Ratiometric fluorescent signals-driven smartphone-based portable sensors for onsite visual detection of food contaminants

Development of efficient and portable biosensor to achieve the accurate onsite detection of food contaminants is of very great significance for safeguarding food safety and human health. With the popularity of smartphone, the digital imaging feature makes it to be an outstanding analytical platform to develop the point-of-care testing sensors. Compared with single-emission fluorescent assay, the ratiometric fluorescent assay possesses the built-in self-calibration function to avoid the interferences caused by various target-independent factors, circumventing/reducing false positive result output, thus improving the detection accuracy and expanding the dynamic detection range in complicated food matrixes. Based on these, vast efforts focus on integrating smartphone with ratiometric fluorescent strategies to develop portable sensors for realizing the onsite visual detection of food contaminants in a rapid, low cost, reliable, and even easy to implement in resource-limited areas way. In this review, we summarize the recent development of ratiometric fluorescent signals-driven smartphone-based sensors for onsite visual detection of food contaminants (e.g., antibiotics, pesticides, & harmful ions), discuss the confronting challenges, and propose an outlook on the future of this advanced analytical technology to help better achieve the precisely onsite detection of food contaminants, ensuring food safety and human health.