Otoliths-composed gelatin/sodium alginate scaffolds for bone regeneration

Abstract

Evidence that otoliths, mineral-rich limestone concrescences present in the inner ear of bone fishes, can accelerate bone formation in vivo has been previously reported. The goal of this work was the development, characterization, and evaluation of the cytocompatibility of otoliths-incorporated sodium alginate and gelatin scaffolds. Cynoscion acoupa-derived otoliths were characterized by X-ray fluorescence spectrometry (FRX), particle size, free lime, and weight loss by calcination. Furthermore, otoliths were incorporated into sodium alginate (ALG/OTL-s) or gelatin (GEL/OTL-s) scaffolds, previously developed by freeze-drying. Then, the scaffolds were characterized by thermogravimetric analysis (TGA/DTG), differential scanning calorimetry (DSC), infrared spectroscopy with Fourier transform (FTIR), swelling tests, and scanning electron microscopy (SEM). Cytotoxicity assays were run against J774.G8 macrophages and MC3T3-E1 osteoblasts. Data obtained from TGA/DTG, DSC, and FTIR analyses confirmed the interaction between otoliths and the polymeric scaffolds. SEM showed the homogeneous porous 3D structure rich in otolith micro-fragments in both scaffolds. Swelling of the GEL/OTL-s (63.54 ± 3.0%) was greater than of ALG/ OTL-s (13.36 ± 9.9%) (p < 0.001). The viability of J774.G8 macrophages treated with both scaffolds was statistically similar to the group treated with DMEM only (p > 0.05) and significantly higher than that treated with Triton-X (p < 0.01) at 72 h. Both scaffolds showed approximately 100% growth of MC3T3-E1 osteoblasts by 24 h, similarly to control (p > 0.05). However, by 48 h, only ALG/OTL-s showed growth similar to control (p > 0.05), whereas GEL/OTL showed a significantly lower growth index (p < 0.05). In conclusion, the physicochemical profiles suggest proper interaction between the otoliths and the two developed polymeric 3D scaffolds. Moreover, both materials showed cytocompatibility with J774.G8 macrophages but the growth of MC3T3-E1 osteoblasts was higher when exposed to ALG/OTL-s. These data suggest that sodium alginate/otoliths scaffolds are potential biomaterials to be used in bone regeneration applications.

Repair of Large-Scale Rib Defects Based on Steel-Reinforced Concrete-Designed Biomimetic 3D-Printed Scaffolds with Bone-Mineralized Microenvironments

“…In contrast, the mechanical properties of the scaffolds gradually increased with increasing GL concentration (Figure S5C and S5D). Considering the influence of pore size, porosity, and mechanical strength on cell loading and tissue regeneration, a concentration of 0.8% GL was determined for subsequent bone regeneration . To clarify the variant characterization of the scaffolds caused by OIS, further analyses showed that the addition of OIS to the GL solution (sGL) had no significant influence on the pore size, porosity, compressive modulus, and tensile modulus (Figure A, B, G, H, K, and L).…”

“…In contrast, the mechanical properties of the scaffolds gradually increased with increasing GL concentration (Figure S5C influence of pore size, porosity, and mechanical strength on cell loading and tissue regeneration, a concentration of 0.8% GL was determined for subsequent bone regeneration. 38 To clarify the variant characterization of the scaffolds caused by OIS, further analyses showed that the addition of OIS to the GL solution (sGL) had no significant influence on the pore size, porosity, compressive modulus, and tensile modulus (Figure 2A, 2B, 2G, 2H, 2K, and 2L). Further analyses showed that the addition of OIS to the GL solution (sGL) had no significant influence on the pore size, porosity, compressive modulus, and tensile modulus (Figure 2A, 2B, 2G, 2H, 2K, and 2L), implying that 0.8% sGL could be used as a porous scaffold for bone regeneration.…”

ALG-bFGF Hydrogel Inhibiting Autophagy Contributes to Protection of Blood–Spinal Cord Barrier Integrity via PI3K/Akt/FOXO1/KLF4 Pathway After SCI

“…The sodium alginate–loaded bFGF (ALG-bFGF) hydrogel significantly prevented BSCB leakage and promoted restoration of posterior limb movement after SCI. As a highly biodegradable, biocompatible, and water-soluble substance ( Guo et al, 2020 ), sodium alginate has been widely used as a bioengineering scaffold for tissue regeneration in damaged tissues, including skin ( Yanlun Zhu et al, 2020 ; Shafei et al, 2020 ), diabetic wounds ( Gustinelli Barbosa et al, 2020 ), bone ( Valido et al, 2020 ), and peripheral nerve system ( Szarek et al, 2013 ; Chaw et al, 2015 ; Rahmati et al, 2021 ). Moreover, sodium alginate has potential application in treatment for traumatic brain injury ( Kun Zhang et al, 2018 ).…”

Osteogenesis Enhancement with 3D Printed Gene-Activated Sodium Alginate Scaffolds

“…Sodium alginate (SA) is a polysaccharide of natural origin, which shows outstanding properties of biocompatibility, gel-forming ability, nontoxicity, and biodegradability [ 20 , 21 ]. The simple method of SA gelation using divalent cations, e.g., Ca 2+ , allows to form microspheres [ 22 ], bulk disks [ 23 ], and porous freeze-dried scaffolds [ 24 , 25 ] with physical and biochemical properties required for bone tissue repair.…”