Fabrication and characterization of graphene-based immunosensor for E. coli O157:H7 detection /
Escherichia coli O157:H7 is a significant water contaminating agent which cause infection and release shiga toxin into host intestine. Shiga toxin can cause hemolytic uremic syndrome (HUS) and even death. Peninsular Malaysia's eastern coast is normally affected flood almost every year. The pres...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
Kuala Lumpur :
Kulliyyah of Engineering, International Islamic University Malaysia,
2017
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| Subjects: | |
| Online Access: | http://studentrepo.iium.edu.my/handle/123456789/4814 |
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| Summary: | Escherichia coli O157:H7 is a significant water contaminating agent which cause infection and release shiga toxin into host intestine. Shiga toxin can cause hemolytic uremic syndrome (HUS) and even death. Peninsular Malaysia's eastern coast is normally affected flood almost every year. The presence of three pathogenic bacteria such as Escherichia coli, Salmonella typhimurium, and Shigella flexneri was reported in the flood water of Pahang. E. coli with a concentration of 671 CFU/mL was found in Pahang's flood water. Moreover, E. coli O157:H7 cause 73,000 infections in the United States annually. Current amperometric-based biosensors need to be highly sensitive, specific, and with a low detection limit. Third generation biosensors utilize nanomaterials such as carbon nanotubes (CNTs), graphene oxide (GO), gold nanoparticles (AuNPs), and silver nanoparticles (AgNPs) to enhance sensor performance parameters. Employing bactericidal nanomaterials to fabricate biosensor can significantly reduce cell viability and ultimately cause signal artifacts. Hence the bactericidal and biocompatible activity of nanomaterials on E. coli was investigated with the goal to select biocompatible nanomaterial, suitable to be used for biosensor fabrication. Based on the bactericidal activity, biocompatible graphene oxide (GO) was selected to employ as the transducer layer. The conductivity and functional groups of rGO/GCE modified electrode were analyzed. A sensitive graphene-based electrochemical immunosensor had been fabricated through covalent immobilization of anti-E. coli O157:H7 onto rGO/GCE modified electrode. The appearance of -NH bending vibration peak in FTIR analysis after 48 hours of sample preparation warrants the immunosensors' stability. CV results indicate the Ab/rGO/GCE immunosensor can successfully detect E. coli O157:H7 when the cathodic peak potential drops down from 0.491 μA to 0.401 μA. Moreover, this graphene-based immunosensor can detect low concentration of E. coli O157:H7 with a wide detection range from 103 to 109 CFU/mL. Furthermore, the FESEM micrograph images were tuned with all results. The corrugated shape of rGO ensures the removal of oxygenated species from GO. The FESEM micrograph image and the size of bacteria verified the attachment of E. coli O157:H7 onto the surface of graphene-based immunosensor. The sensitivity of this immunosensor owes to rGO which provides a suitable microenvironment for immobilization of anti-E. coli O157:H7 and boosts electron transfer on surface of rGO/GCE modified electrode. Immobilization of anti-E. coli O157:H7 provides specificity to the immunosensor. Sensitive, specific, low detection limit and easy fabrication steps make this graphene-based immunosensor a promising point-of-care (POC) device for E. coli O157:H7 detection |
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| Item Description: | Abstracts in English and Arabic. "A dissertation submitted in fulfilment of the requirement for the degree of Master of Science (Biotechnology Engineering)." --On title page. |
| Physical Description: | xv, 86 leaves : illustrations ; 30cm. |
| Bibliography: | Includes bibliographical references (leaves 70-75). |