Page 372 - IJB-10-5

International Journal of Bioprinting Tunable anisotropic gyroid bioscaffolds

mathematical algorithms. The equation-driven architecture properties and stability compared to other bioceramics.
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enables customization of lattice type, unit cell dimensions, By controlling the parameters of the level-set equations
strut sizes, volume fraction, and curvature distribution, of the gyroid structure, we achieved spatially controlled
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which is conducive to regulating cellular behaviors. Recent porosity and anisotropic properties, generating structures
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studies have demonstrated that mimicking the anisotropy with radially graded porosity (40–60%) to mimic trabecular
of natural bone, along with spatially controllable porosity, bone. The scaffolds were fabricated through DLP, followed
can achieve tunable mechanical properties and reduce the by a susceptor-assisted hybrid pyrolysis-sintering (SHPS)
in vivo stress shielding effect, potentially improving scaffold process utilizing MW heating. This innovative method
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integration. This allows for the optimization of mechanical effectively reduces defects and mitigates crack formation
properties, enabling the creation of scaffolds that are strong during rapid MW sintering, leading to reduced defect
and stiff where needed, yet lightweight and porous in other volume by 16.81% and improved compressive strength
regions. This tunability in mechanical properties is crucial by 336% compared to conventional furnace heating.
for matching the mechanical behavior of the scaffold to the Additionally, our study revealed that an increase in aspect
surrounding bone tissue, and consequently enhances the ratio of the unit cell amplified the anisotropic mechanical
integration with the host bone, promoting more effective properties of the gyroid structure. However, while the
bone repair and regeneration. Leveraging advanced additive scaffolds exhibit minimal cytotoxicity, this adjustment
manufacturing techniques and innovative 3D-printable slightly decreases cell proliferation efficiency compared to
biomaterials are expected to contribute to the development the uniform gyroid structure due to variations in Gaussian
of functional biodevices. 7,9–11 However, optimal TPMS curvatures. This paper presents a design approach for
design for enhanced bone regeneration remains a topic of fabricating equation-driven TPMS structures, including but
ongoing research. not limited to gyroid structures, with controlled mechanical
properties, and elucidates the correlation between geometric
Three dimensional (3D) printing is a promising characteristics and both mechanical properties and in vitro
technology for producing bone implants and constructs cell responses. In addition to the potential of mitigating
due to the capability of fabricating complex, precise, and the stress shielding effect through computer-aided scaffold
customized structures with controlled architectures and design, our findings also have wider implications for
properties. The major advantages of 3D cell culture advanced biodevice development. This encompasses the
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are the ability to create a realistic microenvironment for integration of piezoelectric materials, enabling advanced
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cells, facilitate cell–cell and cell–matrix interactions, thus functionalities such as directional biosensing capabilities.
enhancing the cell growth and proliferation. 13,14 Currently,
3D printing of ceramic can be achieved by developing 2. Methodology
photocurable ceramic/polymer composites followed by
lithography-based process such as stereolithography and This study presents a mathematical approach and additive
digital light processing (DLP). 15–18 However, generation of manufacturing process for fabricating different gyroid
dense 3D ceramic generally required lengthy debinding and scaffolds with precisely controlled geometrical properties.
sintering processes to achieve highly densified products, Gyroid scaffolds with controlled porosity and tunable
which reduce the throughput of the manufacturing process anisotropic characteristics were achieved by manipulating
and limit their potential applications. To mitigate this the double iso-surface value and the geometric parameters
limitation, susceptor-assisted microwave heating (SMWH) of the level-set equation. DLP technology was utilized to
offers a promising and time-saving alternative for sintering realize the gyroid design, and an innovative pyrolysis-
ceramic specimens, due to its intrinsic heating mechanism sintering hybridization method based on SMWH was
that lowers sintering activation energy and processing implemented with the goal of improving the quality of
temperature. 19–21 Despite offering a more reliable and the final product. Through this integrated approach, we
controllable sintering process, 22,23 challenges such as crack aimed to demonstrate an advanced design and fabrication
formation associated with the rapid heating have limited its strategy of scaffolds for bone regenerative engineering,
utilization in additive manufacturing processes. Further facilitating their broader application across various fields.
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research is needed to improve the process and fully exploit 2.1. Design of graded gyroid structure with
the advantages of microwave (MW) technology to enhance controlled properties
the throughput of the 3D scaffolds manufacturing. Different criteria need to be considered when designing

In this proof-of-concept study, we introduced a design a scaffold for bone tissue engineering to achieve optimal
methodology for creating sheet gyroid structures with physical, mechanical, and morphological properties.
tailored geometrical properties, employing bioinert silica Sheet gyroid-type TPMS structure was adopted due to
as the model materials due to its superior mechanical its excellent interconnectivity, fluid permeability, and

Volume 10 Issue 5 (2024) 364 doi: 10.36922/ijb.3609