Title: Synthesis of 45S5 bioactive glass-ceramic using the sol-gel method, catalyzed by low concentration acetic acid extracted from homemade vinegar

Abstract

In this paper, two different type of 45S5 bioactive glass-ceramic were compared. Both of them were prepared using the sol-gel method, with two different catalysts: 2 M nitric acid (NACBG) and 10 mM vinegar. Homemade vinegar (HMV) extracted from apples which contained up to 5% acetic acid, as an affordable and low concentration catalyst, was used for the synthesis of 45S5 bioactive glass ceramic called Homemade Vinegar Catalyzed Bioactive Glass (HMVCBG). The substitution of 2 M nitric acid by 87 mM acetic acid strongly reduces the concentration of the acid solution necessary for being a catalyst. The effect of these two catalysts on the structure, morphology, and properties of the bioactive glass-ceramics were investigated. Scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDXS) and Brunauere Emmette Teller (BET) were used to assess surface characteristics and specific surface area, which showed more uniformity and more specific surface area in HMVCBG. Crystallinity and composition were analyzed by X-ray diffraction (XRD), X-ray fluorescence (XRF) and Furrier transform infrared spectroscopy (FTIR) which showed some crystalline phases in BG. In-vitro bioactivity was studied in Phosphate Buffer Saline (PBS) and SEM results showed that HMVCBG has a more uniform hydroxyapatite layer and formation occurs more quickly. This due to the fact that hydroxyapatite is dissolved at a lower rate at higher pH values and it takes longer to form at a higher pH. HMV can form more numerous porosities and a more specific surface area because of higher pH of acetic acid. Hence, PBS solution penetrates to the depth of HMVCBG and hydroxyapatite nucleation form in more spots in the depth of HMVCBG. Thus, HMVCBG has a higher bioactivity level than NACBG.