Browsing by Author "Oguzlar S."
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Item Structural and luminescent properties of Er3+ and Tb3+-doped sol–gel-based bioactive glass powders and electrospun nanofibers(Springer, 2021) Deliormanlı A.M.; Rahman B.; Oguzlar S.; Ertekin K.In this study, sol–gel-based erbium (Er3+), terbium (Tb3+) and Er3+: Tb3 co-doped 1393 bioactive glass powders and electrospun nanofibers were prepared. Structural and morphological properties of the bioactive glasses as well as the photoluminescence characteristics were investigated in detail. The median particle size and average diameter of the prepared glass powders and fibers were in the range of ~ 1.5–3.5 μm and 280–660 nm, respectively. The steady-state photoluminescence and decay kinetics of the samples were investigated under excitation (374 nm) where only Er3+ and Tb3+ ions close to Si nanoclusters can be excited. All the samples prepared in the study exhibited bright green emission upon excitation at 374 nm. Results showed that the dopant concentration and the sample morphology have significant influence on the photoluminescence and decay properties of the glasses. Sol–gel-derived bioactive glass particles exhibited stronger emission intensity, whereas electrospun nanofibers showed extended decay times. In vitro bioactivity experiments revealed that Er3+ and Tb3+ doping did not inhibit the conversion of the glass samples to hydroxyapatite treated in simulated body fluid for 30 days. It was concluded that Er3+ and Tb3+-containing 1393 bioactive glasses have a potential to be used in tissue engineering applications as well as bioimaging studies. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.Item Improvement of optical properties of one-dimensional CaAl12O19:Mn4+ phosphor via Er3+- and Tb3+- doped bioactive glass powders(Elsevier B.V., 2021) Oguzlar S.; Zeyrek Ongun M.; Deliormanlı A.M.Until now, because of the being a candidate for the red-emitting material the CaAl12O19:Mn4+ phosphor (CAO:Mn) has been widely used especially in white light-emitting diodes (WLEDs). In this study, the emission-based luminescence properties of CaAl12O19:Mn4+ red phosphor synthesized via sol-gel method was studied in the absence and presence of Er3+- and Tb3+-doped 13–93 bioactive glass powders in ethyl cellulose (EC) matrix in detail. Upon the addition of un-doped and Er3+- and Tb3+- doped bioactive glass powders, the CAO:Mn phosphor resulted in 44%, 92% and 88% increase in the emission intensity, respectively. The luminescence and decay time characteristics of the synthesized phosphor were also investigated in terms of microsecond time scale. The proposed material may bring a new inside for the existing problems of the red phosphors regarding the brightness, colour correlation temperature and colour rendering index. © 2021 Elsevier B.V.Item Photoluminescence and decay characteristics of cerium, gallium and vanadium - containing borate-based bioactive glass powders for bioimaging applications(Elsevier Ltd, 2021) Deliormanlı A.M.; Oguzlar S.; Ertekin K.Biomaterials having photoluminescent properties play a crucial role in real-time bioimaging after in vivo implantation. In this study, photoluminescence properties and decay characteristics of the borate-based 13–93B3 glasses containing different concentrations of cerium, gallium, and vanadium oxides were investigated for biomedical applications. The borate-based bioactive glass powders were prepared using melt-quench technique and size reduction was performed through planetary ball milling. Bioactivity of the prepared powders was investigated in simulated body fluid at 37 °C under static conditions. The photoluminescent properties and decay kinetics of the as-prepared and the SBF-treated bioactive glass powders were analyzed by steady-state and time-resolved photoluminescence measurements. Results revealed that the cerium activated glasses exhibited an intense luminescence centered at 538 nm. Broad-band emission of the gallium and vanadium doped samples was centered at 440 and 572 nm, respectively. All of the SBF-treated glasses exhibited enhanced lifetimes and bi-exponential decays both in nanosecond and microsecond regime measurements. It was concluded that depending on the dopant concentration, bioactive glass particles prepared in the study showed remarkable photoluminescence and have potential to be used in bioimaging applications. © 2020 Elsevier Ltd and Techna Group S.r.l.Item Effects of Eu3+, Gd3+ and Yb3+ substitution on the structural, photoluminescence, and decay properties of silicate-based bioactive glass powders(Springer Nature, 2022) Deliormanlı A.M.; Oguzlar S.; Zeyrek Ongun M.Bioactive glass (BG) powders containing europium (Eu3+), gadolinium (Gd3+) and ytterbium (Yb3+) were synthesized through sol–gel process. Effects of the related rare-earth ions on the structural, photoluminescence (PL), and decay characteristics were investigated. In vitro, acellular bioactivity of the synthesized powders was examined in simulated body fluid (SBF). Results revealed that all of the BG powders tested in the study showed PL emission under excitation at 374 nm. Among the rare earth dopants tested in the study, Eu3+-containing samples exhibited the strongest emission intensities and for all the glasses optimum dopant concentration was 3 wt% based on the luminescence properties. The synthesized BG have ability to convert to hydroxyapatite (HA) after immersion in SBF. However, more detailed studies with resolution techniques are needed to confirm these observations, that the BG containing Eu3+, Gd3+, and Yb3+ have the ability to form HA and can be used in biomedical applications. Graphical abstract: [Figure not available: see fulltext.] © 2021, The Author(s), under exclusive licence to The Materials Research Society.Item Investigation of the structural, photoluminescence properties, bioactivity and 5-fluorouracil delivery behavior of Dy3+ and Dy:Eu3+-doped bioactive glasses(Elsevier Ltd, 2023) Deliormanlı A.M.; Rahman B.; Oguzlar S.; Ongun M.Z.Nowadays fluorescent biomaterials gained crucial interest in the biomedical field. Here we report the sol-gel synthesis and characterization of Dy3+ and Dy:Eu3+ co-doped bioactive glass powders. Structural, morphological, and photoluminescence (PL) characteristics of the prepared powders were investigated in detail. Additionally, in vitro hydroxyapatite forming ability and the anticancer drug (5-Fluorouracil) release behavior were investigated with respect to time. The influence of drug loading and delivery on the PL properties was monitored. Results showed that the highest PL intensity was obtained for the 5%Dy:Eu3+ co-doped glass samples. The incorporation of rare-earth ions into the glass network did not cause a significant difference in the structural properties. In vitro conversion experiments, performed in simulated body fluid, indicated that the incorporation of Dy3+ to the glass network enhanced the hydroxyapatite deposition however Dy:Eu3+ co-doping slightly decreased the bioactivity. Drug-loaded bioactive glass powders exhibited sustained drug release behavior to the phosphate buffered saline (PBS) medium. An increase was obtained in the fluorescence intensities for 5-FU-loaded samples followed by a further increase in emissions for the powders released drug to the PBS medium. The findings of the study may be useful for monitoring the degradation of bioactive glasses, conversion to hydroxyapatite as well as drug delivery after implantation. © 2023 Elsevier B.V.Item Effect on Improving CO2 Sensor Properties: Combination of HPTS and γ-Fe2O3@ZnO Bioactive Glass(American Chemical Society, 2023) Oguzlar S.; Zeyrek Ongun M.; Deliormanlı A.M.8-Hydroxypyrene-1,3,6-trisulfonic acid (HPTS) dye, a fluorescent dye often used as a pH indicator, is embedded within the bioactive glass matrix and undergoes changes in its fluorescent properties when exposed to carbon dioxide (CO2). The aim of the current study is to investigate the use of bioactive glass (BG) particles containing γ-Fe2O3@ZnO to enhance the CO2 sensitivity of HPTS. X-ray diffraction, Fourier transform infrared, scanning electron microscopy, and photoluminescence spectroscopies were used to characterize the sol-gel synthesized powders. The sensing slides were prepared in the form of a thin film by immobilizing the fluorescent dye and γ-Fe2O3@ZnO-based additives into the poly(methyl methacrylate) matrix. The addition of γ-Fe2O3@ZnO nanoparticles with bioactive glass additives to the HPTS improves the performance characteristics of the sensor, including the linear response range, relative signal variation, and sensitivity. Meanwhile, the CO2 sensitivities were measured as 10.22, 7.73, 16.56, 17.82, 19.58, and 42.40 for the undoped form and M, M@ZnO, 5M@ZnO-BG, 10M@ZnO-BG, and 20M@ZnO-BG NP-doped forms of the HPTS-based thin films, respectively. The response and recovery times of the HPTS-based sensing slide along with 20M@ZnO-BG NPs have been measured as 44 and 276 s, respectively. The γ-Fe2O3/ZnO-containing BG particle-doped HPTS composites can be used as a promising sensor agent in the detection of CO2 gas in various fields such as environmental monitoring, medical diagnostics, and industrial processes. © 2023 The Authors. Published by American Chemical Society.Item Emission based response of Er3+, Tb3+, and Er3+-Tb3+ co-doped 1393 bioactive glasses along with HPTS towards CO2(Elsevier B.V., 2025) Ulucan U.; Oguzlar S.; Deliormanlı A.M.; Ertekin K.The HPTS serves as a versatile tool in pH and CO2 sensing studies, as well as in cell biology studies of various processes. However, the long-term photostability of HPTS as a fluorescent dye is an important consideration in its use, especially for long-term applications. In this work, sol–gel synthesized Er3+, Tb3+ and Er3+: Tb3+ co-doped 1393 bioactive glass particles were incorporated with the HPTS in the presence of ionic liquid in an ethyl cellulose matrix. The interaction of the bioactive glasses with the HPTS was investigated by steady-state luminescence and excited-state lifetime measurements. The prepared composites showed linearizable responses when exposed to different CO2 concentrations. High I0/I100 values (87, 109 and 115) were obtained for the binary blends of HPTS and bioactive glasses. When the imidazolium-based IL was used together with the offered composites, we observed improved stability and longevity for the HPTS up to 315 days. The incorporation of imidazolium-based ionic liquids as additives in HPTS-based fluorescence assays together with the bioactive glasses holds promise for enhancing the photostability of the HPTS and improving the reliability and longevity of fluorescence signals in various research applications. © 2024 Elsevier B.V.