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Öğe Catalytic investigation of hyaluronic acid-stabilized Ag nanoparticles as non-toxic nanocatalysts in the oxidation of morin(Royal Soc Chemistry, 2024) Yilmaz, M. Deniz; Ozsamur, Nezahat Gokce; Erbas-Cakmak, SundusCatalytic oxidation is a widely used technology to eliminate undesired organic substances from water resources. Transition metal catalysts have a critical role to play in catalytic advanced oxidation; however, the toxicity of these catalysts is a major threat to human health and the environment. Therefore, research on the development of efficient oxidation catalysts with reduced toxicity is extremely critical. Herein, we report the catalytic investigation of hyaluronic acid-functionalized silver nanoparticles (HA-AgNPs) as an efficient and non-toxic catalyst in the degradation of morin dye as a model compound. The as-synthesized nanoparticles are characterized by different analytical methods such as ultraviolet-visible (UV-vis) spectroscopy, scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), dynamic light scattering (DLS) and zeta potential. The particle size and charge of the HA-AgNPs are found to be 23.9 +/- 8.3 nm and -43.5 +/- 0.8 mV, respectively. The catalytic activity of HA-AgNPs has been assessed in the oxidation of morin with H2O2. The catalytic studies reveal that the oxidation follows first order reaction kinetics with an apparent rate constant of 1.01 x 10-2 s-1 and the degradation of morin has been completed within 5 min, indicating outstanding catalytic properties of HA-AgNPs. The cytotoxicity of HA-AgNPs was further evaluated by MTT assay and the results show that these nanoparticles are non-toxic to MCF-10A non-tumorigenic breast epithelial cells and MCF-7 breast cancer cells. We report hyaluronic acid-stabilized Ag nanoparticles as highly efficient and nontoxic oxidation nanocatalysts for the first time.Öğe A Dicationic BODIPY-Based Fluorescent Bactericide to Combat Infectious Diseases and to Eradicate Bacterial Biofilms(Amer Chemical Soc, 2023) Kocak, Haluk Samet; Bulut, Onur; Yilmaz, M. DenizIncreased bacterial resistance against extensively used common disinfectants has begun to emerge. The discovery of disinfectants substituting the current commercially available ones is strongly needed. For this purpose, a dicationic BODIPY-based fluorescent amphiphile has been synthesized by specific molecular design. This quaternized BODIPY behaves as a broad-spectrum disinfectant against both Gram-positive and Gram-negative bacteria strains. It exhibits potent antimicrobial activity against tested microorganisms when compared with structurally similar disinfectant benzalkonium chloride (BAC). Moreover, it shows antibiofilm activity against Staphylococcus epidermidis with a minimum biofilm eradication concentration as low as 16 mu g/mL. The interaction of this compound with the bacterial cell and genomic DNA was further evaluated by fluorescence spectroscopy and microscopy to follow cell internationalization and to clarify the mechanism of antibacterial action.Öğe Fluorescent silica nanoparticles as nano-chemosensors for the sequential detection of Pb2+ions and bacterial-spore biomarker dipicolinic acid (DPA) in aqueous solution(Pergamon-Elsevier Science Ltd, 2023) Cetinkaya, Yagmur Nur; Bulut, Onur; Oktem, Huseyin Avni; Yilmaz, M. DenizHerein, we report fluorescein-labelled silica nanoparticles (FSNP) which serve as fluorescent nano-chemosensors for sequential detection of Pb2+ (which is a toxic heavy metal) and dipicolinic acid (DPA) (which is a distinctive indicator biomarker of bacterial spores) with high sensitivity and selectivity. The fluorescence of FSNP is quenched because of the complex formation between Pb2+ ions and surface amide groups, however, the fluorescence is recovered in contact with DPA, resulting from the association of DPA with surface bound Pb2+ ions. FSNP-Pb2+ complexes show high sensitivity towards DPA with a low detection limit of 850 nM which is approximately seventy times lower than the infectious dosage of bacterial spores (60 & mu;M). Lateral flow test platform was further developed to show the applicability and practicability of our system.Öğe Reactive Extraction of Betaine from Sugarbeet Processing Byproducts(Amer Chemical Soc, 2023) Altinisik, Sinem; Zeidan, Hani; Yilmaz, M. Deniz; Marti, Mustafa E.Betaine from natural sources is still preferred over its synthetic analogue in secondary industries. It is currently obtained by expensive separation means, which is one of the main reasons for its high cost. In this study, reactive extraction of betaine from sugarbeet industry byproducts, that is, molasses and vinasse, was investigated. Dinonylnaphthalenedisulfonic acid (DNNDSA) was used as the extraction agent, and the initial concentration of betaine in the aqueous solutions of byproducts was adjusted to 0.1 M. Although maximum efficiencies were obtained at unadjusted pH values (pH 6, 5, and 6 for aqueous betaine, molasses, and vinasse solutions, respectively), the effect of aqueous pH on betaine extraction was negligible in the range of 2-12. The possible reaction mechanisms between betaine and DNNDSA under acidic, neutral, and basic conditions were discussed. Increasing the extractant concentration significantly increased (especially in the range of 0.1-0.4 M) the yields, and temperature positively (but slightly) affected betaine extraction. The highest extraction efficiencies (similar to 71.5, 71, and 67.5% in a single step for aqueous betaine, vinasse, and molasses solutions, respectively) were obtained with toluene as an organic phase solvent, and it was followed by dimethyl phthalate, 1-octanol, or methyl isobutyl ketone, indicating that the efficiency increased with decreasing polarity. Recoveries from pure betaine solutions were higher (especially at higher pH values and [DNNDSA] < 0.5 M) than those from vinasse and molasses solutions, indicating the adverse influence of byproduct constituents; however, the lower yields were not due to sucrose. Stripping was affected by the type of organic phase solvent, and a significant amount (66-91% in single step) of betaine in the organic phase was transferred to the second aqueous phase using NaOH as the stripping agent. Reactive extraction has a great potential for use in betaine recovery due to its high efficiency, simplicity, low energy demand, and cost.Öğe A simple yet effective colorimetric assay for nitrite based on nitration of a near-infrared (NIR) absorbing dye IR780(Elsevier, 2024) Yilmaz, M. DenizNitrite (NO2-) is a unique active ion involved in the nitrogen biochemical cycle which is very important to life on earth. Besides, it is indispensable additive to preserve nutrients in diverse food products. However, the concentrations above allowable limits pose considerable threat to human health and require urgent attention. In this study, we report a novel detection strategy by using IR780 dye as a near-infrared (NIR) probe which shows unexpected colorimetric response to NO2- ions with excellent selectivity, a rapid response (<5 s) and a low detection limit (227 nM). The probe produces the distinct color change from chartreuse to violet with a 220 nm of large hypsochromic (blue) shift caused by the nitration of IR780 in the presence of NO2- ions. Smartphone-based imaging has been further employed for real time and on-site visual detection of NO2- ions which will widen the application area of our system in environmental safety and food quality. In addition, the probe IR780 has shown excellent sensing performance in complex environments such as tap water and processed meat products with high recovery rates (85-113 %) and reproducibility (RSD < 5 %). Overall, the results demonstrate that the new system is capable of sensing NO2- ions in water resources as well as complex food matrices with high sensitivity and selectivity.