Browsing by Subject "Bodipy"

Now showing 1 - 12 of 12

Open Access
Bodipy-based photosensitizers with long alkyl tails at the meso position: efficient singlet oxygen generation in Cremophor-EL micelles
(Elsevier Ltd, 2016) Kilic, B.; Yesilgul, N.; Polat, V.; Gercek, Z.; Akkaya, E. U.
Bodipy dyes with n-decyloxyphenyl-(4, 5) and pentadecyl-(8) meso substituents can easily embed themselves into micellar structures formed from Cremophor-EL. In micelles of approximately 20 nm median size, heavy-atom substituted dyes show remarkable photosensitization properties as evidenced by the rate of reaction with an anthracene-based selective singlet oxygen trap in buffered aqueous solutions. Considering the ease of Bodipy derivatization and the advantages of Cremophor-EL carried therapeutic agents, these photosensitizing agents may offer novel targeting opportunities and enhanced chemical and photophysical stability.
Open Access
Design and characterization of Bodipy derivatives for bulk heterojunction solar cells
(Elsevier, 2014) Kolemen, S.; Cakmak, Y.; Ozdemir, T.; Erten Ela, S.; Buyuktemiz, M.; Dede, Y.; Akkaya, E. U.
Two electron rich Bodipy dyes with strong absorptivities in the visible region were designed and synthesized as potential electron donors in bulk heterojunction photovoltaic constructs. Overall efficiency is above 1%, with impressive responsiveness at both UV and near-IR ends of the visible spectrum. Computational studies reveal an unexpected effect of meso-substituents on the electron transfer efficiency.
Open Access
Design, synthesis and characterization of activatable photosensitizers for photodynamic therapy
(2012) Çakmak, Fatma Pir
Search for new noninvasive methods for diseases has been significant question for years. Therapeutic properties of light are combined with proper chromophore in order to create fundamentals of photodynamic therapy which is a new treatment modality for cancer and other various non-oncological diseases. The method relies on the activation of photosensitizer by using light of certain wavelength and generation of cytotoxic singlet oxygen species in response. Reactive oxygen species kill the targeted tissue within smaller effective diameter through apoptosis/ necrosis mechanism. Through this method, new PDT agents can be proposed and their properties can be tuned by manipulation of other photophysical processes. In this thesis, synthesis, characterization novel water soluble, near IR absorbing Bodipy photosensitizer will be discussed. As opposed to other photosensitizers in literature, this photosensitizer is rationally designed to have singlet oxygen generation capability only in cancer tissue as a result of glutathione triggered activation.
Open Access
Imaging of intracellular singlet oxygen with bright BODIPY dyes
(Elsevier Ltd, 2021-04) Kaya, S.; Kwon, N.; Kim, G.; Bila, Jose Luis; İsmaiel, Yahya A.; Yoon, J.; Seven, Özlem; Akkaya, E.
Singlet oxygen is a cytotoxic reactive species which is involved in the photodynamic therapy of cancer. It is also known to be produced endogenously in most eukaryotic cells and implicated in many biochemical processes, including apoptotic response. We now report that Bodipy based fluorescent dyes with singlet oxygen reactive modules, signal the intracellular generation of singlet oxygen through photosensitization. We believe long wavelength probes of singlet oxygen, based on this approach will be highly valuable.
Open Access
Ion sensing, light harvesting, energy conversion & self-assembly in rationally designed molecular constructs
(2013) Büyükçakır, Onur
In this thesis, we have constructed rationally designed functional supramolecular systems. In the first chapter, we reported two Bodipy based chemodosimeters to detect fluoride both in solution and in polymethylmethaacraylate (PMMA) matrix. In the second part, we synthesized tetrastyrl-Bodipy derivatives by condensing methyl substituents of 1,3,5,7-tetramethyl-Bodipy dyes with different aromatic aldehydes. The resulting dyes have sharp and intense emission maxima in the near-IR region and they are robust candidates for functional supramolecular systems because of their outstanding properties. In next chapter, we investigated light harvesting properties of these new generation near-IR emissive dyes. In designed light harvesters, a near-IR emissive tetrastyrl-Bodipy dye which was decorated with short wavelength Bodipy fluorophores function as antenna units. In the forth chapter, we reported a Cu(I)-diimine complex as a photosensitizer for dye-sensitized solar cells (DSSC). It was demonstrated that Cu(I) diimine complex with capability of ultrafast electron injection to TiO2 nanoparticles can be a very good candidate for replacing ruthenium based polypyridyl complexes with a much lower cost. This research potentially can generate significant impact for those working on solar energy conversion and DSSC. In the final chapter, we propose to utilize oscillations in pH to move the two components of pseudorotoxane in relation to each other and this is the first example of a pseudorotaxane in which the mobile component is shuttling autonomously.
Open Access
Near IR absorbing bodipy-functionalized SPIONs: a potential magnetic nanoplatform for diagnosis and therapy
(De Gruyter, 2014) Ertem, E.; Bekdemir, A.; Atilgan, A.; Akkaya, E. U.
Photodynamic therapy (PDT), especially with the recent advances in photosensitizer (PS) design, has already been established as a noninvasive technique for cancer treatment. Recently, near-IR-based absorbing PSs that have a rising potency to implement light-triggered tumor ablation have attracted much attention since near-IR light in the 650-850 nm range penetrates more deeply in tissues. Up to now, numerous nanomaterials tailored to suitable sizes have been studied for effective delivery of PSs. In this study, four different types of Bodipy-based PSs were covalently attached to magnetic resonance imaging (MRI) active, biocompatible, and nontoxic nanocarriers and generation of singlet oxygen capabilities were evaluated. It was demonstrated that these core-shell nanoparticles are promising delivery vehicles of PSs for use in diagnosis and therapy.
Open Access
Near-IR absorbing Bodipy functionalized Spions : a potential magnetic nanoplatform fo diagnosis and therapy
(2012) Ertem, Elif
Photodynamic therapy (PDT), especially with the recent advances in photosensitizer design has already been established as a noninvasive technique for cancer treatment. In PDT, photosensitizers (PSs) are targeted to tumor sites either actively or passively, and are irradiated with a laser of appropriate wavelength. The stimulated PSs transfer excitation energy to endogenous oxygen converting it to reactive oxygen species (ROS) that can kill tumor cells. Up to now, numerous nanomaterials tailored to suitable size, have been studied for effective delivery of PSs. Recently, Near IR-based absorbing nanomaterials which have a rising potency to implement light-triggered tumor ablation have attracted much attention since near-IR light in the 650–850 nm range penetrates more deeply in tissues. In addition, imaging of these nanomaterials carrying PSs is very important in order to prevent damage to the healthy tissues upon irradiation. Magnetic resonance imaging (MRI) is a powerful technique due to its excellent spatial resolution and depth for in vivo imaging. In this study, a multidisciplinary approach was utilized to create MRI active, near IR-based functional nanomaterials. This approach involves (i) nanochemistry to prepare silica coated super paramagnetic iron oxide (core-shell) nanoparticles, (ii) organic chemistry to synthesize four different type of near- IR absorbing Bodipy derivatives as PSs, and (iii) spectroscopy to verify singlet oxygen production. Four different type of Bodipy based PSs were covalently attached to MRI active, biocompatible, and nontoxic nanocarriers and generation of singlet oxygen capabilities were evaluated. It was demonstrated that these core-shell nanoparticles are promising delivery vehicles of PSs for the use in diagnosis and therapy.
Open Access
PEGylated calix[4]arene as a carrier for a Bodipy-based photosensitizer
(Elsevier, 2014) Cakmak, Y.; Nalbantoglu, T.; Durgut, T.; Akkaya, E. U.
Heavy atom substituted Bodipy compounds, unlike the parent chromophore, undergo rapid intersystem crossing to generate singlet oxygen, which is the primary cytotoxic agent exploited in PDT. In this work, we show that an organic soluble calix[4]arene can be functionalized by Knoevenagel reaction and then converted into an amphiphilic photosensitizer in a few steps. In addition to generating a potentially useful photosensitizer, the sequence of reactions is the first use of a Bodipy dye as a chromophoric/fluorogenic label without the typical reactive functional groups.
Open Access
Selective fluorescence sensing of biological thiols using a bodipy based bifunctional probe and the catalytic activity of short peptide amphiphile nanostructures : implications on the oring of life
(2013) Altay, Yiğit
Chemosensor development is an attractive field of modern chemistry and there exist large amount of contribution from all over the world. The biological importance of thiols triggered the development of sensors to differentiate especially cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) which play key roles in biological systems. Concentration of those thiols results in number of diseases and their structural similarity complicates the differentiation. Optical probes especially fluorescent ones are widely employed for that purpose since it offers simplicity, sensitivity and low detection limits as well as real time analysis. BODIPY core is decorated with a Michael acceptor nitro-styrene group to covalent incorporation of thiols and with an aza-crown moiety to recognition of N-terminus of them. The work in this thesis is the first example in which one of them is separated from others or three of them separated from each other’s by chain length difference using fluorescence spectrometry. Formation of short peptides (2-4 aa residues) is considered to be likely under primordial conditions, following a number of scenarios. In this work, it is constructed a short peptide library limiting our choice of amino acids to those believed to be available at larger concentrations such as Gly, Ala, Asp and Cys. It is demonstrated that when acylated at the N-terminus, nanostructures of varying size and shapes were formed. Investigations on the catalytic activity of these nanostructures under different conditions are presented. The findings on the correlation of peptide structure and nanostructure formation and/or catalytic activity are presented.
Open Access
Synthesis and characterization of Bodipy-derived singlet oxygen sensor
(2017-01) Ismaiel, Yahya Abdelwahed Fikry
Singlet oxygen is a biochemically produced reactive species, which can trigger various cellular responses. It is also produced by photosensitization by the intermediacy of photosensitizer therapy of cancer. Real-time imaging of singlet oxygen is very important to assess the progress of cellular changes leading to apoptosis. We targeted a long wavelength dye, which responds to singlet oxygen with a change in emission color. Color change in emission is particularly important, as it allows internal referencing.
Open Access
Towards unimolecular luminescent solar concentrators: bodipy-based dendritic energy-transfer cascade with panchromatic absorption and monochromatized emission
(2011) Bozdemir, O. A.; Erbas-Cakmak, S.; Ekiz, O. O.; Dana, A.; Akkaya, E. U.
A polymer-embedded dendritic, bodipy-based panchromatic absorber with a built-in energy gradient concentrates incident solar radiation at a terminal chromophore, resulting in a monochromatized emission directed to the sides of the polymer waveguide (see picture). This particular design minimizes self-absorption losses from the peripheral antenna units with an impressive S factor of 10 000.
Open Access
Walking patterns in shopping malls : the case of Ankamall
(2013) Paykoç, Eda
Search for new noninvasive methods for diseases has been significant question for years. Therapeutic properties of light are combined with proper chromophore in order to create fundamentals of photodynamic therapy which is a new treatment modality for cancer and other various non-oncological diseases. The method relies on the activation of photosensitizer by using light of certain wavelength and generation of cytotoxic singlet oxygen species in response. Reactive oxygen species kill the targeted tissue within smaller effective diameter through apoptosis/ necrosis mechanism. Through this method, new PDT agents can be proposed and their properties can be tuned by manipulation of other photophysical processes. In this thesis, synthesis, characterization novel water soluble, near IR absorbing Bodipy photosensitizer will be discussed. As opposed to other photosensitizers in literature, this photosensitizer is rationally designed to have singlet oxygen generation capability only in cancer tissue as a result of glutathione triggered activation.