Chemistry / Kimya
Permanent URI for this collectionhttps://hdl.handle.net/11147/4072
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Article Citation - WoS: 14Citation - Scopus: 16Bodipy-Based Organic Color Conversion Layers for Wleds(Elsevier, 2020) Yüce, Hürriyet; Güner, Tuğrul; Dartar, Suay; Kaya, Beraat Umur; Emrullahoğlu, Mustafa; Demir, Mustafa MuammerThe usage of organic dyes in phosphor conversion layer of WLED is an attractive approach since they have high molar extinction coefficient and photostability. Various types of organic pigments have been employed for this purpose such as BODIPY, perylene diimide, Rhodamine B, pyrene, Nile red, etc. Among those, BODIPY-based organic dyes appear to be promising candidate for white light generation. In this work, for the first time, red and green emitting BODIPY-based organic molecules have been used as colour conversion layer. These molecules were associated with PMMA in DMF solution and the resulting solution was subjected to electrospinning. Colorful electrospun mats were embedded into PDMS matrix and their free-standing PDMS composite films were used as color conversion layers over blue LED to produce white light such that CRI of 95 and CCT of 4200 K was achieved. These values show that BODIPY-based organic molecules containing fiber composites are promising candidates to be used as color conversion layers for white light applications.Article Citation - WoS: 56Citation - Scopus: 55A Bodipy-Based Fluorescent Probe To Visually Detect Phosgene: Toward the Development of a Handheld Phosgene Detector(John Wiley and Sons Inc., 2018) Sayar, Melike; Karakuş, Erman; Güner, Tuğrul; Yıldız, Büşra; Yıldız, Ümit Hakan; Emrullahoğlu, MustafaA boron-dipyrromethene (BODIPY)-based fluorescent probe with a phosgene-specific reactive motif shows remarkable selectivity toward phosgene, in the presence of which the nonfluorescent dye rapidly transforms into a new structure and induces a fluorescent response clearly observable to the naked eye under ultraviolet light. Given that dynamic, a prototypical handheld phosgene detector with a promising sensing capability that expedites the detection of gaseous phosgene without sophisticated instrumentation was developed. The proposed method using the handheld detector involves a rapid response period suitable for issuing early warnings during emergency situations.Article Citation - WoS: 5Citation - Scopus: 6Determination of Force-Free Wet Adhesion of Mussel-Inspired Polymers To Spin Labeled Surface(Elsevier, 2017) Kırpat, İklima; Göksel, Yaman; Karakuş, Erman; Emrullahoğlu, Mustafa; Akdoğan, YaşarHydration repulsive forces oppose the adhesive interactions, especially in the force-free conditions. Here, we studied spontaneous wet adhesion of 3,4-dihydroxyphenylalanine (DOPA) functionalized poly(ethylene glycol) (PEG) polymers inspired by marine mussels. Using electron paramagnetic resonance (EPR) spectroscopy, we can monitor spontaneous adhesion of DOPA containing polymer to suspended spin labeled hydrophobic polystyrene nanobeads at molecular level. The surface coverage up to 82% is obtained from EPR measurements. However, in the force-free condition, EPR measurements do not show any detectable DOPA based adhesion to hydrophilic silica nanobead.Article Citation - WoS: 51Citation - Scopus: 53Bodipy-Au(i): a Photosensitizer for Singlet Oxygen Generation and Photodynamic Therapy(American Chemical Society, 2017) Üçüncü, Muhammed; Karakuş, Erman; Kurulgan Demirci, Eylem; Sayar, Melike; Dartar, Suay; Emrullahoğlu, MustafaUpon complexation with Au(I), a photoinactive BODIPY derivative was transformed into a highly photoactive triplet sensitizer. Along with high efficiency in singlet oxygen generation (φδ = 0.84), the new BODIPY-Au(I) skeleton showed excellent photocytotoxic activity against cancer cell lines (EC50 = 2.5 nM).Article Citation - WoS: 80Citation - Scopus: 82Electrophilic Cyanate as a Recognition Motif for Reactive Sulfur Species: Selective Fluorescence Detection of H2s(American Chemical Society, 2016) Karakuş, Erman; Üçüncü, Muhammed; Emrullahoğlu, MustafaAn ESIPT-based fluorescent dye, 3-hydroxyflavone, is chemically masked with an electrophilic cyanate motif in order to construct a fluorescent probe for cellular sulfur species. This novel probe structure, displays an extremely fast, highly sensitive and selective "turn-on" type fluorescent response toward H2S. We have also documented its utility for imaging of H2S in the living cells.Article Citation - WoS: 22Citation - Scopus: 24A Fluorescein-Based Chemodosimeter for Selective Gold(iii) Ion Monitoring in Aqueous Media and Living Systems(Elsevier Ltd., 2016) Çetintaş, Ceyla; Karakuş, Erman; Üçüncü, Muhammed; Emrullahoğlu, MustafaWe constructed a turn-on type chemodosimeter based upon a fluorescein scaffold for the rapid, selective detection of gold(III) ions over other metal species. This novel probe structure offers distinct features including high water solubility, a low detection limit, rapid response time and applicability in imaging gold(III) ions in living cells.Article Citation - WoS: 15Citation - Scopus: 15Bodipy-Conjugated Chitosan Nanoparticles as a Fluorescent Probe(Taylor and Francis Ltd., 2017) Bor, Gizem; Üçüncü, Muhammed; Emrullahoğlu, Mustafa; Tomak, Aysel; Şanlı Mohamed, GülşahRecently, development of fluorescent nanoparticle-based probes for various bioimaging applications has attracted great attention. This work aims to develop a new type fluorescent nanoparticle conjugate and evaluate its cytotoxic effects on A549 and BEAS 2B cell lines. Throughout the study, ionically crosslinked chitosan nanoparticles (CNs) were conjugated with carboxylated 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY-COOH). The results of conjugates (BODIPY-CNs) were investigated with regard to their physic-chemical, optical, cytotoxic properties and cellular internalization. The morphology of BODIPY-CNs was found to be spherical in shape and quite uniform having average diameter of 70.25 ± 11.99 nm. Cytotoxicty studies indicated that although BODIPY-COOH itself was quite toxic on both A549- and BEAS 2B-treated cells, CNs increased the cell viability of both cell lines via conjugation to BODIPY-COOH fluorescent molecule up to 67% for A549 and 74% for BEAS 2B cells. These results may suggest a possible utilization of the new fluorescent nanoparticle-based probe for bioimaging in biology and medicine.Article Citation - WoS: 22Citation - Scopus: 23A Guanidinium Modified Rhodamine-Based Fluorescent Probe for in Vitro/Vivo Imaging of Gold Ions(Royal Society of Chemistry, 2015) Karakuş, Erman; Çakan Akdoğan, Gülçin; Emrullahoğlu, MustafaWe devised a rhodamine-based fluorescent probe functionalized with a guanidinium moiety, which both operates efficiently in pure aqueous media and displays a selective fluorescence response to Au3+ ions. We also demonstrated the successful fluorescence imaging of Au3+ within living cells and a vertebrate species, the zebrafish.Article Citation - WoS: 36Citation - Scopus: 37A Bodipy-Based Fluorescent Probe for Ratiometric Detection of Gold Ions: Utilization Of: Z -Enynol as the Reactive Unit(Royal Society of Chemistry, 2016) Üçüncü, Muhammed; Karakuş, Erman; Emrullahoğlu, MustafaUsing an irreversible intramolecular cyclisation pathway triggered by gold ions, a boron-dipyrromethene (BODIPY) based fluorescent probe integrated with a reactive Z-enynol motif responds selectively to gold ions. With the addition of gold(iii), the probe displays ratiometric fluorescence behaviour clearly observable to the naked eye under both visible and UV light. © The Royal Society of Chemistry 2016.Article Citation - WoS: 33Citation - Scopus: 36Epr Studies of Intermolecular Interactions and Competitive Binding of Drugs in a Drug-Bsa Binding Model(Royal Society of Chemistry, 2016) Akdoğan, Yaşar; Emrullahoğlu, Mustafa; Tatlıdil, Diğdem; Üçüncü, Muhammed; Çakan Akdoğan, GülçinUnderstanding intermolecular interactions between drugs and proteins is very important in drug delivery studies. Here, we studied different binding interactions between salicylic acid and bovine serum albumin (BSA) using electron paramagnetic resonance (EPR) spectroscopy. Salicylic acid was labeled with a stable radical (spin label) in order to monitor its mobilized (free) or immobilized (bound to BSA) states. In addition to spin labeled salicylic acid (SL-salicylic acid), its derivatives including SL-benzoic acid, SL-phenol, SL-benzene, SL-cyclohexane and SL-hexane were synthesized to reveal the effects of various drug binding interactions. EPR results of these SL-molecules showed that hydrophobic interaction is the main driving force. Whereas each of the two functional groups (-COOH and -OH) on the benzene ring has a minute but detectable effect on the drug-protein complex formation. In order to investigate the effect of electrostatic interaction on drug binding, cationic BSA (cBSA) was synthesized, altering the negative net charge of BSA to positive. The salicylic acid loading capacity of cBSA is significantly higher compared to that of BSA, indicating the importance of electrostatic interaction in drug binding. Moreover, the competitive binding properties of salicylic acid, ibuprofen and aspirin to BSA were studied. The combined EPR results of SL-salicylic acid/ibuprofen and SL-ibuprofen/salicylic acid showed that ibuprofen is able to replace up to ∼83% of bound SL-salicylic acid, and salicylic acid can replace only ∼14% of the bound SL-ibuprofen. This indicates that ∼97% of all salicylic acid and ibuprofen binding sites are shared. On the other hand, aspirin replaces only ∼23% of bound SL-salicylic acid, and salicylic acid replaces ∼50% of bound SL-aspirin, indicating that ∼73% of all salicylic acid and aspirin binding sites are shared. These results show that EPR spectroscopy in combination with the spin labeling technique is a very powerful method to investigate drug binding dynamics in detail.
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