The bioactivity and ion release of titanium-containing glass polyalkenoate cements for medical applications.
ABSTRACT The ion release profiles and bioactivity of a series of Ti containing glass polyalkenoate cements. Characterization revealed each material to be amorphous with a T(g) in the region of 650-660°C. The network connectivity decreased (1.83-1.35) with the addition of TiO(2) which was also evident with analysis by X-ray photoelectron spectroscopy. Ion release from cements were determined using atomic absorption spectroscopy for zinc (Zn(2+)), calcium (Ca(2+)), strontium (Sr(2+)), Silica (Si(4+)) and titanium (Ti(4+)). Ions such as Zn(2+) (0.1-2.0 mg/l), Ca(2+) (2.0-8.3 mg/l,) Sr(2+) (0.1-3.9 mg/l), and Si(4+) (14-90 mg/l) were tested over 1-30 days. No Ti(4+) release was detected. Simulated body fluid revealed a CaP surface layer on each cement while cell culture testing of cement liquid extracts with TW-Z (5 mol% TiO(2)) produced the highest cell viability (161%) after 30 days. Direct contact testing of discs resulted in a decrease in cell viability of the each cement tested.
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ABSTRACT: This study aims to investigate the solubility of a series of titanium (TiO2) containing bioactive glasses and their subsequent effect on cell viability. Five glasses were synthesized in the composition range SiO2-Na2O-CaO with 5mol% increments TiO2 substituted for SiO2. Glass solubility was investigated with respect to 1.) exposed surface area, 2.) particle size, 3.) incubation time and 4.) compositional effects. Ion release profiles showed that sodium (Na+) presented high release rates after 1 day and were unchanged between 7 and 14 days. Calcium (Ca2+) release presented a significant change at each time period and was also composition dependant, where a reduction in Ca2+ release is observed with an increase in TiO2 concentration. Silica (Si4+) release did not present any clear trends while no titanium (Ti4+) was released. Cell numbers were found to increase up to 44%, compared to the growing control population, with a reduction in particle size and with the inclusion of TiO2 in the glass composition.Journal of Biomedical Materials Research Part A 05/2014; DOI:10.1002/jbm.a.35223 · 2.83 Impact Factor
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ABSTRACT: Bone cement used in orthopaedic applications can become colonized with bacterial biofilms, resulting in severe medical complications. Consequently, bone cements are often loaded with antibiotics in an effort to prevent bacterial colonization. However, current formulations may not release antibiotics into the environment at sufficient and sustained concentrations required to impede bacterial growth or may be incompatible with antibiotics that are effective against the colonizing organism. Thus, new cement formulation options are needed. This report describes the performance of a novel SiO2-TiO2-ZnO-CaO-SrO-based glass polyalkenoate cement as a carrier of antimicrobials active against Staphylococcus aureus, the predominant cause of orthopaedic biofilm-associated infections. The antibiotic vancomycin and a novel Staphylococcus aureus RnpA inhibitor under pre-clinical development, RNPA1000, were included in these studies. Rheological testing characterized the workability of the glass polyalkenoate cement over a range of powder-to-liquid ratios and polyacrylic acid concentrations and revealed that the most suitable powder-to-liquid ratio was 2/1.25 with 40 wt% polyacrylic acid. Loading glass polyalkenoate cement with either 20-30% RNPA1000 or vancomycin prevented bacterial growth. However, longer incubations allowed for Staphylococcus aureus colonies to form near the vancomycin-infused cement, indicating that vancomycin may not be suitable for long-term biofilm inhibition in comparison to RNPA1000. Scanning electron microscopy and energy-dispersive X-ray analyses confirmed successful incorporation RNPA1000 into the cement matrix and were indicative of its slow release. These studies establish a drug-eluting formulation of glass polyalkenoate cement with great potential in orthopaedic implants that incorporates known antibiotics as well as RNPA1000 to prevent growth of the dangerous pathogen Staphylococcus aureus.Journal of Biomaterials Applications 09/2013; 28(8). DOI:10.1177/0885328213503388 · 2.76 Impact Factor
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ABSTRACT: This project investigates the characterization and solubility of a bioactive glass series where Strontium (Sr) and Sodium (Na) are substituted. X-ray diffraction (XRD) was employed to ensure that each starting material is amorphous. Differential Thermal Analysis (DTA) was used to determine the thermal profile of each material, in particular, the glass transition temperature (Tg), the crystallization temperature (Tc1) and the melting temperature (Tm). Magic Angle Spinning - Nuclear Magnetic Resonance (MAS-NMR) was used to probe the local 29Si environment. Simulated Body Fluid (SBF) testing revealed a CaP surface layer on each glass after 7 days.Bioengineering Conference (NEBEC), 2013 39th Annual Northeast; 01/2013