Auxetic Artificial Bone Structure with Hexagonal Osteons
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Solution Overview
Problem
Conventional medical implants lack the mechanical properties similar to natural tissues, such as tensile strength and elasticity, which are essential for effective replacement and integration with the body.
Innovation Solution
An artificial bone structure comprising a solid cylindrical portion with an auxetic structure of artificial osteons, each formed by hexagonal units with predefined gaps, and a hollow cylindrical portion for artificial bone marrow, fabricated using a solution of hydroxyapatite and Polyacrylonitrile (PAN) or Dimethylformamide, and manufactured using 3D printing technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional medical implants are used, then biocompatibility is improved, but tensile strength and elasticity are insufficient
Solution Approach 1:
The patent employs composite materials consisting of hydroxyapatite particles embedded in a polyacrylonitrile matrix. This composite structure combines the biocompatibility of hydroxyapatite with the mechanical flexibility and elasticity of the polymer matrix, resolving the contradiction between biocompatibility and tensile strength/elasticity.
Solution Approach 2:
The patent utilizes a porous lattice structure with controlled porosity to provide both mechanical integrity and flexibility. The porous configuration allows the implant to exhibit elastic deformation while maintaining structural strength, addressing the requirement for both tensile strength and elasticity.
2Reliability
If natural bone properties are replicated, then integration with body is improved, but manufacturing complexity increases
Solution Approach 1:
The patent controls the porosity parameter of the lattice structure and adjusts the composition ratio of hydroxyapatite to polyacrylonitrile to achieve natural bone-like mechanical properties. By optimizing these parameters, the implant integrates well with body tissues while maintaining manufacturability through 3D printing.
Solution Approach 2:
The patent applies different material compositions and structural densities to different regions of the implant to match the local quality requirements of natural bone. The lattice structure provides flexibility in certain areas while denser regions provide strength, enabling natural integration without excessive manufacturing complexity.
3Strength
If auxetic structure with negative Poisson's ratio is used, then flexibility and shock absorption are improved, but structural stability may be compromised
Solution Approach 1:
The patent employs a porous lattice structure with optimized pore geometry to achieve auxetic behavior. The specific pore configuration provides negative Poisson's ratio characteristics for enhanced flexibility and shock absorption while maintaining structural stability through the interconnected nature of the lattice.
Solution Approach 2:
The composite of hydroxyapatite and polyacrylonitrile in the lattice structure provides both structural stability and auxetic properties. The polymer matrix maintains the structural integrity of the lattice while the hydroxyapatite particles provide mechanical strength, allowing the structure to be stable yet flexible.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The artificial bone structure mimics natural bone properties, providing enhanced flexibility and shock absorption, potentially improving integration and durability as a medical implant.
Implementation Method 1
a lattice structure with a negative Poisson's ratio... configured to exhibit an auxetic behavior when subject to compression generally perpendicular to a surface plane
Implementation Method 2
a second layer coupled to the first layer, the second layer comprising a plurality of compressible column springs... Each of the plurality of compressible column springs comprises a plurality of stacked coils, and each of the plurality of stacked coils has a spring constant (K)
Implementation Method 3
fabricated using a solution of hydroxyapatite and Polyacrylonitrile (PAN) or Dimethylformamide
Data Source
AI summary
Disclosed is an artificial bone structure for replacement of natural bone and comprising a solid cylindrical portion having an elongate shape. The solid cylindrical portion comprises an auxetic structure of a plurality of artificial osteons and each artificial osteon comprises a first hexagonal unit and a second hexagonal unit having corresponding edges. Furthermore, a first artificial osteon and a second artificial osteon of the plurality of artificial osteons are connected to each other using an edge of a third artificial osteon and about a central axis of each of the first artificial osteon and the second artificial osteon. Moreover, the artificial bone structure comprises a hollow cylindrical portion having an elongate shape, disposed inside of and concentrically with the solid cylindrical portion. The hollow cylindrical portion is configured to comprise an artificial bone marrow therein.