Date

2022-12-9

Author

Arık Kınalı, Nehir

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Heavy metal pollution, which is growing and threatening the health of all living things as well as human health, can lead to serious lifelong consequences. It is very important to detect and monitor these heavy metals that cause environmental pollution. In addition to traditional laboratory techniques, the use of bacterial biosensors to detect heavy metals has come into focus. In addition, it is known that the immobilization of these bacterial biosensors is more advantageous in many respects, such as being more stable and protected than the free ones. In this thesis study, arsenic bioreporters whose expression of the reporter gene increased in the presence of arsenic and which we could record as fluorescent signal, were immobilized on 12.5% cellulose acetate (CA) and 10 wt% polycaprolactone (PCL) electrospun fibers. The characterization tests of the developed electrospun fibers were carried out by means of scanning electron microscopy (SEM), fourier-transform infrared (FTIR) spectroscopy and contact angle meter. It was observed that the developed fiber support membranes were beadless and homogeneous fibers (Diameters: 2.15 μm ±0.55 for CA; 0.61 μm ±0.20 for PCL) and both were hydrophobic (143.6°±13.5 for CA, 106°±0.3 for PCL). The parameters of the immobilization studies were changed, and their optimization was tried to be achieved. For this, experiments were carried out in different conditions to determine the relationship between the fluorescent signal emitted in the presence of arsenic and the concentrations and growth phases of the immobilized cells. In addition, according to the viability test performed by AlamarBlue method, the viability of the bioreporters immobilized on CA fiber was 55.4%, while those immobilized-on PCL fiber were 91%. Afterwards, the studies were continued on the PCL fiber and the effects of the growth medium and different immobilization times on the fluorescent signal were examined and the properties of the bioreporter immobilized on PCL system were tried to be determined. Following the optimization studies, in order to determine the properties of the bioreporter immobilized on PCL system, the sensitivity, selectivity, response time to arsenic metal and storage life were determined by changing the storage conditions. The study results show that the bioreporter immobilized on PCL system can be used to detect arsenic heavy metal at environmentally safe concentrations. In addition, it is thought that the study will fill the deficiencies in this field in the literature and shed light on future studies.

Subject Keywords

Arsenic, Electrospun Fibers, Whole Cell Bioreporter, Adsorption, Bacteria Immobilization

URI

https://hdl.handle.net/11511/101285

Collections

Graduate School of Natural and Applied Sciences, Thesis