Optické vlastnosti kvantových teček a jejich aplikační potenciál v bezpečnostním inženýrství

Abstract

The objective of the dissertation thesis is the study of the fluorescence nanoparticles – Quantum Dots - and the interaction of the nanoparticles with biomolecules – porphyrins, phthalocyanines and azaphthalocyanines with regard of its application potential in safety engineering – primarily the application as potential sensors of dangerous substances. The studied molecules are so called photosensitisers – i.e. substances capable of using the absorbed electromagnetic energy for the destruction of a biological target and its application includes photodynamic therapy. The system is studied with the aid of spectroscopic methods and the study is primarily devoted to the spontaneous interaction between Quantum Dots and selected molecules and to the influence of these interactions on the optical properties of the studied components. These studies are followed by the study of photosensitisers anchored in nanofibers with antibacterial properties, serving at the same time as a model system of immobilized fluorescence sensors. Two types of quantum dots have been studied – commercially available CdSe and CdS semiconductor quantum dots (QD) and graphene quantum dots (GQD). The study of the interaction between phthalocyanines (Pc) and azaphthalocyanines (azaPc) has confirmed the important role of ligands on the binding interactions between QD and (aza)Pc. The optical characteristics of the components remained mainly unchanged. These results are important for the design of a QD-receptor as a part of fluorescence sensor as well as QD-photosensitiser for the application in photodynamic therapy. Furthermore, the interaction between GQD and commercial porphyrins has been studied. The key role is played by the electrostatic force as well as the structure of the GQD surface. In the last part the information about gas diffusion in nanofibers with immobilized porphyrins has been obtained, which is essential for the design of an effective sensor or nanofibers as a functional material.