Laser-Induced Graphene Electrochemical Immunosensors for Rapid and Label-Free Monitoring of Salmonella enterica in Chicken Broth

Gomes, Carmen
Soares, Raquel
Hjort, Robert
Claussen, Jonathan
Pola, Cícero
Parate, Kshama
Reis, Efraim
Soares, Nilda
McLamore, Eric
Claussen, Jonathan
Gomes, Carmen
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Food-borne illnesses are a growing concern for the food industry and consumers, with millions of cases reported every year. Consequently, there is a critical need to develop rapid, sensitive, and inexpensive techniques for pathogen detection in order to mitigate this problem. However, current pathogen detection strategies mainly include time-consuming laboratory methods and highly trained personnel. Electrochemical in-field biosensors offer a rapid, low-cost alternative to laboratory techniques, but the electrodes used in these biosensors require expensive nanomaterials to increase their sensitivity, such as noble metals (e.g., platinum, gold) or carbon nanomaterials (e.g., carbon nanotubes, or graphene). Herein, we report the fabrication of a highly sensitive and label-free laser-induced graphene (LIG) electrode that is subsequently functionalized with antibodies to electrochemically quantify the food-borne pathogen Salmonella enterica serovar Typhimurium. The LIG electrodes were produced by laser induction on the polyimide film in ambient conditions and, hence, circumvent the need for high-temperature, vacuum environment, and metal seed catalysts commonly associated with graphene-based electrodes fabricated via chemical vapor deposition processes. After functionalization with Salmonella antibodies, the LIG biosensors were able to detect live Salmonella in chicken broth across a wide linear range (25 to 105 CFU mL–1) and with a low detection limit (13 ± 7 CFU mL–1; n = 3, mean ± standard deviation). These results were acquired with an average response time of 22 min without the need for sample preconcentration or redox labeling techniques. Moreover, these LIG immunosensors displayed high selectivity as demonstrated by nonsignificant response to other bacteria strains. These results demonstrate how LIG-based electrodes can be used for electrochemical immunosensing in general and, more specifically, could be used as a viable option for rapid and low-cost pathogen detection in food processing facilities before contaminated foods reach the consumer.

<p>This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in <em>ACS Sensors</em>, copyright © American Chemical Society after peer review. To access the final edited and published work see DOI: <a href="" target="_blank">10.1021/acssensors.9b02345</a>. Posted with permission.</p>
graphene, biosensor, electrochemical impedance spectroscopy, foodborne pathogens, food safety, Salmonella Typhimurium