Effect of heat treatment on the properties of SiO2–CaO–MgO–P2O5 bioactive glasses

Abstract

Since the invention of 45S5 Bioglass, researchers never stopped exploring new generation bioactive glass (BG) materials for wider applications in regenerative medicine, among which a novel SiO(2)-CaO-MgO-P(2)O(5) bioactive glass (BG20) is an excellent candidate. However, apart from their biocompatibility and bioactivity, a porous structure is also a must for a tissue engineering scaffold in successfully fixing bone defect. The porosity is the outcome of the high temperature (500-1,000 °C) treatment in the fabricating process of the bioglass scaffold. Under the high temperature, the amorphous glass material will become crystallized at certain percentage in the glass matrix, and possibly leading to consequent changes in the mechanical strength, biodegradability and bioactivity. To elucidate the effect of phase transition on the change of the properties of BG20, the experiments in this report were designed to fine-tuning the heat treating temperatures to fabricate a series of BG20 powders with different crystallization structures. X-ray diffraction revealed a positive correlation between the heating temperature and the crystallization, as well as the compressive strength of the materials. In vitro degradation and ion analysis by ICP-AES demonstrated a similar releasing behavior of different ions including Mg(2+), Ca(2+) and Si(4+), which in common is the tendency of decreasing of the ion concentration along with the increasing of the treating temperature. Cell proliferation assay using both mouse fibroblasts (NIH3T3) and bone marrow stromal cells (BMSCs) showed little toxicity of the ionic extract of the BG20 powders at all the treating temperatures, while fibroblasts demonstrated a significant promoting in the percentage of proliferation. Furthermore, reverse-transcription and polymerase chain reaction analysis on two representative marker genes for early osteogenesis and endochondral ossification, respectively, type I collagen alpha 1 and Indian Hedge-hog, showed an interesting induction of both genes over their basal levels by the treatment of the ionic extract of BG20, implying its important capability in regulating the fate of differentiation of the BMSCs as a novel biomaterial in bone tissue engineering.

Scaffold Design for Bone Regeneration

“…Chang and coworkers 141 fabricated a novel SiO 2 –CaO–MgO–P 2 O 5 bioactive glass (BG20), reporting an advanced technique based on heat-treating to create BG20 powders with different crystallization structures. In vitro studies showed cell proliferation using mouse fibroblast (NIH3T3) and BMSCs.…”

“…Heat treatment of BG20 (bioactive glass) scaffolds modified the percentage of crystallization changing their mechanical strength, biodegradability and bioactivity. 141 Compressive strength of the TiO 2 scaffolds improved using multiple recoating processes. 196 Mechanically adaptive structures can be manufactured by the crucible melt extraction (CME) process and sintering of MgY4 fibers.…”

Functionalized Asymmetric Poly (Lactic Acid)/Gelatin Composite Membrane for Guided Periodontal Tissue Regeneration

“…BG is a traditional biomaterial which has been safely applied in dentistry for a long time. It has been reported that the ions released from BG could in certain extent form a favorable Journal of Biomaterials and Nanobiotechnology microenvironment for the differentiation of the BMSCs [15]. BG can form a carbonated apatite layer between hard and soft tissues.…”

45S5 bioactive glass coatings by atmospheric plasma spraying obtained from feedstocks prepared by different routes

“…For this reason the flowability of WR powder as represented by the Hausner ratio is much higher (lower Hausner ratio) due to its coarser particle size and round morphology of its agglomerates. An approximate flowability 7 threshold for free-flowing powders in terms of Hausner ratio is about 1.25 [16]. Thus the flowability of the finer DR powder (DR 63) is limited.…”

“…To obtain bioactive glass powders there are two well extended techniques: melting and subsequent crushing of a (usually) crystalline powder mixture and the sol-gel technique [6,7]. When the sol-gel method is used, the starting materials are processed at lower temperature giving rise to bioactive glasses that exhibit higher bioactivity and biodegradability in comparison with glasses obtained by the melting procedure [8,9].…”