Food quality and food safety have long been global concerns, especially in developing countries (Karimzadeh and Mahmoudpour, 2022). Common contaminants in food include foodborne hazards such as farm chemicals, heavy metals, pathogens, mycotoxins, and antibiotics (Hua et al., 2021). The U.S. Centers for Disease Control (CDC) and Prevention estimates that approximately 9.4 million people are adversely affected by foodborne diseases each year. To address food safety-related aspects, many sensors have been developed to detect food contaminants (Zhang et al., 2022a). The existing food analysis and detection methods include chromatography and mass spectrometry (Li et al., 2023b), which can achieve quantitative detection. However, these two detection methods require expensive equipment, tedious operation, and professional staff, which are not suitable for field detection. Enzyme-linked immunosorbent assay (ELISA) is based on monoclonal antibodies (recognition elements) for target detection, which has the disadvantages of instability, difficulty in synthesis, and high cost (Flauzino et al., 2023). Therefore, fast, sensitive, and portable biosensors need to be developed for food safety control and quality analysis. Table 1 lists the contents of common types of food hazards and related tests.

Biosensors have been widely concerned because of their characteristics of good detection specificity and high sensitivity (Hua et al., 2021; Yan et al., 2021; Zhang et al., 2021). It contains two parts: a recognition element and a sensor. The recognition elements are generally enzymes, antibodies, and aptamers (Cao et al., 2020). Aptamers are single-stranded DNA (ssDNA) or RNA sequences obtained by ligand exponential enrichment systematic evolution (SELEX), which can fold into a unique geometry after binding to the target, and have high affinity and high specificity (Oliveira et al., 2022; Shin et al., 2023; Zacco et al., 2022). Aptamers, also known as “chemical antibodies”, are targeted probes for biosensors due to their specific advantages (low cost, stability, and easy modification). They are expected to replace antibodies in the food field, clinical diagnosis, and targeted therapy (Hu et al., 2023). However, the low sensitivity and non-portable design limit the application of aptamers in real samples (Wang et al., 2023d). To solve this problem, post-SELEX (Yu et al., 2023b, H. et al., 2023), end fixation (Zhao et al., 2019b, L. et al., 2019), chemical modification (Ji et al., 2021), and other methods were used to improve the binding performance of aptasensors. In addition, after being functionalized, aptamers can be labeled and immobilized on other surfaces (Elskens et al., 2020; Odeh et al., 2019). Therefore, a variety of aptasensors have been developed to detect food hazards, for example, colorimetry, fluorometry, electrochemistry, surface-enhanced Raman spectroscopy (SERS), electrochemiluminescence (ECL) (Hejji et al., 2023).

In recent years, the application of nanomaterials combined with aptamer sensors has attracted much attention to improve the sensitivity. Nanoparticles have unique biological, chemical, and physical properties, such as large specific surface area and adjustable shape. They can form functionalized probes with aptamers through covalent bonding and intermolecular electrostatic interactions. Overall, many nanomaterials act as signal probes. These molecules contain metal nanoparticles (Ag NPs、Au NPs、Ru NPs and Pt NPs) (Liu et al., 2021b; Zhao et al., 2019a; Zhao et al., 2022), quantum dots (CdTe、CdSe, and PbSe) (Lu et al., 2018; Najafi et al., 2020; van der Stam et al., 2018), and metal oxides (CdO NPs and Cu2O NPs) (Zhao et al., 2018a; Zhao et al., 2018b). Yao et al. (Yao et al., 2023) proposed to develop a dual-mode Apt-PAD for targeted detection of tetrodotoxin based on the Ag@Cu2O NPs nanomaterials. In an earlier study, Wang et al. (2022a) found that chito oligosaccharides (COS) significantly enhanced the peroxidase activity of Au nanoparticles (Au NPs). Subsequently, nanoparticles can improve the performance of biosensing systems. At the same time, the nanoparticles can be further exploited for further understanding of their practical applications. Thus, the integration of nanoparticles with PADs increases the diversity of sensing platforms.

Most current techniques for detecting food hazards require expensive instruments and long periods. This makes the detection techniques require more specialized operators and strict laboratory environments, but are difficult to perform in poor areas. To meet the standards set forth by the World Health Organization (fast, low cost, high sensitivity, portable and user-friendly), many researchers have worked on developing low-cost detection devices. As the performance of sensors continues to improve, microfluidic devices with integrated sensors have become the focus of attention. POCT sensing devices are more readily available for a wide range of applications in the analysis of food, pharma, environment, and clinic samples than techniques performed in the laboratory.

Martinez et al. (2007) first reported a PAD, and since then, PADs have been considered a simple platform for POCT. PADs are a new type of POCT tool and their demand as on-site detection tools in the market has been expanding (Díaz-Amaya et al., 2020). PADs as sensing platforms have the advantages of simple manufacturing, lightweight, portable, and low-cost advantages, suitable for field analysis and POCT, and can be popularized in the application of food and environmental samples (Ataide et al., 2023). They can be used in a variety of practical applications, including disease screening, drug testing, environmental testing, and food evaluation (Zheng et al., 2021). To improve the stability of detection performance and meet People's Daily detection needs, different methods of preparing PADs have been innovated. For example, printing (Abe and Citterio, 2008; Sameenoi et al., 2014), lithography (Mettakoonpitak et al., 2021), drawing pen (Hellmann, 2008; Martinez et al., 2007), chemical paper (Nuchtavorn and Macka, 2016), modification (Böhm et al., 2013; Cai et al., 2014), etc. Although PADs are a powerful tool for POC and field analysis, there are still great challenges to the technology that remains to be addressed (Danchana et al., 2023).

This paper presents a comprehensive review of the recent research progress in the last five years regarding the detection of food hazards through the integration of nanomaterials with Apt-PADs (Fig. 1). The first part of the review focuses on the current construction of Apt-PADs. Furthermore, the various types of Apt-PADs are thoroughly discussed for detecting food hazards. Various types of PADs utilized for detecting food hazards are also briefly summarized. Lastly, the paper explores the current challenges in ensuring food safety and provides insights into future research directions for Apt-PADs.