Blends of gelatin and hyaluronic acid stratified by stereolithographic bioprinting approximate cartilaginous matrix gradients

Abstract

Stereolithographic bioprinting holds great promise in the quest for creating artificial, biomimetic cartilage‐like tissue. To introduce a more biomimetic approach, we examined blending and stratifying methacrylated hyaluronic acid (HAMA) and methacrylated gelatin (GelMA) bioinks to mimic the zonal structure of articular cartilage. Bioinks were suspended with porcine chondrocytes before being printed in a digital light processing approach. Homogenous constructs made from hybrid bioinks of varying polymer ratios as well as stratified constructs combining different bioink blends were cultivated over 14 days and analyzed by histochemical staining for proteoglycans/collagen type II, cartilage marker expression analysis, and for cellular viability. The stiffness of blended bioinks increased gradually with HAMA content, from 2.41 ± 0.58 kPa (5% GelMA, 0% HAMA) to 8.84 ± 0.11 kPa (0% GelMA, 2% HAMA). Cell‐laden constructs maintained vital chondrocytes and supported the formation of proteoglycans and collagen type II. Higher concentrations of GelMA resulted in increased formation of cartilaginous matrix proteins and a more premature phenotype. However, decreased matrix production in central areas of constructs was observed in higher GelMA content constructs. Biomimetically stratified constructs retained their gradient‐like structure even after ECM formation, and exclusively exhibited a significant increase in COL2A1 gene expression (+178%). Concluding, we showed the feasibility of blending and stratifying photopolymerizable, natural biopolymers by SLA bioprinting to modulate chondrocyte attributes and to create zonally segmented ECM structures, contributing to improved modeling of cartilaginous tissue for regenerative therapies or in vitro models.

HYDRHA: Hydrogels of hyaluronic acid. New biomedical approaches in cancer, neurodegenerative diseases, and tissue engineering

“…HA has been also bioprinted in mixtures, such as with GelMA, to produce artificial, biomimetic cartilage-like tissue. In fact, as cartilage tissue does not share the same content of HA in every area, the suspension of chondrocytes in mixtures with variable stiffness enables the creation of a modulable cartilage tissue [ 198 ]. 3D-printed HA matrices have contributed to identify an intrinsic relationship between adipocytes and breast cancer cells.…”

3D Printing of Bone Substitutes Based on Vat Photopolymerization Processes: A Systematic Review

“…Tus, the resulting scafolds can be adjusted to the mechanical properties of the defect site by introducing mechanical gradients corresponding to the expected physiological strain. Critical to this combination of materials is the seamless connection between the materials, which enables load transfer without damaging the construct [55][56][57].…”

Designing functional hyaluronic acid-based hydrogels for cartilage tissue engineering

“… 3D bioprinted hydrogels Components Physicochemical properties Biofunctions Ref. HA/PU HA, polyurethane High elastic recovery; processability Promoting self-aggregation and chondrogenesis of MSCs [ 155 ] HA/alginate HA, alginate Printability; biodegradability Promoting chondrogenic genes expression and ECM deposition [ 157 ] HA/elastin/Gel HA, elastin, gelatin Printability with reproducible outcomes Supporting the penetration, proliferation and chondrogenesis of chondrocytes [ 158 ] HA-MA/Gel-MA HA, gelatin, methacrylic anhydride (MA) Controllable pore structure; optimum degradation rate Maintaining chondrocyte phenotype, promoting ECM deposition; accelerating mature cartilage regeneration [ [160] , [161] , [162] ] HA-MA/PCL HA, MA, polycaprolactone Biomimetic multiphase structure; sustained release of drugs Inhibiting inflammation, repairing osteochondral damage; restoring motor function of joints [ 163 ] HA-MA/ECM HA, MA, ECM Improving the compressive strength and modulus Providing a suitable microenvironment to encapsulate and cultivate cells [ 164 ] HA-MA/p (HPMAm-lac)-PEG HA, MA, triblock copolymers Thermosensitive, improving printability Promoting formation of hyaline cartilage (lower concentrations) and fibrocartilage (higher concentrations) [ 165 ] HA-MA-PBA/Gel-MA/HA-Dopa HA, MA, phenylboronic acid, gelatin, dopamine Microporosity; injectability; tissue adhesion; sustained release of drug Promoting chondrogenesis of BMSCs; accelerating articular cartilage repair and regeneration [ 166 ] HA-Ac-PBA/PVA/Gel-HS Acrylated HA, phenylboronic acid, polyvinyl alcohol, thiolated gelatin Tunable viscoelasticity; shear thinning property; high structural fidelity Main...…”

“…The increased HA-MA and Gel-MA contents enhanced the stiffness of the scaffolds and cartilage matrix protein formation. In addition, the biomimetic structure of the 3D printed hydrogel could be retained even after ECM formation [ 162 ]. Liu et al.…”