Oct 2026· Analytica Chimica Acta· Vol 1419, pp.
345981
· 0 citations· 39 references
Medicine
Abstract
Background
Foodborne pathogens remain a major threat to public health and food safety, among which Salmonella typhimurium is a leading cause of bacterial foodborne illness. Conventional culture-, immunoassay-, and nucleic-acid-based methods are reliable but often require laboratory facilities, trained personnel, and relatively long processing times, limiting their use for rapid on-site screening. Lateral flow immunoassays are attractive for field detection but commonly suffer from limited sensitivity and subjective visual interpretation. This study addresses the need for a rapid, specific, and more sensitive on-site assay for S. typhimurium.
Results
We developed a phage-assisted colorimetric-photothermal dual-readout lateral flow immunoassay using zeolitic imidazolate framework-67-aggregated gold nanoparticles (ZIF-67@AuNPs) as signal probes. The ZIF-67 scaffold promoted dense AuNP assembly and aggregation-induced localized surface plasmon resonance coupling, resulting in broadened visible absorption around 650 nm and enhanced photothermal conversion. ZIF-67@AuNPs achieved a photothermal conversion efficiency of 45.7%, markedly higher than that of AuNPs alone (22.7%). Phage-based capture and antibody-functionalized ZIF-67@AuNPs enabled selective recognition of S. typhimurium on the test strip. In the colorimetric mode, the assay showed a linear range of 3 × 104-1 × 107 CFU/mL with a visual limit of detection (LOD) of 3.0 × 104 CFU/mL. In the photothermal mode, the linear range was 103-106 CFU/mL and the LOD improved to 0.997 × 103 CFU/mL, giving approximately 30-fold higher sensitivity.
Significance
AND NOVELTY
This work introduces a MOF-assisted LFIA that integrates phage-based biorecognition with colorimetric screening and photothermal quantification in a single test strip. The strategy reduces reliance on subjective visual judgment while retaining operational simplicity. The platform provides a practical approach for rapid on-site detection of S. typhimurium and can be extended to other foodborne pathogens by changing the recognition elements.
Herein, we propose a novel "low-background" biosensing platform integrating magnetic separation and hybridization chain reaction (HCR) for signal amplification, enabling ratiometric colorimetric detection and visual observation of S. typhimurium. In the presence of S. typhimurium, specific aptamer recognition triggers the HCR to couple the urease-labeled DNA to the HCR reporting system, ultimately generating a ratiometric colorimetric response upon enrichment by Fe3O4@PDA@PEI and magnetic separation. The assay demonstrates excellent sensitivity, achieving a detection limit of 2.34 CFU mL-1. Simultaneously, the ratiometric sensor enables direct visual detection of S. typhimurium at concentrations as low as 103 CFU mL-1. Furthermore, leveraging the photothermal properties of Fe3O4@PDA@PEI under 808 nm NIR irradiation significantly reduced S. typhimurium viability, thereby minimizing the risk of secondary contamination. Recovery rates of 84.2%-115.3% in common spiked food samples containing S. typhimurium confirm its practicality. This integrated "detection and inactivation" strategy offers a proactive defense for food safety.
Foodborne infections and enterotoxin poisoning caused by S. aureus pose serious threats to food safety and public health. However, conventional detection methods are often time-consuming, technically complex, and typically require relatively large sample volumes. Herein, we report an aptamer-functionalized rough gold nanoparticle (RPG)-based photothermal platform that enables rapid and quantitative detection of S. aureus using a smartphone-compatible thermal imaging system in combination with a laser and an infrared thermal camera. RPGs were synthesized via a facile one-step method, and exhibited uniform particle size and a measured photothermal conversion efficiency of ~73.20%. After optimization of the aptamer concentration, laser irradiation time, and probe concentration, the proposed method exhibited a wide detection range from 1.0 × 102 to 1.0 × 107 cfu/mL, with an operational detection threshold of 100 CFU/mL under the optimized experimental conditions, a total assay time of less than 40 min, and a sample requirement of only 30 μL per assay, while maintaining acceptable reproducibility. Spike-and-recovery experiments in real samples, including orange juice, tap water, and milk, yielded recoveries of 91.8–105.5%, indicating suitable analytical performance in complex matrices. This work provides a rapid, portable, and low-sample-volume detection strategy for S. aureus, offering a practical approach for on-site food safety monitoring.
A dual-mode colorimetric–photothermal LFIA platform was successfully constructed for the detection of thrombosis-related biomarkers, including thrombomodulin and α2-plasmin inhibitor–plasmin complex, in clinical serum samples, enhancing analytical sensitivity and reliability.
Jun Yin, Yu Qiu, Yao Nie et al.· RSC Advances· 0 citations
Ensuring rapid, reliable, and quantitative detection of foodborne pathogenic bacteria continues to be a challenge in food safety, particularly in complex matrices where traditional culture methods are time-consuming. In this study, a surface-enhanced Raman spectroscopy (SERS) sensing platform incorporating a polymer affinity agent is developed for the sensitive and quantitative detection of bacterial foodborne pathogens. A linear poly (2-hydroxyethyl methacrylate) affinity agent (pHEMA) was employed in combination with film over nanospheres (FON) substrates to facilitate detection and discrimination of Salmonella typhimurium (Gram-negative) and Listeria monocytogenes (Gram-positive). pHEMA plays an important role in mediating interactions with both extracellular metabolites and bacterial cell wall components. Characteristic vibrational bands enabled quantitative detection with a log-linear response and an observed limit of detection of 158 CFU/mL for both Salmonella typhimurium and Listeria monocytogenes in diluted apple juice. The similar sensitivities observed for both bacteria suggest effective interactions between pHEMA and chemically distinct bacterial cell walls of Gram-negative and Gram-positive organisms. This sensing approach maintained consistent performance in complex food matrices, such as pure apple juice, across a range of temperatures. Sonication experiments provided additional practical advantages: enhanced species discrimination and a strategy for combined disinfection and detection, extending the utility of this platform for food safety applications. Overall, these results show that SERS sensing platforms incorporating polymer affinity agents offer a robust and versatile analytical approach for whole cell foodborne pathogen detection.
Mahmoud Matar Abed, Katie L. Riley, Punarbasu Roy et al.· ACS Sensors· 0 citations
Foodborne pathogenic bacteria are microorganisms characterized by rapid reproduction, posing significant threats to food and environmental safety. Consequently, the development of rapid and accurate detection methods for these pathogens is highly crucial. In this study, a dual-mode in situ detection platform designed for bacterial analysis has been developed. The platform employs a phage-immobilized hydrogel stir bar to specifically capture target bacteria. This process alters the microenvironmental pH value of the stir bar and causes the color change of bromocresol purple that has been buried in the hydrogel. The color change can be observed with the naked eye through the transparent hydrogel, thus achieving the purpose of quickly screening for the positive samples. Additionally, the ZnO/ZIF embedded within the hydrogel will generate reactive oxygen species (ROS) under the light exposure. Through photodynamic action, the targeted live bacteria will be killed effectively, and ATP will be released intracellularly. In the presence of D-luciferin and luciferase, the ATP in the positive samples triggers a bioluminescence reaction, the intensity of which can be quantified using a hand-held ATP bioluminescence sensor. The mutual verification of these two detection modes confers high accuracy and sensitivity to the method. Furthermore, the approach eliminates the need for any large-scale instrumentation, enabling rapid on-site detection. Under optimal conditions, the detection range for target live bacteria spans from 103 to 109 CFU·mL-1 within 35 min. The limit of detection (LOD) for the colorimetric is 103 CFU·mL-1 and the limit of quantification (LOQ) for bioluminescence mode is 30 CFU·mL-1.
Cong Cao, Rong Feng, Zhenzhong Yu et al.· Analytical Chemistry· 0 citations
Shigella is a foodborne bacterial pathogen with a low infectious dose and significant public health impact. Culture-based and molecular techniques provide reliable identification but are time-consuming. Nanoparticle-based biosensors offer sensitive, selective, and compact alternatives. Recent advances in nanoparticle-based biosensors for Shigella spp. (S. flexneri, S. sonnei, S. dysenteriae, and S. boydii) detection have been reviewed in terms of signal amplification, biorecognition, biological targets, sensor types, and performance in real food matrices. Detection strategies rely on gene-level and whole-cell recognition. Targeting virulence genes, invasion plasmid antigen H (ipaH), provides stable genus-level identification, whereas whole-cell recognition facilitates rapid detection without extensive sample preparation. Optical biosensors, including fluorescence-based methods, surface-enhanced Raman spectroscopy (SERS), and localized surface plasmon resonance (LSPR), achieve low detection limits with strong tolerance to complex food matrices. Electrochemical biosensors offer operational simplicity, portability, and suitability for food screening. Lateral flow and hybrid systems provide rapid detection through simplified assay formats and visual readout, with performance influenced by the balance between speed and sensitivity. Validation in real food matrices shows acceptable recoveries, minimal cross-reactivity, and agreement with reference methods. This overview provides a design-oriented framework for nanoparticle-based biosensor selection in food safety by integrating nanomaterial function, biosensor design, and performance characteristics.
Sümeyra Savaş, Seyed Mohammad Taghi Gharibzahedi· Biosensors· 0 citations
