Browsing by Author "Webster, Thomas J."

Now showing 1 - 5 of 5

Citation - WoS: 16
A comparative study of silicon nitride and SiAlON ceramics against E. coli
(Elsevier Sci Ltd, 2021) Akin, Seniz R. Kushan; Garcia, Caterina Bartomeu; Webster, Thomas J.; 224219
In recent decades, due to some limitations from alumina (Al2O3) and zirconia (ZrO2), silicon nitride (Si3N4) has been investigated as a novel bioceramic material, mainly in situations where a bone replacement is required. Si3N4 ceramics and its derivative form, SiAlON, possess advantages in orthopedics due to their mechanical properties and biologically acceptable chemistry, which accelerates bone repair. However, biological applications require additional properties, enabling stronger chemical bonding to the surrounding tissue for better fixation and the prevention of bacteria biofilm formation. Therefore, two commercial Si3N4 and SiAlON ceramics were investigated in this study and compared to each other according to their material properties (like wetting angles and surface chemistry) and their antibacterial behaviors using E. coli. Results provided evidence of a 15% reduction in E. coli colonization after just 24 h on Si3N4 compared to SiAlON which is impressive considering no antibiotics were used. Further, a mechanism of action is provided. In this manner, this study provides evidence that Si3N4 should be further studied for a wide range of antibacterial orthopedic, or other suitable biomaterial applications.
Citation - WoS: 3
Antibacterial behavior of oxynitride glasses as a glassy grain boundary phase for silicon nitride-based ceramics
(Wiley Periodicals, inc, 2021) Kushan Akin, Seniz R.; Dolekcekic, Emrah; Webster, Thomas J.; 224219
Silicon nitride-based ceramics have provided significant advantages due to their high chemical resistance, high elastic modulus, and combination of hardness and fracture toughness (depending on self-reinforcement). Over the past two decades, a significant amount of interest has been generated for the bio-applications of these materials. However, the effect of the grain boundary phase on such applications is still not very well understood. In this study, the effect of different cations on biological (such as antibacterial and cytocompatibilty) and material properties (like wetting angles and isoelectric points [IEP]) of oxynitride glasses, mimicking the grain boundary phase in Si3N4 and SiAlON ceramics, were investigated. Results revealed that the antibacterial behavior and mammalian cell viability were inversely correlated in glasses with rare-earth cation additions. Ca was the best cation when the two properties (bacterial response and cell proliferation) were considered together, and, thus should be further studied for a wide range of applications.
Citation - WoS: 0
Antibacterial Behavior of Oxynitride Glasses as a Glassy Grain Boundary Phase for Silicon Nitride-Based Ceramics (Vol 12, Pg 328, 2021)
(Wiley Periodicals, inc, 2022) Kushan Akin, Seniz R.; Dolekcekic, Emrah; Webster, Thomas J.
Citation - WoS: 0
Citation - Scopus: 0
A Comparative Study of Silicon Nitride and Sialon Ceramics Against E. Coli (Vol 47, Pg 1837, 2021)
(Elsevier Sci Ltd, 2021) Akin, Seniz R. Kushan; Garcia, Caterina Bartomeu; Webster, Thomas J.
Citation - WoS: 5
Citation - Scopus: 5
Effect of nitrogen on the antibacterial behavior of oxynitride glasses
(Elsevier Sci Ltd, 2021) Akin, Seniz R. Kushan; Dolekcekic, Emrah; Webster, Thomas J.; 22421
The main drawback of bioglasses is their restricted use in load bearing applications and the consequent need to develop stronger glassy materials. This has led to the consideration of oxynitride glasses for numerous biomedical applications. This paper investigated two different types of glasses at a constant cationic ratio, with and without nitrogen (a N containing and a N-free glass composition) to better understand the effect of N on the biological properties of glasses. The results revealed that the addition of N increased the glass transition temperature, isoelectric point (IEP) and slightly increased wettability. Moreover, compared to N including glass, N-free glass exhibited better anti-bacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), two key bacteria that infect implants. In summary, these in vitro results indicated that amine functional groups existing in N containing glasses which are missing in N-free glasses, caused a slight difference in wetting behavior and a more obvious change in isoelectric point and in bacterial response. N-free glasses exhibited better inhibitory results both against E. coli and S. aureus compared to N including glass suggesting that oxygen rich glasses should be further studied for their novel antibacterial properties.