A method of making a bionic beetle skeleton implant

Abstract

The application discloses a preparation method of a bionic beetle skeleton implant and belongs to the field of femoral implants. The application innovatively combines the bionic structural features of beetle sheath alae and cuticle, effectively improves the mechanical strength and structural stability of a porous nickel-titanium alloy structural implant by means of a bionic structural design method, successfully solves the stress shielding effect problem of a traditional femoral metal implant, and the porous nickel-titanium alloy bionic skeleton structure prepared by adopting a selective laser melting (SLM) technology not only has good mechanical adaptability, avoids the rejection and shedding reaction of natural bone tissue after implantation, but also can realize complete shape memory recovery function in a room temperature environment, and has good application prospect in the field of medical orthopedic implants.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of femoral implant, in particular, relates to a preparation method of a bionic beetle skeleton implant. BACKGROUND

[0002] As a kind of titanium alloy, nickel-titanium alloy has low elastic modulus and excellent large deformation recoverability compared with other titanium alloys (such as TC4), and its super-elasticity and shape memory characteristics help to stabilize after implantation, so it is considered as a potential material in the field of bone implantation. However, compared with natural bone tissue, the elastic modulus of solid nickel-titanium is too high, and there is a large stiffness mismatch between the metal implant and the adjacent host bone, which can cause stress shielding and lead to implant dislocation.

[0003] Porous titanium alloy has been proven to significantly reduce the elastic modulus and effectively reduce stress shielding. So far, there have been many methods for preparing porous titanium alloy. As early as the 1960s, researchers have prepared porous titanium alloy by powder sintering, foaming, gel casting and other methods, and applied it to the field of bone repair. However, in recent years, researchers have found that metal porous scaffolds prepared by traditional processing methods have limitations in customizing key structural characteristics (such as porosity and pore size) and corresponding mechanical properties. Additive manufacturing (AM) technology not only allows for adjustable porosity according to the needs of the skeleton implant, but also allows for personalized design for different implant sites, and can be widely used in clinical implantation as a customizable processing method.

[0004] Additive manufacturing of porous structures usually uses methods such as computer-aided design, implicit surface modeling, image-based design, and topology optimization to complete the structure design. However, traditional structures such as BCC (body-centered cubic) and FCC (face-centered cubic) prepared using the above methods mostly have problems such as insufficient strength and premature structural instability, making it difficult to achieve a balance between strength and stiffness.

[0005] Therefore, there is a need in the field of bone implant design to explore new structure design and manufacturing methods that adapt to the corresponding materials to meet clinical needs. SUMMARY

[0006] In view of the above problems existing in the prior art, the purpose of the present application is to provide a preparation method of a bionic beetle skeleton implant.

[0007] In order to solve the above problems, the technical scheme adopted by the present application is as follows:

[0008] A preparation method of a bionic beetle skeleton implant, comprising the following steps:

[0009] Step one, based on three-dimensional modeling software to complete the establishment of bionic beetle skeleton, bionic beetle skeleton includes bionic shell structure and bionic rib structure, bionic shell structure and bionic rib structure are spliced to form bionic skeleton, and the bionic skeletons are coupled and spliced to form a multi-level bionic beetle skeleton;

[0010] Step two, the bionic beetle skeleton designed in step one is introduced into Magics software, and the metal material is formed into a bionic beetle skeleton based on selective laser melting technology;

[0011] Step three, the bionic beetle skeleton formed in step two is polished, and then cleaned.

[0012] Further, the bionic shell structure in step one includes bionic three-prong shell structure, bionic four-prong shell structure and bionic six-prong shell structure, and the bionic rib structure includes bionic three-prong rib structure, bionic four-prong rib structure and bionic six-prong rib structure.

[0013] Further, the specific splicing method of the bionic skeleton is as follows:

[0014] The bionic shell structures are connected to each other through the bionic rib structures corresponding to the number of edges.

[0015] Further, the establishment method of the bionic three-prong shell structure in step one is as follows:

[0016] Based on the hollow right triangular prism, determine the three vertices of the top of the right triangular prism as A, B and C, determine the three vertices of the bottom of the right triangular prism as D, E and F, the point directly below A is D, the point directly below B is E, and the point directly below C is F, the face centers of the three sides of the right triangular prism are H, I and J, wherein H is the face center of plane ABED, I is the face center of plane ACDF, and J is the face center of plane BCEF, and the direction of line segment EF is determined as the X axis and the direction of line segment CF is determined as the Z axis.

[0017] Based on the calibration points, a curved surface is established, which includes four parts of line segments, the first part of line segment is:

[0018] Take vertices A and B as the starting point, and construct an arc AB with plane ABED and plane ABC as the reference datum plane, the distance between the midpoint of arc AB and plane ABED is n, and n is less than the shortest distance between line AB and the face center point of plane ABC, the distance between the midpoint of arc AB and plane ABC is m, and m is less than the shortest distance between line AB and the face center point of plane ABED;

[0019] The second and third parts of line segments are:

[0020] Construct symmetrical points V and U on both sides of the face center H. The distance between point V and point U and point H is c. Point V is close to the side of line AD, and point U is close to the side of line BE. With vertices A and B as starting points, construct arcs AV and BU on plane ABED. Arcs AV and BU are the second and third segments respectively.

[0021] The fourth segment is:

[0022] The straight line VU is the fourth segment;

[0023] Merge the four line segments to obtain the curve ABUV, then fill the curve ABUV with a surface to obtain the surface ABUV, and thicken and round the constructed surface;

[0024] Repeat the above steps to create the same surface based on the remaining two sides of the regular triangular prism. Then, mirror the created surface with the plane HIJ formed by the center points of the surface as the reference to form a triangular shell structure monomer.

[0025] The triangular shell structure monomers are arrayed once along the X-axis and the Z-axis respectively, and finally the arrayed structure is solid mirrored along the reference plane BCEF to form a bionic triangular shell structure.

[0026] Furthermore, the method for establishing the bionic tetrahedral shell structure in step 1 is as follows:

[0027] Design based on a hollow regular square prism. Determine a vertex at the top of the regular square prism as K, a vertex at the bottom of the regular square prism as L, and point K is located directly above point L. Determine the center of the regular square prism as M. With point L as the center point, select the three edges connected to a vertex at the bottom of the regular square prism as the X-axis, Y-axis, and Z-axis;

[0028] Using the contour line of plane KLM as the path, a circular scan operation is performed on the path to create a triangular structure with a circular cross-section. The corners of the cylindrical structure are then rounded at points K and L.

[0029] Establish a symmetry axis perpendicular to the base of the regular quadrangular prism and passing through the center point M. Arrange the rounded triangular structure in a circular pattern four times around the symmetry axis to form a quadrangular shell structure.

[0030] The tetrahedral shell structure monomers are arrayed in sequence along the X-axis, Y-axis and Z-axis directions to form a bionic tetrahedral shell structure.

[0031] Furthermore, the method for establishing the bionic hexagonal shell structure in step 1 is as follows:

[0032] Based on the hollow hexagonal prism design, determine a side of the hexagonal prism top vertex respectively N and O, determine a side of the hexagonal prism bottom vertex respectively P and Q, N point in P point directly above, O point in Q point directly above, determine the face center point of plane NOPQ as R, determine the body center point of the hexagonal prism as S, the vertical line through S point and perpendicular to the bottom surface of the hexagonal prism as Z axis, S point and the vertical line of the side of the hexagonal prism as X axis, make a axis perpendicular to Z axis and X axis as Y axis;

[0033] Delete the edge NP and OQ perpendicular to the bottom surface, and make N, O, P, Q four point arc beam towards the face center point R, establish the symmetry axis perpendicular to the bottom surface of the hexagonal prism and through the body center S point of the hexagonal prism, and the arc beam on the plane NPOQ is circularly arrayed six times with the symmetry axis as the reference, while deleting other vertical edges of the hexagonal prism, and replacing the six side surfaces of the hexagonal prism with arc beam structure;

[0034] Based on all the top points and bottom points of the hollow hexagonal prism, make all the top points arc beam towards the body center point S, to form the hexagonal shell structure monomer;

[0035] Array the hexagonal shell structure monomer along the X axis, Y axis and Z axis direction respectively once, to form the bionic hexagonal shell structure.

[0036] Further, the establishment method of bionic three-prong rib structure in step one is as follows:

[0037] Based on the hollow right triangular prism, determine the body center point of the right triangular prism as T, make the arc beam of each vertex of the right triangular prism towards T point, which is the rib structure, and then delete other structures in the right triangular prism except the rib structure, to obtain the three-prong rib structure monomer;

[0038] Array the three-prong rib structure monomer along the X axis direction once, and make the arrayed structure entity mirror image once with the reference surface as the reference, to form the bionic three-prong rib structure.

[0039] Further, the establishment method of bionic four-prong rib structure in step one is as follows:

[0040] Based on the hollow right quadrangular prism, make the arc beam of each vertex of the right quadrangular prism towards the body center point M, which is the rib structure, and then delete other structures in the right quadrangular prism except the rib structure, to obtain the four-prong rib structure monomer;

[0041] Array the four-prong rib structure monomer along the X axis and Y axis direction respectively once, to form the bionic four-prong rib structure.

[0042] Further, the establishment method of bionic six-prong rib structure in step one is as follows:

[0043] Based on the hollow hexagonal prism, an arc-shaped beam is designed, which is the rib structure, and then other structures except the rib structure in the hexagonal prism are deleted to obtain a hexagonal rib structure monomer;

[0044] The hexagonal rib structure monomer is arrayed along the X-axis and Y-axis directions to form a bionic hexagonal rib structure.

[0045] Further, the selective laser melting technology in step two adopts a laser power of 200w, a scanning speed of 1000mm / s, a scanning layer thickness of 40μm and a scanning interval of 80μm as the printing strategy.

[0046] Compared with the prior art, the beneficial effects of the present application are:

[0047] The present application applies the bionic beetle structure to the medical femoral implant field, combines the bionic structures of the beetle sheath wing part and the cuticle part, makes up for the deficiencies of strength and structural stability, solves the long-standing "stress shielding" problem in clinical medicine, and makes it not have rejection reaction with natural bone after implantation;

[0048] Traditional additive manufacturing porous scaffolds have more or less powder particles adhering to the surface of the sample after preparation, and it is difficult to completely remove the powder particles by ultrasonic treatment alone, the present application performs chemical polishing treatment on the prepared bionic nickel-titanium scaffold, effectively removes the metal powder particles adhering to the surface of the scaffold, and avoids the inflammation problem caused by the falling of powder due to impact vibration after implantation.

[0049] The nickel-titanium porous scaffold prepared by additive manufacturing in the prior art is difficult to completely realize shape memory recovery function at room temperature, while the porous nickel-titanium scaffold structure of the present application can realize complete shape memory recovery at room temperature. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 It is a schematic diagram of the micro-characterization of the beetle sheath wing part (left) and the exoskeleton cuticle (right) in nature;

[0051] Figure 2 It is a schematic diagram of the micro-characterization of the beetle sheath wing part (left) and the exoskeleton cuticle (right) in nature;

[0052] Figure 3 It is a schematic diagram of the bionic three-pronged shell structure designed by the present application;

[0053] Figure 4 It is a schematic diagram of the bionic four-pronged shell structure designed by the present application;

[0054] Figure 5 It is a schematic diagram of the bionic six-pronged shell structure designed by the present application;

[0055] Figure 6 is a schematic diagram of three types of rib structure monomers respectively matched with three types of shell structure monomers of the present application;

[0056] Figure 7 is a schematic diagram of three types of biomimetic rib structures of the present application;

[0057] Figure 8 is a coupling schematic diagram of a multilevel biomimetic beetle skeleton of the present application;

[0058] Figure 9 is an effect schematic diagram of the multilevel biomimetic beetle skeleton of the present application completing shape recovery at room temperature and a phase change temperature curve schematic result.

[0059] In the figure: 1, biomimetic three-prong skeleton; 11, biomimetic three-prong shell structure; 12, biomimetic three-prong rib structure; 111, three-prong shell structure monomer; 121, three-prong rib structure monomer; 2, biomimetic four-prong skeleton; 21, biomimetic four-prong shell structure; 22, biomimetic four-prong rib structure; 211, four-prong shell structure monomer; 221, four-prong rib structure monomer; 3, biomimetic six-prong skeleton; 31, biomimetic six-prong shell structure; 32, biomimetic six-prong rib structure; 311, six-prong shell structure monomer; 321, six-prong rib structure monomer; 4, biomimetic beetle skeleton. DETAILED DESCRIPTION

[0060] The present application will be further described below in combination with specific embodiments.

[0061] The present application discloses a preparation method of a biomimetic beetle skeleton implant, and the specific steps are as follows:

[0062] Step one: complete parametric design by using Solidworks three-dimensional modeling software, splice the designed three types of biomimetic shell structures and the corresponding three types of biomimetic rib structures into a biomimetic three-prong skeleton 1, a biomimetic four-prong skeleton 2 and a biomimetic six-prong skeleton 3 respectively, wherein the biomimetic rib structure is placed in the middle of the two biomimetic shell structures and plays a stabilizing deformation effect when subjected to load, while the biomimetic shell structure mainly plays a role of bearing and absorbing energy and dissipating the energy borne when facing load. The biomimetic three-prong skeleton 1, the biomimetic four-prong skeleton 2 and the biomimetic six-prong skeleton 3 are coupled together to form a multilevel biomimetic beetle skeleton 4 (Multilevel biomimetic beetle structure, MBBS), so as to further play a synergistic damping effect.

[0063] Step two: convert the structure of the biomimetic beetle skeleton 4 designed in step one into a Stl format file and import it into Magics software, and based on selective laser melting technology (SLM), form the metal material into a multilevel biomimetic beetle skeleton 4.

[0064] Step three: polish the biomimetic beetle skeleton 4 with chemical method, then remove the surface adhering powder by ultrasonic treatment under alcohol immersion.

[0065] The biomimetic beetle skeleton 4 of this scheme is derived from the carapace structure of the beetle, as shown in Figure 1 The elytra part and the exoskeleton part of the beetle are observed by using electron microscope, and the oval and circular hollow chambers composed of fibers are observed in the elytra part, which has been proved to be an important reason for the good energy absorption characteristics of the beetle. The Bouligand structure with rotation angle is observed in the cuticle layer of the exoskeleton of the beetle, which has also been proved to be one of the reasons for the stable deformation of the beetle.

[0066] As shown in Figure 2 The biomimetic shell structure in step one includes a bionic triangular shell structure 11 (BTSS), a bionic quadrilateral shell structure 21 (BQSS) and a bionic hexagonal shell structure 31 (BHSS), and the biomimetic rib structure includes a bionic trilateral rib structure 12 (BTRS), a bionic quadrilateral rib structure 22 (BQRS) and a bionic hexagonal rib structure 32 (BHRS).

[0067] The monomers of the biomimetic shell structure in step one include a triangular shell structure monomer 111, a quadrilateral shell structure monomer 211 and a hexagonal shell structure monomer 311, the design of the structure monomers of each shell is inspired by the hollow chamber structure of the beetle elytra, and is divided into three categories according to the different chambers formed; and the monomers of the biomimetic rib structure include a trilateral rib structure monomer 121, a quadrilateral rib structure monomer 221 and a hexagonal rib structure monomer 321, the design of which is inspired by the helical twisting feature of the Bouligand structure of the beetle exoskeleton cuticle, and corresponds to the respective shell structure.

[0068] After arraying, mirroring and combining, etc. of each structure monomer, the bionic triangular shell structure 11, the bionic quadrilateral shell structure 21, the bionic hexagonal shell structure 31, the bionic trilateral rib structure 12, the bionic quadrilateral rib structure 22 and the bionic hexagonal rib structure 32 are formed, respectively.

[0069] The biomimetic three-pronged skeleton 1 in the step one is composed of two biomimetic three-pronged shell structures 11 and one biomimetic three-pronged rib structure 12; the biomimetic four-pronged skeleton 2 is composed of two biomimetic four-pronged shell structures 21 and one biomimetic four-pronged rib structure 22; the biomimetic six-pronged skeleton 3 is composed of two biomimetic six-pronged shell structures 31 and one biomimetic six-pronged rib structure 32.

[0070] And the three types of biomimetic beetle skeleton structures all have a common feature, that is, the corresponding biomimetic shell structures are placed on both sides as the top unit and the bottom unit, and the corresponding biomimetic rib structure is located in the middle region of the top unit and the bottom unit to connect them. The biomimetic shell structure mainly plays a role in bearing and absorbing energy and dissipating the energy borne, while the biomimetic rib structure mainly plays a role in stabilizing deformation and smooth transition.

[0071] Referring to Figure 3 As shown in the figure, the design scheme of the biomimetic three-pronged shell structure 11 is as follows:

[0072] Firstly, based on the optimization design of the hollow regular triangular prism, the three vertices of the top of the regular triangular prism are determined as A, B and C, the three vertices of the bottom of the regular triangular prism are determined as D, E and F, the point directly below A is D, the point directly below B is E, and the point directly below C is F, the face centers of the three sides of the regular triangular prism are H, I and J, wherein H is the face center of the plane ABED, I is the face center of the plane ACDF, and J is the face center of the plane BCEF, the body center of the regular triangular prism is T, and the direction of the line segment EF is determined as the X axis and the direction of the line segment CF is determined as the Z axis;

[0073] Firstly, the curve is drawn based on the 3D sketch operation, the curve is composed of four line segments, the first part is an arc, the curvature is extended from the vertex A and B, the arc AB is constructed with the plane ABED and the plane ABC as the reference reference surface, the distance between the midpoint of the arc AB and the plane ABED is n, and n is less than the shortest distance between the straight line AB and the face center point of the plane ABC, the distance between the midpoint of the arc AB and the plane ABC is m, and m is less than the shortest distance between the straight line AB and the face center point of the plane ABED, the second part and the third part are still arcs, which are drawn based on the 3D arc drawing from the vertex A and B, respectively, and extended to V and U of the plane ABED from the vertex A and B, respectively, V and U are located at the left and right ends of H, respectively, and the distance between V and U and H is c, the fourth part is a straight line UV, which is also realized by the 3D sketch command;

[0074] Secondly, the 3D curve ABUV drawn above is subjected to surface filling operation, and the constructed surface is subjected to thickening and local rounding treatment at the same time;

[0075] Repeat the above steps to establish the same curved surface based on the remaining two sides of the right triangular prism, and after the establishment of the entity curved surface BCWX, ACYZ and ABUV, the three curved surfaces are mutually closed, and finally the established curved surface is mirrored based on the plane HIJ composed of the face center points, at this time the combined entity forms a triangular shell structure monomer 111 with length x width x height = a1x b1x c1.

[0076] Wherein, the extension positions of the vertices B and C in the constructed curved surface BCWX are located at X and W of the plane BCEF respectively (X point and W point are located at the left and right ends of J point, and the distance is set to c), and the extension positions of the vertices AC in the constructed curved surface ACYZ are located at Z and Y of the plane ACFD respectively (Y point and Z point are located at the left and right ends of I, and the distance is set to c);

[0077] Array the triangular shell structure monomer 111 along the X axis and the Z axis direction respectively once, and finally array the structure along the reference plane BCEF (i.e. Figure 3 the reference plane 1 in the above formula) to perform entity mirroring operation, thereby constructing a biomimetic triangular shell structure 11 with a size of 2a1x 2b1x 2c1.

[0078] Referring to Figure 4 , the design scheme of the biomimetic quadrangular shell structure 21 is as follows: based on the optimized design of the hollow right quadrangular prism, a vertex at the top of the right quadrangular prism is determined as K, a vertex at the bottom of the right quadrangular prism is determined as L, K point is located directly above L point, the body center of the right quadrangular prism is determined as M, and three edges connected to a vertex at the bottom of the right quadrangular prism are selected as the X axis, the Y axis and the Z axis with L point as the center point;

[0079] Draw a 3D sketch based on the KL vertex to the body center M of the quadrangular prism, and the path can be understood as the contour line of the plane KLM, then use a circular scanning operation on the path, and then perform a fillet processing on the position of the cylindrical structure at the K point and the L point. The role of the fillet processing is to smoothly disperse the stress, and compared with the sharp edges and node structure, the fillet structure can effectively reduce the stress concentration trend, and further improve the fatigue resistance of the structure. Establish the symmetry axis 3 perpendicular to the bottom surface of the right quadrangular prism and passing through the body center M point, and finally perform a circular array based on the symmetry axis 3, and the array number is 4, thereby constructing a quadrangular shell structure monomer 211 with a size of a2x b2x c2.

[0080] Array the quadrangular shell structure monomer 211 with a size of a2x b2x c2 along the X axis, the Y axis and the Z axis direction respectively once, thereby constructing a biomimetic quadrangular shell structure 21 with a size of 2a2x 2b2x 2c2.

[0081] Referring to Figure 5As shown in the figure, the design scheme of the bionic hexagonal shell structure 31 is as follows: based on the hollow regular hexagonal prism, the bottom vertexes of one side of the regular hexagonal prism are determined as P and Q, the point N is located directly above the point P, the point O is located directly above the point Q, the face center point of the plane NOPQ is determined as R, the body center point of the regular hexagonal prism is determined as S, the vertical line passing through the point S and perpendicular to the bottom surface of the regular hexagonal prism is taken as the Z axis, the vertical line passing through the point S and perpendicular to the side surface of the regular hexagonal prism is taken as the X axis, and an axis perpendicular to the Z axis and the X axis is taken as the Y axis;

[0082] Firstly, the original pillars NP and OQ are deleted, and four arc-shaped beams are established with N, P, O and Q as end points, all the arc-shaped beams intersect at the face center position R, the symmetry axis 4 perpendicular to the bottom surface of the regular hexagonal prism and passing through the body center point S of the regular hexagonal prism is established, and then the entity arc-shaped beam structure formed at the plane NOPQ is arranged in a circular array around the symmetry axis 4, the circular array number is 6, the other vertical edges of the regular hexagonal prism are deleted, and the arrayed entities are ensured to be closed to each other, and the overall size is the same as that of the regular hexagonal prism.

[0083] Then, a sketch is drawn to perform path scanning, the starting point of the path is the six vertexes on the upper plane of the regular hexagonal prism, and the ending point of the path is the body center S of the regular hexagonal prism, the path is established as a circular arc, the center of the circular arc is close to the side surface of the regular hexagonal prism, and the scanning contour is a circular contour with a radius of r. Subsequently, the entity unit formed by scanning is subjected to mirror entity operation along the symmetry axis 5 passing through the body center S and parallel to the top surface of the regular hexagonal prism, and the mirror entity is ensured to intersect with the six vertexes on the lower plane of the regular hexagonal prism, in addition, the path can also be directly established with the twelve vertexes on the upper plane and the lower plane of the regular hexagonal prism to perform circular contour scanning, thereby forming the hexagonal shell structure monomer 311 with a size of a3×b3×c3.

[0084] Finally, the hexagonal shell structure monomer 311 with a size of a3×b3×c3 is arrayed along the X axis, the Y axis and the Z axis once respectively, and the combined entity obtains the bionic hexagonal shell structure 31 with a size of 2a2×2b2×2c2.

[0085] Referring to Figure 6 As shown in the figure, the design schemes of the three-rib structure monomer 121, the four-rib structure monomer 221 and the six-rib structure monomer 321 are as follows:

[0086] Similarly, take the hollow regular triangular prism, regular quadrangular prism and regular hexagonal prism as the reference, first perform path scanning with a circular profile radius of r2, wherein the path starting point is the upper plane vertex of the regular triangular prism, the regular quadrangular prism and the regular hexagonal prism, and the path endpoint is the respective body center T, M and S. The path is in the shape of a circular arc, and the center of the circular arc is close to the top surface and the bottom surface of the regular polygonal prism. Finally, remove the entity other than the rib part, and after scaling and combining the entity, obtain the triangular rib structure monomer 121 with a size of a1×b1×c1, the quadrangular rib structure monomer 221 with a structure size of a2×b2×c2, and the hexagonal rib structure monomer 321 with a structure size of a3×b3×c3. The above-mentioned monomer size is to adapt to the respective corresponding biomimetic shell structure.

[0087] Referring to Figure 7 It can be seen that the biomimetic rib structure is obtained from the rib structure monomer array and mirroring, wherein the triangular rib structure monomer 121 (with a size of a1×b1×c1) is arrayed along the X axis, the arraying number is 1, and then the entity is combined and mirrored once with the reference surface 2 (i.e. the plane BCEF corresponding to the construction of the triangular shell structure monomer 111) as the reference. After mirroring, the biomimetic triangular rib structure 12 with a size of 2a1×2b1×c1 is obtained.

[0088] The quadrangular rib structure monomer 221 (with a size of a2×b2×c2) is arrayed along the X axis and the Y axis, respectively, the arraying number is 1, and then the entity is combined to obtain the biomimetic quadrangular rib structure 22 with a size of 2a2×2b2×c2.

[0089] The hexagonal rib structure monomer 321 (with a size of a3×b3×c3) is arrayed along the X axis and the Y axis, respectively, the arraying number is 1, and then the entity is combined to obtain the biomimetic hexagonal rib structure 32 with a size of 2a3×2b3×c3.

[0090] It should be noted that when the quadrangular rib structure monomer 221 and the hexagonal rib structure monomer 321 are connected to the quadrangular shell structure monomer 211 and the hexagonal shell structure monomer 311, the end of each rib of the rib structure monomer is connected to the vertex of the shell structure monomer.

[0091] The exoskeleton of beetles presents a multi-layer structure composed of chitin fibers and proteins (such as the outer cuticle and the inner cuticle), and the binding force between the layers is enhanced by nanoscale interlocking structures to prevent delamination. Similarly, the interlocking of the structures of the beetle's elytra also exists, such as the interlocking of the hardened forewings and the thorax of the beetle through serrated or hooked structures to achieve the effect of tight closure. Therefore, the mechanical interlocking of the beetle in nature can produce a strengthening effect in multiple parts. Therefore, the present application further strengthens the structure by referring to the interlocking characteristics of the beetle, and designs a multi-layered bionic beetle skeleton 4 composed of a bionic three-pronged skeleton 1, a bionic four-pronged skeleton 2 and a bionic six-pronged skeleton 3. The bionic four-pronged skeleton 2 is between the bionic three-pronged skeleton 1 and the bionic six-pronged skeleton 3, and plays a role as a transition layer when the bionic beetle skeleton 4 faces lateral load. The specific design effect is shown in Figure 8

[0092] In step two, the bionic skeleton is prepared according to the SLM technology, and the material used is a nickel-titanium alloy powder (55.8 wt% Ni) made by gas atomization method, with a powder particle size of 15-53 μm. When laser melting printing is performed, the conditions are selected as follows: laser power is 200 W, laser scanning speed is 1000 mm / s, layer thickness is 40 μm, and scanning interval is 80 μm.

[0093] The chemical polishing solution used in step three is composed of hydrofluoric acid (22.5 mol / L), nitric acid (4 mol / L) and deionized water, and is prepared according to a volume ratio of 1:4:5. The purpose of chemical polishing is to eliminate un-melted particle powder to avoid inflammation problems caused by vibration after implantation into the human body.

[0094] The working principle of the present application is shown in Figure 9 The skeleton implant prepared by the present application is mainly used for implanting into the femur. When the implant bears a load, the implant implanted into the human body dissipates energy by deformation, and the memory temperature A f of the implant produced based on the nickel-titanium structure is measured to be 35℃, which conforms to the normal temperature of the human body. Therefore, when the temperature rises to the memory temperature A f , the martensite phase in the nickel-titanium shape memory alloy is completely transformed into the austenite phase, and the bionic structure can recover the deformation. The structure designed based on the present scheme has excellent mechanical properties, and the deformation recovery property based on the normal temperature of the human body of the nickel-titanium alloy material makes the scheme have a good application prospect as a medical stent in the field of bone implants.​

Claims

1. A method of preparing a bionic beetle-skeleton implant, characterized in that, The method comprises the following steps: Step one, based on three-dimensional modeling software, the establishment of bionic beetle skeleton is completed, the bionic beetle skeleton includes bionic shell structure and bionic rib structure, the bionic shell structure and the bionic rib structure are spliced to form the bionic skeleton, and the bionic skeletons are coupled and spliced to form a multi-level bionic beetle skeleton; Step two, the bionic beetle skeleton designed in step one is introduced into the Magics software, and the metal material is formed into the bionic beetle skeleton based on the selective laser melting technology; Step three, the bionic beetle skeleton formed in step two is polished, and then cleaned; The bionic shell structure in step one includes a bionic three-prism shell structure, a bionic four-prism shell structure and a bionic six-prism shell structure, and the bionic rib structure includes a bionic three-prism rib structure, a bionic four-prism rib structure and a bionic six-prism rib structure.

2. The method for preparing a bionic beetle skeleton implant according to claim 1, characterized in that: The specific splicing method of the bionic skeleton is as follows: The bionic shell structures are connected with each other through the bionic rib structures with corresponding rib numbers.

3. The method for preparing a bionic beetle skeleton implant according to claim 1, characterized in that: The establishment method of the bionic three-prism shell structure in step one is as follows: Based on the hollow right triangular prism, three top points A, B and C of the top of the right triangular prism are determined, three top points D, E and F of the bottom of the right triangular prism are determined, the point D is directly below the point A, the point E is directly below the point B, the point F is directly below the point C, the face centers of the three side faces of the right triangular prism are H, I and J, wherein the point H is the face center of the plane ABED, the point I is the face center of the plane ACDF, and the point J is the face center of the plane BCEF, and the direction of the line segment EF is determined as the X axis and the direction of the line segment CF is determined as the Z axis; Based on the calibration points, a curved surface is established, which includes four partial line segments, the first partial line segment is: Taking the points A and B as the starting points, an arc line AB is constructed with the plane ABED and the plane ABC as the reference datum plane, the distance between the midpoint of the arc line AB and the plane ABED is n, and n is less than the shortest distance between the straight line AB and the face center point of the plane ABC, the distance between the midpoint of the arc line AB and the plane ABC is m, and m is less than the shortest distance between the straight line AB and the face center point of the plane ABED; The second partial line segment and the third partial line segment are: Symmetric points V and U are constructed on both sides of the face center point H, the distance between the points V and U and the point H is c, wherein the point V is close to the side of the straight line AD, and the point U is close to the side of the straight line BE, and taking the points A and B as the starting points, an arc line AV and an arc line BU are constructed on the plane ABED, the arc line AV and the arc line BU are the second partial line segment and the third partial line segment respectively; The fourth partial line segment is: The straight line VU is the fourth partial line segment; The four partial line segments are combined to obtain a curve ABUV, and then the curve ABUV is filled with a curved surface to obtain a curved surface ABUV, and the constructed curved surface is thickened and rounded; The above steps are repeated, and the same curved surface is established based on the remaining two side faces of the right triangular prism, and then the established curved surface is mirror-imaged based on the plane HIJ formed by the face center points to form a three-prism shell structure monomer. The tricuspid shell structure monomer is arrayed along the X axis and the Z axis direction respectively once, and finally the arrayed structure is mirror imaged along the reference surface BCEF to form the bionic tricuspid shell structure.

4. The method for preparing a bionic beetle skeleton implant according to claim 1, characterized in that: The establishment method of the bionic four-prong shell structure in step one is as follows: Based on the hollow right quadrangular prism, a vertex on the top of the right quadrangular prism is determined as K, a vertex on the bottom of the right quadrangular prism is determined as L, the K point is located directly above the L point, the body center of the right quadrangular prism is determined as M, the L point is taken as the center point, and three edges of a vertex on the bottom of the right quadrangular prism are selected as the X axis, the Y axis and the Z axis; The contour line of the plane KLM is taken as a path, a circular scanning operation is performed on the path, a triangular structure with a circular cross section is established, and then the positions of the triangular structure at the K point and the L point are rounded; A symmetry axis perpendicular to the bottom surface of the right quadrangular prism and passing through the body center M point is established, and the rounded triangular structure is circumferentially arrayed with the symmetry axis as the reference, and the arraying number is four to form a four-prong shell structure monomer; The four-prong shell structure monomer is arrayed along the X axis, the Y axis and the Z axis direction in turn once to form the bionic four-prong shell structure.

5. The method for preparing a bionic beetle skeleton implant according to claim 1, characterized in that: The establishment method of the bionic six-prong shell structure in step one is as follows: Based on the hollow right hexagonal prism, the top vertices of a side of the right hexagonal prism are determined as N and O respectively, the bottom vertices of a side of the right hexagonal prism are determined as P and Q respectively, the N point is located directly above the P point, the O point is located directly above the Q point, the face center point of the plane NOPQ is determined as R, the body center point of the right hexagonal prism is determined as S, a vertical line passing through the S point and perpendicular to the bottom surface of the right hexagonal prism is taken as the Z axis, the S point and the vertical line of the side of the right hexagonal prism are taken as the X axis, and an axis perpendicular to the Z axis and the X axis is taken as the Y axis; The edges NP and OQ perpendicular to the bottom surface are deleted, and arc-shaped beams of the N, O, P and Q points towards the face center point R are established, a symmetry axis perpendicular to the bottom surface of the right hexagonal prism and passing through the body center S point of the right hexagonal prism is established, the arc-shaped beams on the plane NPOQ are circumferentially arrayed six times with the symmetry axis as the reference, the other vertical edges of the right hexagonal prism are deleted, and the six side surfaces of the right hexagonal prism are replaced by the arc-shaped beam structure; Based on all the top vertices and bottom vertices of the hollow hexagonal prism, arc-shaped beams of all the top vertices towards the body center point S are established to form a six-prong shell structure monomer; The six-prong shell structure monomer is arrayed along the X axis, the Y axis and the Z axis direction in turn once to form the bionic six-prong shell structure.

6. The method of claim 3, wherein the implant is a bionic beetle skeleton implant. The establishment method of the bionic three-prong rib structure in step one is as follows: Based on the hollow right triangular prism, the body center point of the right triangular prism is determined as T, arc-shaped beams of the vertices of the right triangular prism towards the T point are established, the arc-shaped beams are rib structures, and then other structures of the right triangular prism except the rib structures are deleted to obtain a three-prong rib structure monomer; The three-prong rib structure monomer is arrayed along the X axis direction once, and the arrayed structure is mirror imaged once with the reference surface BCEF as the reference to form the bionic three-prong rib structure.

7. The method of claim 4, wherein the implant is a bionic beetle skeleton implant. The establishment method of the bionic four-prong rib structure in step one is as follows: Based on the hollow regular quadrangular prism, an arc-shaped beam is made from each vertex of the regular quadrangular prism to the body center point M, which is the rib structure. Then, other structures in the regular quadrangular prism except the rib structure are deleted to obtain a quadrangular rib structure monomer; The quadrangular rib structure monomers are arrayed along the X-axis and Y-axis directions in sequence to form a biomimetic quadrangular rib structure.

8. The method of claim 5, wherein the implant is a bionic beetle skeleton implant. The establishment method of the biomimetic hexagonal rib structure in step one is as follows: Based on the hollow regular hexagonal prism, an arc-shaped beam is made from each vertex of the regular hexagonal prism to the body center point S, which is the rib structure. Then, other structures in the regular hexagonal prism except the rib structure are deleted to obtain a hexagonal rib structure monomer; The hexagonal rib structure monomers are arrayed along the X-axis and Y-axis directions in sequence to form a biomimetic hexagonal rib structure.

9. The method for preparing a bionic beetle skeleton implant according to claim 1, characterized in that: In the selective laser melting technology in step two, 200w of laser power, 1000mm / s of scanning speed, 40μm of scanning layer thickness and 80μm of scanning interval are used as the printing strategy.

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