Hazer, Derya Burcu | Sakar, Mustafa | Dere, Yelda | Altınkanat, Gülşen | Ziyal, M. İbrahim | Hazer, Baki

Article | 2016 | Spine41 ( 6 )

Study Design. Antimicrobial effect of a novel silverimpregnated pedicle screw in rabbits. Objective. A novel spine implant model was designed to study the antimicrobial effect of a modified Titanium (Ti) pedicle screws with methicillin-resistant Staphylococcus aureus (MRSA) in multiple surgical sites in the lumbar spine of a rabbit. Summary of Background Data. Infection in spinal implant is of great concern. Anti-infection strategies must be tested in relevant animal models that will lead to appropriate clinical studies. Methods. Fourteen New Zealand white rabbits were divided into 2 groups: group 1: infected unmodified Ti screw gro . . .up (n=6), and group 2: infected polyethylene glycol grafted, polypropylene-based silver nanoparticle (PP-g-PEG-Ag) covered Ti screw group (n=6), and 2 rabbits as sterile (sham-operated and control) group. In all groups, left L4-right L6 vertebra levels were exposed and screws were drilled to transverse processes after contamination of burr holes and surrounding tissue with 0.1mL of 106 colony forming units (CFU) MRSA solutions in groups 1 and 2. After 21 days, samples were collected and infection was analyzed via light and scanning electron microscopy and culturing. Silver nanoparticles (Ag-NP) on the screws and tissues were assayed pre and postoperatively. Results. The bacterial colony count for modified-Ti screw group was lower than for unmodified Ti screw (17.2 versus 200 x 103 CFU/mL, P=0.029) with less biofilm formation. There was no difference in duration of surgery among groups and within the surgical sites. Ag-NPs were detected on the screw surface postoperatively. Conclusion. This novel experimental design of implantation in rabbits is easy to apply and resembles human stabilization technique. Modified Ti screws were shown to have antimicrobial effect especially inhibiting the biofilm formation. This anchored Ag NPs that remained after 21st day of implantation shows that it is resistant to tapping forces of the screw. © 2016 Wolters Kluwer Health, Inc. All rights reserved Daha fazlası Daha az

Balcı, Murat | Allı, Abdulkadir | Hazer, Baki | Güven, Olgun | Cavicchi, Kevin | Çakmak, Mükerrem

Article | 2010 | Polymer Bulletin64 ( 7 ) , pp.691 - 705

Kılıç, Muhammet Samet | Korkut, Şeyda | Hazer, Baki | Erhan, Elif

Article | 2014 | Biosensors and Bioelectronics61 , pp.500 - 505

Newly synthesized gold and cobalt oxide nanoparticle embedded Polypropylene-g-Polyethylene glycol was used for a compartment-less enzymatic fuel cell. Glucose oxidase and bilirubin oxidase were selected as anodic and cathodic enzymes, respectively. Electrode fabrication and EFC operation parameters were optimized to achieve high power output. Maximum power density of 23.5µWcm-2 was generated at a cell voltage of +560mV vs Ag/AgCl, in 100mM PBS pH 7.4 with the addition of 20mM of synthetic glucose solution. 20µg of polymer amount with 185µg of glucose oxidase and 356µg of bilirubin oxidase was sufficient to get maximum performance. T . . .he working electrodes could harvest glucose, produced during photosynthesis reaction of Carpobrotus Acinaciformis plant, and readily found in real domestic wastewater of Zonguldak City in Turkey. © 2014 Elsevier B.V Daha fazlası Daha az

Kılıç, Muhammet Samet | Korkut, Şeyda | Hazer, Baki

Article | 2014 | Analytical Letters47 ( 6 ) , pp.983 - 995

A recently synthesized polypropylene-g-polyethylene glycol polymer was used for the first time as the working electrode of a fuel cell. Electrodes were prepared for unmediated and mediated enzymatic reactions including ferrocene as the mediator. Glucose oxidase and bilirubin oxidase was used as the anodic and cathodic enzymes for the working electrodes, respectively. The biofuel cell was operated using glucose as the fuel in a single-compartment and membrane-less cell. Electrochemical results demonstrated that the catalytic efficiency of the ferrocene based cathode was approximately 100-fold higher than that of an unmediated cathode . . .. The mediated fuel cell electrodes yielded a power density of 65 nW/cm2 at a cell potential of +560 mV. © 2014 Copyright Taylor & Francis Group, LLC Daha fazlası Daha az

Hazer, Derya Burcu | Mut, Melike | Dinçer, Nazmiye | Sarıbaş, Zeynep | Hazer, Baki | Özgen, Tunçalp

Article | 2012 | Child's Nervous System28 ( 6 ) , pp.839 - 846

Purpose: Catheter-related infection is a major complication of ventriculoperitoneal shunt in children. The aim of this study is to determine inflammatory response and the efficacy of polypropylene-grafted polyethylene glycol (PP-g- PEG) copolymer and silver nanoparticle-embedded PP-g- PEG (Ag-PP-g-PEG) polymer-coated ventricular catheters on the prevention of catheter-related infections on a new experimental model of ventriculoperitoneal shunt in rats. Methods: Thirty six Wistar albino rats were divided into six groups: group 1, unprocessed sterile silicone catheterembedded group; group 2, sterile PP-g-PEG-coated catheter group; gro . . .up 3, sterile Ag-PP-g-PEG-coated catheter group; group 4, infected unprocessed catheter group; group 5, infected PP-g-PEG-coated catheter group; and group 6, infected Ag-PP-g-PEG-coated catheter group, respectively. In all groups, 1-cm piece of designated catheters were placed into the cisterna magna. In groups 4, 5, and 6, all rats were infected with 0.2 mL of 10×106 colony forming units (CFU)/mL Staphylococcus epidermidis colonies before the catheters were placed. Thirty days after implantation, bacterial colonization in cerebrospinal fluid and on catheter pieces with inflammatory reaction in the brain parenchyma was analyzed quantitatively. Results: Sterile and infected Ag-PP-g-PEG-covered groups revealed significantly lower bacteria colony count on the catheter surface (ANOVA, 0±0, p<0.001; 1.08±0.18, p< 0.05, respectively). There was moderate inflammatory response in the parenchyma in group 4, but in groups 5 and 6, it was similar to that of the sterile group (ANOVA, 16.33± 3.02, p<0.001; 4.00±0.68, p<0.001, respectively). Conclusions: The PP-g-PEG, especially Ag-PP-g-PEG polymer-coated ventricular catheters are more effective in preventing the catheter-related infection and created the least inflammatory reaction in the periventricular parenchyma. © Springer-Verlag 2012 Daha fazlası Daha az