Browsing by Subject "photodynamic therapy"
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Item Open Access Near-IR absorbing Bodipy functionalized Spions : a potential magnetic nanoplatform fo diagnosis and therapy(Bilkent University, 2012) Ertem, ElifPhotodynamic 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.Item Open Access Non-covalently functionalized SWNTs as potential delivery agents for novel BODIPY*based PDT sensitizers & the design and synthesis of dendritic light harvesters(Bilkent University, 2009) Erbaş, SündüsPhotodynamic therapy (PDT) is a non-invasive method used for the treatment of a number of diseases including certain cancers and some cardiovascular diseases. Photodynamic action depends on absorbance of photosensitizer (PS) in near IR region of the spectrum and subsequent generation of cytotoxic singlet oxygen in the vicinity of the PS. Carbon nanotubes are widely used for biomedical applications due to their inertness, biocompatibility, cellular internalization, facile and multi-modification. We have synthesized and characterized novel water soluble boradiazaindacene (BODIPY)-based PS, noncovalently attached on to the single wall carbon nanotube (SWNT). We have observed that near infrared absorbing photosensitizer preserve its singlet oxygen generation capability upon adsorption on SWNT. We have demonstrated that SWNTs can be used as the delivery vehicle of PS for the use in PDT. In the second part of this research, multichromatic cascade-type light harvesting BODIPY dendrimers were synthesized and highly efficient energy transfer was observed. Successful channeling of energy in a predefined region of the dendrimer was revealed.Item Open Access Rational design and synthesis of bodipy dyes for molecular sensing, light harvesting and photodynamic applications(Bilkent University, 2014) Kütük, Tuğba ÖzdemirBODIPY dyes have been addressed in many applications due to highly important features. These unique properties can be summarized as high photostability, high extinction coefficient, easy functionality, etc. Thus, tremendous studies have been published and, ion sensing, photodynamic therapy, dye-sensitized solar cells and light harvesting are some of the areas that BODIPY dyes have been utilized. In this thesis, BODIPY dyes were functionalized to be used for different concepts. In the first study, the main purpose was to seek for ion signaling differences of two isomeric tetra-styryl BODIPY dyes with charge donor ligand located at 1,7 versus 3,5 positions. Second work focuses on the light harvesting concept with the use of tetra-styryl BODIPY derivatives. Third study describes the coupling of energy transfer with internal charge transfer to monitor the alterations in intensity ratios, so, dynamic range of the fluorescent probe is improved. Design and synthesis of BODIPY dyes for detection of biological thiols in aqueous solution both chromogenically and fluorogenically was given in fourth study. Another biologically important molecule, hydrogen sulfide is selectively detected via BODIPY-based probe and depicted in the fifth study. In the sixth work, persistent luminescent nanoparticles are attached to BODIPY-based photosensitizer to activate the photodynamic action.Item Open Access Walking patterns in shopping malls : the case of Ankamall(Bilkent University, 2013) Paykoç, EdaSearch 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.