Page 192 - IJB-10-5

International Journal of Bioprinting Structural design of D-surface scaffolds

minimal surface structures are of particular interest due toughness performance, making them an ideal candidate for
to their favorable advantages, including good strength and scaffold development.
stiffness, interconnected cellular structure, and designed In terms of bioactivity, the combination of lattice
topography. These structures could efficiently load scaffolds with bioactive factors could better promote new
4–6
external stress and provide the implants with sufficient bone ingrowth and regeneration. 24,25 Platelet-rich plasma
supporting capacity, making them excellent scaffold (PRP) has been recently applied as a therapeutic agent to
candidates in tissue engineering. 7,8 heal damaged tissues, especially in wound dressings. 26–28

Geometry engineering is an effective strategy to It is derived from autologous blood with a certain
improve the performance of the scaffold. The structural platelet concentration with several immunoregulatory
design of the triply periodic minimal surface (TPMS) factors. The rich growth factors found in PRP include
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model could be established using mathematical expressions platelet-derived growth factor (PDGF-AA, BB, and AB),
supported by additive manufacturing techniques. 9–11 transforming growth factor (TGF-β1 and β2), insulin-like
Among the diverse periodic geometric parameters, growth factor (IGF), vascular endothelial growth factor
cellular morphology, porosity, and wall thickness greatly (VEGF), and epithelial growth factor (EGF). It has been
influence the mechanical properties of the model. For demonstrated that PRP significantly contributes to wound
instance, gyroid and diamond (D) surfaces possess good dressing. However, the influence of PRP-loaded scaffolds
bearing capacity. 12–14 Previous work has demonstrated the on bone regeneration warrants further research.
remarkable load-carrying and energy absorption capacity Herein, we investigate the mechanical behavior and
of graded lattices, thereby enabling resistance to impact biological performance of PRP-loaded bone scaffolds
and bone stress. 15–17 Liu et al. proposed a 3D controllable with gradient minimal surface structures. Biodegradable
TPMS structure based on Schwarz P and gyroid surfaces PBAT/PLA blends were selected as scaffolding materials.
for application as a hip implant. Zou et al. developed three The typical minimal D-surface was first utilized to
types of TPMS structures to mimic the properties of bone design gradient structures to mimic natural bone and
scaffolds. The TPMS additively manufactured by Ti-6Al- subsequently fabricated by FFF. In particular, two patterns
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4V achieved enhanced elastic modulus and compressive of the graded geometries, i.e., radially from center to edge or
strength within the range of human bones. Since natural vertically from top to bottom, were successfully realized by
bone consists of dense cortical and cancellous bone, the controlling the thickness of the cellular wall. The influence
construction of graded periodic minimal surface structures of gradient thickness on the internal microstructure and
would be more beneficial as artificial scaffolds.
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mechanical performance was determined. After achieving
In contrast, the mechanical and biological performances the optimized gradient D-scaffold structure, bioactive
of these structures are greatly dependent on the material PRPs were loaded onto the D-scaffolds, and the biological
type. Recently, biodegradable materials have been broadly performance was assessed by in vitro cell viability and in
used in biomedical applications. Meanwhile, three- vivo animal femoral condyle defect. The biological results
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dimensionl (3D) printing technology is an efficient tool to demonstrated good biocompatibility and bioactivity
realize scaffold preparation in association with high efficacy, for bone implantation. The current study provides new
convenience, and precision. Biodegradable polyesters, prospects for scaffold structural design in view of bone
including poly(lactic acid) (PLA), poly(caprolactone) bionics and bioactive factors on osteogenesis.
(PCL), poly(glycolic acid) (PGA), and their blends, have
been used for fused filament fabrication (FFF) in biomedical 2. Materials and methods
applications due to their biocompatibility, biodegradability, 2.1. Materials
and adjustable properties. 19–23 Poly(butylene adipate-co- PBAT with a melting temperature (T ) of 125ºC was
terephthalate) (PBAT) is a biodegradable polyester, which provided by Kanghui New Materials Hi-Tech Co., Ltd.
m
exhibits good elasticity and flexibility. Several studies have (China). PLA (4032D) was purchased from Nature Works
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revealed that PBAT-based composites have the potential for (America).
biomedical applications. Ulbrich et al. proposed 3D-printed
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composite scaffolds of PBAT/niobium-containing bioactive 2.2. Fabrication and 3D printing of poly(butylene
glasses for new bone formation. Qiu et al. proposed a adipate-co-terephthalate)/poly(lactic
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PBAT/sodium alginate blend with better mechanical and acid) composites
biological properties as a candidate for vascular stent. In our PBAT/PLA blends with a weight ratio of 70:30 were
previous work, the PBAT/PLA filaments were 3D-printed prepared using a twin-screw extruder according to previous
into complex lattice structures and had balanced stiffness- literature. Before compounding, the raw pellets were
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Volume 10 Issue 5 (2024) 184 doi: 10.36922/ijb.3416