In vivo bioactivity assessment of strontium-containing soda-lime-borate glass implanted in femoral defect of rat

A review on borate bioactive glasses (BBG): effect of doping elements, degradation, and applications

Because of their excellent biologically active qualities, bioactive glasses (BGs) have been extensively used in the biomedical domain, leading to better tissue-implant interactions and promoting bone regeneration and wound healing. Aside from having attractive characteristics, BGs are appealing as a porous scaffold material. On the other hand, such porous scaffolds should enable tissue proliferation and integration with the natural bone and neighboring soft tissues and degrade at a rate that allows for new bone development while preventing bacterial colonization. Therefore, researchers have recently become interested in a different BG composition based on borate (B₂O₃) rather than silicate (SiO₂). Furthermore, apatite synthesis in the borate-based bioactive glass (BBG) is faster than in the silicate-based bioactive glass, which slowly transforms to hydroxyapatite. This low chemical durability of BBG indicates a fast degradation process, which has become a concern for their utilization in biological and biomedical applications. To address these shortcomings, glass network modifiers, active ions, and other materials can be combined with BBG to improve the bioactivity, mechanical, and regenerative properties, including its degradation potential. To this end, this review article will highlight the details of BBGs, including their structure, properties, and medical applications, such as bone regeneration, wound care, and dental/bone implant coatings. Furthermore, the mechanism of BBG surface reaction kinetics and the role of doping ions in controlling the low chemical durability of BBG and its effects on osteogenesis and angiogenesis will be outlined.

Design strategies for composite matrix and multifunctional polymeric scaffolds with enhanced bioactivity for bone tissue engineering

Over the past few decades, various bioactive material-based scaffolds were investigated and researchers across the globe are actively involved in establishing a potential state-of-the-art for bone tissue engineering applications, wherein several disciplines like clinical medicine, materials science, and biotechnology are involved. The present review article's main aim is to focus on repairing and restoring bone tissue defects by enhancing the bioactivity of fabricated bone tissue scaffolds and providing a suitable microenvironment for the bone cells to fasten the healing process. It deals with the various surface modification strategies and smart composite materials development that are involved in the treatment of bone tissue defects. Orthopaedic researchers and clinicians constantly focus on developing strategies that can naturally imitate not only the bone tissue architecture but also its functional properties to modulate cellular behaviour to facilitate bridging, callus formation and osteogenesis at critical bone defects. This review summarizes the currently available polymeric composite matrices and the methods to improve their bioactivity for bone tissue regeneration effectively.

Effects of Boron Oxide Concentration and Carbon Nanotubes Reinforcement on Bioactive Glass Scaffolds for Bone Tissue Engineering

In this work, the effect of varying content of B₂O₃ with respect to SiO₂ on mechanical and bioactivity properties have been evaluated for borosilicate bioactive glasses containing SiO₂, B₂O₃, CaO and P₂O₅. The bioactive glasses have been synthesized using the sol-gel technique. The synthesized glasses were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and Field Emission Scanning electron microscopy (FESEM). These bioactive glasses were fabricated as scaffolds by using polymer foam replication method. Subsequently, in vitro bioactivity evaluation of borosilicate bioactive glass was done. Based on the XRD and energy-dispersive X-ray spectroscopy (EDS) results showing good apatite-formation ability when soaked in simulated body fluid (SBF), one of the bioactive glass (BG-B30 containing 30 mol% B₂O₃) was selected for further study. The compressive strength of the bioactive glass scaffolds was within the range of trabecular bone. However, it was found near the lower limit of the trabecular bone (0.2-12 MPa). Therefore, BG-B30 scaffold was reinforced with carbon nanotubes (CNTs) to allow for mechanical manipulation during tissue engineering applications. The compressive strength increased from 1.05 MPa to 7.42 MPa (a 606% increase) after reinforcement, while the fracture toughness rose from 0.12 MPa √ m to 0.45 MPa √ m (a 275% increase). Additionally, connectivity of the pores in the CNT reinforced BG-B30 scaffolds were evaluated and the pores were found to be well connected. The evaluated properties of the fabricated scaffolds demonstrate their potential as a synthetic graft for possible application in bone tissue engineering.