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

Abstract

Foodborne 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 foodborne pathogen Salmonella enterica serovar Typhimurium. The LIG electrodes were produced by laser induction on polyimide film in ambient conditions, and hence circumvent the need for hightemperature, 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 10 5 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 minutes without the need for sample preconcentration or redox labeling techniques. Moreover, these LIG immunosensors displayed high selectivity as demonstrated by non-significant 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, low-cost pathogen detection in food processing facilities before contaminated foods reach the consumer.

Pathogen detection with electrochemical biosensors: Advantages, challenges and future perspectives

“…In another study, Soares et al developed a novel detection method for Salmonella enterica serovar Typhimurium in chicken meat with EIS [ 12 ]. The authors used a label-free Laser-Induced Graphene (LIG) electrodes, which can be easily manufactured from commercial polymers, functionalized with high-specificity antibodies.…”

“…3 Schematic illustration of the electrode fabrication and the detection scheme of the electrochemical immunosensor based on laser-induced graphene working electrode modified with linkers and capturing antibodies to detect Salmonella bacteria in chicken food products. Reprinted from [ 12 ] with permission: Copyright © 2020 American Chemical Society. …”

“…Electrochemical biosensors have received significant attention thanks to providing rapid, accurate and sensitive responses in a cost-effective manner [ [10] , [11] , [12] ]. Electrochemical biosensors could use different types and forms of nanomaterials and nanocomposites to enhance the sensitivity of the detection mechanisms and to provide better detection limits through different strategies [ 13 , 14 ].…”

Laser-induced graphene for bioelectronics and soft actuators

“…In contrast to semiselective electronic tongue systems, surface modifications have also been explored to endow the pristine LIG with highly selective detections toward specific biochemicals and even bacteria. Functional groups usually involve antibodies, enzymes, aptamers, and molecularly imprinted polymers [83,[96][97][98][99][100][101]. For example, Soares et al have reported LIG-based electrochemical immunosensors for detections of Salmonella enterica, as schematically illustrated in Fig.…”

QCM Sensor Arrays, Electroanalytical Techniques and NIR Spectroscopy Coupled to Multivariate Analysis for Quality Assessment of Food Products, Raw Materials, Ingredients and Foodborne Pathogen Detection: Challenges and Breakthroughs

“…In another recent study, a gold microelectrode was fabricated with single-walled carbon nanotubes for detection of Yersinia enterocolitica in fermented vegetable products [277]. Various graphene-based nanocomposites were also reported for the detection of Salmonella enterica and Escherichia coli [271,278,279]. Moreover, gold nanoparticles have also been extensively incorporated into electrochemical biosensors used in food born pathogen detection, due to their excellent physiochemical properties and biocompatibility [280][281][282][283].…”