Biofabrication of Cell-Laden Gelatin Methacryloyl Hydrogels with Incorporation of Silanized Hydroxyapatite by Visible Light Projection

Abstract

Gelatin methacryloyl (GelMA) hydrogel is a photopolymerizable biomaterial widely used for three-dimensional (3D) cell culture due to its high biocompatibility. However, the drawback of GelMA hydrogel is its poor mechanical properties, which may compromise the feasibility of biofabrication techniques. In this study, a cell-laden GelMA composite hydrogel with a combination incorporating silanized hydroxyapatite (Si-HAp) and a simple and harmless visible light crosslinking system for this hydrogel were developed. The incorporation of Si-HAp into the GelMA hydrogel enhanced the mechanical properties of the composite hydrogel. Moreover, the composite hydrogel exhibited low cytotoxicity and promoted the osteogenic gene expression of embedded MG63 cells and Human bone marrow mesenchymal stem cells (hBMSCs). We also established a maskless lithographic method to fabricate a defined 3D structure under visible light by using a digital light processing projector, and the incorporation of Si-HAp increased the resolution of photolithographic hydrogels. The GelMA-Si-HAp composite hydrogel system can serve as an effective biomaterial in bone regeneration.

Review on vat photopolymerization additive manufacturing of bioactive ceramic bone scaffolds

“…Hydroxyapatite (HA) is a biomimetic calcium phosphate ceramic material with a chemical composition similar to that of natural apatite found in natural bones and teeth. Natural apatite is the main inorganic component of natural bones and teeth, 124,125 which accounts for about 65% and 95%, respectively. As a result, HA has been extensively studying in the field of bone scaffold development.…”

PBP‐based bioprinting of hydrogels for biomedical applications

“…Silanized hydroxyapatite (HAp) as additives were added into the GelMA hydrogel, and C-C double bonds were introduced into HAp by silanization (Figure 4), and the HAp and GelMA were bonded by covalent bonds during the photocrosslinking process, thereby improving the mechanical properties of the hydrogels. 82 Mechanical properties are an essential index to evaluate bioprinting results. The increase in the filler improves the mechanical properties of the hydrogel, and the filler that can produce bonding with the hydrogel such as covalent bonding is better to enhance the stiffness of the hydrogel.…”

Gelatin Methacrylate Hydrogel for Tissue Engineering Applications—A Review on Material Modifications

“…It has been shown that a higher concentration of HAp in the presence of VEGF enhanced bone regeneration [62], as observed in Figure 6c. Su et al [63] showed that a composite hydrogel based on silanized GelMA/HAp enhanced the mechanical properties of the hydrogel and displayed high biocompatibility for bone tissue engineering. A major limitation of HAp is its poor biodegradation.…”