Development of a three‐dimensional model for rapid evaluation of bone substitutes in vitro: Effect of the 45S5 bioglass

Abstract

The evaluation of innovative bone substitutes requires the development of an optimal model close to physiological conditions. An interesting alternative is the use of an immortalized cell line to construct multicellular spheroids, that is, three-dimensional (3D) cultures. In this study, a modified hanging drops method has resulted in the generation of spheroids with a well-established human fetal osteoblasts line (hFOB 1.19), and tests have been focused on the effect of 45S5 bioglass ionic dissolution products in comparison with two-dimensional (2D) cultures. Depending on cell culture type, quantitative analysis (cell proliferation, viability/cytotoxicity, and cellular cycle) and qualitative analysis (electron microscopy and genes expression) showed a differential effect. Cell proliferation was enhanced in 2D-conditioned cultures in accordance with literature data, but decreased in 3D cultures submitted to the same conditions, without change of gene expression patterns. The decrease of cell proliferation, observed in conditioned spheroids, appears to be in agreement with clinical observations showing the insufficiency of commercially available bioglasses for bone repairing within nonbearing sites, such as periodontal defects or small bone filling, in general. Therefore, we suggest that this model could be adapted to the screening of innovative bioactive materials by laboratory techniques already available and extended monitoring of their bioactivity.

Bioactivity of novel functionally structured titanium‐ceramic composites in contact with human osteoblasts

“…In order to evaluate osteogenic cell behavior, immortalized fetal human osteoblasts (HFOB 1.19) were used in this study to mimic the in vivo scenario of interaction between implant surface and osteoblasts of healthy patients. The cellular morphology detected by microscopic assessment in our results is similar to that shown in other studies that also used HFOB 1.19 osteoblasts . The use of high resolution FEGSEM images allowed us to evaluate the cell morphological details such as spreading, cellular extensions (filopodia), and cell stretching onto the morphological structures of the test surfaces, as seen in Figure .…”

“…Bioactive ceramic and glass‐ceramic particles are produced with defined characteristics of size, microstructure, chemical composition, and morphology to enhance bone integration and remodeling. Additionally, the mechanical properties of such ceramic materials are required for incorporation onto implant surfaces and subsurface . Adverse local tissue reactions have been observed after delamination of coating ceramic material…”

“…Such cell is a conditionally immortalized and stably transfected with a gene encoding a temperature‐sensitive mutant (tsA58) of SV40 large T antigen. The cells grown at a permissive temperature at 33.5°C exhibit rapid cell division, whereas little cell division occurs at a restrictive temperature at 39.5°C . Osteoblasts were washed in a 37°C water bath for 2 min and transferred to a 25 cm 3 culture flask for culture at 37°C in an atmosphere of 5% CO 2 and 100% humidity.…”

Comparison of the effects of 45S5 and 1393 bioactive glass microparticles on hMSC behavior

“…Alno et al 44 reported a similar differential effect of 45S5 BAG ionic dissolution products (1 w/v %-400 mm particle size) on the proliferation of human fetal osteoblasts cultured in 2D versus 3D spheroid culture. While they observed an increase in cell viability at 4 and 7 days for TCP cultured cells in contact with BAG conditioned medium, they report a significant decrease in cell viability for 3D cultured cells.…”

“…While they observed an increase in cell viability at 4 and 7 days for TCP cultured cells in contact with BAG conditioned medium, they report a significant decrease in cell viability for 3D cultured cells. 44 In native adult tissues, the microenvironment is characterized by greater cell-matrix interactions than cell-cell interactions. Therefore, spheroid cultures may not be the optimal set up to investigate BAG-cell interactions in 3D.…”