Effect of Bioglass on Growth and Biomineralization of SaOS-2 Cells in Hydrogel after 3D Cell Bioprinting

Abstract

We investigated the effect of bioglass (bioactive glass) on growth and mineralization of bone-related SaOS-2 cells, encapsulated into a printable and biodegradable alginate/gelatine hydrogel. The hydrogel was supplemented either with polyphosphate (polyP), administered as polyP•Ca2+-complex, or silica, or as biosilica that had been enzymatically prepared from ortho-silicate by silicatein. These hydrogels, together with SaOS-2 cells, were bioprinted to computer-designed scaffolds. The results revealed that bioglass (nano)particles, with a size of 55 nm and a molar ratio of SiO2∶CaO∶P2O5 of 55∶40∶5, did not affect the growth of the encapsulated cells. If silica, biosilica, or polyP•Ca2+-complex is co-added to the cell-containing alginate/gelatin hydrogel the growth behavior of the cells is not changed. Addition of 5 mg/ml of bioglass particles to this hydrogel significantly enhanced the potency of the entrapped SaOS-2 cells to mineralize. If compared with the extent of the cells to form mineral deposits in the absence of bioglass, the cells exposed to bioglass together with 100 µmoles/L polyP•Ca2+-complex increased their mineralization activity from 2.1- to 3.9-fold, or with 50 µmoles/L silica from 1.8- to 2.9-fold, or with 50 µmoles/L biosilica from 2.7- to 4.8-fold or with the two components together (100 µmoles/L polyP•Ca2+-complex and 50 µmoles/L biosilica) from 4.1- to 6.8-fold. Element analysis by EDX spectrometry of the mineral nodules formed by SaOS-2 revealed an accumulation of O, P, Ca and C, indicating that the mineral deposits contain, besides Ca-phosphate also Ca-carbonate. The results show that bioglass added to alginate/gelatin hydrogel increases the proliferation and mineralization of bioprinted SaOS-2 cells. We conclude that the development of cell-containing scaffolds consisting of a bioprintable, solid and cell-compatible inner matrix surrounded by a printable hard and flexible outer matrix containing bioglass, provide a suitable strategy for the fabrication of morphogenetically active and biodegradable implants.

RGD functionalized poly(ε-caprolactone)/poly(m-anthranilic acid) electrospun nanofibers as high-performing scaffolds for bone tissue engineering RGD functionalized PCL/P3ANA nanofibers

“…The ALP activity of cells on nanofibers was higher compared to those on cover glass. RGD immobilization increased the ALP activity of the cells, which is in correlation with data reported in the literature [15,57,58]. Mineralization process and osteogenic activity of cells can be investigated by monitoring Ca deposits on mineralized area by Alizarin Red S staining [59].…”

Applications of Alginate-Based Bioinks in 3D Bioprinting

“…Bone-related SaOS-2 cells were 3D bioprinted with gelatin and sodium alginate, and overlayed by agarose and calcium salt of plyphosphate, and they obtained a high cell proliferation and caused an increase in the mineralization of the cells [36]. The same cell phenotype was utilized in a study by Wang et al [37], in which the effect of bioglass on the growth and mineralization of the SaOS-2 cells was investigated in 3D-printed alginate/gelatin hydrogels. Polyphosphate and biosilica increased the cell proliferation and mineralization.…”

Saos‐2 cell‐mediated mineralization on collagen gels: Effect of densification and bioglass incorporation

“…Gregory et al developed a sensitive method for quantification of alizarin red S stained mineralized nodules by acetic acid extraction and neutralization with ammonium hydroxide, which is more sensitive and reliable than previously used cetylpyridinium chloride (CPC) method . This method has been reliably used in previous studies for the quantification of mineralized nodules on hydroxyapatite and bioglass substrates . The current study is the first attempt to quantify the cell‐synthesized mineralized nodules on PC gels.…”