Photo-Crosslinkable Hydrogels for 3D Bioprinting in the Repair of Osteochondral Defects: A Review of Present Applications and Future Perspectives

Abstract

An osteochondral defect is a common and frequent disease in orthopedics and treatment effects are not good, which can be harmful to patients. Hydrogels have been applied in the repair of cartilage defects. Many studies have reported that hydrogels can effectively repair osteochondral defects through loaded cells or non-loaded cells. As a new type of hydrogel, photo-crosslinked hydrogel has been widely applied in more and more fields. Meanwhile, 3D bioprinting serves as an attractive platform to fabricate customized tissue-engineered substitutes from biomaterials and cells for the repair or replacement of injured tissues and organs. Although photo-crosslinkable hydrogel-based 3D bioprinting has some advantages for repairing bone cartilage defects, it also has some disadvantages. Our aim of this paper is to review the current status and prospect of photo-crosslinkable hydrogel-based 3D bioprinting for repairing osteochondral defects.

Advances in Cartilage Tissue Engineering Using Bioinks with Decellularized Cartilage and Three-Dimensional Printing

“…The most significant advantage of digital light printers is the ability to print small scaffold designs at resolutions on the order of 10 µm. A disadvantage to photo-crosslinking is that UV light can damage cell DNA, leading to reduced cell viability [ 8 , 13 , 15 ]. Each bioprinting technique has advantages and disadvantages.…”

“…PEGDA hydrogels possess biocompatibility and the capability to be loaded with specific cells and biological factors. UV cross-linking has been shown to improve mechanical properties [ 5 , 8 , 54 ]. Silk fibroin (SF) is a protein polymer that is biocompatible, cytocompatible, possesses mechanical strength, and is biodegradable.…”

“…Scaffold manufacturing may be carried out by extrusion, inkjet, or laser-assisted bioprinting using a deposited material or bioink [ 2 , 5 ]. Digital light printers provide an advantage due to higher resolution without applying high stress on the cells [ 8 ]. Common to all printing methods is the use of computer-aided design based on patient-specific parameters [ 4 , 5 ].…”

Compressive Mechanical Behavior of Partially Oxidized Polyvinyl Alcohol Hydrogels for Cartilage Tissue Repair

“…Ideally, hydrogel composition and structure should mimic the native cartilage tissue, being able to withstand mechanical stress, especially in load-bearing joints. Among several approaches adopted to tune the mechanical properties, partial oxidation of PVA has been proposed through a chemical reaction with different oxidizing agents, namely potassium permanganate (KMnO 4 ), bromine (Br 2 ), and iodine (I 2 ) [ 27 , 28 , 29 ]. Partially oxidized PVA hydrogels demonstrated high biocompatibility, good protein delivery capacity, and improved biodegradability in both in vitro and in vivo studies testing the polymer material not only for cartilage substitution [ 27 ], but also for peripheral nerve [ 30 ] and gut [ 31 ] TE.…”

“…Among several approaches adopted to tune the mechanical properties, partial oxidation of PVA has been proposed through a chemical reaction with different oxidizing agents, namely potassium permanganate (KMnO 4 ), bromine (Br 2 ), and iodine (I 2 ) [ 27 , 28 , 29 ]. Partially oxidized PVA hydrogels demonstrated high biocompatibility, good protein delivery capacity, and improved biodegradability in both in vitro and in vivo studies testing the polymer material not only for cartilage substitution [ 27 ], but also for peripheral nerve [ 30 ] and gut [ 31 ] TE. Regarding the mechanical behavior, uniaxial tensile tests showed that the oxidation treatment reduces PVA stiffness to a different extent depending on the oxidizing agent.…”