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    Effects of propolis coating on antibacterial resistance of intrauterine devices
    (Taylor & Francis Ltd, 2024) Deniz, Alparslan; Karasu, Tunca; Idil, Neslihan; Uzun, Lokman
    Intrauterine devices (IUDs) are widely used in preventing fertilization as contracepting devices. In market, they are produced as T-shaped polyethylene (or propylene) and metal (especially copper) composites. Although the metal component is utilized to provide antibacterial efficacy, prolonged implantation and the presence of a wide range of bacteria flora in the intrauterine environment make IUDs susceptible to bacterial contamination, biofilm formation, and unpleasant infection. In the presented study, the propolis, a natural anti-bacterial/-viral product used for different biomedical applications, coating strategy was applied comparatively in three different ways: coating directly on metal components, coating on polymeric material, and using carrying polymer. In addition, antibacterial activity against Gram-positive (Staphylococcus aureus, S. aureus) and Gram-negative (Escherichia coli, E. coli) bacterial strains were investigated by both dynamic bacterial culture (bacterial inhibition activity) and biofilm (biofilm formation resistance) tests. As a result of 48 h of dynamic bacterial culture; it was determined that the antibacterial inhibition efficiency depending on propolis concentration increased up to 99.5% and 98.5% for E. coli and S. aureus, respectively. In addition, the carrying polymer allows IUDs to cover surfaces more homogeneously, as well as improve antibacterial activity. Similarly; it was determined that biofilm formation resistance was improved by 44.33% for E. coli and by 45.99% for S. aureus with both the propolis concentration and the use of carrying polymer. As a result, it has been revealed that propolis will be classified as an alternative, promising, and effective coating agent for improving antibacterial properties and biofilm formation resistance of IUDs.
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    Öğe
    PolyPyrrole based-impedimetric aptasensor for selective determination of beta-HCG from urine sample
    (Elsevier Science Sa, 2025) Deniz, Alparslan; Karasu, Tunca; Ozgur, Erdogan; Uzun, Lokman
    Herein, a conjugated conducting polymer-based impedimetric aptasensor has been developed to detect beta-human chorionic gonadotropin (bHCG), the one of the important biomarkers in gynecology, from synthetic human urine samples. In this context, gold electrodes were, firstly coated with pyrrole and pyrrole-3-carboxylic acid to obtain the poly(pyrrole-pyrrole-3-carboxylic acid) [poly(Py-PyCOOH)] conductive copolymer by cyclic voltammetry (CV). Then, bHCG-specific peptide aptamer was covalently linked onto the surface via applying a well-known carbodiimide-succinimide chemistry. The sensor developed was characterized to confirm modification steps via both electrochemical methods including CV, electrochemical impedance spectroscopy (EIS), and chronoamperometry and physico-chemically via attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), atomic force microscope (AFM), and contact angle measurements (CA). The analytical performance of the sensor was evaluated in the concentration range from 1 mu g/mL to 100 mu g/mL for successful detection of bHCG even in the presence of interference agents. The results have also revealed that the sensor could be classified as a promising alternative to its benchmark commercial clinical methods due its superior properties such as cost-friendliness, easy-to-prepare, stable, robust, and selectivity / sensitivity.