Direct scaffolding of biomimetic hydroxyapatite-gelatin nanocomposites using aminosilane cross-linker for bone regeneration

Abstract

Hydroxyapatite-gelatin modified siloxane (GEMOSIL) nanocomposite was developed by coating, kneading and hardening processes to provide formable scaffolding for alloplastic graft applications. The present study aims to characterize scaffolding formability and mechanical properties of GEMOSIL, and to test the in vitro and in vivo biocompatibility of GEMOSIL. Buffer Solution initiated formable paste followed by the sol-gel reaction led to a final hardened composite. Results showed the adequate coating of aminosilane, 11–19 wt%, affected the cohesiveness of the powders and the final compressive strength (69 MPa) of the composite. TGA and TEM results showed the effective aminosilane coating that preserves hydroxyapatite-gelatin nanocrystals from damage. Both GEMOSIL with and without titania increased the mineralization of preosteoblasts in vitro. Only did titania additives revealed good in vivo bone formation in rat calvarium defects. The scaffolding formability, due to cohesive bonding among GEMOSIL particles, could be further refined to fulfill the complicated scaffold processes.

Titanium-Enriched Hydroxyapatite–Gelatin Scaffolds with Osteogenically Differentiated Progenitor Cell Aggregates for Calvaria Bone Regeneration

“…6,7,21 Briefly, the HAP coprecipitation reaction was induced at 38°C in soluble GEL titrated with the Ca(OH) 2 solution. After the coprecipitation, the slurry was centrifuged and the supernatant removed.…”

“…To fabricate TiO 2 -enriched HAP-GEL scaffolds, a similar procedure was followed, but this time, TiO 2 (Evonik AeroxideÒ P25) was added to the HAP-GEL (at silica:titanium atomic ratio of 60:40) before molding, as reported previously. 5,7 Porosity of HAP-GEL scaffolds HAP-GEL scaffolds (8 mm diameter · 3 mm thickness) with and without titania, and same-size specimens from natural calvaria bone from pig were scanned and evaluated by microcomputed tomography (mCT). The mCT scanning was performed with a Portable Skyscan 1074 mCT System (Micro Photonics).…”

“…5 HAP-GEL cross-linked with an aminosilane was previously found to exhibit an appropriate compressive strength (100 MPa), biocompatibility and facilitate surface bone ingrowth. 6,7 The loading of cells on alloplastic grafts such as porous calciumbased scaffolds in the hydroxyapatite form (HAP), followed by in vivo implantation in large bone defects, had been previously shown to promote healing. 8,9 Moreover, injectable and formable calcium-based composites with natural polymeric phases (e.g., gelatin) can further increase their clinical applicability.…”

“…10 Titania additives may constitute an advantage by increasing surface hydrophobicity and protein adsorption to further enhance cell adhesion, osteogenic induction, and formability in bone biomaterials, including in HAP-GEL. 7,11,12 Consequently, bone regeneration of formable titanium dioxide (TiO 2 )-enriched HAP-GEL scaffolds was compared in this study to HAP-GEL alone.…”

In-situ hybridization of calcium silicate and hydroxyapatite-gelatin nanocomposites enhances physical property and in vitro osteogenesis

“…In our previous studies, the HAp-Gel is cross-linked by Bis [3-(trimethoxysilyl)propyl]-ethylenediamine (enTMOS) to produce HAp-Gel modified siloxane (GEMOSIL) nanocomposites [16]. The room temperature processes, including coating, kneading and hardening, form a formable paste to create porous scaffolds.…”