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Viral foodborne diseases cause serious harm to human health and the economy. Rapid, accurate, and convenient approaches for detecting foodborne viruses are crucial for preventing diseases. Biosensors integrating electrochemical and optical properties of nanomaterials have emerged as effective tools for the detection of viruses in foods. However, they still face several challenges, including substantial sample preparation and relatively poor sensitivity due to complex food matrices, which limit their field applications. Hence, the purpose of this review is to provide an overview of recent advances in biosensing techniques, including electrochemical, SERS-based, and colorimetric biosensors, for detecting viral particles in food samples, with emerging techniques for extraction/concentration of virus particles from food samples. Moreover, the principle, design, and advantages/disadvantages of each biosensing method are comprehensively described. This review covers the recent development of rapid and sensitive biosensors that can be used as new standards for monitoring food safety and food quality in the food industry.

Various types of biological and synthetic nanopores have been developed and utilized for the high-throughput investigation of individual biomolecules. Biological nanopores made with channel proteins are so far superior to solid-state ones in terms of sensitivity and reproducibility. However, the performance of a biological nanopore is dependent on the protein in the channel structure its dimensions are predetermined and are difficult to modify for broader applications. Here inspired by the cytotoxic mechanisms of a saponin derivative, alpha-hederin, we report a nonproteinaceous nanopore that can be formed spontaneously in a lipid membrane. We propose the pore-forming mechanism of alpha-hederin in a cholesterol-rich lipid membrane and a strategy to control the pore-forming rate by a lipid partitioning method. The small diameter and effective thickness of alpha-hederin nanopores enabled us to discriminate ssDNA homopolymers as well as four types of nucleotides, showing its potential as a DNA sequencing tool.

Solid-state nanopore has been widely studied as an effective tool to detect and analyze small biomolecules, such as DNA, RNA, and proteins, at a single molecule level. In this study, we demonstrate a rapid identification of the location of zinc finger protein (ZFP), which is bound to a specific locus along the length of a double-stranded DNA (dsDNA) to a single protein resolution using a low noise solid-state nanopore. When ZFP labeled DNAs were driven through a nanopore by an externally applied electric field, characteristic ionic current signals arising from the passage of the DNA/ZFP complex and bare DNA were detected, which enabled us to identify the locations of ZFP binding site. We examined two DNAs with ZFP binding sites at different positions and found that the location of the additional current drop derived from the DNA/ZFP complex is well-matched with a theoretical one along the length of the DNA molecule. These results suggest that the protein binding site on DNA can be mapped or that genetic information can be read at a single molecule level using solid-state nanopores.

We developed a simple and sensitive colorimetric biosensor in the form of microparticles by using polydiacetylene (PDA) vesicles encapsulated within a hydrogel matrix for the detection of phosphinothricin acetyltransferase (PAT) protein, which is one of the most important marker proteins in genetically modified (GM) crops. Although PDA is commonly used as a sensing material due to its unique colorimetric properties, existing PDA biosensors are ineffective due to their low sensitivity as well as their lack of robustness. To overcome these disadvantages, we devised immunohydrogel beads made of anti-PAT-conjugated PDA vesicles embedded at high density within a poly(ethylene glycol) diacrylate (PEG-DA) hydrogel matrix. In addition, the construction of immunohydrogel beads was automated by use of a microfluidic device. In the immunoreaction, the sensitivity of antibody-conjugated PDA vesicles was significantly amplified, as monitored by the unaided eye. The limit of detection for target molecules reached as low as 20 nM, which is sufficiently low enough to detect target materials in GM organisms. Collectively, the results show that immunohydrogel beads constitute a promising colorimetric sensing platform for onsite testing in a number of fields, such as the food and medical industries, as well as warfare situations.