Functionalized magnetite nanoparticles for arsenic detection

For the last 2 decades, the research and development of biosensor increased exponentially whether in terms of investments, the number of scientific articles published (the website science direct has thousands of articles on biosensor) or researchers who work on it. The high interest of biosensor is probably due to technological progress in the field of microelectronic, materials, biology... The requirements of the control of the environment, which are more and more drastic, and the quality of life have contributed on the interest of biosensors. In fact, the great advantage of biosensors lies in their original concept allowing the realization of integrated, self-functional, miniaturizable measurement systems, easy to implement and requiring little or no processing of the sample to be analyzed. Moreover, biosensors require the multidisciplinary knowledge. The evolution demand and necessity in many situations of providing information in real time, for facing a critical event, motivate seeking alternative methods. Among these methods and devices which allow to implement them, biosensors are among the most promising technology. In effect, biosensors appear today to be suitable tools in different areas: biotechnology, biomedicine, environment, ... In particular, real needs exist for the determination of various metabolites and/or toxic elements in different complex environments. The characteristics and performance of these biosensors are very attractive: sensibility, reliability, commodity, simplicity, cheap. The aim of my thesis is the study of functionalized magnetite nanoparticles for arsenic detection. It is divided into four chapters. The first chapter will be dedicated to a general presentation of magnetite NPs, heavy metals and biosensors for heavy metals. The second chapter will explain in detail materials and apparatus used to build the sensor. Functionalized magnetite nanoparticles have been deposited on the substrate. Actually, different sensors will be built. One with NPs of 〖Fe〗_3 O_4 and the other one with NPs of 〖Fe〗_3 O_4 + NPs of gold. We will also see which principles hold the adhesion of the NPs on the substrate. The third chapter will show up the experiments themselves, by which means the sensor detect the presence of arsenic. Experiments will be done on both sensors. The aim is to see how the addition of gold NPs improves the efficiency of the measurement. Finally, the fourth chapter, the conclusion, deals with the interpretation of the results and the conclusion.