A Gallium-Doped Cement for the Treatment of Bone Cancers. the Effect of ZnO ↔ Ga2O3substitution of an Ionomeric Glass Series on the Rheological, Mechanical, PH and Ion-Eluting Properties of their Corresponding Glass Polyalkenoate Cements

The primary treatment for patients suffering from bone cancers is resection of the tumor followed by reconstruction of the damaged bone. Despite the administration of post-operative chemotherapy, tumor recurrence continues to present itself as a severe complication leading to re-operation. Attempts to incorporate chemotherapeutic drugs into bone cements elicits local toxic effects on healthy bone, which could compromise implant fixation. Alternatively, the local administration of gallium (Ga) may prove to be more effective. This report considers the development of a Ga ionomeric glass series (0.48SiO2-0.355ZnO-0.06CaO-0.08SrO-0.02P2O5-0.005Ta2O5, with 0.01-0.05 mol% substitution for ZnO). X-ray Diffraction (XRD) confirmed the amorphous glass structure and Energy Dispersive x-ray Fluorescence (EDXRF) verified the successful addition of Ga into the glass series at the expense of Zinc (Zn). A Ga-GPC series was then formulated by mixing the glass particles with aqueous poly(acrylic) acid (PAA) and trisodium citrate (TSC). Fourier transform infrared (FTIR) spectroscopy demonstrated no structural changes to the GPC matrix with the incorporation of Ga. Measurements of the rheological properties demonstrated an exponential increase in setting time with increasing Ga content. Furthermore, the addition of ≥ 3 mol% Ga demonstrated deleterious effects on the GPC\u27s mechanical properties and an analysis of pH confirmed that it decreased with increasing Ga content, suggesting a reduction in glass reactivity and PAA cross-linking. Finally, inductively coupled plasma - optical emission spectrometry (ICP-OES) demonstrated the controlled release of Ga across the GPC series, which will prove beneficial to future in vitro studies

Bone Cement as a Local Chemotherapeutic Drug Delivery Carrier in Orthopedic Oncology: A Review

Metastatic bone lesions are common among patients with advanced cancers. While chemotherapy and radiotherapy may be prescribed immediately after diagnosis, the majority of severe metastatic bone lesions are treated by reconstructive surgery, which, in some cases, is followed by postoperative radiotherapy or chemotherapy. However, despite recent advancements in orthopedic surgery, patients undergoing reconstruction still have the risk of developing severe complications such as tumor recurrence and reconstruction failure. This has led to the introduction and evaluation of poly (methyl methacrylate) and inorganic bone cements as local carriers for chemotherapeutic drugs (usually, antineoplastic drugs (ANPDs)). The present work is a critical review of the literature on the potential use of these cements in orthopedic oncology. While several studies have demonstrated the benefits of providing high local drug concentrations while minimizing systemic side effects, only six studies have been conducted to assess the local toxic effect of these drug-loaded cements and they all reported negative effects on healthy bone structure. These findings do not close the door on chemotherapeutic bone cements; rather, they should assist in materials selection when designing future materials for the treatment of metastatic bone disease

Effect of TiO2 Doping on Degradation Rate, Microstructure and Strength of Borate Bioactive Glass Scaffolds

A titanium-containing borate glass series based on the system (52-X) B2O3–12CaO–6P2O5–14Na2O–16ZnO-XTiO2 with X varying from 0, 5 and 15 mol% of TiO2 incorporated, identified as BRT0, BRT1 and BRT3, respectively, were used in this study. Scaffolds (pore sizes, 165–230 μm and porosity, 53.51–69.51%) were prepared using a polymer foam replication technique. BRT3 scaffolds exhibited higher compressive strength (7.16 ± 0.22 MPa) when compared to BRT0 (6.02 ± 0.47 MPa) and BRT1 (5.65 ± 0.28 MPa) scaffolds with lower, or no, TiO2 content. The solubility of the scaffolds decreased as the TiO2 content increased up to 15 mol% when samples of each scaffold were immersed in DI water and the pH of all these extracts went up from 7.0 to 8.5 in 30 days. The cumulative ion release from the scaffolds showed significant difference with respect to TiO2 content; addition of 5 mol% TiO2 at the expense of borate (B2O3) decreased the ion release remarkably. Furthermore, it was found that for all three scaffolds, cumulative ion release increased with incubation time. The results indicate that the degradation rates and compressive strengths of borate bioactive glass scaffolds could be controlled by varying the amount of TiO2 incorporated, confirming their potential as scaffolds in TKA and rTKA

Effect of TiO\u3csub\u3e2\u3c/sub\u3e doping on degradation rate, microstructure and strength of borate bioactive glass scaffolds

© 2019 Elsevier B.V. A titanium-containing borate glass series based on the system (52-X) B2O3–12CaO–6P2O5–14Na2O–16ZnO-XTiO2 with X varying from 0, 5 and 15 mol% of TiO2 incorporated, identified as BRT0, BRT1 and BRT3, respectively, were used in this study. Scaffolds (pore sizes, 165–230 μm and porosity, 53.51–69.51%) were prepared using a polymer foam replication technique. BRT3 scaffolds exhibited higher compressive strength (7.16 ± 0.22 MPa) when compared to BRT0 (6.02 ± 0.47 MPa) and BRT1 (5.65 ± 0.28 MPa) scaffolds with lower, or no, TiO2 content. The solubility of the scaffolds decreased as the TiO2 content increased up to 15 mol% when samples of each scaffold were immersed in DI water and the pH of all these extracts went up from 7.0 to 8.5 in 30 days. The cumulative ion release from the scaffolds showed significant difference with respect to TiO2 content; addition of 5 mol% TiO2 at the expense of borate (B2O3) decreased the ion release remarkably. Furthermore, it was found that for all three scaffolds, cumulative ion release increased with incubation time. The results indicate that the degradation rates and compressive strengths of borate bioactive glass scaffolds could be controlled by varying the amount of TiO2 incorporated, confirming their potential as scaffolds in TKA and rTKA

Silica-Based and Borate-Based, Titania-Containing Bioactive Coatings Characterization: Critical Strain Energy Release Rate, Residual Stresses, Hardness, and Thermal Expansion

Silica-based and borate-based glass series, with increasing amounts of TiO2 incorporated, are characterized in terms of their mechanical properties relevant to their use as metallic coating materials. It is observed that borate-based glasses exhibit CTE (Coefficient of Thermal Expansion) closer to the substrate’s (Ti6Al4V) CTE, translating into higher mode I critical strain energy release rates of glasses and compressive residual stresses and strains at the coating/substrate interface, outperforming the silica-based glasses counterparts. An increase in the content of TiO2 in the glasses results in an increase in the mode I critical strain energy release rate for both the bulk glass and for the coating/substrate system, proving that the addition of TiO2 to the glass structure enhances its toughness, while decreasing its bulk hardness. Borate-based glass BRT3, with 15 mol % TiO2 incorporated, exhibits superior properties overall compared to the other proposed glasses in this work, as well as 45S5 Bioglass® and Pyrex