Aug 2026· Biosensors· Vol 16, pp. 419· 0 citations· 41 references
Medicine
Abstract
Precise quantitative monitoring of 17β-estradiol (E2) is important for reproductive management in precision livestock farming. However, E2 determination in complex biological matrices remains challenging because of matrix-derived background and signal variability. Here, we developed a nanoconfinement-assisted solid-state ratiometric fluorescent aptasensor integrating target-induced strand displacement (TISD), magnetic separation, and anodic aluminum oxide (AAO) nanochannel confinement. The sensing probe consisted of streptavidin-coated magnetic nanoparticles (MNPs) carrying a FAM-labeled cDNA internal reference and a Texas Red-labeled E2 aptamer reporter. E2 binding promoted dissociation of the Texas Red-labeled aptamer from the magnetic probe. Magnetic separation and washing reduced soluble matrix-derived interference, while subsequent deposition of the sensing complexes onto an AAO membrane mitigated coffee-ring-associated nonuniformity and produced a more spatially uniform dual-color fluorescence distribution for ratiometric analysis. Under matrix-matched calibration conditions, linear ranges of 5.0–50.0 pM were obtained in tap water and sow saliva, 5.0–40.0 pM in whole milk, and 5.0–15.0 pM in post-estrus sow urine. The LOD determined in tap water was 3.62 pM. The different calibration slopes obtained among the four matrices indicated that residual matrix-dependent effects remained and that matrix-specific calibration was required for quantitative analysis. Matrix-matched spike recoveries ranged from 86.92% to 119.54% across the investigated matrices. The aptasensor exhibited the strongest response toward 17β-E2 among the tested compounds; however, cross-reactivities of 77.3% for E3 and 47.3% for 17α-E2 indicated preferential rather than exclusive recognition. Molecular docking suggested a putative binding pose but did not experimentally establish the molecular recognition mechanism. Overall, the platform demonstrated laboratory-scale analytical feasibility in pretreated tap water, sow saliva, whole milk, and post-estrus sow urine. Further development of sample preparation, magnetic handling, membrane loading, probe selectivity, and portable fluorescence readout will be required before in situ or on-site application.
Nanoplastics (NPs) are new types of pollutants that have emerged in food which has attracted widespread attention. However, due to the small size and low concentration, and the complexity of food matrices, the selective and sensitive determination of NPs in food is challenging. Herein, we report a dual-probe system for determination of trace-level polystyrene (PS) NPs with high sensitivity and selectivity. The proposed dual-probe system was composed of magnetic Fe3O4 nanoparticles functionalized with PS-specific peptides (Fe3O4@Au-PSBP) and a high-quality Li+-doped ZnGa2O4:Cr3+ persistent luminescence nanoparticles (PLNPs) modified with ethylene glycol chitosan. By integrating peptide-based specific recognition, persistent luminescence signaling, and magnetic separation with pH-switchable charge reversal, the proposed system enables effective capture and sensitive detection of PS NPs in complex matrices. Under the optimized conditions, the method showed a linear range of 50–800 pg mL−1 and a detection limit of 8.11 pg mL−1. The precision for the determination of 50 pg mL−1 PS NPs was 5.24% (RSD, n = 11). The method was successfully applied to the analysis of PS NPs in different matrices, including bottled purified water, saltwater (3.5% salinity), artificial lake water, and tea beverage, with recoveries ranging from 91.25% to 110.53%. More importantly, the proposed system can be readily adapted for the analysis of other targets by replacing the recognition unit, providing a versatile and selective sensing strategy for trace-level hazardous analytes.
Beibei Wang, Ling Sun, Kai Liu et al.· Current Research in Food Sci...· 0 citations
The rapid and accurate detection of chlorpyrifos (CPF), a widely used pesticide in agricultural products, is crucial for food safety assurance. While traditional methods like HPLC and GC-MS are accurate, they remain costly, slow, and lack portability. Herein, an ultrasensitive magnetic biosensing platform was developed for the ratiometric detection of CPF in tea by integrating surface-enhanced Raman spectroscopy (SERS) with an aptamer-based recognition strategy. The platform employed a competitive displacement mechanism, where specific binding between aptamer and CPF triggered the release of signal probes upon magnetic separation. This process altered the Raman intensity ratio of two reporter molecules (4-MPY and 4-MBN). The ratiometric sensing approach, combined with magnetic separation, improved operational convenience and reduced matrix interference from complex samples. Furthermore, the platform exhibited a wide linear detection range (10-9 M to 10-4 M) with a limit of detection (LOD) of 1.4 × 10-6 mg/kg. It demonstrated high sensitivity, stability, reproducibility and specificity across six tea varieties, offering an effective solution for detecting pesticide residues in complex food matrices.
Chenxi Jin, Minhui Cao, Geqi Li et al.· Food Chemistry· 0 citations
Thiamethoxam, a widely utilized neonicotinoid insecticide, has been extensively applied in agricultural practices, leading to various adverse effects on human health, such as neurotoxicity, developmental issues, and endocrine disruption. Therefore, establishing a comprehensive and standardized surveillance framework for the quantitative determination of thiamethoxam residues in environmental compartments and food matrices is critical for mitigating its chronic toxicological risks to human health. We developed a biosensor for thiamethoxam detection, which leverages the target-induced formation of G-quadruplexes and subsequent Thioflavin T fluorescence enhancement based on Exonuclease III-driven shear amplification and the hybridization chain reaction. Under optimized conditions, this biosensor exhibited a detection range from 10 pg mL-1 to 1 µg mL-1 and a detection limit of 8.7 pg mL-1. Furthermore, the successful detection of thiamethoxam in real samples confirms the biosensor's practical applicability and reliability.
In this study, we developed an aptamer-mediated surface-enhanced Raman scattering (SERS)-coupled immunochromatographic assay (ICA) for the quantitative detection of pyrethroids. For this approach, core-shell gold nanoparticles (Au@Au NPs) were used as SERS probes by conjugating with aptamers, and fluorescent Raman reporter molecules (MPBN) were incorporated to yield stable, reproducible spectral signals. Leveraging the aptamers' specific recognition of the target analyte, Raman-labeled Au@Au NPs could be effectively captured by the test line of the immunochromatographic strip, thereby enabling the quantitative analysis of fenvalerate-with a limit of detection (LOD) as low as 0.4 ppb. Comparative experiments revealed that the detection sensitivity of this SERS-ICA method was 476 times higher than that of conventional lateral flow assays (LFA), showcasing a remarkable sensitivity advantage. To validate its practicality, spiked recovery experiments were conducted on three real samples, namely welsh onions, cowpeas, and kidney beans. The results showed that the spiked recoveries ranged from 78.3% to 112.5%, with relative standard deviations (RSD) between 1.7% and 20.1%. This fully confirms that the method possesses favorable specificity and accuracy, making it suitable for real-sample detection. This detection platform offers a new technical route for the rapid on-site monitoring of trace contaminants in food safety and environmental surveillance, holding broad application prospects.
Wangyu Nan, Qingdan Ye, Jie Huang et al.· Talanta: The International J...· 0 citations
Detection of 3-MCPD in lipid-rich food matrices remains challenging due to trace analyte levels, high viscosity, and severe matrix interference. Herein, a photothermal-driven magnetic "three-in-one" sensing platform based on L-cysteine-functionalized ZnFe2O4 (L-ZFO) nanoparticles was developed for rapid and sensitive screening of 3-MCPD in edible oils. The multifunctional platform integrates magnetic enrichment, photothermal-assisted signal amplification, and colorimetric sensing, enabling efficient extraction and detection with minimal sample pretreatment. Benefiting from the synergistic interfacial enrichment and photothermal enhancement, the proposed method exhibited a linear range of 0.01-0.20 mg/L with a low detection limit of 1.4 μg/L. The platform showed acceptable recoveries of 75.0-92.0% and relative standard deviations below 5.8% in edible oil samples. Moreover, comparable responses obtained in buffer and oil matrices demonstrated excellent anti-interference capability toward complex lipid systems. The recyclable L-ZFO probe also exhibited good stability and reproducibility over 3 cycles. This work provides an elimination of pretreatment strategy for rapid on-site screening of 3-MCPD in edible oils.
Chenxi Liu, Jihan Huang, Sinuo Cheng et al.· Journal of Hazardous Materia...· 0 citations
Given the hepatotoxicity and widespread contamination of Aflatoxin B1 (AFB1), developing ultra-sensitive, anti-interference analytical platforms is paramount for public health. Herein, a dual signal ratio electrochemical sensing platform for accurate AFB1 analysis was constructed integrating DNA tetrahedrons (TNDA), a dynamic DNA walker, and nitrogen-doped graphene oxide-supported hollow silver-platinum bimetallic nanospheres (NGR-HP-AgPt). The NGR-HP-AgPt cavity provides a uniform microenvironment, synergistically promoting catalytic effects to significantly accelerate interfacial electron transfer. Simultaneously, rigid 3D TNDA prevent spatial probe entanglement, providing a well-oriented track. To avoid false-positive artifacts in complex matrices, a competitive binding strategy is employed. Upon target recognition, AFB1 displaces a complementary sequence (DNA1) from the aptamer. The released DNA1 acts as a walking strand, hybridizing with signal probes (Cd2+-DNA2). Subsequently, Exonuclease III initiates the DNA walker, continuously cleaving probes to amplify the ratiometric signal variation for reliable self-calibration. Under optimal conditions, this sensor exhibits a broad linear range from 2 × 10-4 to 20 ng/mL, with an ultra-low detection limit of 73.99 fg/mL. Furthermore, its practical utility and high accuracy were successfully validated in complex food and medicinal matrices, yielding consistent results with the standard HPLC-FL method. This work broadens the robust design paradigm of anti-interference biosensing.