent: The proportion of ethanol is increased to 50% (1:1 with deionized water) to reduce the surface tension of the solution and improve wettability on the capillary surface.

[0052] Precision coating and curing: A low-flow atomization spraying technique combined with a precision rotating pipe is employed. During spraying, the pipe rotates at 3000 rpm to ensure circumferential uniformity of the coating. The spraying pressure is 0.08 MPa, forming a submicron-level wet film.

[0053] Curing process: First, gently dry at 40℃ for 10 minutes, then under low oxygen partial pressure (nitrogen protection), use a high-intensity LED-UV light source (wavelength 385nm, light intensity 60mW / cm²). 2 Irradiation for 30 seconds achieves rapid surface drying and curing, followed by curing at 70°C for 30 minutes to complete the final cross-linking.

[0054] Performance testing: Coating uniformity: Under a microscope, the coating is continuous and defect-free, with a thickness of about 1-2 μm and a thickness deviation of <10% along the axial and circumferential directions of the pipe.

[0055] Micropuncture Test: In a rat tail vein puncture model, the fine needle of this embodiment exhibited excellent puncture feel, with operators reporting a clearer "breakthrough sensation" and minimal vascular damage after puncture. This verifies that even at a microscale, the microstructure combined with the self-lubricating layer of this invention can effectively reduce puncture resistance and improve accuracy. The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A stainless steel tube with low-resistance puncture and self-lubricating functions, characterized in that, It includes a pipe substrate, the puncture end of which is provided with a biomimetic microstructure tip, and the outer surface of the pipe substrate is provided with an in-situ activated lubricating layer; The biomimetic microstructure tip includes a primary skin-breaking zone and a secondary expansion zone arranged sequentially along the puncture direction; the primary skin-breaking zone is a nanoscale sharp cutting edge with a cutting edge angle of 7°-13°; the secondary expansion zone is a spiral or stepped microgroove array on the outer surface of the tube, the width of the microgroove is 20-100μm, the depth is 10-50μm, and the ridge width between adjacent microgrooves is 10-30μm; The in-situ activated lubricating layer is a hydrophilic polymer composite gel coating that can be rapidly hydrated upon contact with tissue fluid or blood.

2. The stainless steel tubing with low-resistance tissue puncture and self-lubricating function according to claim 1, characterized in that, When the secondary extension region is a spiral microgroove array, its spiral angle is 15°-45°.

3. The stainless steel tube with low-resistance tissue puncture and self-lubricating function according to claim 1, characterized in that, The in-situ activated lubricating layer, by weight percentage, consists of the following components: 85-95% hydrophilic polymer matrix, 5-10% lubricating enhancer, 0.5-2% crosslinking agent, 0.5-1.5% photoinitiator, with the balance being solvent; The hydrophilic polymer matrix is ​​composed of polyvinylpyrrolidone and carboxymethyl chitosan, wherein the weight ratio of polyvinylpyrrolidone to carboxymethyl chitosan is (50-70):(20-35). The lubricant enhancer is composed of polyethylene glycol and sodium alginate; The crosslinking agent is genipin or 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride.

4. The stainless steel tubing with low-resistance tissue puncture and self-lubricating function according to claim 1, characterized in that, The polyvinylpyrrolidone has a K value of 90; the carboxymethyl chitosan has a degree of substitution ≥0.8; and the polyethylene glycol has a molecular weight of 1000-10000.

5. A method for processing stainless steel pipes, used to process the stainless steel pipes with low resistance puncture and self-lubricating function as described in any one of claims 1-4, characterized in that, Includes the following steps: S1: Pretreatment of the stainless steel pipe substrate; S2: The biomimetic microstructure tip is fabricated at the puncture end of the pipe substrate using ultrashort pulse laser micro-engraving technology or mask electrochemical micromachining technology. S3: Prepare a coating solution for forming the in-situ activated lubricating layer; S4: The coating solution is applied to the outer surface of the tube substrate with the processed biomimetic microstructure tip, and then cured to form the in-situ activated lubricating layer.

6. The processing method for stainless steel pipes according to claim 5, characterized in that, In S2, the parameters of the ultrashort pulse laser micro-engraving process are as follows: femtosecond or picosecond laser is used, wavelength is 1064nm or 355nm, pulse width is <10ps, single pulse energy is 10-100μJ, repetition frequency is 100-500kHz, scanning speed is 100-1000mm / s, and focused spot diameter is 5-20μm.

7. A method for processing stainless steel pipes according to claim 6, characterized in that, In step S2, the parameters of the mask electrochemical micromachining process are as follows: using the tube as the anode, employing a specially designed microstructure mask, using a 10-20 wt% NaNO3 solution as the electrolyte, a processing voltage of 8-15 V, and a current density of 5-20 A / dm². 2 Processing time is 1-5 minutes.

8. A method for processing stainless steel pipes according to claim 5, characterized in that, In S3, the coating solution is prepared as follows: polyvinylpyrrolidone and carboxymethyl chitosan are dissolved in a mixed solvent of deionized water and ethanol according to the ratio to obtain solution A; then polyethylene glycol, sodium alginate, crosslinking agent and photoinitiator are added to solution A, stirred and ultrasonically dispersed for 2-4 hours to obtain coating solution B; wherein, the volume ratio of deionized water to ethanol is 7:

3.

9. A method for processing stainless steel pipes according to claim 5, characterized in that, In step S4, coating is performed using either a dip-coating method or a precision spraying method; the dip-coating method involves a dip time of 30-60 seconds and a coating speed of 1-5 mm / s.

10. A method for processing stainless steel pipes according to claim 9, characterized in that, In step S4, the curing process includes: first, preheating and curing at 50-70°C for 5-10 minutes, and then curing under inert gas protection using ultraviolet light with a wavelength of 365nm and a light intensity of 20-50mW / cm². 2 Irradiation time is 30-120 seconds, and finally post-curing heat treatment is carried out at 80-100℃ for 10-30 minutes.

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