What is the purpose of replacing calcium with strontium in simulating body fluid solutions?   How were the process parameters defined for the analyzes carried out? Did they come from any previous study?

I would like to understand in more detail the extent of the antimicrobial study of the compounds, as well as a more comprehensive explanation of the results obtained for the aforementioned test.   Although the results presented show that the two produced inks are printable, presenting good mechanical resistance and high biocompatibility, do any of the other tests show better applicability of one of the inks than the other?