Beşer, Burcu Meryem; Altay, Ahmet; Talaz, Oktay; Türkmenoğlu, Burçin

In this study, the fluorescent probe property of a bis indole compound (5,14-dimethyl-5,6,7,8,9,14-hexahydroindolo [2 ', 3′: 3,4] cycloocta [1,2-b] indole), a Caulerpin derivative, which is a member of the indole family, was investigated. For this purpose, firstly, the fluorescence character of the molecule was investigated by absorption and fluorescence spectroscopy techniques in both solvent and surfactant environments. Afterwards, the cytotoxicity of the molecule was tested on the human colon cancer HT-29 cells and breast cancer MCF-7 cells as well as mouse fibroblast 3T3-L1 cells. After determining that the molecule has no cytotoxic effect against all the tested cell lines by 100 µM, the cell staining feature of the probe was examined. The obtained data showed us that the molecule, whose confocal microscopy images were taken at 360 nm excitation wavelength, stained the cell cytoplasm. In addition, optical absorption spectra, oscillator strength (f), transition configuration and transition characteristics of the Ars-In in different solvents were investigated at the theoretical level using Time Dependent-Density Functional Theory (TD-DFT). In conclusion, these results confirm that this indole derivative molecule could be evaluated as an effective fluorescence probe for biological systems.

Caglar, Bulent; Guner, Eda Keles; Özdokur, Kemal Volkan; Özdemir, Agah Oktay; İçer, Fatih; Caglar, Sema; Doğan, Bilge; Beşer, Burcu Meryem; Çırak, Çağrı; Tabak, Ahmet

To improve the photocatalytic performance and solve the aggregation problem of BiFeO3 nanoparticles, kaolinite-BiFeO3 photocatalyst was successfully prepared for the first time by decoration of ferromagnetic BiFeO3 nanoparticles onto kaolinite surface. Comparative characteristics of kaolinite, bare BiFeO3 and kaolinite-BiFeO3 photocatalyst were investigated in detail by XRD, TEM, SEM-EDX, XPS, FTIR, VSM, UV-DRS, PL, zeta potential and BET techniques. The photocatalytic activities of the samples were also evaluated by photodegradation of rhodamine B as a model reaction under different irradiations like UVA, visible and sunlight. The kaolinite-BiFeO3 exhibited more superior photocatalytic activity as compared with other samples, which is best fitted to pseudo-first-order kinetic. The reactive species trapping experiments indicated that photogenerated-holes play major roles in the degradation process whereas superoxide radicals possess a secondary effect. Enhanced photocatalytic activity of kaolinite-BiFeO3 is attributed to its kaolinite platform that reduces the recombination opportunities of the photogenerated holes and electrons as well as increases the surface area, decreases the particle size and aggregation of nanoparticles. In addition, we also designed a novel electrocatalytic platform based on gold nanoparticles loaded on kaolinite-BiFeO3 modified carbon paste electrode surface for the examination of electrocatalytic activity for oxygen reduction reaction in alkaline medium. Electrochemical characterizations of the Au/BiFeO3/kaolinite modified carbon paste electrode and other bare surfaces were comparatively carried out with the aid of cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. Au/BiFeO3/kaolinite modified carbon paste electrode exhibited 15-fold current enhancement together with 100 mV anodic potential shift compared with bare carbon paste electrode.