Manipulation of the degradation behavior of calcium sulfate by the addition of bioglass

Abstract

A bioactive calcium sulfate/glass composite was prepared using a sintering technique, and Ca-P-Si glass particles were prepared by spray pyrolysis. The glass exhibited bioactivity in terms of its ability to form apatite in a simulated body fluid. The glass was transformed into two crystallized phases, i.e., calcium phosphate and calcium silicate, respectively, during the heating stage. The presence of the crystallized phases retarded the densification of calcium sulfate. A high sintering temperature of 1200 °C was needed to prepare the composite. The increased addition of glass enhanced the strength and decreases the degradation rate of calcium sulfate. The new composite is not only degradable but also bioactive.

Keywords: Bioceramic; Bioglass; Calcium sulfate; Composite; Degradation.

Fig. 1

Morphology of the glass particles prepared by spray pyrolysis

Fig. 2

a Morphology of one glass particle and b its cross section exposed by the FIB technique

Fig. 3

TEM image and the corresponding SAED pattern (inset) of the glass particle

Fig. 4

XRD patterns of the glass after soaking in PBS for 24 h and after firing at 800 °C, 1000 °C, and 1200 °C

Fig. 5

Density of the calcium sulfate (CS)/glass (BG) composites as a function of sintering temperature. Also shown is the density of the glass pellet after sintering at 1200 °C (red diamond). Inset shows the morphology of a glass pellet on the top of a calcium sulfate specimen after sintering to 1200 °C

Fig. 6

XRD patterns of the calcium sulfate/10% glass composite after sintering at various temperatures

Fig. 7

Fracture surfaces of the calcium sulfate/glass composites. The content of glass in the composites is a 0%, b 1%, c 5%, and d 10%

Fig. 8

Viability of MC3T3-E1 cells in the extract from CSA/1% glass pellets

Fig. 9

Accumulated weight loss for the calcium sulfate (CS)/glass (BG) composite in the PBS solution as a function of time

Fig. 10

Concentrations of a Ca²⁺, b PO₄³⁻, and c Si⁴⁺ in the PBS solution after soaking the calcium sulfate/glass composites. Also shown is the concentration of Ca²⁺, PO₄³⁻, and Si⁴⁺ in the blank PBS solution

Fig. 11

Surface morphology of the a calcium sulfate/1% glass and b calcium sulfate/10% glass composites after soaking in PBS for 28 days

Fig. 12

XRD patterns of the calcium sulfate (CS)/glass (BG) composites after soaking in PBS for 28 days

Fig. 13

Schematic of surface ion-exchange process for a calcium sulfate and the b calcium sulfate composite. Calcium sulfate and its composite can release calcium ions and exchange with the phosphate ions in the solution, affording calcium phosphate flakes