Sularda Fekal Kirlilik Tayinine Yönelik Biyosensör Geliştirilmesi

Abstract

Contamination of drinking and surface waters with microorganisms is a threatening health problem that attracts attention. One of the microorganisms that determine fecal contamination in water is bacteriophages which infect coliform bacteria. The methods currently used for microoganism detection are time consuming and require more labor. Therefore, there is a need for fast, precise and low-cost methods as an alternative. At this point, biosensors are useful tools for microorganism detection. One of these is surface plasmon resonance (SPR) sensors which are in the class of optical biosensors. The use of molecularly imprinted polymers on the sensor surface is a preferred method because of its high selectivity and sensitivity. The aim of this thesis is to prepare bacteriophage imprinted biosensors to detect T4 bacteriophage which is one of the fecal indicator microorganisms. Two different biosensors were prepared with nanoparticle and nanofilm based polymers and compared. In this context, the functional monomer N-methacroyl- (L) -histidine methyl ester was synthesized and its characterization was made by fourier transformed infrared spectroscopy and nuclear magnetic resonance. T4 bacteriophage imprinted and non-imprinted nanoparticles were synthesized by mini-emulsion polymerization method and immobilized on SPR biosensor surface after zeta size, fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and atomic force microscopy analysis. After the biosensor surface was characterized by ellipsometry and contact angle, the prepared biosensor was used for kinetic, selectivity, reusability and real sample analysis. While T2 and MS2 bacteriophages were used for selectivity studies, tap water and sea water were used in real sample analyzes. T4 bacteriophage imprinted and non-imprinted nanofilms were prepared using the micro-contact imprinting method. The prepared biosensor surface was analyzed by contact angle, ellipsometry and atomic force microscopy and used for kinetic, selectivity, reusability and real sample analysis under the same conditions. According to the results obtained, SPR biosensors prepared using nanoparticles and nanofilm polymers were able to measure 99% and 92% accuracy in 1x104-4x106 pfu/mL concentration range, respectively. The limit of detection was 6x103 pfu/mL for the nanoparticle based biosensor and 8x103 pfu/mL for the nanofilm based biosensor. In addition, recovery values of nanoparticle based surface plasmon resonance biosensor were calculated as 91-96% in tap and sea water samples while recovery values of nanofilm based surface plasmon resonance biosensor were calculated as 85-90%. The results show that both surface plasmon resonance biosensors can measure with high selectivity, but nanoparticle polymer based surface plasmon resonance biosensor has higher sensitivity and selectivity.