An aptasensor for ampicillin detection in milk by fluorescence resonance energy transfer between upconversion nanoparticles and Au nanoparticles

A point-of-care aptasensor based on the upconversion nanoparticles/MoS2 FRET system for the detection of Pseudomonas aeruginosa infection

The rapid detection of Pseudomonas aeruginosa (P. aeruginosa) is of great significance for the diagnosis of medical infection. In view of the above, a novel aptasensor based on fluorescence resonance energy transfer (FRET) was developed. It contained aptamer-coupled upconversion nanoparticles (UCNPs-apt) as a donor (excitation 980 nm) and molybdenum disulfide (MoS2) nanosheets as an acceptor. The upconversion fluorescence aptamer system was investigated to obtain the optimal parameters of MoS2 concentration, the incubation time of UCNPs-apt/MoS2 and P. aeruginosa, and pH. Based on the optimal parameters, a linear calibration equation (emission 654 nm) with a wide detection range 8.7 × 10 ~ 8.7 × 107 cfu/mL, a high coefficient of determination R2 0.9941, and a low limit of determination (LOD) 15.5 cfu/mL were established. The method was validated with P. aeruginosa infected foci of mouse wound. The advantage of this aptasensor is that analysis results can be obtained  within 1.5 h, which was much faster than that of the standard method (18-24 h). Furthermore, combined with a portable instrument, it can be used as a point-of-care testing for the early detection of P. aeruginosa infection, which is useful for selecting the correct antibiotics to achieve good therapeutic effects. Additionally, it also has a broad application prospect in food and environmental areas.

Recent Advances in Fluorescent Nanoprobes for Food Safety Detection

Fluorescent nanoprobes show similar fluorescence properties to traditional organic dyes, but the addition of nanotechnology accurately controls the size, shape, chemical composition, and surface chemistry of the nanoprobes with unique characteristics and properties, such as bright luminescence, high photostability, and strong biocompatibility. For example, modifying aptamers or antibodies on a fluorescent nanoprobe provides high selectivity and specificity for different objects to be tested. Fluorescence intensity, life, and other parameters of targets can be changed by different sensing mechanisms based on the unique structural and optical characteristics of fluorescent nanoprobes. What's more, the detection of fluorescent nanoprobes is cost-saving, simple, and offers great advantages in rapid food detection. Sensing mechanisms of fluorescent nanoprobes were introduced in this paper, focusing on the application progress in pesticide residues, veterinary drug residues, heavy metals, microbes, mycotoxins, and other substances in food safety detection in recent years. A brief outlook for future development was provided as well.

Nanomaterial-Based Fluorescent Biosensor for Food Safety Analysis

Food safety issues have become a major threat to public health and have garnered considerable attention. Rapid and effective detection methods are crucial for ensuring food safety. Recently, nanostructured fluorescent materials have shown considerable potential for monitoring the quality and safety of food because of their fascinating optical characteristics at the nanoscale. In this review, we first introduce biomaterials and nanomaterials for food safety analysis. Subsequently, we perform a comprehensive analysis of food safety using fluorescent biosensors based on nanomaterials, including mycotoxins, heavy metals, antibiotics, pesticide residues, foodborne pathogens, and illegal additives. Finally, we provide new insights and discuss future approaches for the development of food safety detection, with the aim of improving fluorescence detection methods for the practical application of nanomaterials to ensure food safety and protect human health.