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An fluorescent aptasensor for sensitive detection of tumor marker based on the FRET of a sandwich structured QDs-AFP-AuNPs
摘要： The detection of alpha-fetoprotein (AFP) is of great importance for hepatocellular carcinoma (HCC) diagnosis, but it needs to be further improved because of poor sensitivity and complicated operating steps. In this paper, a simple and sensitive homogeneous aptasensor for AFP has been developed based on F?rster resonance energy transfer (FRET) where the AFP aptamer labeled luminescent CdTe quantum dots (QDs) as a donor and anti-AFP antibody functional gold nanoparticles (AuNPs) as an acceptor. In the presence of AFP, the bio-affinity between aptamer, target, and antibody made the QDs and AuNPs close enough, thus the fluorescence of CdTe QDs quenched though the FRET between QD and AuNP. The fluorescent aptasensor for AFP showed a concentration-dependent decrease of fluorescence intensity in the low nanomolar range and a detecting linear range of 0.5-45 ng mL?1, with a detection limit of 400 pg mL?1. Moreover, this homogeneous aptasensor is simple and reliable, and obtained satisfying results for the detection of AFP in human serum samples. With more and more aptamers for biomarkers have been selected gradually, this approach could be easily extended to detection of a wide range of biomarkers. The proposed aptasensor has great potential for carcinoma screening in point-of-care testing and even in field use.
关键词： alpha fetoprotein (AFP),fluorescent aptasensor,biomarker,hepatocellular carcinoma,F?rster resonance energy transfer (FRET)
更新于2025-09-23 15:23:52
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Precisely Encoded Barcodes Using Tetrapod CdSe/CdS Quantum Dots with a Large Stokes Shift for Multiplexed Detection
摘要： A serious obstacle to the construction of high-capacity optical barcodes in suspension array technology is energy transfer, which can prompt unpredictable barcode signals, limited barcode numbers, and the need for an unfeasible number of experimental iterations. This work reports an effective and simple way to eliminate energy transfer in multicolor quantum dots (QDs)-encoded microbeads by incorporating tetrapod CdSe/CdS QDs with a large Stokes shift (about 180 nm). Exploiting this unique feature enables the facile realization of a theoretical 7 × 7-1 barcoding matrix combining two colors and seven intensity levels. As such, microbeads containing tetrapod CdSe/CdS QDs are demonstrated to possess a powerful encoding capacity which allows for precise barcode design. The ability of the Shirasu porous glass membrane emulsification method to easily control microbead size facilitates the establishment of a 3D barcode library of 144 distinguishable barcodes, indicating the enormous potential to enable large-scale multiplexed detection. Moreover, when applied for the multiplexed detection of five common allergens, these barcodes exhibit superior detection performance (limit of detection: 0.01–0.02 IU mL?1) for both spiked and patient serum samples. Therefore, this new coding strategy helps to expand barcoding capacity while simultaneously reducing the technical and economic barriers to the optical encoding of microbeads for high-throughput multiplexed detection.
关键词： large Stokes shift,F?rster resonance energy transfer (FRET),photon re-absorption,quantum dots-encoded microbeads,multiplexed detection
更新于2025-09-11 14:15:04
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Assessment of Gate Width Size on Lifetime-Based F?rster Resonance Energy Transfer Parameter Estimation
摘要： F?rster Resonance Energy Transfer (FRET) enables the observation of interactions at the nanoscale level through the use of fluorescence optical imaging techniques. In FRET, fluorescence lifetime imaging can be used to quantify the fluorescence lifetime changes of the donor molecule, which are associated with proximity between acceptor and donor molecules. Among the FRET parameters derived from fluorescence lifetime imaging, the percentage of donor that interacts with the acceptor (in proximity) can be estimated via model-based fitting. However, estimation of the lifetime parameters can be affected by the acquisition parameters such as the temporal characteristics of the imaging system. Herein, we investigate the effect of various gate widths on the accuracy of estimation of FRET parameters with focus on the near-infrared spectral window. Experiments were performed in silico, in vitro, and in vivo with gate width sizes ranging from 300 ps to 1000 ps in intervals of 100 ps. For all cases, the FRET parameters were retrieved accurately and the imaging acquisition time was decreased three-fold. These results indicate that increasing the gate width up to 1000 ps still allows for accurate quantification of FRET interactions even in the case of short lifetimes such as those encountered with near-infrared FRET pairs.
关键词： fluorescence lifetime,F?rster Resonance Energy Transfer (FRET),gated ICCD,near infrared (NIR) dyes,time-resolved imaging,gate width,in vivo imaging
更新于2025-09-10 09:29:36