Chemiluminescent fibre optic immuno- and genosensors for pathogens detection in water

• Main Author: Ye, Kehan
• Other Authors: Alfred Tok Iing Yoong
• Format: Theses and Dissertations
• Language: English
• Published: 2018
• Subjects: DRNTU::Engineering::Bioengineering
• Online Access: http://hdl.handle.net/10356/74178
• Institution: Nanyang Technological University

Waterborne pathogens related diseases are the major threats to public health worldwide. They not only cause high levels of enormous morbidity and mortality losses but also inflict great economic harm on human society. More challenges can be expected in the future, as due to the increasing water scarcity, reuse or recovery of water is becoming an important strategy. Proper assessment of pathogens on water and water quality monitoring are the key procedures for waterborne pathogen infections prevention. Chemiluminescent fibre optic biosensors emerge as the powerful tools for this purpose attributed to their specificity, sensitivity, rapidity, cost-effectiveness, the possibility for in-field operation and being user-friendly. This work focuses on the development of a chemiluminescent fibre optic immunosensor (for detection of E. coli, as a fecal indicator bacteria) and a genosensor (for detection of hepatitis A virus, as a common RNA virus) which are fitted in a portable black box. The immunosensor is based on a micro-ELISA procedure implemented on the end face of a fibre optic. A critical factor that defines the sensing performance is the antibody immobilization on the fibre optic. Silane-diazirine, as an effective photoinducible crosslinker, has been studied and applied in this system. After optimization, it has shown superior adaptability over the traditional chemiluminescent ELISA and a commonly used glutaraldehyde chemical immobilization method in terms of lower detection limit and dynamic range. For the genosensor, a set of ssDNA probes were designed and a sandwich-type hybridization process was constructed. After optimization of the probes and the working conditions, it has demonstrated the ability to work on both cDNA and RNA of HAV with a relatively large signal/noise ratio and a good sensitivity. An excellent specificity was also confirmed by screening with a broad range of other pathogen samples. The nucleic acid probes method was also validated by optimized PCR and qPCR techniques. The relatively affordable and dispatchable biosensor can be used in the early warning monitoring for the putative presence of target pathogens either in an individual sample screening or in continuous monitoring of the environment to indicate the need for further investigation.