New Functional Tracer—Two-Dimensional Nanosheet-Based Immunochromatographic Assay for Salmonella enteritidis Detection

Abstract

The rapid monitoring of foodborne pathogens by monoclonal antibody (McAb)-based immunochromatographic tests (ICTs) is desirable but highly challenging as a result of the screening obstacle for a superior performance probe, which will greatly determine the capture efficiency of targets and the sensitivity of the immunoassay. In this work, on the basis of two-dimensional (2D) nanosheets (including MoS2 and graphene) as the extraordinary capture probe and signal indicator, we fabricated a label-free ICT method for Salmonella enteritidis detection. Especially, without the customarily labeled antibody probe, these 2D versatile probes presented strong capture ability toward bacteria by directly assembling onto the surface of bacteria. An ideal analytical performance with high sensitivity and specificity was achieved by virtue of the novel nanosheet–bacteria–McAb sandwich format. On the basis of MoS2 2D nanosheets as a fabulous probe element, the developed ICT exhibited a lowest detectable concentration of 103 colony-forming units/mL for S. enteritidis and could be well-applied in drinking water and watermelon juice samples. By the smart design, this work removes a series of conditionality issues of traditional double antibody sandwich-based ICTs and can give a new application direction for 2D nanosheet materials in the rapid detection field.

Overview of Rapid Detection Methods for Salmonella in Foods: Progress and Challenges

“…In addition to signal collection, the choice of detection platform is also an important issue. ELISA and lateral flow test strips have been commercialized on a large scale and are the most recognized detection platforms [153,154]. New detection platforms such as microfluidic devices have also been actively developed.…”

Development of Nanozymes for Food Quality and Safety Detection: Principles and Recent Applications

“…The visual signal of LFIA is mainly derived from the gathering effect of intrinsically colored NPs, such as AuNPs (Bu et al., ), which will fail if the concentration of NPs is too low to be visible. Therefore, probe materials are of significance to enhance the detection efficiency and sensitivity of LFIA (Bu, Huang, Sung et al., , Bu, Wang et al., ; Dou et al., ). In this regard, it is an important choice to integrate nanozymes as a signal tag with detection systems to construct a nanozyme‐based FLIA assay (N‐FLIA) (Loynachan et al., ).…”

Graphene-labeled synthetic antigen as a novel probe for enhancing sensitivity and simplicity in lateral flow immunoassay

“…8 (iii) Physical and chemical environments, such as inorganic ions, organic solvents, pH and temperature, are other obstacles to the binding affinity of Ab; therefore, the environment needs to be carefully controlled and adjusted to preserve the Ab recognition capability. 9,10 To alleviate the above problems, we have proposed some solutions, as follows: (i) graphene nanosheets have drawn growing interest and are being applied in various elds. Owing to their excellent properties, such as simple fabrication procedure, chemical stability, superb optical properties, costeffectiveness, unique large surface area and strong adsorption capacity for protein without additional modications, this promising nanomaterial was employed in this work to fabricate an effective and robust signal to improve detection sensitivity.…”