|
|
Polystyrene photoactive nanomaterials producing singlet oxygen
Henke, Petr ; Mosinger, Jiří (advisor) ; Dědic, Roman (referee) ; Kolářová, Hana (referee)
The increasing number of multidrug-resistant strains of bacteria call for alternatives to antibiotic therapy and, more generally, for the antimicrobial material as a component of prevention. Of particular interest is the photodynamic inactivation of bacteria and other pathogens caused by photogenerated singlet oxygen. This work is focused on the field of photoactive polymer nanofiber membranes and nanoparticles, generating singlet oxygen, suitable for medical applications. We prepared different types of photoactive modified polystyrene nanofiber membranes with encapsulated or externally bound porphyrin photosensitizers. These materials efficiently produce highly reactive and cytotoxic singlet oxygen capable of restricted diffusion into to the external environment. Our results demonstrate the crucial role of wettability for materials of this type with a short diffusion length of generated singlet oxygen, illustrate the effect of temperature and indicate their potential use as multifunctional materials. Due to their antimicrobial properties, these materials are suitable alternative to antibiotics and local antiseptics. With good breathability and short diffusion length of singlet oxygen good results can be expect in in vivo tests. From these nanofiber materials we also prepared photoactive extremely...
|
|
|
Preparation and photophysical evaluation of tetra-3,4-pyridoporphyrazines suitable for the photodynamic therapy
Čermák, Pavel ; Nováková, Veronika (advisor) ; Roh, Jaroslav (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department: Department of Biophysics and Physical Chemistry Candidate: Pavel Cermak Supervisor: Assoc. Prof. Veronika Novakova, PhD. Title of Thesis: Preparation and photophysical evaluation of tetra-3,4- pyridoporphyrazines suitable for the photodynamic therapy Tetra-3,4-pyridoporphyrazines (TPyPz) are aza-analogues of phthalocyanines. Their large system of conjugated bonds enables them to absorb light in the red part of the absorption spectrum. Due to their ability to produce singlet oxygen, they can be potentially used as photosensitizers in photodynamic therapy (PDT). Its mechanism is based on co-functioning of three elements - photosensitizer, light and oxygen. Photosensitizer excited by light absorption transfers its energy into tissue oxygen, thus, creating cytotoxic singlet oxygen. This method is beneficial for its high selectivity, low toxicity, minimal invasion and fast effect. The aim of this work was to synthetize and study water-soluble TPyPz suitable for PDT. Water solubility was achieved by quarternized amines, forming of salts or using suitable delivery systems (hydrophilic emulsion). Hydrophilicity was also increased by introduction of hydrophilic non-charged substituents (OH). At first, appropriate precursors for...
|
|
|
Nanofiber materials simultaneously photogenerating NO and 1O2 species; Reversible NO binding on boron-containing clusters
Dolanský, Jiří
This project is concerned with the preparation of electrospun polystyrene (PS) nanofiber materials with covalently bonded NO-photodonor and electrostatically attached tetracationic porphyrinoid photosensitizers. These photofunctional nanofiber materials exhibit effective simultaneous photogeneration of small antibacterial NO and O2(1 ∆g) species under irradiation with daylight creating an antibacterial surface and near surrounding. NO species can be also generated just by gentle heating. Nanofiber materials were analyzed with SEM, FTIR, emission and UV/vis spectroscopy and time-resolved emission and absorption spetroscopy. The antibacterial effect was tested on Escherichia coli. The dual antibacterial action, in combination with the nanoporous character of the material that detains pathogens like bacteria on its surface, is ideal for any application where a sterile environment is neces- sary. The known bimetallic cluster system [(PMe2Ph)4Pt2B10H10] that possesses the propen- sity to reversibly bind small gaseous molecules (O2, SO2, CO) was synthesized in good yields for NO reversible binding investigation. Seven new monometallic precursors (Pt, Pd and Ni) to new bimetallic species were succesfully synthesized with the aim of future study of NO reversible binding. All new compounds were purified by...
|
|
|
Synthesis and photophysical study of hydrophilic tetrapyridoporphyrazines bearing charged substituents on the periphery
Demuth, Jiří ; Nováková, Veronika (advisor) ; Vávrová, Kateřina (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department Department of Biophysics and Physical Chemistry Candidate Jiří Demuth Supervisor Assoc. Prof. Veronika Nováková, PhD. Title of Thesis Synthesis and photophysical study of hydrophilic tetrapyridoporphyrazines bearing charged substituents on the periphery Phthalocyanines are planar organic molecules, which have a metal cation coordinated in their centre. This work deals with their aza-analogues - tetra-3,4-pyridoporphyrazines (TPyPz). TPyPz can absorb light in red part spectrum and then produce singlet oxygen. Due to this ability, they may be used in photodynamic therapy (PDT) of cancer. PDT's mechanism is based on three components: photosensitizer, light and singlet oxygen. Photosensitizer transfers energy of absorbed light to oxygen making, thus, cytotoxic singlet oxygen. The goal of this thesis was to synthesize water soluble TPyPzs absorbing in red part of absorption spectrum. TPyPzs bearing different charged substituents will be compared within the series. The synthesis consisted of preparation of 2-chloro-5,6-dimethylpyridine-3,4-dicarbonitrile (1), which was the starting precursor for other reactions. Nucleophilic substitution of 1 was used for the introducing of various hydrophilic substituents. Prepared precursors...
|
|
|
Optimalization of methods for determination of singlet oxygen production and fluorescence emission of azaphthalocyanine derivatives
Hrubá, Lenka ; Nováková, Veronika (advisor) ; Kubíček, Vladimír (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department: Department of Biophysics and Physical Chemistry Candidate: Lenka Hrubá Supervisor: Assoc. Prof. Veronika Nováková, Ph.D. Title of Thesis: Optimization of methods for determination of singlet oxygen production and fluorescence emission of azaphthalocyanine derivatives Photodynamic therapy (PDT) with a singlet oxygen as an essential agent is believed to be an alternative way of cancer treatment or treatment of some cutaneous diseases. The principle of PDT is based on excitation of a photosensitizer by light absorption, followed by transfer of energy to tissue oxygen (3 O2) forming cytotoxic singlet oxygen (1 O2). The efficiency by which photosensitizer transforms absorbed energy to singlet oxygen is characterized by singlet oxygen quantum yields (ΦΔ). The aim of this thesis was to develop and optimize absolute method for determination of ΦΔ. In comparison to a relative method, no reference is needed in this case, which enables accurate results with lower error. Verification of the new method was performed in N,N- dimethylformamide with a zinc phthalocyanine as a model photosensitizer because of its well-known ΦΔ and with 1,3-diphenylisobenzofuran as a chemical quencher of 1 O2. Different sources of light for excitation...
|
|
|
Optimalization of methods for determination of singlet oxygen production and fluorescence emission of azaphthalocyanine derivatives
Hrubá, Lenka ; Nováková, Veronika (advisor) ; Kubíček, Vladimír (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department: Department of Biophysics and Physical Chemistry Candidate: Lenka Hrubá Supervisor: Assoc. Prof. Veronika Nováková, Ph.D. Title of Thesis: Optimization of methods for determination of singlet oxygen production and fluorescence emission of azaphthalocyanine derivatives Photodynamic therapy (PDT) with a singlet oxygen as an essential agent is believed to be an alternative way of cancer treatment or treatment of some cutaneous diseases. The principle of PDT is based on excitation of a photosensitizer by light absorption, followed by transfer of energy to tissue oxygen (3 O2) forming cytotoxic singlet oxygen (1 O2). The efficiency by which photosensitizer transforms absorbed energy to singlet oxygen is characterized by singlet oxygen quantum yields (ΦΔ). The aim of this thesis was to develop and optimize absolute method for determination of ΦΔ. In comparison to a relative method, no reference is needed in this case, which enables accurate results with lower error. Verification of the new method was performed in N,N- dimethylformamide with a zinc phthalocyanine as a model photosensitizer because of its well-known ΦΔ and with 1,3-diphenylisobenzofuran as a chemical quencher of 1 O2. Different sources of light for excitation...
|
|
|
Nanofiber materials simultaneously photogenerating NO and 1O2 species; Reversible NO binding on boron-containing clusters
Dolanský, Jiří ; Mosinger, Jiří (advisor) ; Klán, Petr (referee)
This project is concerned with the preparation of electrospun polystyrene (PS) nanofiber materials with covalently bonded NO-photodonor and electrostatically attached tetracationic porphyrinoid photosensitizers. These photofunctional nanofiber materials exhibit effective simultaneous photogeneration of small antibacterial NO and O2(1 ∆g) species under irradiation with daylight creating an antibacterial surface and near surrounding. NO species can be also generated just by gentle heating. Nanofiber materials were analyzed with SEM, FTIR, emission and UV/vis spectroscopy and time-resolved emission and absorption spetroscopy. The antibacterial effect was tested on Escherichia coli. The dual antibacterial action, in combination with the nanoporous character of the material that detains pathogens like bacteria on its surface, is ideal for any application where a sterile environment is neces- sary. The known bimetallic cluster system [(PMe2Ph)4Pt2B10H10] that possesses the propen- sity to reversibly bind small gaseous molecules (O2, SO2, CO) was synthesized in good yields for NO reversible binding investigation. Seven new monometallic precursors (Pt, Pd and Ni) to new bimetallic species were succesfully synthesized with the aim of future study of NO reversible binding. All new compounds were purified by...
|
|
| |
|
|
The study of sulphonated polystyrene nanofabrics with encapsulated sensitizer
Hrdinková, Veronika ; Mosinger, Jiří (advisor) ; Vojtíšek, Pavel (referee)
The diploma thesis is dedicated to the exploitation of sulphonated polystyrene nanofibres as ion exchange nanomaterial. Ion exchange capacity of these nanomaterials has been determined by titration method and AAS. The effect of sulphonation on photophysical, photooxidative and photocytotoxic properties of sensitizer 5,10,15,20-meso- tetraphenylporphyrin (TPP) encapsulated in polystyrene nanofibres has been studied as well. Properties of TPP have been examined with time-resolved spectroscopy, photooxidation of uric acid as substrate and bactericidal tests on Escherichia coli DH5α with pGEM11Z plasmid. It has been discovered that following the sulphonation of the nanofabrics, the encapsulated sensitizer is partly present even in aggregation form. The polystyrene nanofabrics with encapsulated sensitizer keep its bactericidal efficiency also after sulphonation.
|
|
|
Photooxidative and photodisinfective polymeric nanofabrics: The effect of oxygen permeability
Jesenská, Soňa ; Lang, Kamil (referee) ; Mosinger, Jiří (advisor)
The diploma thesis compares the photophysical, photooxidative and photocytotoxic properties of four polymer nanofabrics with encapsulated 5,10,15,20 - meso - tetraphenylporphyrin (TPP). The main focus of the work lies especially in the study of the effect of polymer oxygen permeability on the ability of nanofabrics to produce singlet oxygen and the utilization of nanofabrics for measurement of the polymer oxygen permeability and polymer oxygen diffusion coefficients. A possible application of nanofabrics in the framework of oxygen detection, photooxidation of substrates and photodesinfection has been studied as well.
|
guest ::
