CN109880152B - Preparation method of oriented communicated porous biomedical stent, stent prepared by preparation method and application of stent in preparation of medical products - Google Patents
Preparation method of oriented communicated porous biomedical stent, stent prepared by preparation method and application of stent in preparation of medical products Download PDFInfo
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Abstract
The invention discloses a preparation method of a polycaprolactone oriented communicating porous biomedical stent, which comprises the following steps: (1) melting and blending polycaprolactone and polyethylene oxide to obtain a co-continuous blend, and pressing and molding the co-continuous blend to obtain a polycaprolactone/polyethylene oxide co-continuous base material; (2) extracting the polycaprolactone/polyethylene oxide co-continuous base material obtained in the step (1) by using water to remove a water-soluble polyethylene oxide phase to obtain a polycaprolactone porous scaffold; (3) and (3) solid-phase stretching the polycaprolactone porous scaffold obtained in the step (2) to enable the pore form to generate orientation deformation along the stretching direction, so as to obtain the polycaprolactone orientation communication porous biomedical scaffold. The polycaprolactone oriented connected porous biomedical scaffold prepared by the method has an obvious high-connectivity and anisotropic porous structure. The invention also discloses a polycaprolactone oriented connected porous biomedical stent and application of the stent in preparation of medical products.
Description
Technical Field
The invention belongs to the field of biomedical scaffolds for tissue engineering, and particularly relates to a preparation method of an oriented communicated porous biomedical scaffold, a scaffold prepared by the method and application of the scaffold in preparation of medical products.
Background
With the aging of the population and the diversification of the exercise patterns, tissue damage has become one of the most common diseases endangering the health and normal life of human beings, and the tissue engineering means are mainly adopted for treatment nowadays. Tissue engineering research is one of important components in modern biomedical engineering technology, and the adoption of a proper biological scaffold has important significance for regeneration and repair, recombination and regeneration of organs and tissues (Czernuszka J T, et al. European cells & materials 2003,5(5), 29; O' Brien F J, et al. materials Today 2011,14(3), 88). It is widely believed that the ideal scaffold needs to provide a suitable environment for cell growth, not only plays a basic supporting role, but also provides a channel for the absorption of nutrients and the discharge of metabolic wastes, and simultaneously, endows the scaffold with degradability so that the scaffold is gradually absorbed and degraded by the organism in the process of promoting the formation of new tissues. The polymer degradable three-dimensional porous scaffold is considered to be an ideal scaffold by virtue of the advantages of high specific surface area, good pore morphology and easiness in processing, and can greatly promote the adhesion, proliferation and differentiation of cells. It is absorbable and avoids secondary surgery inflicting pain on patients (Lv W, et al biomaterials 2011,32(29), 6900; basemeyer M, et al small 2012,8(3), 336).
The existing method for producing and preparing the polymer porous scaffold mainly comprises the following steps: fiber Bonding (Fiber Bonding), Solvent Casting/particle Leaching (Solvent Casting/Particulate Leaching), Freeze Drying (Freeze Drying Method), Gas Foaming (Gas Foaming Method), thermal Induced Phase Separation (thermal Induced Phase Separation Technique), Electrospinning (Electrospinning Technique), and Rapid Prototyping (Rapid Prototyping Technique) among others (Ma PX, et al. materials Today 2004,7(5), 30; Clyne AM, et al. journal of Heat Transfer, 133(3), 034001). However, the stents produced by the above processing methods are mostly of an isotropic pore structure, and although the stents can regenerate and repair damaged tissues, they often require a long time (Liu CS, et al. Most tissues of the human body (e.g., bone, tendon, nerve, blood vessel, etc.) are anisotropic structures. In the face of regeneration and repair of these tissues, it is important to construct scaffolds with oriented structures that can induce cell oriented growth to finally form anisotropic new tissues, thereby obtaining faster and better tissue regeneration effects (k.y.suh, et al.adv.drug delivery.rev.2013, 65, 536; e.s.thian, et al.sci.adv.2018,4,4537).
Currently, the ice template method has been used to prepare porous scaffolds having a three-dimensionally oriented arrangement of microtubule structures. The bracket is prepared by the steps of enabling ice crystals to grow in an oriented mode through an oriented temperature gradient field, and removing a solvent phase through freeze drying. However, the micro-tubular pores of the porous scaffold prepared by the method are only connected through the micropores, so that the connectivity is poor and the pore structure is incomplete, so that the mechanical property is poor (<1MPa), and meanwhile, the biocompatibility of the scaffold itself is influenced by introducing an organic solvent in the preparation process (Yang DZ, et al materials Letters 2018,233, 78). Therefore, how to prepare the highly-communicated three-dimensional oriented porous scaffold is a problem to be solved in the field of tissue engineering scaffolds at present.
Disclosure of Invention
The invention aims to provide a preparation method of a polycaprolactone orientation communication porous biomedical scaffold, the prepared polycaprolactone orientation communication porous biomedical scaffold presents an obvious high communication and anisotropic porous structure, and the polycaprolactone orientation communication porous biomedical scaffold can be used for regeneration and repair of anisotropic tissues (such as bones, tendons, nerves, blood vessels and the like) in preparation of medical products.
The technical scheme of the invention for realizing the purpose is as follows:
a preparation method of a polycaprolactone oriented communicated porous biomedical stent comprises the following steps:
(1) preparation of polycaprolactone/polyethylene oxide co-continuous base material: melting and blending polycaprolactone and polyethylene oxide to obtain a co-continuous blend, and pressing and molding the co-continuous blend to obtain a polycaprolactone/polyethylene oxide co-continuous base material;
(2) preparing a polycaprolactone porous scaffold: extracting the polycaprolactone/polyethylene oxide co-continuous base material obtained in the step (1) by using water to remove a water-soluble polyethylene oxide phase to obtain a polycaprolactone porous scaffold;
(3) preparing a polycaprolactone oriented intercommunicating pore scaffold: and (3) solid-phase stretching the polycaprolactone porous scaffold obtained in the step (2) to enable the pore form to generate orientation deformation along the stretching direction, so as to obtain the polycaprolactone orientation communication porous biomedical scaffold.
In the step (1), an internal mixer is adopted to melt and mix polycaprolactone and polyethylene oxide, so that the blend of polycaprolactone and polyethylene oxide forms a co-continuous phase.
In the step (1), the mass ratio of polycaprolactone to polyethylene oxide in the co-continuous blend is 4: 6-6: 4.
In the step (1), the polycaprolactone and the polyethylene oxide are vacuum-dried before melt blending.
In the step (1), the pressing and forming temperature is 70-150 ℃.
In the step (2), the water is deionized water or distilled water.
In the step (3), the solid phase stretching temperature is 30-60 ℃, and the strain of the solid phase stretching is 75-400%.
The invention also aims to provide a polycaprolactone oriented connected porous biomedical stent which is prepared by adopting the preparation method and has an obvious anisotropic porous structure.
Still another object of the present invention is to provide the use of the polycaprolactone oriented interconnected porous biomedical scaffold prepared by the above preparation method in the preparation of medical products for regeneration and repair of anisotropic tissues.
The invention has the beneficial effects that:
compared with the prior art of preparing anisotropic porous scaffolds, such as an ice template method, the preparation method of the polycaprolactone oriented communicated porous biomedical scaffold provided by the invention realizes the high orientation of the pore structure on the premise of ensuring high communication rate.
(1) The polycaprolactone oriented communicating porous biomedical scaffold is prepared by combining co-continuous phase construction, water (deionized water, distilled water and the like) extraction and solid-phase stretching, has an obvious anisotropic porous structure, and can be used for regeneration and repair of anisotropic tissues (such as bones, tendons, nerves, blood vessels and the like);
(2) the polycaprolactone oriented communicating porous biomedical scaffold prepared by the invention has good connectivity, and is beneficial to uniform inoculation and distribution of cells;
(3) the preparation method of the invention does not use organic solvent, does not influence the biocompatibility of the stent, and has simple process, environmental protection and easy industrial production.
The invention has simple preparation process and good application prospect.
Drawings
FIG. 1 is a scanning electron microscope photograph of comparative example 2.
FIGS. 2-5 are scanning electron micrographs, in sequence, of sections quenched in the direction of stretching, corresponding to examples 14-17.
FIG. 6 is a graph showing the statistics of pore size for examples 14-17 and comparative example 2.
FIG. 7 is a graph showing the results of the connectivity test for examples 14-17 and comparative example 2.
FIG. 8 is a graph showing the results of the mechanical properties (compression) tests of examples 14 to 17 and comparative example 2.
Detailed Description
The following examples are given to illustrate the present invention and it is necessary to point out here that the following examples are given only for the purpose of further illustration of the invention and are not to be construed as limiting the scope of the invention.
Examples 1 to 33
Preparing a polycaprolactone oriented communicating porous biomedical scaffold according to the following steps:
(1) preparation of polycaprolactone/polyethylene oxide co-continuous base material: weighing polycaprolactone and polyethylene oxide raw materials, drying the polycaprolactone and polyethylene oxide raw materials in vacuum, carrying out melt mixing by using an internal mixer to obtain a co-continuous blend, and carrying out compression molding on the co-continuous blend to obtain a polycaprolactone/polyethylene oxide co-continuous base material; the mass ratio and the press forming temperature of polycaprolactone to polyethylene oxide in the co-continuous blend are shown in table 1;
(2) preparing a polycaprolactone porous scaffold: extracting the polycaprolactone/polyethylene oxide co-continuous base material obtained in the step (1) with water (deionized water, distilled water and the like) to remove a water-soluble polyethylene oxide phase to obtain a polycaprolactone porous scaffold;
(3) preparing a polycaprolactone oriented intercommunicating pore scaffold: solid-phase stretching the polycaprolactone porous scaffold obtained in the step (2) to enable the pore form to generate orientation deformation along the stretching direction, so as to obtain a polycaprolactone orientation communication porous biomedical scaffold; the solid phase stretching temperature and the solid phase stretching strain are shown in Table 1.
Comparative examples 1 to 3
The isotropic polycaprolactone porous scaffold is prepared by the following steps:
(1) preparation of polycaprolactone/polyethylene oxide co-continuous base material: weighing polycaprolactone and polyethylene oxide raw materials, drying the polycaprolactone and polyethylene oxide raw materials in vacuum, carrying out melt mixing by using an internal mixer to obtain a co-continuous blend, and carrying out compression molding on the co-continuous blend to obtain a polycaprolactone/polyethylene oxide co-continuous base material; the mass ratio and the press forming temperature of polycaprolactone to polyethylene oxide in the co-continuous blend are shown in table 1;
(2) preparing a polycaprolactone porous scaffold: and (2) extracting the polycaprolactone/polyethylene oxide co-continuous base material obtained in the step (1) with water (deionized water, distilled water and the like) to remove a water-soluble polyethylene oxide phase, so as to obtain the polycaprolactone porous scaffold with the isotropic pore structure.
TABLE 1 formulations and preparation Process conditions for examples 1-33 and comparative examples 1-3
TABLE 2 average pore size, aspect ratio, connectivity and mechanical Properties of examples 1-33 and comparative examples 1-3
The invention also describes a polycaprolactone oriented connected porous biomedical stent which is prepared by adopting the preparation method and has an obvious anisotropic porous structure.
The invention further describes the application of the polycaprolactone oriented connected porous biomedical scaffold prepared by the preparation method in the preparation of medical products for regeneration and repair of anisotropic tissues.
As can be seen from the data in tables 1 and 2:
(1) when the compression molding temperature and the solid-phase tensile strain are fixed, the pore size of the polycaprolactone oriented and communicated porous biomedical scaffold is gradually reduced and the mechanical property is gradually increased along with the increase of the mass percentage of the polycaprolactone in the co-continuous blend (for example, examples 1, 10 and 22; examples 4, 14 and 26; examples 7, 18 and 30);
(2) when the mass percentage and the solid phase tensile strain of the polycaprolactone in the co-continuous blend are fixed, the pore size of the polycaprolactone oriented and communicated porous biomedical scaffold is gradually increased and the mechanical property is gradually reduced along with the increase of the compression molding temperature (for example, examples 1, 4 and 7; examples 10, 14 and 18; examples 22, 26 and 30);
(3) when the mass percentage and the press forming temperature of the polycaprolactone in the co-continuous blend are fixed, the pore size of the polycaprolactone oriented and connected porous biomedical scaffold is gradually increased and the mechanical property is gradually increased along with the increase of solid-phase tensile strain (for example, comparative example 1, examples 1, 2 and 3; comparative example 2, examples 14, 15, 16 and 17; comparative example 3, examples 30, 31, 32 and 33 and the like).
Examples 14 to 17 and comparative example 2 are further described below with reference to the drawings. As for the information on the average pore size, aspect ratio, communication rate, mechanical properties, etc. of the other examples and comparative examples except for examples 14 to 17 and comparative example 2, which are expressed in table 2 and correspond to the same information as that expressed in fig. 1 to 8, the figures related to the other examples and comparative examples except for examples 14 to 17 and comparative example 2 are omitted herein for the sake of convenience.
In order to characterize the pore morphology of the polycaprolactone oriented interconnected porous biomedical scaffold, the quench sections of examples 14-17 and comparative example 2 in the stretching direction were observed using a field emission scanning electron microscope (FE-SEM). The comparative example 2 shown in fig. 1 is a conventional polycaprolactone porous scaffold, which has an isotropic pore structure, relatively uniform pore size, and interconnected pores. Examples 14 to 17 shown in fig. 2 to 5 are polycaprolactone oriented interconnected porous biomedical scaffolds with different tensile strains prepared by the preparation method of the present invention, wherein the high connectivity of the polycaprolactone oriented interconnected porous biomedical scaffold is still maintained, and the pore morphology is deformed to different degrees along the stretching direction, such that an obvious anisotropic porous structure is presented.
The pore sizes of examples 14 to 17 and comparative example 2 were counted using image analysis software, and the results are shown in FIG. 6. The comparative example 2 shows an isotropic polycaprolactone porous scaffold, the average pore size is about 12 μm, while the pore size of the polycaprolactone oriented communicating porous biomedical scaffold prepared by the preparation method disclosed by the embodiments 14-17 increases along with the increase of tensile strain along the major axis and the minor axis, the major diameter can be up to 107 μm, the minor diameter can be up to 22 μm, and the pore size of the polycaprolactone oriented communicating porous biomedical scaffold is larger than that of the polycaprolactone isotropic porous scaffold; and as the stretching ratio is increased, the length-diameter ratio of the oriented pores is also increased continuously, and the oriented morphology is more obvious.
In order to evaluate the connectivity of the polycaprolactone oriented interconnected porous biomedical scaffold prepared by the preparation method of the present invention, the connectivity of examples 14-17 and comparative example 2 was calculated by using the following formula 1, and the results are shown in fig. 7, in which the connectivity of all scaffolds is close to 100%.
Equation 1:
in formula 1, mInitial PEODenotes the mass of polyethylene oxide in the initial state, mFinal PEORepresenting the mass of polyethylene oxide remaining after extraction by water.
In order to evaluate the mechanical properties of the polycaprolactone oriented interconnected porous biomedical scaffold prepared by the preparation method of the invention, the mechanical (compression) properties of examples 14-17 perpendicular to the stretching direction and comparative example 2 were tested by an electronic universal tensile tester, and the results are shown in fig. 8. The compression strength of the polycaprolactone oriented communicating porous biomedical scaffold shown in the examples 14 to 17 can be up to 17MPa, and the compression modulus can be up to 19MPa, while the compression strength of the polycaprolactone isotropic porous scaffold shown in the comparative example 2 is only 10MPa, and the compression modulus is only 12MPa, and the comparison shows that the compression performance of the polycaprolactone oriented communicating porous biomedical scaffold is superior to that of the polycaprolactone isotropic porous scaffold.
The invention utilizes the principle that the water-soluble pore-foaming agent polyethylene oxide and polycaprolactone are mutually incompatible, and a polycaprolactone/polyethylene oxide co-continuous blend is obtained by melt blending; extracting water-soluble polyethylene oxide phase with water (deionized water, distilled water, etc.) to obtain mutually communicated polycaprolactone porous scaffold; and further performing solid-phase stretching to induce the communicating pores to perform orientation deformation along the stretching direction to obtain the polycaprolactone oriented communicated porous biomedical scaffold, so as to form an obvious anisotropic structure. On the basis of keeping the high connectivity of the porous scaffold, the preparation of the three-dimensional polycaprolactone oriented and communicated porous biomedical scaffold is realized; the whole preparation process does not use any organic solvent, and the process is easy to master, green and environment-friendly and is convenient for large-scale production; meanwhile, the prepared polycaprolactone oriented communicating porous biomedical scaffold can be applied to promoting cell migration and accelerating regeneration and repair of anisotropic tissue (such as bones, tendons, nerves, blood vessels and the like) injuries.
It should be noted that the various features described in the foregoing embodiments may be combined in any suitable manner without departing from the scope of the invention. The invention is not described in any further detail in order to avoid unnecessary repetition.
The present invention has been described in detail with reference to the embodiments, which are illustrative rather than restrictive, and variations and modifications thereof are possible within the scope of the present invention without departing from the general inventive concept.
Claims (5)
1. A preparation method of a polycaprolactone oriented communicated porous biomedical scaffold is characterized by comprising the following steps:
(1) preparation of polycaprolactone/polyethylene oxide co-continuous base material: melting and blending polycaprolactone and polyethylene oxide to obtain a co-continuous blend, and pressing and molding the co-continuous blend to obtain a polycaprolactone/polyethylene oxide co-continuous base material;
(2) preparing a polycaprolactone porous scaffold: extracting the polycaprolactone/polyethylene oxide co-continuous base material obtained in the step (1) by using water to remove a water-soluble polyethylene oxide phase to obtain a polycaprolactone porous scaffold;
(3) preparing a polycaprolactone oriented intercommunicating pore scaffold: solid-phase stretching the polycaprolactone porous scaffold obtained in the step (2) to enable the pore form to generate orientation deformation along the stretching direction, so as to obtain the polycaprolactone orientation communication porous biomedical scaffold;
in the step (1), the mass ratio of polycaprolactone to polyethylene oxide in the co-continuous blend is 4: 6-6: 4;
in the step (3), the solid phase stretching temperature is 30-60 ℃, and the strain of the solid phase stretching is 75-400%.
2. The method of claim 1, wherein in the step (1), the polycaprolactone and the polyethylene oxide are melt-mixed by an internal mixer, and the blend of the polycaprolactone and the polyethylene oxide forms a co-continuous phase.
3. The production method according to claim 1, wherein in the step (1), the polycaprolactone and the polyethylene oxide are vacuum-dried before melt-blending.
4. The method according to claim 1, wherein in the step (1), the press forming temperature is 70 to 150 ℃.
5. The method according to claim 1, wherein in the step (2), the water is deionized water or distilled water.
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| Manipulating co-continuous polymer blends to create PCL scaffolds with fully interconnected and anisotropic pore architecture;Vincenzo Guarino1;《J Appl Biomater Biomech》;20110430;34-39 * |
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