Dual-readout lateral flow immunoassay based on upconversion nanoparticle-gold nanoparticle luminescence resonance energy transfer for rapid determination of 17β-estradiol
A luminescence resonance energy transfer (LRET)-regulated dual-readout lateral flow immunoassay (LFIA) is reported that integrates naked-eye colorimetric screening and near-infrared-excited quantitative luminescence analysis on a single test strip, offering a versatile platform for rapid on-site screening of small-molecule contaminants in complex matrices.
The rapid, sensitive, and quantitative detection of small-molecule analytes in complex matrices remains fundamentally constrained by severe optical interference and limited signal transduction efficiency. Herein, we report a turn-on near-infrared (NIR) fluorescence lateral flow immunoassay (NFLFIA) that integrates indocyanine green-embedded nanoparticles and horseradish peroxidase-loaded gold nanorods as a spectrally matched donor-acceptor pair. Benefiting from the intrinsically low optical background of the NIR window and a cascade quenching mechanism governed by synergistic inner-filter effect and Förster resonance energy transfer, the NFLFIA enables ultrasensitive detection of aflatoxin M1 over an exceptionally broad dynamic range spanning 4 orders of magnitude, with a low limit of detection of 10.3 fg mL-1. With a sample-to-answer time of 30 min, this portable NIR-readout platform achieves sensitivity 3 orders of magnitude higher than commercial colloidal gold strips and delivers more reliable quantitative performance than 3-h-long enzyme-linked immunosorbent assays. This work establishes a robust and field-deployable platform for rapid, on-site monitoring of trace-level small molecules in complex matrices.
Jing-Rui Yuan, Liang Huang, Ya-Qi Luo et al.· Analytical Chemistry· 0 citations
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
A dual-aptamer-based, dual-mode FRET lateral flow strip is developed for the rapid and sensitive detection of thrombin in serum samples, achieving a fluorescence-based detection limit of 0.135 nM-twice as sensitive as the colorimetric method.
A preliminary evaluation using serum samples from five breast cancer patients and five healthy individuals showed clearly distinguishable colorimetric and fluorescent responses between the two groups, supporting the effectiveness of the proposed probe for miRNA-21 detection in real serum samples and indicating the potential of the dual-signal LFA platform for further clinical application.
Ruien Shi, Qian Xiang, Yajuan Chang et al.· Talanta: The International J...· 0 citations
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.
Lun Luo, Renjie Zhou, Wenhai Wang et al.· Analytica Chimica Acta· 0 citations
D-Proline has been reported as a potential biomarker for gastric (stomach) cancer, creating a demand for practical and rapid analytical approaches for early diagnosis using simple and non-invasive clinical samples. In this work, a microfluidic paper-based analytical device (µPAD) integrating molecularly imprinted polymer-functionalized upconversion nanoparticles (UCNPs@MIPs) was developed for the selective fluorescence-based detection of D-proline. Owing to near-infrared excitation (980 nm), UCNPs provide background-free fluorescence with high photostability, while MIPs serve as artificial receptors to impart molecular selectivity. The sensing mechanism relies on fluorescence quenching of UCNPs@MIPs induced by D-proline through multiphonon relaxation, resulting in an inverse relationship between fluorescence intensity and analyte concentration. Quantitative analysis was achieved using a homemade IR-laser-controlled light box and smartphone-based image capture, with signal evaluation based on blue-channel intensity. The proposed platform exhibited a linear response over the concentration range of 0.01-0.30 mM, with a limit of detection of 0.016 mM. The method was successfully applied to the determination of spiked D-proline in human saliva and serum samples. Owing to its simplicity, low sample consumption, portability, and adaptability, the proposed sensing strategy shows strong potential for on-site analysis and can be extended to broader applications in chemical analysis, biosensing, and environmental monitoring.
Akarapong Prakobkij, Jiajia Zhou, Mahnaz Maddahfar et al.· In Analysis· 0 citations
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