A 3D-printed biodegradable drug-loaded artificial bone repair scaffold

Abstract

This invention discloses a 3D-printed biodegradable drug-loaded artificial bone repair scaffold, belonging to the field of orthopedic implant technology. The scaffold adopts a gradient porous structure and biodegradable composite material, with internal through-holes and tapered interfaces on the surface, which can load drugs for sustained release. It also has functions of bone induction, anti-infection, mechanical support and prosthesis adaptation, and is suitable for individualized repair of large bone defects after bone tumor resection.

Description

Technical Field

[0001] This invention relates to the fields of orthopedic implants, bone defect repair, biodegradable materials and 3D printing technology, specifically to a biodegradable, drug-loaded, gradient porous artificial bone scaffold for repairing large bone defects after bone tumor resection. Background Technology

[0002] Bone defects and osteonecrosis are common orthopedic diseases, caused by factors such as trauma, tumor resection, infection, and ischemic necrosis, severely impacting patients' skeletal function and quality of life. Currently, mainstream clinical repair methods include autologous bone grafting, allogeneic bone grafting, and artificial bone scaffold implantation. Autologous bone grafting has drawbacks such as significant donor site trauma, limited bone volume, and numerous complications; allogeneic bone grafting is prone to immune rejection and carries risks of disease transmission and low bone healing efficiency. Artificial bone scaffolds, providing a three-dimensional support for bone cell growth and integrating functions such as drug release and biomechanical adaptation, have become a core research direction in the field of bone repair.

[0003] However, compared to existing technologies, the applicant has identified the following issues: I. Non-degradability and the risk of foreign body reaction: Traditional artificial bone scaffolds mostly use non-degradable materials such as metals and inert ceramics, which remain in the body for a long time after implantation and cannot be absorbed or replaced by the body. These foreign bodies can continuously trigger the body's immune response, leading to complications such as inflammation, fibrous capsule encapsulation, and tissue adhesion, and may even require a second surgery to remove them, increasing patient suffering and medical burden.

[0004] Second, vascularization is difficult, bone healing efficiency is low, and bone regeneration depends on a sufficient blood supply to ensure the transport of nutrients and the removal of metabolic waste. Traditional scaffolds are mostly porous structures with a single pore size, poor pore permeability, and lack a dedicated drainage channel design, making it difficult for host blood vessels to grow into the core area of ​​the scaffold, forming an "ischemic necrosis" area, where bone cells cannot survive and proliferate due to lack of nutrition; Third, traditional repair materials also have problems such as high risk of infection, lack of drug release, and poor compatibility with prostheses, resulting in a lack of integrated and individualized precise repair solutions in clinical practice.

[0005] Therefore, this invention proposes a 3D-printed biodegradable drug-loaded artificial bone repair scaffold to solve the above problems. Summary of the Invention

[0006] This invention provides a 3D-printed biodegradable drug-loaded artificial bone repair scaffold. Through structural innovation, material optimization, functional integration, and upgraded manufacturing process, it achieves synergy between biodegradability and bone healing cycle, efficient vascularization induction and nutrient delivery, precise sustained release of anti-infection and bone induction, dual stable matching between the prosthesis and host bone, and unified individualized and integrated repair. It fundamentally solves the technical pain points of traditional solutions, improves bone repair effect, and reduces the incidence of complications.

[0007] Therefore, this invention provides a 3D-printed biodegradable drug-eluting artificial bone repair scaffold, comprising a scaffold body made of a biodegradable material formed by a composite of β-TCP and hydroxyapatite. Both β-TCP and HA are natural inorganic components of human bone tissue, exhibiting excellent biocompatibility and no immunogenicity. They can be gradually degraded and absorbed by the body, and their degradation products can participate in bone tissue metabolism, promoting new bone formation. The material degradation cycle is precisely controlled to 6–12 months, completely synchronized with the human bone healing cycle. After the newly formed bone tissue has sufficient mechanical strength, the scaffold gradually degrades and disappears, completely avoiding foreign body residue and reactions. The scaffold features a gradient porous structure with interconnected drainage pores to promote vascularization. The scaffold body has a three-layer gradient porous structure: an outer layer, a middle layer, and an inner layer from the outside in. The outer layer has a pore size of 300–500 μm, facilitating rapid migration and attachment of host bone cells and initial vascular ingrowth. The middle layer has a pore size of 200–300 μm, serving as a transitional channel for blood vessels and bone cells to permeate into the core region. The inner layer has a pore size of 100–200 μm, facilitating drug adsorption and sustained release while providing fine support for new bone formation. The overall porosity of the scaffold is 60%–80%, ensuring a balance between porosity and mechanical strength.

[0008] In addition, the stent body has at least one through-hole with a diameter of 50-150 μm along the axial direction inside. It penetrates both ends of the stent body and is interconnected with the gradient porous structure, which accelerates blood vessel ingrowth, nutrient infiltration and metabolic waste removal, thus structurally solving the pain point of difficult vascularization of traditional stents.

[0009] The scaffold utilizes a composite drug loading and precise sustained release system. Its gradient porous structure contains a composite drug system consisting of antibiotics and osteoinductive factors. Through the adsorption effect of the porous structure and the synergistic regulation of material degradation, the drug release cycle is precisely controlled to 2–4 weeks, perfectly matching the postoperative infection peak and critical period of osteocyte proliferation. Initially, rapid drug release establishes an effective antibacterial concentration, inhibiting bacterial growth; subsequent slow release maintains therapeutic efficacy while continuously stimulating bone regeneration. This eliminates the need for additional systemic medication, reducing the risk of infection while enhancing osteoinduction, achieving a synergistic effect of anti-infection and bone repair. The surface of the scaffold body is provided with a tapered interface that matches the matching prosthesis, with a taper of 1:10. An interference fit ensures a tight connection between the scaffold and the prosthesis, resulting in a high degree of fit and zero gap, preventing loosening and displacement. Simultaneously, an integrated connection interface is provided on the outer side of one end of the scaffold body. This interface can be a ring groove, a threaded structure, or a snap-fit ​​structure, used for fixation to the host bone tissue via screws, bone cement, or a one-piece molding method, further enhancing connection stability. This dual-interface design structurally solves the problems of poor compatibility and insecure fixation in traditional scaffolds and prostheses, achieving a stable connection between the scaffold, prosthesis, and host bone. The scaffold body is individually fabricated using CT / MRI three-dimensional reconstruction and 3D printing technology. This fabrication method can achieve complete fit between the scaffold and the patient's bone defect area, solving the problem of poor adaptability of traditional standardized scaffolds; at the same time, the type and dosage of drug loading and the material composite ratio can be adjusted according to the different patients' infection risk and bone healing ability.

[0010] Compared with existing technologies, the advantages of this invention are: the β-TCP / HA composite biomaterial is degradable and has excellent biocompatibility, with a degradation cycle of 6 to 12 months, which is precisely matched with the bone healing cycle. The scaffold gradually degrades and is absorbed by the human body, leaving no foreign matter. This fundamentally avoids the immune response and secondary surgery risks caused by traditional non-degradable materials. The three-dimensional transport network formed by the gradient porous structure and the through-holes has a large outer pore size that facilitates vascular ingrowth, a middle layer with transitional pore size that promotes vascular permeability, and through-holes that accelerate nutrient transport. This solves the pain point of difficult vascularization in traditional stents, ensures the survival and proliferation of osteocytes in the core area of ​​the stent, and significantly shortens the bone healing cycle.

[0011] The loaded antibiotics achieve precise sustained release over 2 to 4 weeks, forming a sustained and effective antibacterial concentration during the high-incidence period of postoperative infection. This eliminates the need for systemic medication, enhances anti-infection efficacy, reduces drug resistance and drug toxicity, and fundamentally lowers the risk of postoperative infection. The synergistic release of osteoinducing factors and antibiotics continuously stimulates osteoblast proliferation and differentiation, solving the problem of insufficient osteoinducing capacity of traditional scaffolds and promoting rapid growth and remodeling of new bone. The 1:10 tapered interface achieves a precise interference fit with the prosthesis, while the integrated connection interface ensures a firm fixation with the host bone. This dual protection prevents the stent from loosening or shifting, solving the defects of poor matching and insecure fixation of traditional stents and prostheses.

[0012] Based on CT / MRI three-dimensional reconstruction and 3D printing for individualized fabrication, the stent can be perfectly adapted to the anatomical morphology of the patient's bone defect; at the same time, it integrates multiple functions such as biodegradability, vascularization induction, anti-infection, drug sustained release, and matching fixation, providing an integrated and precise repair solution, and completely overcoming the limitations of traditional stents with single function and poor adaptability. In summary, this invention, through multi-dimensional technological innovation, comprehensively solves the core defects of traditional bone repair materials, achieving an integrated repair goal of "degradability, promoting angiogenesis, anti-infection, stable and sustained release, precise matching, and individualization." It has extremely high clinical application value and is expected to become a new generation of core products in the field of bone repair. Attached Figure Description

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

[0014] Figure 1 This is a schematic diagram of the main structure of a 3D-printed biodegradable drug-loaded artificial bone repair scaffold provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the front end of a 3D-printed biodegradable drug-loaded artificial bone repair scaffold provided in an embodiment of the present invention; Figure 3 This is an appendix to the present invention. Figure 1 Enlarged structural diagram of the central through-hole.

[0015] As shown in the figure, the reference numerals in the accompanying drawings of this invention are as follows: 1. Support body; 2. Through-flow guide hole; 3. Tapered interface; 4. Integrated connection interface. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0017] The present invention provides a 3D-printed biodegradable drug-loaded artificial bone repair scaffold, which includes the following embodiments: First embodiment: Combination Figures 1-2This invention discloses a 3D-printed biodegradable drug-loaded artificial bone repair scaffold, comprising a scaffold body 1. The scaffold body 1 has a gradient porous structure and is made of a composite biodegradable material of β-TCP and hydroxyapatite. The scaffold body 1 can be gradually degraded and absorbed by the human body in vivo. The degradation products can participate in bone tissue metabolism. After the newly formed bone tissue has sufficient mechanical strength, the scaffold gradually degrades and disappears, completely avoiding foreign body residue and foreign body reaction. The scaffold body 1 has a through-hole 2 along the axial direction inside. The through-hole 2 penetrates both ends of the scaffold body 1. The diameter of the through-hole 2 is 50–150 μm, and the through-hole 2 is interconnected with the gradient porous structure of the scaffold body 1.

[0018] It forms a three-dimensional transport system with a main flow channel and a branch pore network, which accelerates blood vessel ingrowth, nutrient infiltration and metabolic waste removal, and structurally solves the pain point of traditional stent vascularization difficulties.

[0019] The surface of the support body 1 is provided with a prosthesis-matching tapered interface 3, and the tapered interface 3 has a taper of 1:10; It is loaded with antibiotics and osteoinducing factors; through interference fit, the stent and the prosthesis are tightly connected, with high fit and zero gap, avoiding loosening and displacement.

[0020] The gradient porous structure comprises an outer layer, a middle layer, and an inner layer, which are distributed sequentially from the outside to the inside. The outer layer has a pore size of 300–500 μm, which facilitates the rapid migration and attachment of host bone cells and the initial ingrowth of blood vessels; The middle layer has a pore size of 200–300 μm, serving as a transitional channel for blood vessels and bone cells to penetrate into the core region.

[0021] The inner layer has a pore size of 100–200 μm, and the overall porosity of the scaffold body 1 is 60%–80%, which is conducive to drug adsorption and sustained release, while providing fine support for new bone formation.

[0022] Second embodiment: Combination Figures 1-2 This invention discloses a 3D-printed biodegradable drug-loaded artificial bone repair scaffold, wherein... The drug release cycle inside the scaffold body 1 is 2–4 weeks, and the material degradation cycle is 6–12 months, which is completely synchronized with the human bone healing cycle. After the newly formed bone tissue has sufficient mechanical strength, the scaffold gradually degrades and disappears, completely avoiding foreign body residue and foreign body reaction.

[0023] The scaffold body 1 has an integrated connection interface 4 on one outer side. This interface can be an annular groove or a snap-fit ​​structure, used to fix it to the host bone tissue by screws, bone cement, or integrated molding, further enhancing the connection stability. Structurally, this solves the problems of poor compatibility and unstable fixation between traditional scaffolds and prostheses, achieving a stable connection between the scaffold, prosthesis, and host bone.

[0024] Third embodiment: Combination Figures 1-2 This invention discloses a 3D-printed biodegradable drug-loaded artificial bone repair scaffold, wherein... The scaffold body 1 is fabricated using CT / MRI 3D reconstruction and 3D printing for individualized preparation. Precise anatomical data of the patient's bone defect area is obtained through CT or MRI scans. A digital model of the bone defect area is constructed using 3D reconstruction software. The structural parameters of the scaffold, such as gradient aperture, drainage hole location, and interface size, are optimized based on the patient's anatomical morphology and the mechanical requirements of the repair site. The scaffold body is then fabricated using selective laser sintering (SLS) or fused deposition modeling (FDM) 3D printing. This fabrication method achieves complete fit between the scaffold and the patient's bone defect area, solving the problem of poor adaptability of traditional standardized scaffolds. Furthermore, the type and dosage of drug loading and the material composite ratio can be individually adjusted according to different patients' infection risk and bone healing ability, achieving individualized and precise repair tailored to each patient.

[0025] In summary, the above description is merely a preferred embodiment of the technical solution of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A 3D-printed biodegradable drug-loaded artificial bone repair scaffold, comprising a scaffold body (1), characterized in that, The scaffold body (1) has a gradient porous structure and is made of a biodegradable composite material of β-TCP and hydroxyapatite; The support body (1) has a through-flow hole (2) inside along the axial direction, and the through-flow hole (2) passes through both ends of the support body (1).

2. The surface of the stent body (1) is provided with a prosthesis-matching tapered interface (3) and is loaded with antibiotics and osteoinducing factors.

3. The 3D-printed biodegradable drug-loaded artificial bone repair scaffold according to claim 1, characterized in that, The gradient porous structure comprises an outer layer, a middle layer, and an inner layer, which are distributed sequentially from the outside to the inside. The outer pore size is 300–500 μm; The pore size of the middle layer is 200–300 μm; The inner layer has a pore size of 100–200 μm, and the overall porosity of the support body (1) is 60%–80%.

4. The 3D-printed biodegradable drug-loaded artificial bone repair scaffold according to claim 1, characterized in that, The through-flow hole (2) has a diameter of 50–150 μm, and the through-flow hole (2) is interconnected with the gradient porous structure of the support body (1).

5. The 3D-printed biodegradable drug-loaded artificial bone repair scaffold according to claim 1, characterized in that, The taper of the tapered interface (3) is 1:

10.

6. The 3D-printed biodegradable drug-loaded artificial bone repair scaffold according to claim 1, characterized in that, The drug release period is 2–4 weeks, and the material degradation period is 6–12 months.

7. The 3D-printed biodegradable drug-loaded artificial bone repair scaffold according to claim 1, characterized in that, The scaffold body (1) is prepared by CT / MRI three-dimensional reconstruction and 3D printing individualized fabrication.

8. The 3D-printed biodegradable drug-loaded artificial bone repair scaffold according to claim 1, characterized in that, An integrated connection interface (4) is provided on the outer side of one end of the bracket body (1).

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