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International Journal of Bioprinting Bioprinted osteoarthritis scaffolds

OA-related pathology and effectively model bone–cartilage Gel + 1% Alg (9 Gel–1 Alg). Briefly, accurately weighed
interactions under both healthy and diseased conditions. amounts of 7% Gel (3.5 g) and 3% Alg (1.5 g) (Biosharp,
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However, this technology faces challenges in terms of China) were UV-sterilized (254 nm) for 3 h. The sterilized
reproducibility, organ maturity, and the integration powders were then aseptically transferred into a 50 mL
of key elements, such as vasculature, innervation, centrifuge tube containing 10 mL of culture medium.
and immune cells. Further technical development is The tube was sealed with parafilm to maintain sterility.
essential for expanding its utility in disease modeling and The mixture was homogenized by continuous agitation
drug screening. 31,32 at 150 rpm in a 60°С incubator shaker for 3 h to ensure
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3D bioprinting represents a cutting-edge platform complete dissolution. The resulting bioinks were loaded
that enables the fabrication of living tissues using bioinks into 3D bioprinting cartridges using sterile 3 mL Pasteur
composed of cells, growth factors, and biocompatible pipettes and centrifuged at 800 rpm for 3 min to remove
materials. Compared to other 3D models, bioprinting air bubbles. The prepared bio-inks were stored at 4°С and
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offers superior spatial precision, structural fidelity, and remained stable for up to 7 days.
mechanical tunability, making it especially attractive for 2.2. Viscosity and printability of bioinks
regenerative medicine and disease modeling. In cartilage To assess the viscoelastic properties of Gel–Alg bioinks
tissue engineering, the scaffold material must possess with three different concentration ratios, a rotational
excellent biocompatibility, mechanical integrity, and rheometer (Thermo Fisher, United States of America
support for cellular activity. 34,35 Gelatin (Gel) and sodium [USA]) was employed. Briefly, the bioinks were thoroughly
alginate (Alg) are widely used in 3D bioprinting due to their mixed to eliminate air bubbles and then loaded between
favorable biological properties and printability. Recent the parallel plates of the rheometer, with the initial gap
studies have successfully encapsulated chondrocytes in set at 1 mm. Shear rates ranging from 0.1 to 1000 s ¹ were
–
Gel–Alg hydrogels using bioprinting, maintaining high cell applied, and measurements were conducted at a constant
viability and regional gene expression. 36–39 Another study temperature of 25°C. The viscosity (η) versus shear rate
developed Gel–Alg-based bioinks crosslinked with calcium curve was recorded to evaluate the shear-thinning behavior
chloride to fabricate scaffolds with robust mechanical of the bioinks.
properties and biocompatibility. These scaffolds supported
long-term chondrocyte survival and functionality in vitro 2.3. Fabrication of 3D-bioprinted scaffolds
and demonstrated effective cartilage repair in vivo. 39 Hydrogel scaffolds were fabricated using 3D bioprinting
In this study, we established a novel cartilage technology. Briefly, a stereolithography file of the scaffold
senescence model using Gel–Alg hydrogels at three model was designed using Autodesk Fusion 360 CAD
different concentration ratios. ACs were encapsulated software (Figure 2A) and imported into a 3D bioprinter
in 3D-bioprinted constructs, followed by H₂O₂-induced (Regenovo, China) for fabrication. Gel and Alg were
senescence. The innovation lies in the integration selected as the scaffold materials. A nozzle with an inner
of biofabricated cartilage with precisely engineered diameter of 0.34 mm was used, and scaffolds were printed
structural and biochemical cues, coupled with oxidative layer-by-layer with an alternating 0–90° stacking pattern
stress-induced aging. This two-stage modeling strategy, to ensure high structural precision. Immediately after
which mimics age-related cartilage degeneration, has printing, the scaffolds were crosslinked in 3% sterile
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not been reported in current OA models (Figure 1). The CaCl₂ solution (Sigma, USA) for 5 min, rinsed with
resulting platform provides a physiologically relevant sterile phosphate-buffered saline (PBS), and prepared for
microenvironment that supports AC viability, maintains subsequent experiments.
region-specific phenotypic markers, and reproduces 2.4. Surface morphology analysis
senescence-associated changes under oxidative stress. This The microstructure and surface morphology of the
3D-bioprinted cartilage senescent model offers a promising 3D-bioprinted Gel–Alg hydrogel scaffolds were examined
experimental system for investigating OA pathogenesis using field emission scanning electron microscopy (SEM)
and developing targeted therapeutic interventions. (Jeol, Japan). Briefly, the scaffolds were freeze-dried under

2. Materials and methods a vacuum for 24 h to preserve their structural integrity.
The dried samples were then fractured to obtain cross-
2.1. Preparation of bioinks sectional views for microscopic analysis. To improve
Three different Gel–Alg bioink formulations were prepared electron conductivity, the surfaces were treated with a gold
for the 3D bioprinting of hydrogel scaffolds: 7% Gel + 3% jet machine (Jeol, Japan). Imaging was performed at an
Alg (7 Gel–3 Alg), 8% Gel + 2% Alg (8 Gel–2 Alg), and 9% acceleration voltage of 10 kV.

Volume 11 Issue 4 (2025) 191 doi: 10.36922/IJB025150136