CN217548307U

CN217548307U - PTFE artificial blood vessel and covered stent

Info

Publication number: CN217548307U
Application number: CN202221232424.7U
Authority: CN
Inventors: 赵荟菁; 徐溶; 孟凯; 张克勤
Original assignee: Suzhou University
Current assignee: Suzhou University
Priority date: 2022-05-20
Filing date: 2022-05-20
Publication date: 2022-10-11
Anticipated expiration: 2032-05-20

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

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

The Polytetrafluoroethylene (PTFE) material is non-toxic and harmless, has physiological inertia, hydrophobic surface and aging resistance, is an ideal artificial blood vessel material and is widely applied to clinic. However, when the material is used for small-caliber (the diameter is less than 6 mm) artificial blood vessels, the blood flow speed is slow, the compatibility of blood and tissue cells on the surface of the material is poor, thrombus and neointimal hyperplasia are easily caused, the long-term patency rate of the blood vessels is extremely low, and the formation of thrombus and intimal hyperplasia can be prevented by the endothelial cell layer, so that the establishment of the surface which is favorable for the rapid endothelialization of the blood vessels is the key research direction for solving the problem of poor long-term patency rate of the small-caliber polytetrafluoroethylene artificial blood vessels at present.

The rise of the bionic concept provides inspiration for preparing the surface which is beneficial to endothelialization, the intima of the natural blood vessel is provided with a groove on the micrometer scale along the blood flowing direction, and the structure which simulates the intima of the natural blood vessel is beneficial to endothelial cells to quickly grow along the groove direction, so that the endothelialization of the surface of the artificial blood vessel is realized. In addition, the structure of the micro-nano fiber membrane prepared by the electrostatic spinning technology is similar to that of a natural extracellular matrix, and the adhesion and proliferation of endothelial cells are facilitated. At present, artificial blood vessels made of various materials by utilizing an electrostatic spinning technology have received wide attention, but the conditions that PTFE basically does not flow after being heated to a temperature higher than a melting point (melt electrostatic spinning is difficult to realize) and a solvent can dissolve PTFE (solution electrostatic spinning is difficult to realize) are limited, at present, few reports are reported for preparing PTFE small-caliber artificial blood vessels by utilizing the electrostatic spinning technology, PTFE tubular fiber membranes prepared by utilizing the electrostatic spinning technology are mainly combined with metal stents to be implanted into a body in a covered stent mode, the surfaces of the PTFE tubular fiber membranes are not further treated, and the problems that the compatibility of internal surface blood and cells is poor and the long-term patency rate is poor are still faced.

Disclosure of Invention

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

The utility model provides a PTFE artificial blood vessel, includes the body, the body include the pipe wall and enclose the circulation passageway of establishing by the pipe wall, the pipe wall including the inboard towards circulation passageway one side, the pipe wall inboard is provided with a plurality of slots, the body still includes along length direction's head end and tail end, the slot extend to the tail end from the head end, just, the pipe wall entangle each other by the PTFE fibre and form network structure.

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

Furthermore, the diameter of the PTFE fiber is 400nm-2500nm, the tensile breaking strength of the tube body is 1-3MPa, and the breaking elongation is 50-350%.

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

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

Furthermore, the width of the opening of the groove is 400-1000 μm, and the depth is 10-1000 μm.

Further, the distance between adjacent grooves is 10-1000 μm.

Further, the PTFE fibers are in a random arrangement.

The utility model provides a covered stent, covered stent include the tectorial membrane pipe and set up the elastic support in the tectorial membrane pipe, wherein, the tectorial membrane pipe include the body, the body include the pipe wall and enclose the circulation passageway of establishing by the pipe wall, the pipe wall include towards the inboard of circulation passageway one side, the pipe wall inboard is provided with a plurality of slots, the body still includes along length direction's head end and tail end, the slot extend to the tail end from the head end, just, the pipe wall entangle each other by the PTFE fibre and form the network form structure.

Has the advantages that: an embodiment of the utility model provides a PTFE artificial blood vessel, which comprises a pipe body, the body include the pipe wall and enclose the circulation passageway of establishing by the pipe wall, the pipe wall include towards the inboard of circulation passageway one side, the pipe wall inboard is provided with a plurality of slots, the body still includes along length direction's head end and tail end, the slot extend 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 to adsorb, grow and inside infiltration at the artificial blood vessel internal surface, faster endothelial speed of promotion artificial blood vessel's internal surface, the utility model discloses still provide a tectorial membrane support simultaneously.

Drawings

FIG. 1 is a schematic view of a PTFE artificial blood vessel provided by an embodiment of the present invention;

FIG. 2 isbase:Sub>A schematic sectional view taken along line A-A;

FIG. 3 is an enlarged view of the tube wall;

FIG. 4 is a schematic cross-sectional view of a stent graft;

FIG. 5 is a schematic view of a device for preparing a PTFE artificial blood vessel.

Description of the illustrated elements:

a tube body 10; a head end 101; a tail end 102; the

tube walls

11, 21; PTFE fibers 110; an inner side 111; an outer side 112; a trench 113; a flow-through channel 12; an elastic support 23; a receiving rod 31; a spinning nozzle 32; a drive device 33.

Detailed Description

Referring to fig. 1 to 3, the present invention provides a PTFE artificial blood vessel, including a tubular body 10, where the tubular body 10 includes a tubular wall 11 and a flow channel 12 surrounded by the tubular wall 11 and used for flowing blood therethrough.

Preferably, said flow-through channels 12 have a diameter of 1-6mm, more particularly 2mm, 3mm, 4mm, 5mm or 6mm.

The tube wall 11 is formed by intertwining 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 of 400nm to 2500nm, and the tube 10 has a tensile breaking strength of 1 to 3MPa and an elongation at break of 50% to 350%.

Preferably, the wall 11 has a thickness of between 60 and 300 microns and a porosity of between 65 and 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, the inner side 111 is provided with a plurality of grooves 113, it can be understood that the grooves 113 are recessed grooves formed on the pipe wall 11 from the inner side 111 to the outer side 112, the grooves 113 are elongated, specifically, the pipe body 10 includes a head end 101 and a tail end 102, it can be understood that the head end 101 and the tail end 102 refer to two ends along the length direction of the pipe body 10, meanwhile, the head end 101 can be any one of the two ends, the tail end 102 is the other end, and the grooves 113 extend from the head end 101 to the tail end 102, i.e., the grooves 113 penetrate 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 the grooves 113 on the inner side 111 of the vessel wall 11, micropatterns are formed on the vessel wall 11, and the micropatterns can further promote and guide the endothelial cells in the blood to adsorb, grow and permeate inwards on the inner surface of the artificial blood vessel, so that the endothelialization speed of the inner surface of the artificial blood vessel is promoted more quickly.

Further, the PTFE fibers 110 are in a random arrangement.

In order to further understand the structure of the PTFE artificial blood vessel of the present application, the following description will be made with reference to fig. 5 and a method for manufacturing the PTFE artificial blood vessel, and fig. 5 is a schematic view of a manufacturing apparatus for manufacturing the PTFE artificial blood vessel.

S1: a receiving rod 31 is provided, and a composite electrospun tube comprising a PET layer attached to the receiving rod 31 and a PTFE/PEO layer formed outside the PET layer is formed on the receiving rod 31.

The mandrel is substantially in the shape of a round bar, preferably made of metal, more preferably stainless steel, preferably having a diameter of 1-6mm, and a driving device 33 is connected to the mandrel for driving the mandrel to rotate, in one embodiment, the driving device 33 may be a motor, and a coupling is provided between the mandrel and the driving device 33 for facilitating connection and installation of the mandrel to the mandrel.

Above the receiving rod 31 is provided a spinning nozzle 32 for allowing the spinning solution extruded from the spinning nozzle 32 to be wound around the receiving rod 31 and formed in a predetermined form when the receiving rod 31 is rotated, and specifically, the spinning nozzle 32 is a spinning needle, and at the same time, the spinning nozzle 32 is reciprocated in the axial direction of the mandrel to form a multi-layered electrospun fiber on the receiving rod 31, it can be understood that the multi-layered electrospun fiber having the same material is referred to as 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 reciprocating speed of the spinning nozzle 32 along the axial direction of the mandrel is 10-30mm/s, the extruding speed of the spinning solution is 0.1-1mL/h, the distance between the spinning nozzle 32 and the receiving rod 31 is 10-20cm, the ambient temperature is 20-30 ℃, the humidity is 10-30%, and the voltage is 8-15kV.

In forming the composite electrospun 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 the method also comprises a step of preparing a PET spinning solution before forming the PET layer, and a step of preparing a PTFE/PEO spinning solution before forming the PTFE/PEO layer, wherein the solvent of the PET spinning solution is a trifluoroacetic acid/dichloromethane mixed solution, the mass fraction of PET in the solution is 8-15%, the PTFE/PEO spinning solution comprises a PTFE aqueous dispersion, a PEO aqueous solution and deionized water, the mass fraction of solute is 24-42%, and the viscosity of the PTFE/PEO spinning solution is 800-5000mP.S. Preferably, the molecular weight of PTFE is 100-150Da, the mass fraction of PTFE in PTFE aqueous dispersion is 58% -62%, the molecular weight of PEO is 4000,000-7,000,000Da, and the mass fraction of PEO in prepared PEO aqueous solution is 1-5%.

In addition, the role of PEO in the PTFE/PEO dope is: the PTFE is used as a spinning carrier of PTFE, and the problem that pure PTFE dispersion liquid cannot be spun is solved. Under the action of the electric field, as the PEO is stretched into fibers, the PTFE particles loaded on the PEO are also piled into fibers, the decomposition temperature of the PEO is lower than the sintering temperature, the PEO is removed after sintering, and the molten PTFE fills the vacancy generated after the PEO is decomposed to form the PTFE fibers 110.

S2: a grooved tube is provided and the composite electrospun tube is transferred onto the grooved tube.

The fluted tube is in a hollow tubular shape and comprises a middle hole, the outer diameter of the fluted tube is slightly smaller than the outer diameter of the mandrel, preferably, the outer diameter of the fluted tube is smaller than the outer diameter of the mandrel by 0.5-1mm, and under the condition, the composite electro-spun yarn tube formed in the step S1 can be conveniently sleeved on the fluted tube; in the second aspect, the main component of the composite electrospun pipe is PTFE, the linear expansion coefficient of PTFE is large, the PTFE has poor thermal conductivity, and deformation and cracking phenomena easily occur, so that in order to prepare a thin and non-cracking pure PTFE electrospun pipe, a gap needs to be reserved between the composite electrospun pipe and the grooved pipe, and the PTFE electrospun pipe can be conveniently shrunk without cracking after subsequent high-temperature sintering.

The outer surface of the grooved tube is provided with a plurality of straight-line protrusions which penetrate through the length direction of the grooved tube, and it can be understood that the opposite groove portions are arranged between the straight-line protrusions, and meanwhile, the straight-line protrusions are used for forming the grooves 113 on the tube wall 11.

Furthermore, the straight-line protrusions have the height of 10-1000 microns, the distance between every two adjacent straight-line protrusions is 10-1000 microns, meanwhile, the grooved tube is a metal tube, on one hand, the hollow metal tube is more beneficial to uniformly heating the supported composite electro-spun tube, on the other hand, the electro-spun tube is tightly attached to the outer surface of the grooved tube after being melted and flowed and shrunk inwards after being sintered, so that longitudinal grooves 113 are also formed in the inner surface of the composite electro-spun tube, and further, the grooved tube is an aluminum tube or a metal tube with the heat conductivity coefficient larger than or equal to that of metal aluminum.

S3: and sintering the composite electro-spun tube at high temperature.

It can be understood that the grooved tube sleeved with the composite electrospinning tube is placed on the bracket, the temperature is raised, the PET and the PEO are decomposed, the PTFE is melted and flows to fill gaps generated by the decomposition of the PET and the PEO and gaps of the grooves 113, preferably, the composite electrospinning tube can be sintered at high temperature by adopting a box furnace, the temperature is raised to 360-400 ℃ at 4-6 ℃/min, and then the temperature is kept for 8-15min.

On one hand, PET and PEO components in the composite electric spinning tube are removed through high-temperature sintering, the sintering temperature and the heat preservation time are enough to decompose other components, and PTFE is only molten and is not decomposed; secondly, PTFE is melted and flows to be filled into gaps, wherein the gaps comprise gaps generated after other components are decomposed and gaps between the composite electrospun pipe and the grooved pipe, particularly straight-line convex gaps on the grooved pipe, so that the change of the inner surface structure of the composite electrospun pipe after cooling and shrinkage is facilitated; in the third aspect, the PTFE particles are fused and mutually diffused and bonded into a whole, so that the mechanical strength of the pure polytetrafluoroethylene tubular membrane is greatly improved.

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

Meanwhile, please refer to fig. 4, the present application further provides a stent graft, which includes a stent graft and an elastic stent 23 disposed inside the stent graft and used for supporting the tube wall 21, wherein the structure of the stent graft is the same as that of the PTFE artificial blood vessel.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. The utility model provides a PTFE artificial blood vessel, includes the body, its characterized in that, the body include the pipe wall and enclose the circulation passageway of establishing by the pipe wall, the pipe wall including the inboard towards circulation passageway one side, the pipe wall inboard is provided with a plurality of slots, the body still includes along length direction's head end and tail end, the slot extend to the tail end from the head end, just, the pipe wall twine each other by the PTFE fibre and form network form structure.

2. The PTFE prosthesis of claim 1, wherein the flow channel has a diameter of 1-6 mm.

3. The PTFE artificial blood vessel of claim 2, wherein the PTFE fiber diameter is between 400nm and 2500nm, and wherein the tensile break strength of the tubular body is between 1 MPa and 3MPa, and the elongation at break is between 50% and 350%.

4. The PTFE vascular prosthesis of claim 3, wherein the wall thickness is between 60 and 300 microns and the porosity is between 65 and 85%.

5. The PTFE prosthesis of claim 3, wherein the length of the groove is parallel to the axis of the tube.

6. The PTFE artificial blood vessel of claim 3, wherein the groove has an opening width of 400 to 1000 μm and a depth of 10 to 1000 μm.

7. The PTFE artificial blood vessel of claim 3, wherein the spacing between adjacent grooves is 10 to 1000 μm.

8. The PTFE prosthesis of claim 3, wherein the PTFE fibers are in a random arrangement.

9. The utility model provides a covered stent, its characterized in that, covered stent include the tectorial membrane pipe and set up at the intraductal elastic support of tectorial membrane, wherein, the tectorial membrane pipe include the body, the body include the pipe wall and enclose the circulation passageway of establishing by the pipe wall, the pipe wall include towards the inboard of circulation passageway one side, the pipe wall inboard is provided with a plurality of slots, the body still includes along length direction's head end and tail end, the slot extend to the tail end from the head end, just, the pipe wall entangle each other by the PTFE fibre and form the network form structure.