Sürdürülebilir Yeşil Kampüs Koleksiyonu / Sustainable Green Campus Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7755
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Article Citation - WoS: 27Citation - Scopus: 34Chitosan/Montmorillonite Composite Nanospheres for Sustained Antibiotic Delivery at Post-Implantation Bone Infection Treatment(IOP Publishing Ltd., 2019) Kımna, Ceren; Değer, Sibel; Tamburacı, Sedef; Tıhmınlıoğlu, FundaDespite the advancements in bone transplantation operations, inflammation is still a serious problem that threatens human health at the post-implantation period. Conventional antibiotic therapy methods may lead to some side effects such as ototoxicity and nephrotoxicity, especially when applied in high doses. Therefore, local drug delivery systems play a vital role in bone disorders due to the elimination of the disadvantages introduced by conventional methods. In the presented study, it was aimed to develop Vancomycin (VC) and Gentamicin (GC) loaded chitosan-montmorillonite nanoclay composites (CS/MMT) to provide required antibiotic doses to combat post-implantation infection. CS/MMT nanocomposite formation was supplied by microfluidizer homogenization and spherical drug carrier nanoparticles were obtained by electrospraying technique. Three factors; voltage, distance and flowrate were varied to fabricate spherical nanoparticles with uniform size. Emprical model was developed to predict nanosphere size by altering process variables. Nanospheres were characterized in terms of morphology, hydrodynamic size, zeta potential, drug encapsulation efficiency and release profile. Drug loaded nanospheres have been successfully produced with a size range of 180-350 nm. Nanocomposite drug carriers showed high encapsulation efficiency (80%-95%) and prolonged release period when compared to bare chitosan nanospheres. The drug release from nanocomposite carriers was monitored by diffusion mechanism up to 30 d. The in vitro release medium of nanospheres showed strong antimicrobial activity against gram-positive S. aureus and gram-negative E. coli bacteria. Furthermore, it was found that the nanospheres did not show any cytotoxic effect to fibroblast (NIH/3T3) and osteoblast (SaOS-2) cell lines. The results demonstrated that the prepared composite nanospheres can be a promising option for bone infection prevention at the post implantation period.Article Citation - WoS: 9Citation - Scopus: 11Oxidation Behavior of C-And Au-Ion Biodegradable Polymers(Institute of Electrical and Electronics Engineers Inc., 2012) Sokullu Urkaç, Emel; Öztarhan, Ahmet; Tıhmınlıoğlu, Funda; Nikolaev, Alexey; Brown, IanBiodegradable polymers are widely used in biomedical and tissue engineering applications due to their biocompatibility and hydrolysis properties in the body. However, their low surface energy and lack of functional groups to interact with the cellular environment have limited their applications for in vivo studies. Ion beam modification is a convenient method for improving the surface properties of polymeric materials for functional biomedical applications. In the work described here, vacuum arc metal ion implantation was used to modify the composition of the near-surface region of three kinds of polymerspoly(L-lactide), poly(D, L-lactide-co-glycolide), and poly(L-lactide/caprolactone)chosen as representative of biodegradable polymers. X-ray photoelectron spectroscopy analysis was used to characterize the chemical effects of these polymers after implantation with C and with Au, and the results were compared with untreated control samples. We find that oxidation behavior is brought about for certain implantation fluences, resulting in improved surface hydrophilicity. © 2011 IEEE.Article Citation - WoS: 44Citation - Scopus: 54Protection of Marble Surfaces by Using Biodegradable Polymers as Coating Agent(Elsevier, 2009) Ocak, Yılmaz; Sofuoğlu, Aysun; Tıhmınlıoğlu, Funda; Böke, HasanBiodegradable polymers have been replaced over the synthetic polymers in many applications due to their good properties such as reversibility and biodegradability. Therefore they allow new treatment on the surface of the material to be protected and they fulfil the principles generally accepted by the International Conservation Community of Historic Monuments and Buildings. In this study, the efficiency of four different biodegradable polymers as protective coatings on marble-SO2 reaction was investigated. The polymers used were zein, chitosan, polyhydroxybutyrate (PHB), and poly-l-lactide (PLA). The mineralogical composition, bulk density and porosity of uncoated marble were determined. The water vapor permeability, water absorption by capillary forces, surface wettability, and color alteration of uncoated and coated marbles were measured. For sulphation reaction, marble slabs were coated with these polymers and then they were exposed at nearly 8 ppm SO2 concentration at 100% relative humidity conditions together with uncoated ones in a reaction chamber for several days for testing their protection efficiency. The extent of reaction was determined by leaching of gypsum formed on the marble surfaces in deionized water and then determining the sulphate content by ion chromatography. The protection efficiency of polymer treatments was expressed as comparing the gypsum crust thickness of the coated and uncoated marble plates. The comparison among the polymers showed that the surface hydrophobicity, water capillary absorption and structure of polymer would be important factors affecting the protection efficiency. The use of high molecular weight PLA (HMWPLA) polymer on marble surfaces provided significant protection up to 60% which was indicated that HMWPLA polymer seems to be promising polymer as protective coating agent in reducing gypsum formation on marble surfaces in the polluted environment.