Optimization and characterization of a biosensor assembly for detection of Salmonella Typhimurium

Authors: ARAUJO MELO, AIRIS - Universidade Federal Do Ceara (UFC); ALEXANDRE, DALILA - Universidade Estadual Do Ceara; OLIVEIRA, M - Universidade Federal Do Ceara (UFC); FURTADO, ROSELAYNE - Embrapa; DE FATIMA BORGES, MARIA - Embprapa; VASCONCELOS RIBEIRO, PAULO - Embrapa; Biswas, Atanu; Cheng, Huai; ALVES, CARLUCIO - Universidade Estadual Do Ceara; DE FIGUEIREDO, EVANIA - Universidade Federal Do Ceara (UFC)

Submitted to: Journal of Solid State Electrochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/5/2017
Publication Date: 9/14/2017
Citation: Melo, A.M.A., Alexandre, D.L., Oliveira, M.R.F., Furtado, R.F., Borges, M.F., Ribeiro, P.R.V., Biswas, A., Cheng, H.N., Alves, C.R., Figueiredo, E.A.T. 2017. Optimization and characterization of a biosensor assembly for detection of Salmonella Typhimurium. Journal of Solid State Electrochemistry. 22(5):1321-1330. https://doi.org/10.1007/s10008-017-3767-0.
DOI: https://doi.org/10.1007/s10008-017-3767-0

Interpretive Summary: Salmonella is a major foodborne pathogen in the world and can infect animals and humans alike. Analysis for Salmonella spp. in food is one of the mandatory procedures in order to guarantee food safety. However, conventional detection methods are laborious and time-consuming, sometimes requiring several days to confirm the results. In this work, an electrochemical immunosensor was developed and optimized such that Salmonella can be detected at a detection limit of 10 CFU mL-1. The detection time can be as low as 125 minutes for each test. This work is important because it can serve as a useful tool for food safety; for example, it can be used by government health officials and food suppliers worldwide to monitor food quality and ensure food safety.

Technical Abstract: The performance of biosensors depends directly on the strategies adopted during their development. In this paper, a fast and sensitive biosensor for Salmonella Typhimurium detection was assembled by using optimization studies in separate stages. The pre-treatment assays, biomolecular immobilization (primary antibody and protein A concentrations), and analytical response (hydroquinone and hydrogen peroxide concentrations) were optimized via voltammetric methods. In the biosensor assembly, a gold surface was modified via the self-assembled monolayer technique (SAM) using cysteamine thiol and protein A for immobilization of anti-Salmonella antibody. The analytical response of the biosensor was obtained through the use of a secondary antibody labeled with a peroxidase enzyme, and the signal was evaluated by applying the chronoamperometry technique. The biosensor was characterized by infrared spectroscopy and cyclic voltammetry. Optimization of protein A and primary antibody concentrations enabled higher analytical signals of 7.5 and 75 mg mL-1, respectively, to be achieved. The hydroquinone and H2O2 concentrations selected were 3 and 300 mM, respectively. The biosensor developed attained a very low detection limit of 10 CFU mL-1 and a fast response with a final detection time of 125 min. These results indicate that this biosensor is very promising for the food safety and emergency response applications.