Disclosure of Invention
In order to solve the technical problems, the invention provides a high-strength and easy-to-sew non-absorbable medical suture and a preparation method thereof. According to the invention, the silicone rubber base skin layer is adopted to cover the ultra-high molecular weight polyethylene core layer, so that the surface roughness of the suture can be reduced, and the suture can conveniently pass through tissues and be tightened.
The specific technical scheme of the invention is as follows:
in a first aspect, the invention provides a high-strength easily-sutured non-absorbable medical suture, which comprises a core layer and a skin layer coated outside the core layer; the core layer is formed by weaving ultrahigh molecular weight polyethylene fibers; the skin layer is a silicone rubber-based skin layer.
The present inventors have focused on ultra-high molecular weight polyethylene (UHMWPE) fiber sutures, although having high strength, having poor surface smoothness and high friction with tissue during suturing, which results in suture threads that are not easily penetrated and tightened through tissue, and particularly, when suturing methods using large lengths of suture thread hidden in tissue and suturing methods requiring multiple penetration and penetration into tissue, such as kessler suturing, bunnell suturing, etc., are used, the rough surface of UHMWPE suture threads presents a significant obstacle to suturing.
In order to solve the technical problems, the suture is designed into a skin layer structure, and the UHMWPE core layer is coated with the silicone rubber-based skin layer, so that the suture can be endowed with a smoother surface, the friction force between the suture and tissues is reduced, and the suture can conveniently penetrate through and be tightened up from the tissues.
In addition, the suture line comprises a coreless suture line and a cored suture line, the coreless suture line is easy to collapse when the wire diameter is thicker, and the strength of the coreless suture line can be improved and the coreless suture line can be prevented from collapsing by covering a silicon rubber base skin layer outside a core layer formed by weaving UHMWPE fibers.
Preferably, the skin layer is a non-imbibing expansion type skin layer; the non-imbibition expansion type skin layer is methyl vinyl silicone rubber.
Methyl vinyl silicone rubber has good chemical stability, physiological inertia and histocompatibility, and is widely used in the field of medicine for artificial organs, medical instruments, face-lifting repair, drug slow release and the like. The invention is applied to the suture line as the cortex layer, and has higher safety.
Preferably, the skin layer is a liquid-absorbing expansion type skin layer; the imbibition expansion type skin layer is a compound of methyl vinyl silicone rubber and polyvinylpyrrolidone.
Polyvinylpyrrolidone (PVP) is an amphiphilic high molecular polymer, has good biocompatibility, low toxicity, solubility and biological inertia, and is widely applied to the fields of medical treatment, medical detection, pharmaceutical preparation and the like. According to the invention, the polyvinyl pyrrolidone is added into the methyl vinyl silicone rubber, so that the water-absorbing expansion function of the skin layer can be endowed, and the suture has better service performance, specifically: because the liquid absorption expansion of the suture line needs a certain time, the suture line is dry and the cortex is not obviously expanded when the suture is sutured, so that the diameter of the suture line is smaller, the friction force between the suture line and the tissue is smaller, and the suture line can conveniently penetrate through the tissue and be tightened; after sewing up, in the cortex of stylolite was infiltrated gradually to tissue liquid, its inside polyvinylpyrrolidone can combine with the hydrone with stronger effort to remain water in the cortex, make the cortex take place the inflation, closely laminate with the tissue, frictional force increases, helps anchoring the stylolite in the tissue, prevents that the department of sewing up from taking place to shift and causing wearing and tearing or influence healing.
In a second aspect, aiming at the scheme of adopting the non-imbibition expansion type skin layer, the invention provides a preparation method of the medical suture, which comprises the following steps: weaving ultrahigh molecular weight polyethylene fibers into a core wire; adding raw methyl vinyl silicone rubber, an initiator, a leveling agent and a defoaming agent into an organic solvent, and preparing a coating solution after fully dissolving; immersing the core layer wire into the cladding liquid, taking out after immersion, penetrating through the prefabricated hole, and curing while circularly blowing air along the axial direction; after the solidification is finished, the medical suture is obtained by cleaning and drying.
According to the invention, the leveling agent and the defoaming agent are added into the skin layer, and the core layer wire is circularly blown while being cured, so that the methyl vinyl silicone rubber is uniformly coated outside the core layer wire, the surface of the skin layer has lower roughness, and the suture wire can conveniently penetrate through and be tightened up from tissues.
Preferably, the immersion time is 1.5 to 2 hours.
Preferably, the usage ratio of the raw rubber of the methyl vinyl silicone rubber and the organic solvent is 1g: 30-40 mL.
Preferably, the initiator comprises one or more of benzoyl peroxide, 2,4-dichlorobenzoyl peroxide and tert-butyl perbenzoate.
Preferably, the mass ratio of the raw rubber of the methyl vinyl silicone rubber to the initiator is 1: 0.02-0.05.
Preferably, the curing temperature is 110-140 ℃ and the curing time is 0.5-1.5 h.
In a third aspect, aiming at the scheme of adopting the imbibition expansion type skin layer, the invention provides a preparation method of the medical suture, which comprises the following steps:
(1) Weaving the core layer: weaving the ultra-high molecular weight polyethylene fiber into a core layer wire;
(2) PVP prepolymerization: adding 1-vinyl-2-pyrrolidone and a photoinitiator into an organic solvent, fully dissolving, and polymerizing for 20-30 min under ultraviolet light to obtain a PVP prepolymer solution;
(3) Core layer pretreatment: immersing the core layer wire into a photosensitizer solution, irradiating for 3-10 min by using ultraviolet light, and taking out to obtain a pretreated core layer wire;
(4) Coating a skin layer: adding raw methyl vinyl silicone rubber, a photoinitiator, a leveling agent and a defoaming agent into an organic solvent, fully dissolving, and mixing with a PVP prepolymer solution to prepare a mixed coating solution; immersing the pretreated core layer wire into the mixed coating liquid, and reacting for 30-40 min under ultraviolet light; after the reaction is finished, taking out the core layer wire, penetrating through the prefabricated hole, and curing for 20-30 min under ultraviolet light while performing circular blowing along the axial direction; after completion of the curing, the resultant was washed and dried to obtain a medical suture.
In the step (2), under the action of ultraviolet light and a photoinitiator, 1-vinyl-2-pyrrolidone is subjected to polymerization reaction to generate a polyvinylpyrrolidone (PVP) prepolymer; in the step (4), under the action of ultraviolet light and an initiator, the molecular chain of the PVP prepolymer is continuously extended, and simultaneously, the side chain vinyl in the raw rubber of the methyl vinyl silicone rubber participates in the polymerization of PVP, so that covalent crosslinking is formed between the PVP and the methyl vinyl silicone rubber, and the two polymer molecular chains are coated outside the core layer wire in a crosslinking network mode. In this way, the bonding strength between PVP and silicon rubber in the cortex can be improved, thereby preventing the cortex from being damaged to influence the service life of the suture.
In the process, the 1-vinyl-2-pyrrolidone is pre-polymerized and then participates in the coating of the raw methyl vinyl silicone rubber on the core wire, rather than directly participating in the coating by adopting a 1-vinyl-2-pyrrolidone monomer, because: if the monomer is directly involved in coating, 1-vinyl-2-pyrrolidone is dispersed and grafted on the silicon rubber, the formed PVP molecular chain is shorter, the crosslinking degree of PVP and the silicon rubber is too large, and the water-absorbing expansion performance of the cortex is adversely affected; by synthesizing the prepolymer, the PVP molecular chain is increased to a certain degree and then forms covalent crosslinking with the silicon rubber, so that the degree of covalent crosslinking between the PVP and the silicon rubber can be reduced, and the cortex has better water-absorbing expansion performance.
In addition, for the suture adopting the imbibition expansion type cortex, when the cortex is imbibed and expanded, the combination between the cortex and the core layer is easy to be damaged, the combination strength is reduced, the cortex is easy to peel off, and the service life of the suture is influenced. Therefore, the core layer wire is pretreated before being coated with the skin layer, and the hydrogen on the surface of the core layer wire is deprived by ultraviolet light and a photosensitizer to form free radicals on the surface of the core layer wire (namely step (2)), so that in the subsequent coating process of the skin layer, the methyl vinyl silicone rubber and the PVP can form covalent connection with the core layer wire, the bonding strength between the skin layer and the core layer is further improved, and the bonding strength between the skin layer and the core layer after imbibition expansion is prevented from being greatly reduced.
And (4) after ultraviolet crosslinking is carried out in the coating liquid, taking out the core wire, carrying out ultraviolet curing, and carrying out circular blowing on the core wire in the curing process, so that the methyl vinyl silicone rubber can be uniformly coated outside the core wire, the surface of the skin layer has lower roughness, and the suture can conveniently penetrate through tissues and can be tightened.
Preferably, in step (2), the photosensitizer is benzophenone; in the photosensitizer solution, the concentration of the photosensitizer is 5-15 mg/mL.
Preferably, in the step (1), the 1-vinyl-2-pyrrolidone, the photoinitiator and the organic solvent are used in a ratio of 1g:0.01 to 0.03g: 15-25 mL.
Preferably, in the step (3), the usage ratio of the raw methyl vinyl silicone rubber, the photoinitiator and the organic solvent is 1g: 0.1-0.5 g: 80-100 mL.
Compared with the prior art, the invention has the following advantages:
(1) The ultra-high molecular weight polyethylene core layer is coated by the silicone rubber base skin layer, so that the suture line can be endowed with a smoother surface, the friction force between the suture line and tissues is reduced, and the suture line can conveniently penetrate through the tissues and can be tightened;
(2) Through adopting the inflation of imbibition cortex, can reduce the suture line when sewing up and the frictional force between the tissue, be convenient for sew up, can also make the line footpath grow thick through cortex imbibition inflation simultaneously sewing up the completion back, and then make the suture line and by the increase of the pressure of sewing up between the tissue, cause the frictional force increase, play the anchoring effect.
Detailed Description
The present invention will be further described with reference to the following examples.
General examples
A high-strength easily-sutured non-absorbable medical suture comprises a core layer and a skin layer coated outside the core layer; the core layer is formed by weaving ultrahigh molecular weight polyethylene fibers; the skin layer is a silicone rubber-based skin layer.
In one embodiment, the medical suture is a non-imbibition expansion type suture, wherein the skin layer is a non-imbibition expansion type skin layer; the non-imbibition expansion type skin layer is methyl vinyl silicone rubber.
The preparation method of the medical suture comprises the following steps: weaving ultrahigh molecular weight polyethylene fibers into a core wire; adding raw methyl vinyl silicone rubber, an initiator, a leveling agent and a defoaming agent into an organic solvent, wherein the initiator comprises one or more of benzoyl peroxide, 2,4-dichlorobenzoyl peroxide and tert-butyl perbenzoate, and the dosage ratio of the raw methyl vinyl silicone rubber, the initiator and the organic solvent is 1g: 0.02-0.05 g: 30-40 mL, and preparing a coating solution after fully dissolving; immersing the core layer wire into the cladding liquid, taking out after 1.5-2 h of immersion, penetrating through the prefabricated hole, and curing for 0.5-1.5 h at 110-140 ℃ while performing circular blowing along the axial direction; and then washed and dried to obtain the medical suture.
In another embodiment, the medical suture is a liquid-imbibing expansion type suture, wherein the skin layer is a liquid-imbibing expansion type skin layer; the imbibition expansion type skin layer is a compound of methyl vinyl silicone rubber and polyvinylpyrrolidone.
The preparation method of the medical suture comprises the following steps:
(1) Weaving the core layer: weaving the ultra-high molecular weight polyethylene fiber into a core layer wire;
(2) Pre-polymerization of PVP: adding 1-vinyl-2-pyrrolidone and a photoinitiator into an organic solvent, wherein the dosage ratio of the 1-vinyl-2-pyrrolidone to the photoinitiator to the organic solvent is 1g:0.01 to 0.03g: 15-25 mL, and polymerizing for 20-30 min under ultraviolet light after fully dissolving to obtain PVP prepolymer solution;
(3) Core layer pretreatment: immersing the core layer wire into 5-15 mg/mL benzophenone solution, irradiating for 3-10 min by using ultraviolet light, and taking out to obtain a pretreated core layer wire;
(4) Coating a skin layer: adding raw methyl vinyl silicone rubber, a photoinitiator, a leveling agent and a defoaming agent into an organic solvent, wherein the dosage ratio of the raw methyl vinyl silicone rubber, the photoinitiator and the organic solvent is 1g: 0.1-0.5 g: 80-100 mL, and after fully dissolved, mixing with PVP prepolymer solution according to the ratio of 38-43: 1 to prepare a mixed coating solution; immersing the pretreated core layer wire into the mixed coating liquid, and reacting for 30-40 min under ultraviolet light; after the reaction is finished, taking out the core layer wire, penetrating through the prefabricated hole, and curing for 20-30 min under ultraviolet light while performing circular blowing along the axial direction; and then washed and dried to obtain the medical suture.
Example 1
A non-absorbable medical suture is prepared by the steps of:
(1) 8 strands of 110dtex ultrahigh molecular weight polyethylene fibers are woven into a core layer wire with the diameter of 0.250 +/-0.02 mm by adopting an 8-spindle weaving machine;
(2) Raw methyl vinyl silicone rubber, benzoyl peroxide, polydimethylsiloxane and an organic silicon defoamer HT-507 are mixed according to the weight ratio of 1g:0.02g:0.013g:0.008g: adding 30mL of the mixture into dimethylbenzene, heating to 40 ℃, stirring and dissolving to prepare a coating solution;
(3) Immersing the core layer wire into the coating liquid, taking out after 1.5h of immersion, penetrating through a round prefabricated hole with the aperture of 0.32mm, and curing for 1.5h at 120 ℃ while circularly blowing air along the axial direction at the flow rate of 5m/s by using industrial nitrogen; then washing with water, drying and sterilizing to obtain the medical suture with the diameter of 0.302 +/-0.02 mm.
Example 2
A non-absorbable medical suture is prepared by the steps of:
(1) Weaving 8 strands of 110dtex ultrahigh molecular weight polyethylene fibers into a core layer wire with the diameter of 0.250 +/-0.02 mm by using an 8-spindle weaving machine;
(2) Raw methyl vinyl silicone rubber, 2,4-dichlorobenzoyl peroxide, polydimethylsiloxane and silicone defoamer HT-507 were mixed according to a ratio of 1g:0.03g:0.015g:0.007g: adding 35mL of the mixture into dimethylbenzene, heating to 40 ℃, stirring and dissolving to prepare a coating solution;
(3) Immersing the core layer wire into the coating liquid, taking out after 105min of immersion, penetrating through a round prefabricated hole with the aperture of 0.32mm, and curing for 0.5h at 110 ℃ while performing circular blowing along the axial direction at the flow rate of 8m/s by using industrial nitrogen; then washing with water, drying and sterilizing to obtain the medical suture with the diameter of about 0.306mm +/-0.01 mm.
Example 3
A non-absorbable medical suture is prepared by the steps of:
(1) Weaving 16 strands of 110dtex ultrahigh molecular weight polyethylene fibers into a core layer wire with the diameter of 0.491 +/-0.02 mm by adopting a 16-spindle weaving machine;
(2) Raw methyl vinyl silicone rubber, tert-butyl perbenzoate, polydimethylsiloxane and an organic silicon defoamer HT-507 were mixed according to a weight ratio of 1g:0.05g:0.01g:0.01g: adding 40mL of the mixture into dimethylbenzene, heating to 40 ℃, stirring and dissolving to prepare a coating solution;
(3) Immersing the core layer line into the cladding liquid, taking out after 2h of immersion, penetrating through a round prefabricated hole with the aperture of 0.60mm, and curing for 1h at 140 ℃ while circularly blowing air along the axial direction at the flow rate of 10m/s by using industrial nitrogen; then washing with water, drying and sterilizing to obtain the medical suture with the diameter of about 0.588mm +/-0.01 mm.
Example 4
A non-absorbable medical suture is prepared by the steps of:
(1) Weaving 8 strands of 110dtex ultrahigh molecular weight polyethylene fibers into a core layer wire with the diameter of 0.250 +/-0.02 mm by using an 8-spindle weaving machine;
(2) Pre-polymerization of PVP: 1-vinyl-2-pyrrolidone and photoinitiator 907 was added as 1g:0.01g: adding 15mL of the solution into dimethylbenzene, stirring and dissolving, and polymerizing for 20min under ultraviolet light to obtain a PVP prepolymer solution;
(3) Core layer pretreatment: immersing the core layer wire into 5mg/mL benzophenone solution (solvent is dimethylbenzene), irradiating for 10min by using ultraviolet light, and taking out to obtain a pretreated core layer wire;
(4) Coating a skin layer: raw methyl vinyl silicone rubber, a photoinitiator 907, polydimethylsiloxane and an organic silicon defoamer HT-507 are mixed according to the weight ratio of 1g:0.1g:0.01g:0.006g: adding 80mL of the solution into dimethylbenzene, heating to 40 ℃, stirring and dissolving, and mixing with PVP prepolymer solution according to the ratio of 38:1 to prepare a mixed coating solution; immersing the pretreated core wire into the mixed coating liquid, reacting for 40min under ultraviolet light, taking out the core wire, penetrating through a round prefabricated hole with the aperture of 0.32mm, and curing for 20min under ultraviolet light while circularly blowing industrial nitrogen along the axial direction at the flow rate of 5 m/s; then washing with ethanol and water in sequence, drying, and sterilizing to obtain the medical suture with the diameter of about 0.309 +/-0.01 mm.
Example 5
A non-absorbable medical suture is prepared by the steps of:
(1) 8 strands of 110dtex ultrahigh molecular weight polyethylene fibers are woven into a core layer wire with the diameter of 0.250 +/-0.02 mm by adopting an 8-spindle weaving machine;
(2) PVP prepolymerization: 1-vinyl-2-pyrrolidone and photoinitiator 907 was added as 1g:0.02g: adding 20mL of the solution into dimethylbenzene, stirring and dissolving, and polymerizing for 25min under ultraviolet light to obtain a PVP prepolymer solution;
(3) Pretreatment of a core layer: immersing the core layer wire into 10mg/mL benzophenone solution (solvent is dimethylbenzene), irradiating for 8min by using ultraviolet light, and taking out to obtain a pretreated core layer wire;
(4) Coating a skin layer: raw methyl vinyl silicone rubber, a photoinitiator 907, polydimethylsiloxane and an organic silicon defoamer HT-507 are mixed according to the weight ratio of 1g:0.3g:0.011g:0.007g: adding 90mL of the solution into dimethylbenzene, heating to 40 ℃, stirring and dissolving, and mixing with a PVP prepolymer solution according to the weight ratio of 40:1 to prepare a mixed coating solution; immersing the pretreated core wire into the mixed coating liquid, reacting for 35min under ultraviolet light, taking out the core wire, penetrating through a round prefabricated hole with the aperture of 0.32mm, and curing for 25min under ultraviolet light while performing circular blowing along the axial direction at the flow rate of 7m/s by using industrial nitrogen; then washing with ethanol and water in sequence, drying, and sterilizing to obtain the medical suture with the diameter of about 0.308 +/-0.01 mm.
Example 6
A non-absorbable medical suture is prepared by the steps of:
(1) Weaving 16 strands of 110dtex ultrahigh molecular weight polyethylene fibers into a core layer wire with the diameter of 0.491 +/-0.02 mm by adopting a 16-spindle weaving machine;
(2) PVP prepolymerization: 1-vinyl-2-pyrrolidone and photoinitiator 907 was added as 1g:0.03g: adding 25mL of the solution into dimethylbenzene, stirring and dissolving, and polymerizing for 30min under ultraviolet light to obtain a PVP prepolymer solution;
(3) Pretreatment of a core layer: immersing the core layer wire into 15mg/mL benzophenone solution (solvent is dimethylbenzene), irradiating for 3min by using ultraviolet light, and taking out to obtain a pretreated core layer wire;
(4) Coating a skin layer: raw methyl vinyl silicone rubber, a photoinitiator 907, polydimethylsiloxane and an organic silicon defoamer HT-507 are mixed according to the weight ratio of 1g:0.5g:0.013g:0.005g: adding 100mL of the solution into dimethylbenzene, heating to 40 ℃, stirring and dissolving, and mixing with a PVP prepolymer solution according to the weight ratio of 43:1 to prepare a mixed coating solution; immersing the pretreated core wire into the mixed coating liquid, reacting for 30min under ultraviolet light, taking out the core wire, penetrating through a round prefabricated hole with the aperture of 0.60mm, and curing for 30min under ultraviolet light while circularly blowing industrial nitrogen along the axial direction at the flow rate of 10 m/s; then washing with ethanol and water in sequence, drying, and sterilizing to obtain the medical suture with the diameter of about 0.582 +/-0.01 mm.
Comparative example 1
A non-absorbable medical suture is prepared by the steps of:
8 strands of 110dtex ultrahigh molecular weight polyethylene fiber are braided into a core layer wire with the diameter of 0.250 +/-0.02 mm by using an 8-spindle braiding machine.
Comparative example 2
A non-absorbable medical suture is prepared by the steps of:
(1) Weaving 8 strands of 110dtex ultrahigh molecular weight polyethylene fibers into a core layer wire with the diameter of 0.250 +/-0.02 mm by using an 8-spindle weaving machine;
(2) Raw methyl vinyl silicone rubber, benzoyl peroxide, polydimethylsiloxane and an organic silicon defoamer HT-507 are mixed according to the weight ratio of 1g:0.02g:0.013g:0.008g: adding 30mL of the mixture into dimethylbenzene, heating to 40 ℃, stirring and dissolving to prepare a coating solution;
(3) Immersing the core layer wire into the cladding liquid, taking out after immersing for 1.5h, penetrating through a round prefabricated hole with the aperture of 0.32mm, and curing for 1.5h at 120 ℃; then washing with water, drying and sterilizing to obtain the medical suture with the diameter of about 0.310 +/-0.03 mm.
Comparative example 3
A non-absorbable medical suture is prepared by the steps of:
(1) 8 strands of 110dtex ultrahigh molecular weight polyethylene fibers are woven into a core layer wire with the diameter of 0.250 +/-0.02 mm by adopting an 8-spindle weaving machine;
(2) Pre-polymerization of PVP: 1-vinyl-2-pyrrolidone and photoinitiator 907 was added as 1g:0.01g: adding 15mL of the solution into dimethylbenzene, stirring and dissolving, and polymerizing for 20min under ultraviolet light to obtain a PVP prepolymer solution;
(3) Core layer pretreatment: immersing the core layer wire into 5mg/mL benzophenone solution (solvent is dimethylbenzene), irradiating for 10min by using ultraviolet light, and taking out to obtain a pretreated core layer wire;
(4) Coating a skin layer: raw methyl vinyl silicone rubber, a photoinitiator 907, polydimethylsiloxane and an organic silicon defoamer HT-507 are mixed according to the weight ratio of 1g:0.1g:0.01g:0.006g: adding 80mL of the solution into dimethylbenzene, heating to 40 ℃, stirring and dissolving, and mixing with a PVP prepolymer solution according to the weight ratio of 38:1 to prepare a mixed coating solution; immersing the pretreated core wire into the mixed coating liquid, reacting for 40min under ultraviolet light, taking out the core wire, penetrating through a round prefabricated hole with the aperture of 0.32mm, and curing for 20min under ultraviolet light; then washing with ethanol and water in sequence, drying, and sterilizing to obtain the medical suture with the diameter of about 0.312 +/-0.03 mm.
Comparative example 4
A non-absorbable medical suture is prepared by the steps of:
(1) Weaving 8 strands of 110dtex ultrahigh molecular weight polyethylene fibers into a core layer wire with the diameter of 0.250 +/-0.02 mm by using an 8-spindle weaving machine;
(2) Pre-polymerization of PVP: 1-vinyl-2-pyrrolidone and photoinitiator 907 was added to the mixture in 1g:0.01g: adding 15mL of the solution into dimethylbenzene, stirring and dissolving, and polymerizing for 20min under ultraviolet light to obtain a PVP prepolymer solution;
(3) Core layer pretreatment: immersing the core layer wire into 5mg/mL benzophenone solution (solvent is dimethylbenzene), irradiating for 10min by using ultraviolet light, and taking out to obtain a pretreated core layer wire;
(4) Coating a skin layer: raw methyl vinyl silicone rubber, a photoinitiator 907, polydimethylsiloxane and an organic silicon defoamer HT-507 are mixed according to the weight ratio of 1g:0.1g:0.01g:0.006g: adding 80mL of the solution into dimethylbenzene, heating to 40 ℃, stirring and dissolving, and mixing with a PVP prepolymer solution according to the weight ratio of 38:1 to prepare a mixed coating solution; immersing the pretreated core wire into the mixed coating liquid, reacting for 40min under ultraviolet light, taking out the core wire, washing with ethanol and water in sequence, drying, and sterilizing to obtain the medical suture with the diameter of about 0.327 +/-0.10 mm.
Comparative example 5
A non-absorbable medical suture is prepared by the steps of:
(1) Weaving 8 strands of 110dtex ultrahigh molecular weight polyethylene fibers into a core layer wire with the diameter of 0.250 +/-0.02 mm by using an 8-spindle weaving machine;
(2) Core layer pretreatment: immersing the core layer wire into 10mg/mL benzophenone solution (xylene as solvent), irradiating for 8min by using ultraviolet light, and taking out to obtain a pretreated core layer wire;
(3) Coating a skin layer: raw methyl vinyl silicone rubber, 1-vinyl-2-pyrrolidone, a photoinitiator 907, polydimethylsiloxane and an organic silicon defoamer HT-507 were mixed according to a ratio of 1g:0.11g:0.3g:0.011g:0.007g: adding 90mL of the mixture into dimethylbenzene, heating to 40 ℃, stirring and dissolving to prepare a mixed coating solution; immersing the pretreated core wire into the mixed coating liquid, reacting for 35min under ultraviolet light, taking out the core wire, penetrating through a round prefabricated hole with the aperture of 0.32mm, and curing for 25min under ultraviolet light while circularly blowing industrial nitrogen along the axial direction at the flow rate of 7 m/s; then washing with ethanol and water in sequence, drying, and sterilizing to obtain the medical suture with the diameter of about 0.304 +/-0.01 mm.
Comparative example 6
A non-absorbable medical suture is prepared by the steps of:
(1) 8 strands of 110dtex ultrahigh molecular weight polyethylene fibers are woven into a core layer wire with the diameter of 0.250 +/-0.02 mm by adopting an 8-spindle weaving machine;
(2) Polymerization of PVP: 1-vinyl-2-pyrrolidone and photoinitiator 907 was added to the mixture in 1g:0.02g: adding 20mL of the mixture into dimethylbenzene, stirring and dissolving the mixture, polymerizing the mixture for 85min under ultraviolet light, and separating and purifying the mixture to obtain polyvinylpyrrolidone;
(3) Core layer pretreatment: immersing the core layer wire into 10mg/mL benzophenone solution (solvent is dimethylbenzene), irradiating for 8min by using ultraviolet light, and taking out to obtain a pretreated core layer wire;
(4) Coating a skin layer: raw methyl vinyl silicone rubber, polyvinylpyrrolidone, 2,4-dichlorobenzoyl peroxide, polydimethylsiloxane and silicone defoamer HT-507 were mixed according to the weight ratio of 1g:0.11g:0.03g:0.011g:0.007g: adding 35mL of the mixture into dimethylbenzene, heating to 40 ℃, stirring and dissolving to prepare a mixed coating solution; immersing the pretreated core wire in the mixed coating liquid, taking out after 1.5h of immersion, penetrating through a round prefabricated hole with the aperture of 0.32mm, carrying out circular blowing along the axial direction by using industrial nitrogen at the flow rate of 7m/s, curing at the temperature of 110 ℃ for 0.5h, washing with water, drying, and sterilizing to obtain the medical suture with the diameter of about 0.306 +/-0.01 mm.
Comparative example 7
A non-absorbable medical suture is prepared by the steps of:
(1) Weaving 8 strands of 110dtex ultrahigh molecular weight polyethylene fibers into a core layer wire with the diameter of 0.250 +/-0.02 mm by using an 8-spindle weaving machine;
(2) Pre-polymerization of PVP: 1-vinyl-2-pyrrolidone and photoinitiator 907 was added as 1g:0.02g: adding 20mL of the solution into dimethylbenzene, stirring and dissolving, and polymerizing for 25min under ultraviolet light to obtain a PVP prepolymer solution;
(3) Coating a skin layer: raw methyl vinyl silicone rubber, a photoinitiator 907, polydimethylsiloxane and an organic silicon defoamer HT-507 are mixed according to the weight ratio of 1g:0.3g:0.011g:0.007g: adding 90mL of the solution into dimethylbenzene, heating to 40 ℃, stirring and dissolving, and mixing with a PVP prepolymer solution according to the weight ratio of 40:1 to prepare a mixed coating solution; immersing the core layer wire into the mixed coating liquid, reacting for 35min under ultraviolet light, taking out the core layer wire, penetrating through a round prefabricated hole with the aperture of 0.32mm, and curing for 25min under ultraviolet light while circularly blowing air along the axial direction at the flow rate of 7m/s by using industrial nitrogen; then washing with ethanol and water in sequence, drying, and sterilizing to obtain the medical suture with the diameter of about 0.309 +/-0.01 mm.
Test example 1: coefficient of static friction
The medical sutures obtained in examples 1 to 6 and comparative examples 1 to 4 were subjected to a surface static friction coefficient test, and the results are shown in Table 1.
TABLE 1
As can be seen from table 1, examples 1 to 6, using the method of the present invention, after the surface of the UHMWPE core layer was coated with the silicone rubber-based skin layer, the obtained suture thread had a significantly lower surface coefficient of static friction than the UHMWPE suture thread with an uncoated skin layer (comparative example 1).
Comparative examples 2 and 3 in the process of coating the skin layer, circular blowing was not performed at the time of curing, and the rest of the process was the same as examples 1 and 4, respectively. As can be seen from table 1, the coefficient of static friction of the suture surfaces of examples 1 and 4 was significantly reduced compared to comparative examples 2 and 3, indicating that by performing the ring blowing while curing, the methylvinylsilicone rubber was promoted to be uniformly coated outside the core layer, and the smoothness of the skin layer surface was improved.
Comparative example 4 the same procedure as in example 4 was repeated except that the core wire was not taken out and then uv-cured after uv-crosslinking was performed in the coating solution during the coating of the skin layer. As can be seen from table 1, compared with comparative example 4, the coefficient of static friction of the suture surface of example 4 is significantly reduced, which indicates that for the imbibition expansion type suture, in the process of coating the skin layer, after ultraviolet crosslinking is performed in the coating solution, the core layer wire is taken out, and then ultraviolet curing is performed, which is beneficial to uniformly coating the methyl vinyl silicone rubber outside the core layer wire, and improving the smoothness of the surface of the skin layer.
Test example 2: liquid absorption and expansion properties
The medical sutures obtained in examples 4 to 6 and comparative examples 5 to 7 were soaked in water for 48 hours, and then the diameters thereof were measured, and the water swelling ratios were calculated according to the following formulas: water absorption swelling ratio = (diameter after water absorption-diameter before water absorption)/diameter before absorption × 100%. The results are shown in Table 2.
TABLE 2
|
Water swelling rate/%)
|
Example 4
|
5.36
|
Example 5
|
5.52
|
Example 6
|
5.60
|
Comparative example 5
|
2.17
|
Comparative example 6
|
5.64
|
Comparative example 7
|
5.48 |
As can be seen from table 2, the medical suture threads can be endowed with the water swelling function after the UHMWPE core layer is coated with the methylvinylsiloxane rubber/polyvinylpyrrolidone composite layer by the methods of examples 4 to 6.
Comparative example 5 the PVP prepolymerization was not carried out, but 1-vinyl-2-pyrrolidone monomer was directly involved in the coating, and the rest of the procedure was the same as in example 5. As can be seen from Table 2, compared with example 5, the suture of comparative example 5 has a significantly reduced water swelling rate, which indicates that the suture has a poor water swelling function when the 1-vinyl-2-pyrrolidone monomer directly participates in the coating, presumably because the formed PVP has a relatively short molecular chain and the crosslinking degree of PVP and silicone rubber is too large due to the dispersion and grafting of the 1-vinyl-2-pyrrolidone on the silicone rubber; in the embodiment 5, by synthesizing the prepolymer, the PVP molecular chain is increased to a certain extent and then forms covalent crosslinking with the silicone rubber, so that the degree of covalent crosslinking between the PVP and the silicone rubber can be reduced, and the skin layer is ensured to have better water-swelling property.
Test example 3: bond strength of skin layer
The medical sutures prepared in examples 4 to 6 and comparative examples 5 to 7 were soaked in water for 48 hours and then dried, and then rubbed 30 times at a rate of 150r/min using a fiber cohesion tester, and after washing and drying, the weight loss rate of the medical sutures before and after rubbing was measured, and the results are shown in table 3.
TABLE 3
|
Weight loss rate/%)
|
Example 4
|
0.72
|
Example 5
|
0.58
|
Example 6
|
0.54
|
Comparative example 5
|
0.52
|
Comparative example 6
|
2.77
|
Comparative example 7
|
2.96 |
In comparative example 6, the skin layer was not coated by ultraviolet irradiation, but a method of dipping first and then curing was used. As can be seen from table 3, the suture of comparative example 6 had significantly reduced wear resistance compared to example 5, presumably due to the inability of the dip-then-cure method to form covalent crosslinks between the PVP and silicone rubber in the skin layer; in the embodiment 5, the PVP prepolymer and the methyl vinyl silicone rubber are mixed, the sandwich line is coated under the action of ultraviolet light and an initiator, and side chain vinyl in the silicone rubber participates in the polymerization of PVP, so that covalent crosslinking is formed between the PVP and the methyl vinyl silicone rubber, and the strength of the skin layer of the suture line is improved.
Comparative example 7 the core line was not pretreated with a photosensitizer and the rest of the procedure was the same as example 5. As can be seen from table 3, the suture of comparative example 7 has significantly reduced wear resistance compared to example 5, which is presumed to be because in example 5, under the action of uv light and photosensitizer, free radicals can be formed on the surface of the core layer, so that during the subsequent covering of the skin layer, the methylvinylsilicone rubber and PVP can form covalent bonds with the core layer, thereby improving the bonding strength between the skin layer and the core layer, and preventing the bonding strength between the skin layer and the core layer from being greatly reduced after imbibing and swelling.
The raw materials and equipment used in the invention are common raw materials and equipment in the field if not specified; the methods used in the present invention are conventional in the art unless otherwise specified.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, alterations and equivalents of the above embodiments according to the technical spirit of the present invention are still within the protection scope of the technical solution of the present invention.