Factors governing the sinterability, In vitro dissolution, apatite formation and antibacterial properties in B2O3 incorporated S53P4 based glass powders

Abstract

In this report, we have systematically evaluated the role of boron in regulating the degradation, apatite formation and antibacterial properties of bioactive glasses by substituting SiO 2 with B 2 O 3 in S53P4 based glass composition. The structural analysis of the glasses has been carried out using neutron diffraction and Raman spectroscopic techniques. The structural analysis of S53P4 base glass has revealed the presence of silicate and phosphate units in the form of Q 2 Si , Q 3 Si and isolated Q 0 P units. With the increasing replacement of SiO 2 with B 2 O 3 , Raman spectroscopy revealed the formation of non-ring metaborate units and borate rings consisting of both BO 3 and BO 4 units at the expense of Q 2 Si and Q 3 Si units. Furthermore, DSC, HSM and dilatometry results confirmed that the sinterability parameter (S c ) and fragility index (m) values of borosilicate bioactive glasses help in achieving superior sintering and thermal processing without devitrification. Additionally, in vitro SBF immersion studies revealed an accelerated release of Si 4+ and Ca 2+ ions from the borosilicate glasses. In vitro antibacterial assays against E.coli bacterial inoculum illustrate the critical role of B 2 O 3 in the bioactive glass composition.