Fabrication of graphene-based resistive sensor for eschericia coli bacteria sensing

The presence of fecal coliform bacteria like Escherichia coli (E. coli) in aquatic environments indicates that the water has been contaminated with the fecal material of human or animals. The risk of health threatening to humans become high when E. coli bacteria are exposed to water, not only causes diarrhea but also lead to death if not treated immediately. Many existing sensors to detect E. coli bacteria are not portable and expensive, while the conventional methods are time consuming and need the sterile procedure. Therefore, it is important to develop a sensor to detect E. coli rapidly, portable and user friendly. In this work, bacteria sensor based on resistivity was developed using graphene nanostructure as a sensing layer, since carbon material like graphene has been known to have a biocompatibility and excellent electrical property. The E. coli bacteria used in this experiment were collected from domestic wastewater and commercial of E. coli strain no. ATCCC 25922. A biochemical test was performed to detect the presence of E. coli in wastewater. The physical characterization of the bacteria was carried out by using FESEM and it was found that the E. coli has size ranging from 1.4-1.6 μm in length. The wettability properties of graphene confirmed that graphene surface is hydrophobic with contact angle of 108.9o which is suitable for bacterial detection. Raman spectroscopy measurements shows that the ratio of G peak and D peak intensity increase due to increase in the number of E. coli. Moreover, the electrical property of graphene shows increasing the number of the bacteria from 4 to 273 colony forming-unit (cfu) result decreasing the resistance from 4.371 to 3.903 ohm gradually. Finally, the sensor was successfully designed using SolidWorks and fabricated by integrating graphene film as a sensing layer with Arduino micro-controller. The validation of the sensor was performed by comparing the data obtained by sensor device and plate culture and has been found to have an error rate of ±12.3%.

Name dc:type.qualificationname

mphil

Level dc:type.qualificationlevel

masters

Grantor dc:publisher.institution

Universiti Tun Hussein Onn Malaysia

Year dc:date.issued

2018

Author dc:creator

• Wibowo, Kusnanto Mukti

• T173.2-174.5 Technological change

Language dc:language

en