Optimization of methacrylated gelatin /layered double hydroxides nanocomposite cell‐laden hydrogel bioinks with high printability for 3D extrusion bioprinting

Abstract

Layered double hydroxides (LDHs) offer unique source of inspiration for design of bone mimetic biomaterials due to their superior mechanical properties, drug delivery capability and regulation cellular behaviors, particularly by divalent metal cations in their structure. Three-dimensional (3D) bioprinting of LDHs holds great promise as a novel strategy thanks to highly tunable physiochemical properties and shear-thinning ability of LDHs, which allow shape fidelity after deposition. Herein, we introduce a straightforward strategy for extrusion bioprinting of cell laden nanocomposite hydrogel bioink of gelatin methacryloyl (GelMA) biopolymer and LDHs nanoparticles. First, we synthesized LDHs by co-precipitation process and systematically examined the effect of LDHs addition on printing parameters such as printing pressure, extrusion rate, printing speed, and finally bioink printability in creating grid-like constructs. The developed hydrogel bioinks provided precise control over extrudability, extrusion uniformity, and structural integrity after deposition. Based on the printability and rheological analysis, the printability could be altered by controlling the concentration of LDHs, and printability was found to be ideal with the addition of 3 wt % LDHs. The addition of LDHs resulted in remarkably enhanced compressive strength from 652 kPa (G-LDH0) to 1168 kPa (G-LDH3). It was shown that the printed nanocomposite hydrogel scaffolds were able to support encapsulated osteoblast survival, spreading, and proliferation in the absence of any osteoinductive factors taking advantage of LDHs. In addition, cells encapsulated in G-LDH3 had a larger cell spreading area and higher cell aspect ratio than those encapsulated in G-LDH0. Altogether, the results demonstrated that the developed GelMA/LDHs nanocomposite hydrogel bioink revealed a high potential for extrusion bioprinting with high structural fidelity to fabricate implantable 3D hydrogel constructs for repair of bone defects.

Nanocomposite Bioprinting for Tissue Engineering Applications

“…As cartilage is a hypocellular tissue with extremely limited regeneration potential, several 3D bioprinting approaches with a variety of nanocomposite additives have been researched for their chondrogenic and therapeutic potentials. One of these examples includes the integration of methacrylated gelatin layered with layered hydroxide nanoparticles for the formulation of highly printable hydrogel bioink [156]. Here, hydroxide particles were investigated for their mechanical properties that may be able to assist the soft nature of methacrylated gelatin to provide a mechanically durable printed construct.…”

Recent Advances in the Development of Biomimetic Materials

“…Nadernezhad et al demonstrated that agarose and Laponite nanosilicates not only developed nanocomposite shear thinning of nanocomposite bioinks for extrusion 3D bioprinting applications but also significantly improved the bioactivity of nanocomposite hydrogels with increased metabolic activity of encapsulated cells and the ability of cells to extend and change their morphology [206]. Alarçin et al optimized the printability of methacrylated gelatin (gelatin methacrytoyl, GelMA) with layered double hydroxides (LDHs) [207]. Their results indicated that the addition of LDHs into the GelMA network could improve the physical and biological properties of the nanocomposite scaffolds.…”

Biomaterials Based on Organic Polymers and Layered Double Hydroxides Nanocomposites: Drug Delivery and Tissue Engineering

“…These limitations can be minimized, and even novel properties on polymer-based materials can be achieved, by the presence of a wide variety of inorganic structures. Especially for bone-related applications, hybrid materials based on the combination of LDH and polymers are promising to owe to: (i) the enhancement of the mechanical properties of the resulting composite [ 271 , 277 ]; (ii) the improvement of osteogenic differentiation associated with the release of Mg 2+ ions from the LDH structure and the alkaline microenvironment [ 272 , 278 ]; (iii) good biocompatibility, low toxicity and structural homogeneity [ 169 ]; (iv) thermal stability and drug release of bioactive compounds from the intercalated LDH structure [ 279 ]; (v) thermal insulation from the exothermic polymerization process, and (vi) creation of surface irregularities that could benefit osteointegration [ 272 ].…”

“…LDH-based hybrid materials were also proposed for bone-related applications when combined with pristine or modified natural polymers to improve their physical and biological properties. Alarçir et al [ 278 ] combined a Mg 4 Al intercalated with carbonate ions, gelatin methacryloyl (GelMA) and alginate to produce printable bioinks for additive manufacture to generate biocompatible hydrogel scaffolds. The presence of the inorganic phase in the composite aided the filament formation and the stackability of layers of filaments to yield different printed shapes.…”