Hexagonal Boron Nitride/PCL/PLG Coatings on Borate Bioactive Glass Scaffolds for Bone Regeneration

Advances in Biomimetic Scaffolds for Hard Tissue Surgery

Hard tissues are living mineralized tissues that possess a high degree of hardness and are found in organs such as bones and teeth (enamel, dentin, and cementum) [...].

Preparation, Characterization, and Drug Delivery of Hexagonal Boron Nitride-Borate Bioactive Glass Biomimetic Scaffolds for Bone Tissue Engineering

In this study, biomimetic borate-based bioactive glass scaffolds containing hexagonal boron nitride hBN nanoparticles (0.1, 0.2, 0.5, 1, and 2% by weight) were manufactured with the polymer foam replication technique to be used in hard tissue engineering and drug delivery applications. To create three-dimensional cylindrical-shaped scaffolds, polyurethane foams were used as templates and covered using a suspension of glass and hBN powder mixture. Then, a heat treatment was applied at 570 °C in an air atmosphere to remove the polymer foam from the structure and to sinter the glass structures. The structural, morphological, and mechanical properties of the fabricated composites were examined in detail. The in vitro bioactivity of the prepared composites was tested in simulated body fluid, and the release behavior of gentamicin sulfate and 5-fluorouracil from glass scaffolds were analyzed separately as a function of time. The cytotoxicity was investigated using osteoblastic MC3T3-E1 cells. The findings indicated that the hBN nanoparticles, up to a certain concentration in the glass matrix, improved the mechanical strength of the glass scaffolds, which mimic the cancellous bone. Additionally, the inclusion of hBN nanoparticles enhanced the in vitro hydroxyapatite-forming ability of bioactive glass composites. The presence of hBN nanoparticles accelerated the drug release rates of the system. It was concluded that bioactive glass/hBN composite scaffolds mimicking native bone tissue could be used for bone tissue repair and regeneration applications.

Borate Bioactive Glasses (BBG): Bone Regeneration, Wound Healing Applications, and Future Directions

Since the early 2000s, borate bioactive glasses (BBGs) have been extensively investigated for biomedical applications. The research so far indicates that BBGs frequently exhibit superior bioactivity and bone healing capacity compared to silicate glasses. They are also suitable candidates as drug delivery devices for infection or disease treatment such as osteoporosis. Additionally, BBGs are also an excellent option for wound healing applications, which includes the availability of commercial (FDA approved) microfibrous BBG dressings to treat chronic wounds. By addition of modifying ions, the bone or wound healing capacity of BBGs can be enhanced. For instance, addition of copper ions into BBGs was shown to drastically increase blood vessel formation for wound healing applications. Moreover, addition of ions such as magnesium, strontium, and cobalt improves bone healing. Other recent research interest related to BBGs is focused on nerve and muscle regeneration applications, while cartilage regeneration is also suggested as a potential application field for BBGs. BBGs are commonly produced by melt-quenching; however, sol-gel processing of BBGs is emerging and appears to be a promising alternative. In this review paper, the physical and biological characteristics of BBGs are analyzed based on the available literature, the applications of BBGs are discussed, and future research directions are suggested.