Browsing by Author "Uzer, B."

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Citation - WoS: 9
Citation - Scopus: 10
The Relationship of Surface Roughness and Wettability of 316L Stainless Steel Implants With Plastic Deformation Mechanisms
(Elsevier Science Bv, 2019) Cicek, S.; Karaca, A.; Torun, I.; Onses, M. S.; Uzer, B.
The wettability of the implant plays significant role in successful tissue-implant integration and shows strong dependence on the surface topography of the material. Recent studies showed that the plastic deformation mechanisms can improve cell response, and increase surface roughness and energy. In order to understand the effect of these mechanisms on wettability, 316L stainless steel samples were subjected to tensile test and deformed up to 15% to 35% of strain levels. Atomic force microscopy (AFM) presented approximately 22-fold greater average surface roughness on the 35% deformed sample compared to undeformed one. On the other hand, sessile drop test showed contact angle decrease from 82 degrees to 52 degrees as the deformation increased. This finding is significant since much higher contact angle value at similar surface roughness was presented in the literature. This demonstrates that the plastic deformation mechanisms can play significant role in enhancing the surface wettability without a need for a surface treatment technique. Hence, through the activation of these mechanisms, wettability and surface energy of the implant materials could be further increased which would result with enhanced cell response and lessened post-surgical complications. (C) 2018 Elsevier Ltd. All rights reserved.
Citation - Scopus: 2
The Influence of Plastic Deformation Mechanisms on the Adhesion Behavior and Collagen Formation in Osteoblast Cells
(Springer International Publishing, 2018) Uzer, B.; Monte, Felipe Alves Do; Awad, Kamal R.; Aswath, Pranesh; Varanasi, Venu Gopal; Canadinc, Demircan
In many of biomedical applications, the implant might get in direct contact with the bone tissue where the osteogenesis needs to be stimulated. If osteoblasts can not successfully attach on the implant surface, the bone might resorb and implant can fail. In the current study MC3T3 cells were cultured on the 316L stainless steel samples which were deformed up to four different strain levels (5, 15, 25 and 35%) to activate plastic deformation mechanisms (slip and twinning) in different volume fractions. Scanning electron microscopy (SEM) images showed that cells adhered and spread significantly on the 25 and 35% deformed samples owing to the greater surface roughness and energy provided by the increased density of micro-deformation mechanisms which promoted the formation of focal contacts. In addition, significant amount of collagen formation was observed on the sample deformed up to 25% of strain which can be due to the ideal match of the surface roughness and collagen molecules. Overall these results show that material’s microstructure can be manipulated through plastic deformation mechanisms in order to enhance the cell response and collagen deposition. As a result long lasting implants could be obtained which would eliminate additional surgical interventions and provide a successful treatment. © 2018 Elsevier B.V., All rights reserved.