Reduced graphene oxide on screen-printed carbon electrodes as biosensor for escherichia coli O157:H7 detection

• Main Authors: Barthasarathy, Piravin Raj, Ahmed, Nasteho Ali, Wan Salim, Wan Wardatul Amani
• Format: Article
• Language: English
• Published: MDPI 2020
• Subjects: TP248.13 Biotechnology
• Online Access: http://irep.iium.edu.my/85179/13/85179_Reduced%20Graphene%20Oxide.pdf; http://irep.iium.edu.my/85179/; https://www.mdpi.com/2504-3900/60/1/13; https://doi.org/10.3390/IECB2020-07056
• Institution: Universiti Islam Antarabangsa Malaysia

Mixture of drinking-water supplies with sewage discharges poses disease threats in flood-stricken areas. In such exigent conditions, on-site testing of water samples is the only option, as water samples cannot be transported to laboratories owing to severely impacted transportation services. Hence, we developed a low-cost electrochemical biosensor fabricated from a screen-printed carbon electrode (SPCE) to detect E. coli O157:H7, a virulent pathogen often found in sewage discharges. We focused on understanding antigen-antibody interaction when the antibody used is not specific for E. coli O157:H7. We found that antibody immobilized on a reduced graphene oxide (rGO)–modified SPCEs distinguished between E. coli O157:H7 concentrations of 4 × 108 and 4 CFU/ml, with lowest current reported for 4 × 108 CFU/ml. In contrast, a reduced graphene oxide–modified SPCEs without antibody immobilization does not produce a prominent peak that distinguishes the highest and lowest E. coli concentrations. However, a few E. coli cells were still attached to the rGO/SPCEs in the absence of antibody, as shown in FESEM images. A processing step of differential readings from reference and active electrodes needs to be programmed into an Arduino® microprocessor to realize a prototype of a bacteria sensor for field use.