Fabrication and characterization of microstructure-controllable COL-HA-PVA hydrogels for cartilage repair

Abstract

Polyvinyl alcohol (PVA) hydrogel has gained interest in cartilage repair because of its highly swollen, porosity, and viscoelastic properties. However, PVA has some deficiencies, such as its poor biocompatibility and microstructure. This research aimed to design novel hydroxyapatite (HA)-collagen (COL)-PVA hydrogels. COL was added to improve cell biocompatibility, and the microstructure of the hydrogels was controlled by fused deposition modeling (FDM). The feasibility of the COL-HA-PVA hydrogels in cartilage repair was evaluated by in vitro and in vivo experiments. The scanning electron microscopy results showed that the hybrid hydrogels had interconnected macropore structures that contained a COL reticular scaffold. The diameter of the macropore was 1.08–1.85 mm, which corresponds to the diameter of the denatured PVA column. The chondrocytes were then seeded in hydrogels to assess the cell viability and formation of the cartilage matrix. The in vitro results revealed excellent cellular biocompatibility. Osteochondral defects (8 mm in diameter and 8 mm in depth) were created in the femoral trochlear of goats, and the defects were implanted with cell-seeded hydrogels, cell-free hydrogels, or a blank control. The in vivo results showed that the COL-HA-PVA hydrogels effectively repaired cartilage defects, especially the conditions inoculated with chondrocyte in advance. This research suggests that the COL-HA-PVA hydrogels have promising application in cartilage repair.

Collagen‐Based Hydrogels for Cartilage Regeneration

“…123 Xie et al utilized 3D printing to synthesize a novel hybrid PVA collagen hydrogel that mimics the properties of natural cartilage and provides mechanical support in which the collagen scaffold allows the hydrogel to integrate with the surrounding natural cartilage. 124 Polycaprolactone/Collagen Composite Hydrogels Polycaprolactone (PCL) is a synthetic polymer, which has certain rigidity, good compatibility with polymer materials, can also be used as a modifier for other polymers, and is widely used in biomedical field. And yet, disadvantages such as low hardness, few cell binding sites, poor bioactivity, and poor hydrophilicity limit its further promotion.…”

“…Thus, PVA combined with collagen can be used in different ratios to synthesize new composite hydrogels with different functions for cartilage regeneration 123 . Xie et al utilized 3D printing to synthesize a novel hybrid PVA collagen hydrogel that mimics the properties of natural cartilage and provides mechanical support in which the collagen scaffold allows the hydrogel to integrate with the surrounding natural cartilage 124 …”

Recent Advances in Macroporous Hydrogels for Cell Behavior and Tissue Engineering

“…Increasing the proportion of solids, including polymers and nanoparticles, is another strategy. For example, the addition of hydroxyapatite to polyvinyl alcohol macroporous hydrogels upregulated the modulus, favoring chondrocyte adhesion [ 203 ]. Zeolites are microporous materials made of metal cations or organic amine/ammonium cations as templates or structure directing agents, which are commonly used to enhance the mechanical properties of chitosan scaffolds and modulate cellular behavior [ 204 ].…”

“…The introduction of ECM molecules into macroporous hydrogels is the most used method for enhancing cell adhesion via integrins. For example, genipin has been used to cross-link collagen with 3D-printed macroporous HA-PVA hydrogels, which showed good chondrocyte adhesion [ 203 ]. Covalent cross-linking of laminin to macroporous synthetic polymer hydrogels using poly l-ornithine solution or N-(3-dimethyl aminopropyl)-N-ethyl carbodiimide hydrochloride upregulated stem cell adhesion, including embryonic stem D-3 (ES-D3) mouse embryonic stem cells [ 206 ], Lund human mesencephalic (LUHMES), and human embryonic stem cells (hESCs) [ 207 ].…”

Recent Developments and Current Applications of Organic Nanomaterials in Cartilage Repair

“…The mechanical strength of 3D scaffolds made with PVA is similar to that of natural cartilage, and the PVA-based hydrogel has a better tensile modulus than natural cartilage and is biocompatible, which can repair articular cartilage defects and delay the onset of degenerative changes after implantation in joints [ 123 , 124 ]. PVA mixed with other nanomaterials can also have good effects, for example, when mixed with titanium fiber mesh, it can help the growth of subchondral bone and play a role in fixation [ 121 ]; the composite material mixed with chitosan can promote the proliferation of bone marrow mesenchymal stem cells to assist in the repair of cartilage defects [ 125 ].…”