Abstract
Redox activity is an important indicator for evaluating electrochemical biosensors. In this work, we have successfully polymerized indole-5-carboxylic acid into poly-5-carboxyindole nanomaterials (PI-5-CA), using its superior redox activity, and introduced carboxylated single-walled carbon nanotubes (C-SWCNTs) to synthesize a composite material. Finally, a synthesized composite material was used for the modification of the glass carbon electrode to fabricate the PI-5-CA/C-SWCNTs/GCE-based immunosensor and was successfully applied for the sensitive detection of E. coli O157:H7. The fabricated immunosensor exhibited an outstanding electrocatalytic activity toward the detection of E. coli O157:H7 with a remarkably lowest limit of detection (2.5 CFU/ml, LOD = 3 SD/k, n = 3) and has a wide linear range from 2.98×101 to 2.98×107 CFU/ml. Inspired from the excellent results, the fabricated electrode was applied for the detection of bacteria from real samples (water samples) with a good recovery rate (98.13–107.69%) as well as an excellent stability and specificity. Owing to its simple preparation, excellent performance, and detection time within 30 min, our proposed immunosensor will open a new horizon in different fields for the sensitive detection of bacteria from real samples.
Highlights
To date, the most important topic of concern for food industries is the alarming increase of food- and waterborne diseases (Law et al, 2015; Patra and Baek, 2016)
The scanning electron microscope (SEM) images of PI-5-CA/ C-SWCNT nanocomposite at different magnifications showed in Figures 2A–C formed a three-dimensional layered porous structure, which can facilitate the combination of various biorecognition molecules and improve the analytical performance of the electrochemical sensor based on PI-5-CA/ C-SWCNTs
In that case, when antibodies bound to the carboxyl groups present on the surface of PI-5-CA/C-SWCNTs, a reduction in the peak redox current can be clearly observed
Summary
The most important topic of concern for food industries is the alarming increase of food- and waterborne diseases (Law et al, 2015; Patra and Baek, 2016). Factors that cause foodborne diseases include bacteria, parasites, viruses, chemicals, and toxins (Aziz et al, 2021; Rad et al, 2021) Among these factors, bacterial contamination is an alarming threat to human health (Chen et al, 2017; Sai-Anand et al, 2019). Many electrochemical redox active materials have been used as electronic media for the development of electrochemical biosensors, such as ferrocene (Hu L. et al, 2021), graphene oxide (GO) (Aziz et al, 2019a), and Prussian blue (22) Most of these materials suffer low conductivity and poor stability, so their effects in the field of electrochemical detection are not satisfactory (Kang et al, 2016). We used this constructed biosensor to successfully detect E. coli in domestic water, and compared the results with the traditional culture method to determine the sensitivity and reliability of the fabricated sensor
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
