Page 27 - v11i4

International Journal of Bioprinting 3D-printed scaffolds for osteochondral defect

5. Discussion within the cartilage changes at a length scale ranging from
10 to 100 μm. 149,150
5.1. 3D printing methodology
With the development of bioprinting methods and ink In contrast, scaffolds designed with a microarchitectural
materials compatible with bone engineering, various gradient strategy tend to apply SLA and DLP, 60,61,58,59 as
3D printing techniques have been applied to fabricate these printing methods offer higher resolution and can
osteochondral scaffolds. Conventional 3D printing, such create finely detailed microstructures. 151,152 In particular,
as SLA, FDM, and selective laser sintering (SLS), involves microstereolithography (μSLA) enables layer-by-layer
layer-by-layer deposition of materials. In contrast, 3D fabrication of high-resolution constructs with spatially
bioprinting creates 3D artificial implants or complex programmable mechanical properties. By precisely
tissues through layer-by-layer deposition of living cells, regulating exposure parameters (e.g., duration, light
ECM, and other biomaterials. Common techniques for intensity), this technique achieves z-axis control over both
bioprinting include inkjet-based bioprinting, extrusion- microstructure and compressive modulus at 10–50 μm
based bioprinting, and laser-assisted bioprinting. 147 resolution. 58,153 Such precision facilitates the development
of biomimetic osteochondral scaffolds replicating
As shown in the studies of hierarchical printed scaffolds
in Table 2, scaffolds employing different strategies tend to native tissue’s hierarchical mechanical gradients. The
characteristics of various printing technologies are
adopt specific 3D printing technologies. Extrusion-based summarized in Table 3.
printing is the most commonly used method across all
strategies. Extrusion-based bioprinting is compatible In addition to manufacturing the structure of the
with a wide variety of materials and does not involve scaffold itself, creating fine micro-structures at the
a heating process, making it particularly suitable for interlayer interfaces using high-precision 3D printing
printing materials with high cell densities and biological techniques also positively impacts the interfacial bonding
activity. 147,148 Due to nozzle size limitations, extrusion- and strength. Section 4.2 discusses methods to enhance
inkjet-based 3D printing can only produce microstructures interface strength through interlocking design. The
at a minimum scale of 100 µm. However, the fine strain interlocking features created by high-resolution methods,
58

Table 3. Comparison of 3D printing technologies for osteochondral scaffold design

Technology Advantages Disadvantages Materials
Inkjet-based Low cost Limited resolution Low-viscosity biomaterials (<20 mPa·s)
printing 147,154,155 High cell viability Non-continuous printing
High throughput Nozzle clogging
Heat damage to cells
Extrusion-based Broad range of bioink selection Limited resolution Compatible with a wide range of materials
printing 62,148,150,156 Short fabrication time Shear stress damage to cells
High cell density and ≠viability
Laser-based printing 157 High resolution High cost Photocurable resins/nanocomposites
High cell viability and density Long fabrication time Wide range of viscosities
Nozzle-free Relatively low 3D built-up
capability
SLA 158,159 High resolution Limited materials Resins only
Layer thickness adjustable High cost
Smooth surface finish Post-processing required
FDM 73,151,160,161 Quick fabrication Limited materials Molten thermoplastic material only
Low-cost Limited resolution
Strong layer bonding
DLP 61,162 High resolution Limited materials Photopolymers
Slow fabrication
MEW 45,155 Ultra-fine fiber production Limited materials Thermoplastic conductive polymers
Precise porosity control High cost
Slow fabrication
Abbreviations: DLP, digital light processing; FDM, fused deposition modeling; MEW, melt electrospinning writing; SLA, stereolithography.

Volume 11 Issue 4 (2025) 19 doi: 10.36922/IJB025120100