Enhancing In Vitro Bioactivity of Melt‐Derived 45S5 Bioglass^® by Comminution in a Stirred Media Mill

Abstract

45S5 Bioglass® (45S5 BG) is a frequently applied Type A bioactive material, capable of forming an inherent bond to bone and soft tissue. Currently, applied melt‐derived bioactive glass powders (BG) exhibit particle sizes between a few to several hundred micrometers. Recent studies on nanometer‐sized bioactive glasses (nBGs), produced by bottom‐up methods like sol–gel processing or flame spray pyrolysis, have indicated their great potential for several biomedical applications. In this study, the feasibility of top‐down processing starting from bulk 45S5 BG by wet comminution in a stirred media mill was investigated. The products were assessed by in vitro hydroxycarbonate apatite (HCAp) formation in simulated body fluid, which is a marker for bioactive behavior. The study reveals the paramount influence of the used solvent for a successful top‐down processing: In comparison with the as‐received material bioactivity is lost for powders processed in water, preserved for comminution in ethanol and increased for powders processed using the alcohols n‐butanol, n‐pentanol, and n‐hexanol. It was also found that only for the latter solvents, the chemical composition of the glass is maintained during comminution. Flake‐like, slightly porous particles with specific surface areas of ~25–30 m2/g are obtained. Thus, the presented comminution approach offers a convenient technique to process 45S5 BG with enhanced bioactivity.

Biocompatibility of submicron Bioglass® powders obtained by a top‐down approach

“…On the other hand, stirred media milling is a simple, versatile and scalable method to produce a large variety of micron and nanosized powders . Recently, Romeis et al comminuted a melt‐derived 45S5BG in a stirred media mill and obtained submicron particles of enhanced in vitro bioactivity. Biocompatibility and the response of cells to these new particles have not been tested yet.…”

Bio-templated bioactive glass particles with hierarchical macro–nano porous structure and drug delivery capability

“…The highest loading efficiency of PBGPs can be attributed to their higher SSA, which could provide more sites for drug anchoring. The SSA of the meltderived 45S5 BGPs is usually lower than 10 m 2 /g [48,49], which can account for their lowest drug loading ability. In addition, abundant Si-OH groups can be found on gel-derived BGs due to the wet synthesis process and the lower temperature treatments involved in the synthesis.…”

Mechanically induced phase transformation of zinc sulfide

“…During the production of devices, zinc sulfide particles may be exposed to mechanical forces, such as in the dispersing steps. In previous work we showed for a number of oxidic materials that stirred media milling can induce mechanochemical changes, which lead to a strong modification of material properties (Damm & Peukert, 2009;Stenger, Götzinger, Jakob, & Peukert, 2004;Romeis et al, 2014). Therefore, an improved understanding of the influence of mechanical forces on the microstructure and photoluminescence behavior of zinc sulfide particles is essential.…”