Development, Characterization and In Vitro Biological Properties of Scaffolds Fabricated From Calcium Phosphate Nanoparticles

Abstract

Ceramic materials mimic the mineral composition of native bone and feature osteoconductive properties; they are therefore used to regenerate bone tissue. Much research focuses on increasing the porosity and pore interconnectivity of ceramic scaffolds to increase osteoconductivity, cell migration and cell-cell interaction. We aimed to fabricate biocompatible 3D-scaffolds featuring macro- and microporous calcium phosphates with high pore interconnection. Nanoparticles of hydroxyapatite (HA) and calcium deficient hydroxyapatite (CDHA) were synthesized by wet chemical precipitation. Scaffolds were produced from them by the replication polymeric foam technique. Solid content and sintering temperature were varied. Nanoparticles and scaffolds were characterized regarding morphology, chemical and mineral composition, porosity and mechanical properties. Biocompatibility, cell attachment and distribution were evaluated in vitro with human adipose mesenchymal stem cells. Scaffolds with total porosity of 71%–87%, pores in the range of 280–550 µm and connectivity density up to 43 mm−3 were obtained. Smaller pore sizes were obtained at higher sintering temperature. High solid content resulted in a decrease of total porosity but increased interconnectivity. Scaffolds 50HA/50β-TCP featured superior interconnectivity and mechanical properties. They were bioactive and biocompatible. High HA solid content (40 wt.%) in the HA pure scaffolds was negative for cell viability and proliferation, while in the 50HA/50β-TCP composite scaffolds it resulted more biocompatible.

Biomimetic Synthesis of Nanocrystalline Hydroxyapatite Composites: Therapeutic Potential and Effects on Bone Regeneration

“…In this study, the newly synthesized gelatin/nano-hydroxyapatite microspheres (GHM) demonstrated the incorporation of hydroxyapatite into the gelatin fibril which was similar to that of the natural bone (Figure 2B,C) [26]. High HA solid content (40 wt%) in the HA pure scaffolds was reported to be negative for cell viability and proliferation [27]; the ratio between organic and inorganic components (wt% = 37:63) of biomimetic hydroxyapatite microspheres (GHM-S) was similar to that found in natural bone tissue (Figure 2D) [28] and did not show any cytotoxic effect on the hMSCs (Figure 1D).…”

ADSC-Based Cell Therapies for Musculoskeletal Disorders: A Review of Recent Clinical Trials

“…For example, although the size of osteoblasts is in the range of 10–50 μm [ 112 ], regeneration of mineralized bone was enhanced with macropores (100–200 μm) possibly because the lager pore size allows the infiltration of other cells involved in colonization and vascularization [ 113 ]. On the other hand, in contrast to macropores, micropores (pore size <10 μm) provide a greater surface area for cell adhesion and showed better bone protein adsorption [ 114 ].…”

Hydroxyapatite Formation on Self-Assembling Peptides with Differing Secondary Structures and Their Selective Adsorption for Proteins

“…Hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 , termed HAp) composes the primary inorganic contents of human tooth and bone and is a representative of biomineralization and bioinspired materials [34,35,36,37,38,39,40]. Hadagalli et al established mineralization of porous HAp scaffolds, in which pores are obtained using organic pore formers, such as wax, wheat flour, or milk powder, and exhibit good cytocompatibility with osteoblasts in vitro [41].…”