Biomimetic helical chiral porous bone repair and augmentation scaffold

Abstract

This invention discloses a biomimetic helical chiral porous bone repair and bone augmentation scaffold, comprising: a scaffold body composed of an array of multiple lattice units, each lattice unit being a biomimetic trabecular bone cell; the lattice units follow the natural helical arrangement of human bone trabeculae, forming a continuous and interconnected helical channel network within the scaffold body; the lattice units are distributed in a helical gradient along the radial direction of the scaffold body, and the outer wall of the scaffold body has a protruding structure integrally formed with the lattice units. This invention, through the deep coupling of the biomimetic helical chiral structure and cellular fluid dynamics, overcomes the limitations of traditional scaffolds with "static channels," forming a composite flow field of "high-speed guidance - low-speed vortex," effectively solving the problem of "nutrient islands," and significantly improving the survival rate and quality of osteoblasts in the central region.

Description

Technical Field

[0001] This invention relates to the field of biomedical materials and 3D printing technology, and in particular to a biomimetic helical chiral porous bone repair and bone augmentation scaffold, specifically a biomimetic scaffold with rapid blood absorption capability verified by simulating a physiological limited droplet environment. Background Technology

[0002] With advancements in materials science and 3D printing technology, the fabrication of biodegradable scaffolds with porous structures has become an important development direction in the field of bone repair. However, traditional porous scaffolds struggle to simultaneously meet the core clinical needs of osteogenic stability and vascular ingrowth, resulting in significant limitations in their application. Taking alveolar bone augmentation therapy as an example, the surrounding tissue fluid is limited in the early stages of bone implantation (12-24 hours post-operation), necessitating the rapid establishment of initial blood supply with the assistance of scaffolds. Furthermore, during the postoperative healing stage, the scaffolds need to provide a suitable microenvironment for osteocyte proliferation, differentiation, and new bone formation. However, traditional scaffolds are constrained by both cellular hydrodynamic properties and clinical operating conditions, resulting in weak initial blood supply establishment and significantly inferior osteogenic effects in the central region compared to the peripheral region during the healing stage. Traditional scaffolds often employ a straight-pore structure, resulting in a flow field exhibiting axial linear attenuation. The inflow rate of nutrient-rich fluids and bone cells in the oral cavity is slow, lacking guiding and eddy current effects. Nutrients such as glucose and amino acids, as well as oxygen, are difficult to actively transport to the scaffold center, leading to extremely low diffusion efficiency. Simultaneously, waste products from bone cell metabolism, such as lactic acid and carbon dioxide, tend to accumulate in the center, forming "nutrient islands" and "metabolic waste accumulation zones." This results in nutrient deprivation and a deteriorated metabolic environment for bone cells in the central region, hindering proliferation and reducing differentiation capacity. Ultimately, the new bone formation rate in the central region of the scaffold is only 30%-40% of that in the peripheral region, severely limiting bone growth. Although some existing technologies attempt to optimize by adjusting the pore size, distribution density, or modifying the configuration, they still haven't broken through the design constraints of "static channels" and haven't deeply coupled the structural morphology with the hydrodynamic properties of cells. While straight-pore structures offer uniform fluid shear force distribution, their low strength prevents sustained activation of intracellular mechanotransmission pathways. This results in weak osteoblast differentiation, easy dedifferentiation or fibrosis, and an inability to meet precise repair requirements. Furthermore, they suffer from weak mechanical interlocking with the extracellular matrix, low interfacial bonding strength, and a high risk of implantation detachment. Therefore, developing a porous scaffold that combines efficient material transport, metabolic balance, and precise regulation of cell behavior, while matching the physiological structure of bone trabeculae, is a key need to address the shortcomings of existing technologies. Summary of the Invention

[0003] The purpose of this invention is to provide a biomimetic helical chiral porous bone repair and bone augmentation scaffold to solve the problems existing in the prior art.

[0004] To achieve the above objectives, the present invention provides the following solution: The present invention provides a biomimetic spiral chiral porous bone repair and bone augmentation scaffold, comprising: The scaffold body is composed of an array of multiple lattice units, each of which is a biomimetic trabecular bone cell. The lattice units follow the natural spiral arrangement of human trabecular bone, forming a continuous and interconnected spiral channel network inside the scaffold body. The lattice units are distributed in a spiral gradient along the radial direction of the scaffold body, and the outer side wall of the scaffold body is provided with a protrusion structure integrally formed with the lattice units.

[0005] According to the biomimetic helical chiral porous bone repair and bone augmentation scaffold provided by the present invention, the average pore size of the lattice unit is 200-500 micrometers, and the filament diameter is 100-250 micrometers; the helical channel network is helical in either a left-handed or right-handed helix, with a pitch of 500-1200 micrometers and a helical radius of 2-4 millimeters.

[0006] According to the biomimetic helical chiral porous bone repair and bone augmentation scaffold provided by the present invention, the helical type of the helical channel network is selected from one or more combinations of helices generated by Archimedes' spirals, helices generated by logarithmic spirals, helices generated by cylindrical spirals, or double helical structures.

[0007] According to the biomimetic helical chiral porous bone repair and bone augmentation scaffold provided by the present invention, during the arrangement of the lattice units, the blood perfusion state of the helical pore network is adjusted by regulating the cell parameters of adjacent lattice units, thereby promoting the gradual penetration of blood flow along the helical direction.

[0008] According to the present invention, the biomimetic helical chiral porous bone repair and bone augmentation scaffold is prepared by one or more of bioceramic materials, metallic materials or polymeric materials; the bioceramic materials include bioglass, tricalcium phosphate, hydroxyapatite, the metallic materials include titanium and titanium alloys, tantalum and tantalum alloys, magnesium and magnesium alloys, zinc and zinc alloys, and the polymeric materials include PLA, PCL, PLGA, PEEK, PEKK.

[0009] The biomimetic helical chiral porous bone repair and bone augmentation scaffold provided by the present invention is integrally formed by 3D printing technology.

[0010] The biomimetic helical chiral porous bone repair and bone augmentation scaffold provided by the present invention has a central region of a through-hole structure.

[0011] According to the biomimetic helical chiral porous bone repair and bone augmentation scaffold provided by the present invention, the protruding structure on the outer wall of the scaffold body forms a mechanical interlocking effect with the extracellular matrix.

[0012] The present invention discloses the following technical effects: This invention breaks through the limitations of traditional scaffolds' "static channels" by deeply coupling a biomimetic helical chiral structure with cellular fluid dynamics, forming a composite flow field of "high-speed guidance and low-speed vortex" to efficiently solve the problem of "nutrient islands" and significantly improve the survival rate and quality of osteoblasts in the central region. The shear force distributed along the tangential gradient of the helical surface continuously activates the YAP / TAZ pathway, promoting the directional differentiation of osteoblasts. The outer protrusions enhance the mechanical interlock with the extracellular matrix, reducing the risk of detachment, while adapting to the bone repair needs of multiple fields, taking into account both structural stability and osteogenic efficiency. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the structure of the biomimetic helical chiral porous bone repair and bone augmentation scaffold of the present invention. Figure I ; Figure 2 This is a schematic diagram of the structure of the biomimetic helical chiral porous bone repair and bone augmentation scaffold of the present invention. Figure II . Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] Reference Figures 1-2 This invention provides a biomimetic helical chiral porous bone repair and bone augmentation scaffold, comprising: The scaffold body is composed of multiple lattice units arranged in an array, each lattice unit being a biomimetic trabecular bone cell. The lattice units follow the natural spiral arrangement of human trabecular bone, forming a continuous and interconnected spiral channel network inside the scaffold body. The lattice units are distributed in a spiral gradient along the radial direction of the scaffold body, and the outer wall of the scaffold body has a protrusion structure integrally formed with the lattice units.

[0018] Surgical Application of Bionic Helical Chiral Porous Bone Repair and Bone Augmentation Scaffold Step 1: Preoperative assessment and stent customization; Imaging examinations such as oral CBCT or orthopedic CT are performed on the patient's surgical area to accurately measure the size, bone density, and surrounding blood supply distribution of the bone defect / bone augmentation area, clarify the natural alignment of the trabeculae, and determine the core parameters of the scaffold body based on the patient's clinical needs. These parameters include the appropriate helix type (Archimedean helix, logarithmic helix, etc.), helix direction (left-handed or right-handed helix), pitch (500-1200 micrometers, with 800 micrometers being the optimal value), helix radius (2-4 millimeters), and the average pore size of the lattice unit (biomimetic trabecular cell) (200-500 micrometers, with 300 micrometers being the optimal value). The scaffold body is formed using 3D printing technology, ensuring continuous spiral channel network, uniform radial spiral gradient distribution of lattice units, and complete outer wall protrusion structure. The scaffold is sterilized before surgery, and routine examinations such as complete blood count and coagulation function are performed to rule out contraindications for surgery and develop a personalized anesthesia plan (local anesthesia or general anesthesia). The filament diameter is 100-250 micrometers, with 150 micrometers being the ideal value. Suitable preparation materials (bioceramics, metals or polymers, such as bioglass / hydroxyapatite for dental implants and titanium alloy for load-bearing bone repair) are selected. The scaffold body is formed in one piece using 3D printing technology to ensure that the spiral channel network is continuous and interconnected, the radial spiral gradient distribution of lattice units is uniform, and the outer wall protrusion structure is complete. The scaffold is sterilized before surgery, and routine examinations such as complete blood count and coagulation function are performed to rule out contraindications for surgery and develop a personalized anesthesia plan (local anesthesia or general anesthesia).

[0019] Step 2, surgical area pretreatment; Following surgical protocol, the surgical area is disinfected and draped. After anesthesia is administered and its effectiveness confirmed, the soft tissue is incised along the pre-designed incision (for oral surgery, the incision is made along the gingival margin; for orthopedic surgery, a conventional incision is selected based on the location of the bone defect). Subcutaneous / submucosal tissue is bluntly dissected to fully expose the bone defect area or the target area for bone augmentation, avoiding damage to surrounding blood vessels and nerves. Necrotic bone tissue, inflammatory granulation tissue, and foreign bodies within the bone defect area are then removed. The surgical area is rinsed with saline solution, and the bone surface at the edge of the bone defect is lightly abraded to create a fresh bone wound surface to improve the integration of the scaffold with the bone tissue. Finally, electrocoagulation or biological hemostatic materials are used to thoroughly stop bleeding in the surgical area, ensuring a clear surgical field and preventing blood pooling from affecting the establishment of blood supply after scaffold implantation.

[0020] Step 3: Precise positioning and implantation of the stent; Based on preoperative imaging planning and the orientation of bone trabeculae, the customized scaffold body is precisely placed in the bone defect / bone augmentation area, ensuring that the direction of the scaffold's helical channel network is consistent with the direction of blood flow perfusion in the surgical area, and that the radial helical gradient distribution of the lattice units is adapted to the blood supply gradient of the surrounding bone tissue. The scaffold position is adjusted to ensure that the scaffold body fits tightly against the bone wound, and that the convex structure on the outer wall is aligned with the edge of the bone tissue to lay the foundation for the mechanical interlocking effect. If the central area of ​​the scaffold has a through-channel structure, it is necessary to ensure that the channels are connected to the blood supply pathways of the surrounding bone tissue. If it is an auxiliary support structure, it is confirmed that the support structure does not obstruct the flow path of the helical channels. The stability of the scaffold is initially checked to ensure that the scaffold is not loose or displaced, and that the helical channel network is not blocked due to the implantation operation, ensuring that body fluids and nutrients can flow in normally.

[0021] Step 4: Fixing the bracket and reinforcing the interface; The scaffold's lateral wall protrusions form a mechanical interlock with the surrounding bone tissue and extracellular matrix. If the bone tissue conditions in the surgical area permit, the protrusions are fixed to the bone tissue using biocompatible screws, or absorbable bone cement is used to fill the gap between the scaffold and the bone surface to enhance the interfacial bonding strength and prevent postoperative scaffold detachment. Based on the principles of cellular fluid dynamics, the arrangement of lattice units is confirmed through intraoperative imaging to ensure that the cell parameters of adjacent lattices are adapted to the blood perfusion requirements of the surgical area, promoting the gradual infiltration of blood flow along the spiral channel network and creating conditions for the formation of a "high-speed guide-low-speed vortex" composite flow field. The surgical area is then rinsed again with physiological saline to remove bone debris and tissue residue generated during the operation, preventing blockage of the spiral channels and affecting the efficiency of material transport.

[0022] Step 5: Surgical area closure and drainage setup; The soft tissue is sutured in layers. First, the periosteum is sutured to ensure that the stent is completely wrapped and firmly fixed. Then, the subcutaneous tissue and the skin / mucosa are sutured in sequence. During suturing, excessive traction should be avoided to prevent stent displacement. Ensure that the surgical area is tightly closed. If the surgical area is large or a lot of exudate is expected, a drainage tube (such as a negative pressure drainage tube) is placed before suturing. The drainage port should be placed away from the core area of ​​the stent to ensure that postoperative fluid and metabolic waste can be drained smoothly. This works in conjunction with the "passive pump" effect of the stent to prevent the accumulation of fluid in the surgical area. Finally, the surgical area is bandaged with pressure (orthopedic surgery) or hemostatic cotton rolls are placed (oral surgery) to reduce postoperative bleeding and swelling.

[0023] Further optimization of the scheme resulted in an average aperture of 200-500 micrometers for the lattice units and a wire diameter of 100-250 micrometers; the spiral channel network was either a left-handed or right-handed spiral with a pitch of 500-1200 micrometers and a spiral radius of 2-4 millimeters.

[0024] To further optimize the scheme, the spiral type of the spiral channel network is selected from one or more combinations of spirals generated by Archimedes spirals, spirals generated by logarithmic spirals, spirals generated by cylindrical spirals, or double spiral structures.

[0025] Further optimization of the scheme involves adjusting the cell parameters of adjacent lattice units during the arrangement of lattice units to regulate the blood perfusion state of the helical pore network, thereby promoting the gradual penetration of blood along the helical direction.

[0026] Further optimization of the design involves using one or more of the following materials to prepare the scaffold body: bioceramic materials, metallic materials, or polymeric materials. Bioceramic materials include bioglass, tricalcium phosphate, and hydroxyapatite; metallic materials include titanium and titanium alloys, tantalum and tantalum alloys, magnesium and magnesium alloys, and zinc and zinc alloys; and polymeric materials include PLA, PCL, PLGA, PEEK, and PEKK.

[0027] The design was further optimized, and the support body was integrally formed using 3D printing technology.

[0028] The design was further optimized so that the central area of ​​the support body is a through-hole structure.

[0029] Further optimization of the design resulted in a mechanical interlocking effect between the protruding structure on the outer wall of the scaffold and the extracellular matrix.

[0030] To preliminarily verify the ability of the stent of this invention to establish initial blood supply in a simulated physiological limited fluid environment, a dynamic blood absorption rate comparison experiment was designed, using an evaluation method that simulates the limited tissue fluid environment in the early stage of bone implantation, as detailed below: Three types of scaffolds with a porosity of 60±5% (the biomimetic helical chiral scaffold, the helical chiral cubic scaffold, and the simple cellular scaffold of this invention) were prepared to ensure that the structure was the only variable. The droplet test method, which simulates the physiological limited fluid environment, was used to test and compare the dynamic blood absorption rate of the three scaffolds to verify the advantages of the helical biomimetic structure in rapidly guiding body fluid infiltration. The scaffold is placed vertically and gently on a pre-dropped quantitative liquid at the bottom of the culture dish. The volume of the liquid droplet is calibrated in a pre-experiment (calculated based on the porosity and volume of the scaffold) and is just slightly larger than the theoretical saturated water absorption capacity of the scaffold. This mode accurately simulates the physiological process in which the surgical area can only achieve infiltration and establish blood supply through limited local tissue fluid in the early stage of bone implantation. It can effectively amplify the differences in body fluid transport performance of different scaffold structures under capillary force, making the evaluation results more physiologically significant and clinically valuable. A high-speed camera was used to record the entire process of the stent from contact with the droplet to the complete absorption of the droplet and the disappearance of surface reflection. The complete filling time was accurately measured by video frame analysis. Fresh anticoagulated bovine blood (containing sodium citrate anticoagulant) at 37°C was used to simulate the blood environment at human physiological temperature. The ambient temperature was kept constant at 25°C. Three parallel samples were set for each group of stents to ensure the objectivity and repeatability of the experimental results.

[0031] The specific process is as follows: 1. Design and print helical chiral biomimetic scaffolds, helical simple cell scaffolds, and simple cell scaffolds with the same porosity (60±5%); 2. Test the blood absorption capacity of three types of stents to verify the advantages of the spiral biomimetic structure in preserving blood supply; 3. To provide structural design references for the application of bioceramic scaffolds in tissue engineering.

[0032] Experimental materials Bioceramic AW composite powder (hydroxyapatite / β-tricalcium phosphate = 7:3), polyethylene glycol-polypropylene glycol block copolymer binder, fresh anticoagulant bovine blood, physiological saline, sodium citrate.

[0033] Experimental equipment Bioceramic 3D printer (makex product), vacuum drying oven, electronic balance, pipette, water bath, petri dish, filter paper, etc.

[0034] 1. Support dimensions: Cylindrical support, 6mm in diameter × 6mm in height, with a 1.5mm diameter channel in the middle to simulate a Haver tube. 2. Target porosity: 60±5%; The blood-sucking ability test data is as follows:

[0035] Experimental Analysis and Discussion The three scaffolds have similar porosity and cell parameters, so the significant difference in blood absorption rate is mainly due to the differences in their structural design: The spiral channel of the helical bionic stent simulates the spiral direction and surface curvature of human blood vessels, forming a continuous and unobstructed three-dimensional fluid channel, reducing resistance during blood permeation and promoting rapid and uniform filling of pores (uniform overall distribution). The cubic orthogonal structure of simple unit cell scaffolds has problems such as abrupt channel corners and discontinuous fluid paths. Blood is prone to forming eddies or stagnating in the pores, resulting in some pores not being fully filled with blood and reducing blood absorption efficiency.

[0036] The mechanism by which the helical structure retains a stronger blood supply capacity The continuity of the spiral channel enhances the depth of blood penetration, allowing blood to reach deeper pores inside the stent rather than just staying on the surface. The curved design of the spiral structure reduces the frictional resistance between blood and the stent wall, while enhancing the stability of blood retention in the pores, making it less prone to loss due to slight external disturbances, thus better maintaining long-term blood supply.

[0037] The results showed that, under simulated physiological limited fluid supply conditions, the biomimetic helical chiral scaffold had the best blood absorption rate, with a complete filling time of only 1.3 ms, which was about 130% faster than the traditional simple cellular scaffold. This demonstrated its absolute advantage in rapidly guiding body fluid infiltration and establishing blood supply in the early stages. Moreover, the evaluation results can accurately reflect the scaffold's ability to establish blood supply in actual clinical applications.

[0038] In summary, the helical chiral biomimetic scaffold structure proposed in this invention outperforms the simple cubic structure in terms of blood absorption speed, blood permeability uniformity, and blood supply retention capacity. In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0039] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A biomimetic helical chiral porous bone repair and augmentation scaffold, characterized in that, The application relates to a scaffold body which is composed of a plurality of lattice cell arrays, each of the lattice cells being a bionic trabecular bone cell element; the lattice cells follow the natural spiral arrangement rule of human trabecular bones, so that a continuous and through spiral channel network is formed in the scaffold body; the lattice cells are distributed in a spiral gradient along the radial direction of the scaffold body, and the outer wall of the scaffold body is provided with a convex structure which is integrally formed with the lattice cells. The average pore diameter of the lattice cells is 200-500 microns, and the wire diameter is 100-250 microns; the spiral direction of the spiral channel network is left-handed spiral or right-handed spiral, the pitch is 500-1200 microns, and the spiral radius is 2-4 mm.

2. The bionic helical chiral porous bone repair and augmentation scaffold according to claim 1, wherein, The spiral type of the spiral channel network is selected from one or more combinations of spirals generated by Archimedes spiral lines, spirals generated by logarithmic spiral lines, spirals generated by cylindrical spiral lines or double helix structures.

3. The bionic helical chiral porous bone-repairing and bone-augmenting scaffold according to claim 1, characterized in that, In the arrangement process of the lattice cells, the blood perfusion state of the spiral channel network is adjusted by regulating the cell parameters of adjacent lattice cells, so that the blood flow gradually penetrates along the spiral direction.

4. The bionic helical chiral porous bone-repairing and bone-augmenting scaffold according to claim 1, wherein, The scaffold body is prepared by using one or more of a bioceramic material, a metal material or a polymer material; the bioceramic material includes bioglass, tricalcium phosphate and hydroxyapatite, the metal material includes titanium and titanium alloy, tantalum and tantalum alloy, magnesium and magnesium alloy, zinc and zinc alloy, and the polymer material includes PLA, PCL, PLGA, PEEK and PEKK.

5. The bionic helical chiral porous bone-repair and bone-augmentation scaffold of claim 1, wherein, The scaffold body is integrally formed by a 3D printing technology.

6. The bionic helical chiral porous bone-repairing and bone-augmenting scaffold according to claim 1, wherein, The central region of the scaffold body is a through channel structure.

7. The bionic helical chiral porous bone-repairing and bone-augmenting scaffold according to claim 1, wherein, The convex structure of the outer wall of the scaffold body forms a mechanical interlocking effect with the extracellular matrix.

8. The bionic helical chiral porous bone-repairing and bone-augmenting scaffold according to claim 1, wherein, ​

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