Dolomite-Foamed Bioactive Silicate Scaffolds for Bone Tissue Repair

Abstract

The use of three-dimensional (3D) scaffolds is recognized worldwide as a valuable biomedical approach for promoting tissue regeneration in critical-size bone defects. Over the last 50 years, bioactive glasses have been intensively investigated in a wide range of different clinical applications, from orthopedics to soft tissue healing. Bioactive glasses exhibit the unique capability to chemically bond to the host tissue and, furthermore, their processing versatility makes them very appealing due to the availability of different manufacturing techniques for the production of porous and interconnected synthetic bone grafts able to support new tissue growth over the whole duration of the treatment. As a novel contribution to the broad field of scaffold manufacturing, we report here an effective and relatively easy method to produce silicate glass-derived scaffolds by using, for the first time in the biomedical field, dolomite powder as a foaming agent for the formation of 3D bone-like porous structures. Morphological/structural features, crystallization behavior, and in vitro bioactivity in a simulated body fluid (SBF) were investigated. All the tested scaffolds were found to fulfil the minimum requirements that a scaffold for osseous repair should exhibit, including porosity (65–83 vol.%) and compressive strength (1.3–3.9 MPa) comparable to those of cancellous bone, as well as hydroxyapatite-forming ability (bioactivity). This study proves the suitability of a dolomite-foaming method for the production of potentially suitable bone grafts based on bioactive glass systems.

Copper-Doped Ordered Mesoporous Bioactive Glass: A Promising Multifunctional Platform for Bone Tissue Engineering

“…These values are higher than the Ca-to-P atomic ratio of stoichiometric hydroxyapatite (1.67), but can be justified considering the boundary effects due to the finite volume involved in compositional assessment by EDS. On the other hand, non-stoichiometric hydroxyapatite has been reported to commonly form on silicate glasses in SBF [ 37 , 38 ]. XRD analysis ( Figure 6 c) confirmed the formation of hydroxyapatite (PDF code: 01-086-0740) on the surface of samples during immersion in SBF.…”

Biological Evaluation of a New Sodium-Potassium Silico-Phosphate Glass for Bone Regeneration: In Vitro and In Vivo Studies

“…In this preliminary study, 30 adult mongrel male mice with initial mass ranging between 20 and 23 g were divided into 5 groups of 6 individuals and subjected to intraperitoneal administration. Briefly, the infusion for injection was prepared as follows: in the first instance, 1 g of glass powder (mean particle size = 16.57 µm; density = 2.64 g/cm 3 ; specific surface area = 0.64 m 2 /g [27]) was vigorously mixed in a glass beaker with 9 mL of physiological solution; then, the suspension was stored in a thermostat at 37 • C for 24 h and subsequently passed through a filtering paper. Intraperitoneal delivery of the infusion was conducted in the following dose ranges: (500 mg/kg) 0.1 mL/20 g, (1000 mg/kg) 0.2 mL/20 g, (1500 mg/kg) 0.3 mL/20 g, (2000 mg/kg) 0.4 mL/20 g and (2500 mg/kg) 0.5 mL/20 g. After infusion, animals were individually kept in acrylic boxes and observed for the first four hours, 24 h and daily over 14 days for detecting any possible signs of toxicity.…”

“…Before applying systemic anesthesia, animals were properly kept in individual cages and then identified according to the period and group, as indicated in Table 1. Prior to surgery, 47.5B silicate glass powder [23,24,27] (mean particle size = 16.57 µm; density = 2.64 g/cm 3 ; specific surface area = 0.64 m 2 /g [27]) was sterilized by autoclaving at 180 • C for 2 h and implanted in the femoral diaphysis region of each animal (Figure 1). For additional information about particle characteristics, the reader can refer to Refs.…”

“…For additional information about particle characteristics, the reader can refer to Refs. [23,24,27]. Specifically, a drilled hole (diameter = 2 mm; length= 10 mm) was filled out with glass powder and the incised hole was subsequently sewed up (Figure 2).…”

Porous Materials for Applications in Energy and Environment

“…Therefore, materials with excellent properties are required to help remedy and/or reduce environmental pollution and power generation [20][21][22]. Among the different types, "porous materials" have received great attention in recent decades, due to their applications in the science of biomaterials [23][24][25][26][27], catalysis [28], sound adsorption [29], environment [30,31], and energy conversion [32]. This importance obeys to the fact that it consists of a solid matrix with interconnected pores, its size, and adjustable pore shape [33].…”