Parametric Modeling of Biomimetic Cortical Bone Microstructure for Additive Manufacturing

Abstract

In this work we present a novel algorithm for generating in-silico biomimetic models of a cortical bone microstructure towards manufacturing biomimetic bone via additive manufacturing. The software provides a tool for physicians or biomedical engineers to develop models of cortical bone that include the inherent complexity of the microstructure. The correspondence of the produced virtual prototypes with natural bone tissue was assessed experimentally employing Digital Light Processing (DLP) of a thermoset polymer resin to recreate healthy and osteoporotic bone tissue microstructure. The proposed tool was successfully implemented to develop cortical bone structure based on osteon density, cement line thickness, and the Haversian and Volkmann channels to produce a user-designated bone porosity that matches within values reported from literature for these types of tissues. Characterization of the specimens using a Scanning Electron Microscopy with Focused Ion Beam (SEM/FIB) and Computer Tomography (CT) revealed that the manufacturability of intricated virtual prototype is possible for scaled-up versions of the tissue. Modeling based on the density, inclination and size range of the osteon and Haversian and Volkmann´s canals granted the development of a dynamic in-silico porosity (13.37–21.49%) that matches with models of healthy and osteoporotic bone. Correspondence of the designed porosity with the manufactured assessment (5.79–16.16%) shows that the introduced methodology is a step towards the development of more refined and lifelike porous structures such as cortical bone. Further research is required for validation of the proposed methodology model of the real bone tissue and as a patient-specific customization tool of synthetic bone.

Biologically Inspired Collagen/Apatite Composite Biomaterials for Potential Use in Bone Tissue Regeneration—A Review

“…Adaptation of bone structure to perform such important functions includes a number of organizational levels. These include: the molecular structure and distribution of crystals and organic components (nanoscale); the structure of bone plates; the structure and arrangement of spongy bone tissue and osteons of compact bone tissue; and macroscopic structure (macroscale) ( Figure 1) [20,21]. The bone has a hierarchical structure: from the level of the whole tissue, i.e., the occurrence of various types of long and short bones, flat or tubular, to the level of the tissues which are arranged in cortical and spongy structures, through to the microscopic level (images of cells, matrices and minerals) to the level of nanometers from single bone apatite crystals and collagen fibers [20,22].…”

“…Bone tissue also includes other non-collagen proteins and water. In general, apatite ensures bone hardness, while the organic fraction forms the scaffold for the biomineral and regulates the biomineralization process [21].…”

An original method of simulating the articular cartilage in the context of in vitro biomechanical studies investigating the proximal femur

“…The characteristics of the hip cartilage were taken from data reported in the literature (1). Acrylonitrile butadiene styrene (ABS) is a thermoplastic polymer of fossil source obtained through the polymerization of styrene and butadiene in the presence of acrylonitrile, which allows the manufacturing of models using additive manufacturing technology (14,15). To simulate the articular cartilage at the level of the femoral head and condyles and to achieve a uniform distribution of the compression forces, the loading was carried out using two 3D-printed parts made on a Stratasys FORTUS 250 mc computer numerical control (CNC) machine (Stratasys, Ltd.) using ABS-M30 (Stratasys, Ltd.).…”

“…The characteristics of the hip cartilage were taken from data reported in the literature ( 1 ). Acrylonitrile butadiene styrene (ABS) is a thermoplastic polymer of fossil source obtained through the polymerization of styrene and butadiene in the presence of acrylonitrile, which allows the manufacturing of models using additive manufacturing technology ( 14 , 15 ).…”

A Review on Development of Bio-Inspired Implants Using 3D Printing

“…Initially, in silico biomimetic models were generated through parametric modeling. From the microstructures, it was understood that the intricate hierarchical structure has acceptable porosity levels [ 39 ]. Direct Ink Writing (DIW), an AM approach used to construct viscoelastic ink layer by layer, can be made of hydroxyapatite for engineered bone applications [ 40 ].…”