CN217548307U - A kind of PTFE artificial blood vessel and covered stent - Google Patents

Abstract

An embodiment of the utility model provides a PTFE artificial blood vessel, including the body, the body includes the pipe wall and encloses the circulation passageway of establishing by the pipe wall, and the pipe wall includes towards the inboard of circulation passageway one side, and the pipe wall inboard is provided with a plurality of slots, and the body still includes along length direction's head end and tail end, and the slot extends to the tail end from the head end, just, the pipe wall entangle each other by the PTFE fibre and form network form structure, through forming the slot in the pipe wall inboard for form micropattern on the pipe wall, these micropatterns can further promote and guide endothelial cell in the blood adsorb at the artificial blood vessel internal surface, grow and inside infiltration, faster promotion artificial blood vessel's the endothelialization speed of internal surface, the utility model discloses still provide a tectorial membrane support simultaneously.

Description

A kind of PTFE artificial blood vessel and covered stent

technical field

The invention relates to an artificial blood vessel, in particular to a PTFE artificial blood vessel and a covered stent.

Background technique

Polytetrafluoroethylene (PTFE) material is non-toxic, harmless, physiologically inert, surface hydrophobic, and resistant to aging. It is an ideal artificial blood vessel material and has been widely used in clinical practice. However, when used for small-diameter (diameter <6mm) artificial blood vessels, the blood flow rate is slow, the compatibility of blood and tissue cells on the surface of the material is not good, thrombosis and excessive neointimal hyperplasia are very likely to occur, resulting in extremely high long-term patency of blood vessels. The existence of endothelial cell layer can prevent thrombosis and intimal hyperplasia. Therefore, building a surface that is conducive to rapid endothelialization of blood vessels is a key research direction to solve the poor long-term patency rate of small-diameter PTFE artificial blood vessels.

The rise of the biomimetic concept provides inspiration for the preparation of surfaces conducive to endothelialization. The intima of natural blood vessels has grooves on the micrometer scale along the direction of blood flow. The structure of imitating the intima of natural blood vessels facilitates endothelial cells to quickly follow the grooves. growth direction, so as to achieve endothelialization on the surface of artificial blood vessels. In addition, the structure of the micro-nanofibrous membrane prepared by electrospinning technology is similar to that of the natural extracellular matrix, which is beneficial to the adhesion and proliferation of endothelial cells. At present, the use of electrospinning technology to prepare artificial blood vessels of various materials has received extensive attention, but it is limited to the fact that PTFE basically does not flow after being heated above its melting point (difficult to achieve melt electrospinning) and no solvent can dissolve it (difficult to achieve solution). Electrospinning), there are few reports on the preparation of PTFE small-diameter artificial blood vessels by electrospinning technology. At present, the PTFE tubular fiber membrane prepared by electrospinning technology is mainly used in combination with metal stents and implanted in the form of covered stents. In vivo, the surface of the PTFE tubular fiber membrane has no further treatment, and still faces the problems of poor blood and cell compatibility on the inner surface and poor long-term patency rate.

SUMMARY OF THE INVENTION

Therefore, the present invention provides a PTFE artificial blood vessel to solve the above technical problems.

A PTFE artificial blood vessel, comprising a pipe body, the pipe body includes a pipe wall and a circulation channel surrounded by the pipe wall, the pipe wall includes an inner side facing one side of the circulation channel, and the inner side of the pipe wall is provided with a number of grooves , the pipe body also includes a head end and a tail end along the length direction, the groove extends from the head end to the tail end, and the pipe wall is entangled with PTFE fibers to form a network structure.

Further, the flow channel has a diameter of 1-6mm.

Further, the diameter of the PTFE fiber is between 400nm-2500nm, and the tensile breaking strength of the pipe body is between 1-3MPa, and the elongation at break is between 50%-350%.

Further, the thickness of the tube wall is between 60-300 microns, and the porosity is between 65-85%.

Further, the length direction of the groove is parallel to the axis of the pipe body.

Further, the opening width of the trench is 400-1000 μm, and the depth is 10-1000 μm.

Further, the spacing between adjacent trenches is 10-1000 μm.

Further, the PTFE fibers are randomly arranged.

A covered stent, the covered stent includes a covered tube and an elastic support arranged in the covered tube, wherein the covered tube includes a tube body, and the tube body includes a tube wall and a structure formed by the tube wall. The surrounding circulation channel, the pipe wall includes an inner side facing the side of the circulation channel, a number of grooves are arranged on the inner side of the pipe wall, and the pipe body also includes a head end and a tail end along the length direction, and the groove starts from the head end. Extending to the tail end, and the tube wall is formed by PTFE fibers entangled with each other to form a network structure.

Beneficial effect: The embodiment of the present utility model provides a PTFE artificial blood vessel, including a pipe body, the pipe body includes a pipe wall and a circulation channel surrounded by the pipe wall, and the pipe wall includes an inner side facing the side of the circulation channel , the inner side of the pipe wall is provided with a number of grooves, the pipe body also includes a head end and a tail end along the length direction, the groove extends from the head end to the tail end, and the pipe wall is entangled by PTFE fibers to form a network By forming grooves on the inner side of the tube wall, micropatterns are formed on the tube wall. These micropatterns can further promote and guide the endothelial cells in the blood to adsorb, grow and infiltrate on the inner surface of the artificial blood vessel. The endothelialization speed of the inner surface of the artificial blood vessel is quickly promoted, and the utility model also provides a covered stent at the same time.

Description of drawings

The schematic diagram of the PTFE artificial blood vessel provided by the embodiment of the present utility model;

Fig. 2 is A-A sectional schematic diagram;

Fig. 3 is the enlarged schematic diagram of the pipe wall;

Figure 4 is a schematic cross-sectional view of the covered stent;

Figure 5 is a schematic diagram of a preparation device for preparing a PTFE artificial blood vessel.

Description of graphic components:

Tube body 10; head end 101; tail end 102; tube walls 11, 21; PTFE fiber 110; inner side 111; outer side 112; groove 113; flow channel 12; elastic support 23; receiving rod 31; spinning nozzle 32; device 33.

Detailed ways

1-3, the present invention provides a PTFE artificial blood vessel, including a tube body 10, the tube body 10 includes a tube wall 11 and a circulation channel 12 surrounded by the tube wall 11 for blood to flow through .

Preferably, the flow channel 12 has a diameter of 1-6mm, more specifically 2mm, 3mm, 4mm, 5mm or 6mm.

The tube wall 11 is formed by entanglement of PTFE fibers 110 to form a network structure. Preferably, the PTFE fibers 110 are formed by electrospinning, wherein the electrospun PTFE fibers 110 have a diameter between 400nm-2500nm, and , the tensile breaking strength of the pipe body 10 is 1-3MPa, and the breaking elongation is between 50%-350%.

Preferably, the tube wall 11 has a thickness of 60-300 microns, and a porosity of 65-85%.

The pipe wall 11 includes an inner side 111 facing the flow channel 12 and an outer side 112 facing away from the inner side 111. Several grooves 113 are provided on the inner side 111. It can be understood that the grooves 113 are located in the pipe. The wall 11 presents a recessed groove from the inner side 111 to the outer side 112, and the groove 113 is elongated. Specifically, the pipe body 10 includes a head end 101 and a tail end 102, which can be understood , the head end 101 and the tail end 102 refer to the two ends along the length direction of the pipe body 10, and at the same time, the head end 101 can be any end of the two ends, and the tail end 102 is the other end, and the groove The groove 113 extends from the head end 101 to the tail end 102 , that is, the groove 113 runs through the length direction of the pipe body 10 .

Preferably, the length direction of the groove 113 is parallel to the axis of the pipe body 10 .

Preferably, the opening width of the trench 113 is 400-1000 μm, and the depth is 10-1000 μm.

Preferably, the spacing between adjacent trenches 113 is 10-1000 μm.

By forming grooves 113 on the inner side 111 of the tube wall 11, micropatterns are formed on the tube wall 11. These micropatterns can further promote and guide the endothelial cells in the blood to adsorb, grow and infiltrate on the inner surface of the artificial blood vessel. Quickly promote the endothelialization speed of the inner surface of artificial blood vessels.

Further, the PTFE fibers 110 are randomly arranged.

In order to further understand the structure of the PTFE artificial blood vessel of the present application, the following description is made with reference to FIG. 5 and the preparation method of the PTFE artificial blood vessel. FIG. 5 shows a schematic diagram of a preparation device for preparing the PTFE artificial blood vessel.

S1: Provide a receiving rod 31, and form a composite electrospinning tube on the receiving rod 31, the composite electrospinning tube includes a PET layer attached to the receiving rod 31 and a PTFE/PEO layer formed outside the PET layer.

The mandrel is roughly in the shape of a round bar, and its material is preferably metal, more preferably stainless steel, preferably, it has a diameter of 1-6mm, and a driving device 33 is connected to the mandrel for driving the mandrel. For rotation, in a specific embodiment, the driving device 33 can be a motor, and at the same time, in order to facilitate the connection with the mandrel and the installation of the mandrel, a coupling is also provided between the mandrel and the driving device 33 .

A spinning nozzle 32 is arranged above the receiving rod 31, so that when the receiving rod 31 rotates, the spinning solution extruded from the spinning nozzle 32 can be wound on the receiving rod 31 and form a predetermined shape. The spinning nozzle 32 is a spinning needle. At the same time, the spinning nozzle 32 reciprocates along the axis of the mandrel to form multi-layer electrospinning on the receiving rod 31. It can be understood that in the present invention A multi-layer electrospinning with the same material is called one layer, such as a PET layer or a PEO/PTFE layer in the following description.

The rotating speed of the receiving rod 31 is 100-500r/min, the speed of the spinning nozzle 32 reciprocating along the axial direction of the mandrel is 10-30mm/s, the spinning solution extrusion speed is 0.1-1mL/h, the spinning nozzle The distance between 32 and the receiving rod 31 is 10-20cm, the ambient temperature is 20-30°C, the humidity is 10%-30%, and the voltage is 8-15kV.

When forming the composite electrospinning tube on the receiving rod 31, a PET layer is first formed on the receiving rod 31, and a PTFE/PEO layer is formed on the formed PET layer. It can be understood that before forming the PET layer, it also includes a step of preparing a PET spinning solution, and before forming a PTFE/PEO layer, it includes a step of preparing a PTFE/PEO spinning solution, wherein the solvent of the PET spinning solution is It is a mixed solution of trifluoroacetic acid/dichloromethane, the mass fraction of PET in the solution is 8-15%, and the PTFE/PEO spinning solution includes PTFE aqueous dispersion, PEO aqueous solution, and deionized water, wherein the solute is The mass fraction is 24%-42%, and the viscosity of PTFE/PEO spinning solution is 800-5000mP.S. Preferably, the molecular weight of PTFE is 100-150Da, the mass fraction of PTFE in the PTFE aqueous dispersion is 58%-62%, the molecular weight of PEO is 4000,000-7,000,000Da, and the mass fraction of PEO in the prepared PEO aqueous solution is 1-5 %.

In addition, the role of PEO in the PTFE/PEO spinning solution is to act as a spinning carrier for PTFE to solve the problem that pure PTFE dispersion cannot be spun. Under the action of the electric field, as the PEO is stretched into fibers, the PTFE particles supported on the PEO are also piled into fibers. The decomposition temperature of PEO is lower than the sintering temperature, and it is removed after sintering. The molten PTFE fills the particles generated by the decomposition of PEO. The vacancies form the PTFE fibers 110 .

S2: Provide the grooved tube and transfer the composite electrospun tube onto the grooved tube.

The grooved tube is in the form of a hollow tube, including a middle hole, and its outer diameter is slightly smaller than the outer diameter of the mandrel. Preferably, the outer diameter of the grooved tube is 0.5-1mm smaller than the outer diameter of the mandrel. In this case, a On the one hand, the composite electrospinning tube formed in step S1 can be easily sleeved on the grooved tube; on the other hand, because the main component of the composite electrospinning tube is PTFE, the coefficient of linear expansion of PTFE is large, and the thermal conductivity of PTFE is poor, which is prone to deformation and cracking. Therefore, in order to prepare a thin and non-cracked pure PTFE electrospinning tube, it is necessary to ensure that there is a gap between the composite electrospinning tube and the grooved tube, so that the PTFE electrospinning tube can shrink without cracking after subsequent high temperature sintering.

The outer surface of the grooved pipe is provided with a number of straight-grained protrusions, and these straight-grained protrusions run through the length direction of the grooved pipe. The ridges are used to form the grooves 113 on the pipe wall 11 .

Further, the straight-grained protrusions have a height of 10-1000 μm, and the distance between adjacent straight-grained protrusions is 10-1000 μm. Meanwhile, the grooved pipe is a metal pipe. On the one hand, a hollow metal The tube is more conducive to the even heating of the supported composite electrospinning tube. On the other hand, after sintering, the electrospinning tube melts and flows, shrinks inwards and then closes to the outer surface of the grooved tube, so that the inner surface of the composite electrospinning tube also has a longitudinal direction. The groove 113, further, the groove tube is an aluminum tube or a metal tube with a thermal conductivity greater than or equal to metal aluminum.

S3: High temperature sintered composite electrospinning tube.

It can be understood that the grooved tube covered with the composite electrospinning tube is placed on the bracket, and the temperature is increased to decompose the PET and PEO. The composite electrospinning tube is sintered at high temperature in a box furnace, heated to 360°C-400°C at 4-6°C/min, and then kept for 8-15min.

On the one hand, the PET and PEO components in the composite electrospinning tube are removed by high-temperature sintering. The sintering temperature and holding time are sufficient to decompose other components, while PTFE only melts and does not decompose; The voids generated after the components are decomposed, as well as the voids between the composite electrospinning tube and the grooved tube, especially the straight-grained protrusions on the grooved tube, help to change the inner surface of the composite electrospun tube after cooling and shrinkage Structure; three aspects, the PTFE particles are melted and mutually diffused and bonded into a whole, which greatly improves the mechanical strength of the pure PTFE tubular membrane.

S4: cooling and separating the composite electrospun tube from the grooved tube to form a PTFE artificial blood vessel.

Meanwhile, please refer to FIG. 4 together, the present application also provides a stent-graft, the stent-graft includes a covered tube and an elastic support 23 arranged inside the covered tube and used to support the tube wall 21, it can be understood that The structure of the covered tube is the same as that of the above-mentioned PTFE artificial blood vessel.

The above description is only an embodiment of the present invention, and is not intended to limit the scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied to other related technologies Fields are similarly included in the scope of patent protection of the present invention.

Claims (9)

1. a PTFE artificial blood vessel, comprising pipe body, is characterized in that, described pipe body comprises pipe wall and the circulation passage that is surrounded by pipe wall, and described pipe wall comprises the inner side towards circulation passage side, pipe wall. A number of grooves are arranged on the inside, the pipe body also includes a head end and a tail end along the length direction, the groove extends from the head end to the tail end, and the pipe wall is entangled with PTFE fibers to form a network structure. . 2 . The PTFE artificial blood vessel according to claim 1 , wherein the circulation channel has a diameter of 1-6 mm. 3 . 3. PTFE artificial blood vessel as claimed in claim 2, is characterized in that, described PTFE fiber through diameter is between 400nm-2500nm, and, the tensile breaking strength of pipe body is 1-3MPa, and the elongation at break is 1-3MPa. Between 50%-350%. 4. The PTFE artificial blood vessel according to claim 3, wherein the thickness of the tube wall is between 60-300 microns, and the porosity is between 65-85%. 5. The PTFE artificial blood vessel according to claim 3, wherein the longitudinal direction of the groove is parallel to the axis of the tube body. 6 . The PTFE artificial blood vessel according to claim 3 , wherein the opening width of the groove is 400-1000 μm, and the depth is 10-1000 μm. 7 . 7 . The PTFE artificial blood vessel according to claim 3 , wherein the distance between adjacent grooves is 10-1000 μm. 8 . 8 . The PTFE artificial blood vessel according to claim 3 , wherein the PTFE fibers are randomly arranged. 9 . 9. A covered stent, characterized in that the covered stent comprises a covered tube and an elastic support arranged in the covered tube, wherein the covered tube comprises a tube body, and the tube body comprises The pipe wall and the circulation channel enclosed by the pipe wall, the pipe wall includes an inner side facing the side of the circulation channel, a number of grooves are arranged on the inner side of the pipe wall, and the pipe body also includes a head end and a tail end along the length direction, so The groove extends from the head end to the tail end, and the pipe wall is entangled with PTFE fibers to form a network structure.

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