Macroporous hydroxyapatite scaffolds for bone tissue engineering applications: Physicochemical characterization and assessment of rat bone marrow stromal cell viability

Abstract

In this work, a new methodology is reported for developing hydroxyapatite (HA) scaffolds using an organic sacrifice template. The novelty of work consists of possibility of obtaining porous and highly interconnected scaffolds mimicking the sacrificial component. Our purpose consisted of evaluating the physicochemical properties of the HA scaffolds by means of Fourier transform infra-red spectroscopy, X-ray diffraction analysis, and scanning electron microscopy (SEM) attached with an X-ray detector. The HA scaffolds obtained possess a porosity of approximately 70%, and macropores diameter in the range of 50-600 microm. In contrast, results regarding the microcomputed tomography analysis have demonstrated both high pore uniformity and interconnectivity across the scaffolds. The compressive strength of the HA scaffolds was found to be 30.2 +/- 6.0 MPa. Bioactivity of the HA scaffolds was assessed by immersion into a simulated body fluid solution, in vitro. SEM observations have showed a deposition of apatite on the surface of the HA scaffolds, with a "cauliflower-like" morphology after 1 day, and tend to be more pronounced with the immersion time. The changes in calcium and phosphorus concentration were monitored by inductively-coupled plasma optical emission spectrometry. Cytotoxicity of the HA scaffolds was preliminarily investigated by carrying direct observation of mouse fibroblasts cells (L929 cell-line) death in the inverted microscope, and then cell viability was determined by means of carrying out a MTS assay. Complementarily, a luminescent cell viability assay based on the quantification of adenosine triphosphate was performed using rat bone marrow stromal cells (RBMSCs). A LIVE/DEAD assay and SEM analysis allowed the visualization of the RBMSCs adhesion and proliferation on the surface of the HA scaffolds. According to the results obtained from 3D architecture, mechanical properties, biocompatibility, and adhesion tests, it is suggested that HA scaffolds has potential to find applications in bone tissue engineering scaffolding.

Thin Hydroxyapatite Coating on Porous Beta-Tricalcium Phosphate (β-TCP) Enhances Osteoblast Function Activity

“…Oliveira et al 21) reported that the relatively high bioactivity of HA is related to a phenomenon involving the dissolution of calcium phosphate ions from HA. Weng et al 22) and Radin and Ducheyne 23) reported that dissolution of calcium and phosphate ions from the outermost surface of HA implants leads to an increase in the local concentrations of these ions that favors biological apatite precipitation.…”

Sol-gel bioceramic material from bentonite clay

“…The following chemicals were used as obtained for the preparation of the bioceramic material; bentonite clay-(OH) 4 …”

“…Bentonite clay of the type (OH) 4 Si 8 Al 4 O 20 ·nH 2 O shown in Figure 2(a) was reacted in strong basic medium to initially afford sodium metasilicate (reaction equation is shown elsewhere [26]) after evaporating the alkaline filtrate slowly to dryness at 120˚C. The waterglass obtained, Figure 2(b), from this reaction is hydrolysed under acidic conditions to silicic acid which undergoes condensation to disilicic acid and further reaction to a polycondensed hydrogel [26,27].…”

“…Tissue engineering and regenerative medicine assist with restoration of damaged tissues using both functional cells and biodegradable scaffolds made from engineered biomaterials [2,3]. Significant efforts in the last decades have been devoted to the fabrication of porous and highly interconnected bioceramic scaffolds based on hydroxyapatite (HA), tricalcium phosphate and related composite materials for application in bone tissue engineering [4][5][6].…”

Biomimetic Strategies to Engineer Mineralized Human Tissues

“…Oliveira et al [8] developed hydroxyapatite (HA) single scaffolds with a porosity of~70 % and macropore diameter in the range of 50-600 μm with high pore uniformity and interconnectivity across the scaffolds by means of sponge replica method (Fig. 1).…”