Moleküler Baskılı Floresan Nanoparçacıkların Sentezlenmesi ve Sensör Sistemlerinde Kullanımlarının İncelenmesi ; Synthesıs of Molecularly Imprınted Fluorescent Nanopartıcles and Theır Use in Sensor Systems

In recent years, lanthanide-doped nanoparticles (upconversion nanoparticles - UCNP) have attracted much attention in many different areas because of their superior fluorescence properties, photochemical stability and ability to use in different application areas and they have been preferred over commonly used quantum dot and organic dyes. UCNPs are frequently used in medical imaging, treatment, drug release, forensic sciences, etc. due to their visibility in daylight with naked eyes, strong irradiation properties, non-toxicity, high photo stability, biocompatibility and highly efficient usage. UCNPs of different geometries and sizes can also be used successfully in many sensor applications. In this thesis, ytterbium (Yb) and erbium (Er) doped sodium yttrium fluoride (NaYF4) matrix (β–NaYF4: Yb3+, Er3+) was synthesized as the UCNP structure. The basic red 9 (BR9) molecule, which is an azoic dye, has been selected as a model compound and the UCNP surface was modified with this compound-specific molecularly printed polymer (MIP) and a UCNP-based sensor system has been developed. The synthesis of UCNPs was optimized using different hydrothermal methods, the most suitable synthesis method was determined, and the characterization studies of these nanostructures were carried out. To use the synthesized UCNPs in the sensor system, their surfaces were covered by MIP layer by 3 different methods and the most suitable modification method was determined. In the optimum procedure, UCNP was first modified with tetraethylorthosilicate (TEOS), then with triethoxyvinyl silane (TEVS) to enrich the surface in vinyl groups. In the next step, BR9 imprinted polymeric structure was covered to the surface via reversible addition-fragmentation chain transfer (RAFT) polymerization technique. Morphological properties and chemical structures of the obtained structures were evaluated with various experimental techniques such as fourier transform infrared spectrometer- attenuated total reflectance (ATR-FTIR), scanning electron microscope ...