Bioactive glasses were introduced to the world in 1969 by the late Dr. Larry Hench when he developed the novel glass composition 45S5, commercially known as Bioglass®, through discovering the optimized ternary Na2O–CaO–SiO2 structure and incorporating phosphorous into that matrix. This came about after an enlightening, in-depth conversation with a soldier during World War II while on a train to a conference. They discussed the common types of injuries that were sustained, often resulting in avoidable amputation because there was no treatment available at that time to prevent it. That conversation led to the idea to develop a material capable of interacting with the bodily environment, thus facilitating cellular and bone regeneration. With the invention of the novel Bioglass® composition, Hench observed that his creation mimicked many properties of normal bone and stimulated the regrowth of bone between fractures by forming a hydroxyapatite structure on its surface, once exposed to the aqueous bodily environment, and therefore allowing it to bond with both hard and soft tissue, with less chance of rejection. Since then, Bioglass® has been used in bone tissue engineering, drug delivery, as a graft material, endosseous implants, remineralizing agent, and as an antibacterial agent. Years later, other scientists and engineers would use this novel composition as the foundational concept for numerous families of bioactive glass-ceramics.
Enhancing Bioactive Glass Coatings for Metallic Implants
Our lab, in collaboration with Professor Jincheng Du from the Department of Materials Science, is investigating phosphosilicate bioactive glass coatings for metallic implants. These coatings are crucial for improving implant integration with bone tissue and reducing the risk of implant failure. However, developing bioactive glass compositions with optimal thermal stability, mechanical durability, and bioactivity remains a significant challenge.
In our recent study, “The Effect of Boron Oxide on the Structures and Thermal Properties of Phosphosilicate Bioactive Glasses for Metallic Implants’ Coatings,” we explored how varying concentrations of boron oxide (B₂O₃) influence the structural and thermal properties of phosphosilicate bioactive glasses. By integrating molecular dynamics (MD) simulations with experimental characterization techniques, we gained a deeper understanding of how boron incorporation affects the glass network and its performance as a coating material.
Key Findings:
- Structural Modifications:
- Increasing boron oxide content disrupts the silicate network by introducing borate structural units, leading to increased network flexibility.
- The presence of boron alters the glass’s bonding characteristics, which may influence its bioactivity and dissolution behavior.
- Thermal and Mechanical Properties:
- The addition of boron oxide enhances the thermal expansion coefficient, making the glass more compatible with metallic substrates by reducing thermal mismatch.
- Certain boron levels contribute to improved processability of the glass, which is essential for fabricating durable coatings.
- Potential Biomedical Applications:
- The findings suggest that boron-modified phosphosilicate glasses could be optimized for bioactive coatings on titanium and other implant materials.
- Such coatings may improve bone regeneration, minimize implant rejection, and extend the longevity of orthopedic and dental implants.
Significance of This Research:
This study exemplifies our lab’s commitment to developing smart biomaterials for biomedical applications, particularly in the area of implant coatings and tissue engineering. Our collaboration with Professor Du’s team combines expertise in materials science, computational modeling, and biomedical engineering, allowing us to design novel biomaterials with tailored properties.
Moving forward, we aim to further optimize these bioactive glass compositions, explore their biocompatibility and degradation behavior, and assess their performance in biological environments. This research is a step toward creating next-generation implant coatings that enhance osseointegration, mechanical stability, and long-term functionality in patients.
Effect of Manganese on the S53P4 Bioactive Glass Composition
The novel S53P4 bioactive glass, a synthetic bone graft substitute that has known bone-bonding properties including osteoconductivity, ability to facilitate osteostimulation, and bone proliferation around the material. Additionally, this bioactive glass has an intrinsic antibacterial property that sets it apart from other bioactive glasses, making it vital in septic bone defects. Moreover, S53P4 is known to affect the angiogenesis process. This glass composition is one of the most commonly used bioactive glasses used for clinical application to date, apart from the novel Bioglass®. A few clinical applications that the S53P4 bioactive glass has been used for a bone graft material after benign bone tumor resection, as a substitution in autogenous bone grafting for degenerative spondylolisthesis, as a substitution for PMMA in the treatment for osteomyelitis, just to name a few. Reasons that make S53P4 a suitable substitute for these applications are because of its “off-the-shelf” nature, its excellent bone healing capacity, its lower degradation rate than 45S5, and its antibacterial properties which allow for a much more reliable behavior than antibiotics due to its difference in antibiotic mechanism resulting in an increased provenance of antibiotic resistance behavior. Additionally, S53P4 bioactive glass offers a one-step treatment, compared to the gold standard application which offers a two-step treatment, and a more taxing clinical process.
We are investigating the effect of MnO2 on the S53P4 glass composition by substituting CaCO3 in varying concentrations from 0% to 8% total manganese. Manganese is an essential nutrient found naturally in the body that plays a big role in many chemical processes such as the metabolism of amino acids, cholesterol, fat, and carbohydrates. Additionally, manganese when introduced into the body promotes the formation of connective tissues, bones, blood-clotting factors, and sex hormones. With the incorporation of MnO2 into this glass composition, we aim to improve its biological behavior, while either maintaining or even improving its mechanical properties and bioactivity.
Najwa’s Related Publications:
Blood-Brain Barrier Integrity and Clearance of Amyloid-β from the BBB
https://pubmed.ncbi.nlm.nih.gov/30315550/
Bioactive glass coatings on metallic implants for biomedical applications
https://www.sciencedirect.com/science/article/pii/S2452199X19300465
https://pubmed.ncbi.nlm.nih.gov/31667443/
Bioactive Glasses in Orthopedic Applications
https://link.springer.com/chapter/10.1007/978-3-030-34471-9_21
Incorporation of novel elements in bioactive glass compositions to enhance implant performance
https://www.intechopen.com/online-first/77966
References:
Baino, Francesco, Sepideh Hamzehlou, and Saeid Kargozar. 2018. “Bioactive Glasses: Where Are We and Where Are We Going?” Journal of Functional Biomaterials 9(1).
Fiume, Elisa, Jacopo Barberi, Enrica Verné, and Francesco Baino. 2018. “Bioactive Glasses: From Parent 45S5 Composition to Scaffold-Assisted Tissue-Healing Therapies.” Journal of Functional Biomaterials 9(1).
Van Gestel, N. A. P., J. Geurts, D. J. W. Hulsen, B. Van Rietbergen, S. Hofmann, and J. J. Arts. 2015. “Clinical Applications of S53P4 Bioactive Glass in Bone Healing and Osteomyelitic Treatment: A Literature Review.” BioMed Research International 2015.
Krishnan, Vidya and T. Lakshmi. 2013. “Bioglass: A Novel Biocompatible Innovation.” Journal of Advanced Pharmaceutical Technology & Research 4(2):78.