Role of alkali metal oxide type on the degradation and in vivo biocompatibility of soda-lime-borate bioactive glass.

In this work, it is the first time to study the effect of replacing of Na O by a fixed amount of Li O or K O in soda-lime-borate glass on its in vivo biocompatibility. The glass composition was based on xM O-20x Na O20 CaO60 B O , (wt %), where, M OLi O and K O, and consequently, samples encoded BN100, BK50, and BL50. The degradation test was carried out in 0.25 M K HPO solution. The in vivo test was performed in the femoral bone defect of Sprague-Dawley adult male rat. Following up bone formation was conducted by the histological analyses and bone formation markers (alkaline phosphatase [ALP] and osteocalcin [OCN]). Furthermore, the glass effect on the liver and kidney functions was addressed in this study using (alanine transaminase [ALT] and aspartate transaminase [AST]) and (urea and creatinine), respectively. The results of the degradation test showed that the glass dissolution rate was increased by incorporating of K O, and its ion release was occurred by a diffusion-controlled process. Moreover, in vivo bioactivity test showed that serum activity of ALP, OCN level, and the newly formed bone was higher in BL50-implanted group than that of BN100 andBK50at 3 w and 6 w post-surgery. As well as, implantation of all glass samples in the femoral bone defect did not alter the liver and kidney functions. In conclusion, the synthesized borate glass was well served as a controlled delivery system for Li ion release, which enhanced bone formation as shown from the bone formation markers (ALP and OCN).