CN111833431A - Bionic bone scaffold modeling method based on ellipsoid intersection model - Google Patents
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- 210000000988 bone and bone Anatomy 0.000 title claims abstract description 29
- 238000000034 method Methods 0.000 title claims abstract description 26
- 239000011664 nicotinic acid Substances 0.000 title claims abstract description 11
- 238000004088 simulation Methods 0.000 claims abstract description 3
- 238000004422 calculation algorithm Methods 0.000 claims description 6
- 230000003592 biomimetic effect Effects 0.000 claims description 5
- 238000010603 microCT Methods 0.000 claims description 5
- 210000002303 tibia Anatomy 0.000 claims description 5
- 230000001788 irregular Effects 0.000 claims description 4
- 238000012545 processing Methods 0.000 claims description 4
- 230000000694 effects Effects 0.000 claims description 2
- 239000011148 porous material Substances 0.000 description 6
- 210000004027 cell Anatomy 0.000 description 5
- 238000010276 construction Methods 0.000 description 5
- 210000001519 tissue Anatomy 0.000 description 4
- 230000001413 cellular effect Effects 0.000 description 3
- 238000004891 communication Methods 0.000 description 3
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 239000002407 tissue scaffold Substances 0.000 description 2
- 238000010146 3D printing Methods 0.000 description 1
- 210000002449 bone cell Anatomy 0.000 description 1
- 230000024245 cell differentiation Effects 0.000 description 1
- 230000010261 cell growth Effects 0.000 description 1
- 230000004663 cell proliferation Effects 0.000 description 1
- 238000004590 computer program Methods 0.000 description 1
- 238000005094 computer simulation Methods 0.000 description 1
- 230000004069 differentiation Effects 0.000 description 1
- 230000002900 effect on cell Effects 0.000 description 1
- 238000001523 electrospinning Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000005187 foaming Methods 0.000 description 1
- 238000004108 freeze drying Methods 0.000 description 1
- 230000000877 morphologic effect Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000035755 proliferation Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
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Abstract
The modeling method of the bionic bone scaffold based on the ellipsoid intersection model mainly comprises the steps of simulating the distribution of microporous structures in human bones and providing the modeling method based on the ellipsoid intersection. The simulation of the microporous structure in the human bone is to utilize an elliptical least square fitting function for fitting a micro CT image of the natural bone and analyze parameters of the fitting ellipse to obtain a distribution rule of a long radius and a short radius. The long radius and the short radius of the ellipsoid can determine a shape function of the ellipsoid, the direction and the central point coordinate of the ellipsoid can determine a position function of the ellipsoid, the shape function and the position function are combined and parameterized, a core ellipsoid function can be formed, and the central point of the ellipsoid is distributed into a stable cubic structure, so that the stability of the whole structure is kept.
Description
Technical Field
The invention relates to a modeling method of a bionic bone scaffold in the field of bone tissue engineering, in particular to a modeling method based on an ellipsoid intersection model.
Technical Field
In bone tissue reconstruction engineering, an ideal bone tissue scaffold needs to have a guiding effect on cells, so that the cells form corresponding bone tissues with mechanical, biological and chemical functions. These biomimetic tissue scaffolds provide a growing environment for cell attachment, proliferation and differentiation. At the same time, cellular behavior is influenced by the molecular composition of these contact sites and their spatial distribution. Therefore, the construction of the irregular bionic porous scaffold with the complex microstructure of the human tissue has important significance for the research of tissue engineering.
The existing various tissue microstructure construction methods have successfully constructed scaffolds with high porosity, including gas foaming method, freeze-drying method, electrospinning method, etc., but these methods have difficulty in precisely controlling pore size, porosity, pore shape and pore connectivity. In recent years, with the development of medical 3D printing technology, a CAD-based manual construction method and a triple-period minimum surface (TPMS) -based computational modeling method are successfully applied to the preparation of porous scaffolds. However, modeling time-consuming and micro-via geometry are the main drawbacks of CAD construction methods alone. The porous structure based on TPMS can conveniently and quickly control the internal porous structure through a computer program, but the structures are regular, and certain limitations exist in the aspect of simulating the anisotropic porous structure of human bones. To overcome the above problems, it is a feasible and effective method to construct an anisotropic porous structure using specific parameters of the microstructure of human bone tissue.
Disclosure of Invention
The invention provides a modeling algorithm of a bionic bone scaffold based on ellipsoid intersection. The method mainly comprises the steps of simulating the distribution of the microporous structure in the human bone and providing the method based on the ellipsoid intersection modeling. The internal structure of the scaffold has a significant influence on the cellular microenvironment. The cellular microenvironment comprises the three-dimensional structure of the bone scaffold, biochemical complexes and biological stimuli, which play a key role in directing bone cell proliferation and differentiation. Therefore, modeling the structure of human bone can help to construct a porous scaffold with geometric compatibility and biocompatibility.
In order to analyze the distribution characteristics of human bones, an image of the cross section of the tibia is obtained through Micro-CT scanning, image binarization processing and denoising processing, and as shown in FIG. 1, the shape of a porous microstructure in the tibia is irregular and has high similarity of an ellipse in morphology. Therefore, the simulation was performed by capturing a CT image of FIG. 1, which shows the pore characteristics well, and using an elliptical least squares method.
An elliptic curve is represented by a quadratic polynomial as:
f(x,y)＝Ax2+Bxy+Cy2+Dx+Ey+F, (1)
to construct an ellipse using geometric features, the geometric parameters are the center points (x)0，y0) Minor and major axes { a, b }, and orientation θ are defined as:
to calculate the parameters a, B, C, D, E, F, an objective function is defined:
after constraint a + C is added to 1:
the function is biased using the extremum theorem by solving the minimum of equation (7):
by solving the system of equation (8) and the constraint condition a + C equal to 1, the coefficient a of the elliptic curve is obtained,b, C, D, E and F. Substituting the values of the coefficients A, B, C, D, E, F into equations (2), (3), (4), (5), the geometric parameter x of the ellipse0、y0A, b, and θ can also be obtained. So that the geometric parameter x can be utilized0、y0A, b, θ create a fitted ellipse. For a communication hole, by selecting edge points of a part, an intersection fitting ellipse of the communication hole can be created. The ellipse fitted by the ellipse least square method can better approximate the human bone structure. Compared with the existing porous scaffold construction method, the bionic scaffold constructed by taking ellipsoids as unit bodies has more advantages in form.
Similarly, the Micro-CT image of fig. 1, which shows the pore characteristics well, was captured and fitted using the elliptical least squares method. The Micro-CT images were fitted using 350 ellipses. All fitted ellipses have respective different major radii, minor radii and directions. In order to study the distribution law of the ellipse radius, the paper analyzes the geometric parameters of the fitting ellipse to obtain distribution maps of the short radius and the long radius, which are concentrated around 0.24mm and 0.48mm, respectively.
Drawings
FIG. 1 is a proximal tibia Micro-CT scan image;
FIG. 2 is a schematic of the morphological structure of a non-homogeneous pore;
Detailed Description
And generating the bionic scaffold based on a fitting and synthesizing algorithm of the ellipsoid intersection model.
The adopted center distribution structure is a cube, the side length of each edge of the cube is the length l of the center distance of the ellipsoid, and each point has 6 equidistant adjacent central points, so the cube distribution structure has good uniformity. To facilitate storing coordinate information of points, we distribute structure point coordinates A to cubeijkThe coding is carried out:
Aijk＝(il,jl,kl) (6)
wherein i, j, k is 0,1,2,
when the dimensions of the created model are known in length, width and height (L, W, H), we can store the coordinates of the center point of the different distribution structures. The coordinate of the center point of the cube distribution structure is stored and distributed through:
P[r]＝Cijk,r＝i+jnL+knLnW≤nLnWnH＝n, (7)
where P stores a set of point coordinates of the cube distribution structure, nL,nW,nHThe number of the center points with the maximum allowable center distance l in the length, width and height directions for the model with different distribution structures is defined as:
encoding and storing information of the ellipsoid central points will help simplify the process of creating a large number of ellipsoids and improve the ellipsoid constructing speed of the ellipsoid intersection model algorithm.
In a two-dimensional space, the fitted intersected ellipse is more similar to the microstructure of the human bone, so that in a three-dimensional space, the ellipsoid is selected as a basic unit body for constructing the porous scaffold, and the shape is more advantageous. And the concave surfaces formed by the communicated ellipsoids are similar to the concave surfaces naturally formed by the microstructure of the human bone, so that cells can grow and reproduce in the concave surfaces more favorably. In order to better adapt to cell growth, it is important to determine a proper center-to-center distance by keeping the micropores in communication with each other.
The distance between the centers of the two ellipsoids is determined by the center distance of the ellipsoids, and the density, porosity, connectivity and mechanical properties of the ellipsoid intersection negative model can be directly influenced. Under the conditions that the directions of the ellipsoids are random and the major axis and the minor axis of the ellipsoids are determined, an excessively large center distance of the ellipsoids generates isolated ellipsoids which cannot be intersected with other ellipsoids, and in the negative ellipsoid intersection model, the isolated ellipsoids cannot enable cells to enter and provide a flow channel for cell tissue fluid. However, too small a center distance may result in too many intersected parts of the ellipsoid and too large a porosity, which may affect the mechanical properties of the negative ellipsoid intersection model.
If a complete structure is created by using the ellipsoid unit bodies, a large number of ellipsoid unit bodies are needed and the directions of the ellipsoids need to be randomized, and the traditional manual operation is difficult to realize. Therefore, a modeling method and a program design are combined to form a modeling algorithm of the bionic bone scaffold by utilizing a CAD secondary development module, the determined ellipse central point is repeatedly subjected to ellipsoid creation operation in an entity by utilizing a circulation function, and Boolean subtraction operation is performed, so that a complex irregular porous structure can be quickly formed, as shown in figure 2.
In order to realize a fast modeling algorithm, it is very important to establish a parameterized ellipsoid function. The main parameters of the ellipsoid, including the long radius, short radius, orientation and coordinates of the center point, are key factors in creating the ellipsoid function and have a significant effect on the performance of the anisotropic porous structure. The long radius and the short radius of the ellipsoid can determine a shape function of the ellipsoid, the direction and the central point coordinate of the ellipsoid can determine a position function of the ellipsoid, and the shape function and the position function are combined and parameterized to form a core ellipsoid function.
As the central distance l of the ellipsoids is reduced, the intersection chance and the intersection volume of the two ellipsoids are increased, and parameters such as porosity and connectivity of the porous structure are changed along with the ellipsoids, so that the biological and mechanical properties of the structure are influenced. Therefore, the research on the influence of the ellipsoid center distance l on the structure is of great significance. The variation range of the value of l is set to be 0.45mm to 0.75mm, and when the value of l is 0.75mm, the number of intersecting ellipsoids is small, the connectivity of the porous structure is not high, and the porosity is only 45.55%. When the value of l is changed to be near 0.65mm and 0.6mm, the number of intersected ellipsoids of l is obviously increased, the connectivity is also increased, and the porosity is also obviously increased. When the value of l changes by 0.6mm originally, each ellipsoid intersects at least one adjacent ellipsoid, the connectivity of the structure is obviously increased, and the porosity is also increased to 64.82%. When the value of l is changed to be less than 0.6mm, a single ellipsoid is intersected with more ellipsoids, the intersected volume is increased, the connectivity is increased, and the porosity is increased to 86.40%.
Claims (5)
1. The bionic bone scaffold modeling method based on the ellipsoid intersection model mainly comprises two steps, and is characterized in that: the method comprises the following steps of firstly, providing a least square fitting function of an ellipse, fitting the least square fitting function for a micro CT image of a natural bone, and analyzing parameters of the fitting ellipse to obtain a distribution rule of a long radius and a short radius; and secondly, generating the bionic scaffold based on a fitting and forming algorithm of the ellipsoid intersection model.
2. The first step of the modeling method of a biomimetic bone scaffold in an ellipsoid intersection model according to claim 1, characterized in that: in order to analyze the distribution characteristics of human bones, an image of the cross section of the tibia is obtained through Micro-CT scanning, image binarization processing and denoising processing, the shape of a porous microstructure in the tibia is irregular, the porous microstructure has higher similarity of an ellipse in shape, and simulation is carried out by using a least square method of the ellipse.
3. The second step of the modeling method of a biomimetic bone scaffold in an ellipsoid intersection model according to claim 1, characterized by: the adopted central distribution structure is a cube, the side length of each edge of the cube is the ellipsoid central distance length l, and each point has 6 equidistant adjacent central points, so the cube distribution structure has good uniformity, and in order to store the coordinate information of the points, the cube distribution structure point coordinates Aijk are encoded.
4. The second step of the modeling method of a biomimetic bone scaffold in an ellipsoid intersection model according to claim 1, characterized by: the main parameters of the ellipsoid, including the long radius, short radius, orientation and coordinates of the center point, are key factors in creating the ellipsoid function and have a significant effect on the performance of the anisotropic porous structure.
5. The second step of the modeling method of a biomimetic bone scaffold in an ellipsoid intersection model according to claim 1, characterized by: the long radius and the short radius of the ellipsoid can determine a shape function of the ellipsoid, the direction and the central point coordinate of the ellipsoid can determine a position function of the ellipsoid, and the shape function and the position function are combined and parameterized to form a core ellipsoid function.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102024076A (en) * | 2010-09-21 | 2011-04-20 | 上海大学 | Modeling method for micropore structure in bionic bone scaffold |
| US20150265824A1 (en) * | 2012-12-14 | 2015-09-24 | The Trustees Of Columbia University In The City Of New York | System and method to locally deliver therapeutic agent to inner ear |
| CN106355586A (en) * | 2016-08-31 | 2017-01-25 | 黑龙江拓盟科技有限公司 | Automatic extraction method of human chest organ tissue |
| CN107320221A (en) * | 2017-06-21 | 2017-11-07 | 四川大学 | A kind of lopsided knee joint skeleton model preparation method based on 3D printing technique |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102024076A (en) * | 2010-09-21 | 2011-04-20 | 上海大学 | Modeling method for micropore structure in bionic bone scaffold |
| US20150265824A1 (en) * | 2012-12-14 | 2015-09-24 | The Trustees Of Columbia University In The City Of New York | System and method to locally deliver therapeutic agent to inner ear |
| CN106355586A (en) * | 2016-08-31 | 2017-01-25 | 黑龙江拓盟科技有限公司 | Automatic extraction method of human chest organ tissue |
| CN107320221A (en) * | 2017-06-21 | 2017-11-07 | 四川大学 | A kind of lopsided knee joint skeleton model preparation method based on 3D printing technique |
Non-Patent Citations (3)
| Title |
|---|
| R SABETRASEKH等: "Impact of trace elements on biocompatibility of titanium scaffolds" * |
| 李宏等: "股骨标本颈干角的非接触式测量" * |
| 王素等: "计算机辅助硅胶假体建模、分析与制作方法" * |
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Application publication date: 20201027 |