Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 3Citation - Scopus: 2Development of Transition Metal Oxide Platforms for Aptasensing of Psa in Cell Cultures(Springer Heidelberg, 2024) Kirlangic, Irem Aydin; Uner, Goklem; Kara, Pinar; Kirmizibayrak, Petek Ballar; Ertas, Fatma NilIn this study, a novel aptasensor based on a transition metal oxide-modified pencil graphite electrode (PGE) was developed for the diagnosis of early-stage prostate cancer (PCa) via monitoring the prostate-specific antigen (PSA), which is the main biomarker for PCa. Single-use PGEs modified with pulsed deposited manganese oxide (MnOx) film were used to attach the amino-terminated aptamer specific to the PSA via carbodiimide chemistry. The designed aptasensor was placed in an electrochemical cell containing ferri/ferrocyanide ions as a redox probe to measure the charge transfer resistances (Rct) of the electrode surface by electrochemical impedance spectroscopy (EIS) to follow the response of each modification step. The effect of the medium pH on the ionic structure of the aptamer molecule according to its pI value and, thus, the reversing of the direction of the response (Delta Rct) by the pH change was also discussed. The level of PSA secreted from PCa cells was investigated using impedimetric transduction. The specificity of the aptasensor was validated through selectivity studies against non-specific tumor markers like VEGF and different cancer cell lines including breast cancer and androgen-insensitive prostate cancer. The developed system showcases a label-free, fast, specific, and cost-effective approach for PSA detection, highlighting the importance of medium pH and the electrostatic environment on the aptamer's response. Our work emphasizes the potential for such aptasensors in clinical diagnostics and paves the way for further exploration into using transition metal oxides in biosensing applications.Article Citation - WoS: 3Citation - Scopus: 3Effects of Different Precursors on the Aging and Electrocaloric Properties of Mn-Doped Ba0.95sr0.05tio3 Ceramics(Springer, 2023) Karakaya, Merve; Erdem, Emre; Akdoğan, Yaşar; Adem, UmutIn this study, the effects of different types of Mn precursors (MnO2 and Mn2O3) and sintering temperature on the defect dipole formation, ferroelectric aging and electrical properties were investigated by using Ba0.95Sr0.05TiO3 ceramics as the base. Both Mn precursors were substituted to the Ti-site as 1 mol% and two different sintering temperatures of 1325 and 1400 degrees C were used to study the effect of grain size. We deduced that slightly higher amounts of Mn2+ can be incorporated into the perovskite structure when MnO2 is used as the precursor, by using X-ray diffraction and electron paramagnetic resonance spectroscopy. Mn-doped samples sintered at 1325 degrees C age faster than those sintered at 1400 degrees C. Aging caused a decrease in the electrocaloric effect whereas Mn-doping increased it. This study shows that Mn precursor used for the acceptor doping affects the amount of Mn incorporated into the structure and therefore electrical properties of the resulting ceramics.Article Citation - WoS: 17Citation - Scopus: 17Monitoring the Doping and Diffusion Characteristics of Mn Dopants in Cesium Lead Halide Perovskites(American Chemical Society, 2018) Güner, Tuğrul; Akbalı, Barış; Özcan, Mehmet; Topçu, Gökhan; Demir, Mustafa Muammer; Şahin, HasanCesium lead perovskites, in the form of CsPbX3 or Cs4PbX6, have been widely used for various optoelectronic applications due to their exceptionally good optical properties. In this study, the effect of Mn doping on the structural and optical properties of cesium lead halide perovskite crystals are investigated from both experimental and theoretical points of view. It is found that adding MnCl2 during the synthesis not only leads to a Mn-driven structural phase transition from Cs4PbBr6 to CsPbCl3 but also triggers the Br- to Cl- halide exchange. On the other hand, it is observed that, under UV illumination, the color of Mn-doped crystals changes from orange to blue in approximately 195 h. While the intensity of Mn-originated photoluminescence emission exponentially decays in time, the intensity of CsPbCl3-originated emission remains unchanged. In addition, diffusive motion of Mn ions results in both a growing population of MnO2 at the surface and transition of the host into a cesium-rich Cs4PbCl6 phase.