Jul 2026· Journal of the American Chemical Society· Vol 148, pp. 30096 - 30101· 0 citations· 24 references
Medicine
Abstract
N-Nitrosodimethylamine (NDMA) is a water-soluble carcinogen typically quantified using mass spectrometry coupled with chromatographic separation, which requires extensive sample preparation and sophisticated instrumentation. Here, we report a fluorescence-based detection strategy for NDMA in aqueous media that replaces column-based separation with affinity capture. Photochemical transformation of NDMA, followed by reaction with a biotinylated polymeric reagent, generates a biotin-labeled fluorescent product that can be selectively enriched through streptavidin–biotin interaction, enabling effective separation of the analytical signal from background. The assay is performed entirely in water without sample pretreatment, preconcentration, or solvent exchange. Under optimized conditions, quantitative detection is achieved in a plate-based format using only 100 μL samples, affording a limit of detection of 235 ppb. The chemical transformation is completed within 22 min, followed by rapid affinity capture via streptavidin-coated agarose beads or plates. The method is rigorously validated through spectroscopic characterization, selective capture experiments, and quantitative analysis, and demonstrates consistent performance in spiked commercial water samples. These results establish a chemically defined platform for chromatography-independent optical NDMA detection and provide a basis for further development toward scalable sensing formats built on streptavidin-functionalized solid phases.
Formaldehyde (FA), a toxic and carcinogenic compound used extensively in industrial and preservation processes, requires reliable and selective detection methods, particularly in environmental, food, and biomedical samples. Herein, we report the development of a water-soluble, naphthalimide-based fluorescent polymeric probe, DCP-1, for the selective and rapid sensing of FA in aqueous solutions at physiological pH. The polymer has aromatic amine functional groups in its side chains, which specifically react with FA to form a stable imine. This transformation inhibits the native photoinduced electron transfer (PET), resulting in a distinct "turn-on" fluorescence response in an aqueous medium. The generation of the imine adduct was confirmed by mass spectrometry (MS) and 1H NMR spectroscopy for the representative reaction between a small molecule analogue and FA. DCP-1 exhibits excellent sensitivity, detecting FA at concentrations as low as 1.28 nM and displaying a strong fluorescence response within minutes at 100 nM FA. The probe exhibited reversible behavior upon bisulfite addition, demonstrating its ability to be reused efficiently for multiple FA detection cycles with consistent performance. Density functional theory (DFT) calculations further validated the proposed PET-based sensing mechanism.
Swagata Pan, Subhadip Roy, Satendra Kumar et al.· Chemistry - An Asian Journal· 0 citations
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.
As a key chemical raw material, hydrazine hydrate (N2H4) is widely used in chemical manufacturing, aerospace propulsion and pharmaceuticals synthesis. However, excessive N2H4 causes serious harms to the environment and organisms. Herein, a ratiometric fluorescence probe CDP has been designed and synthesized from p-hydroxycinnamic acid. Upon interaction with N2H4, the major fluorescence emission peak at 570 nm is blue-shifted to 455 nm, accompanied by a fluorescence color change from pale orange to blue. The detection limit of CDP for N2H4 is determined as 17.08 nM. Experimental data further indicate that probe CDP can effectively detect N2H4 across a broad pH range (5-12). More notably, probe CDP demonstrates significant potential for imaging N2H4 in living cells and mice models. Moreover, probe CDP can be employed for the detection of N2H4 in soil samples and water samples. This work describes a versatile fluorescence probe for detecting N2H4, underscoring its considerable potential in environmental analysis and public health monitoring.
Zhuoran Song, Haoqi Zhang, Xiaoqing Yang et al.· Ecotoxicology and Environmen...· 0 citations
Sulfites are widely used as preservatives and antioxidants in food, but excessive intake poses health risks. Therefore, rapid, sensitive, and on‑site detection of sulfites is essential for food safety. In this work, a cationic small‑molecule fluorescent probe was synthesized via the condensation of
N
‑ethylcarbazole (electron donor) and a benzoindolium ion (electron acceptor). It exhibits a D–π–A architecture with an intramolecular charge transfer (ICT) effect, showing red fluorescence at 617 nm. Upon reaction with HSO
3
−
through Michael addition at the conjugated C═C bond, the ICT pathway is blocked, leading to fluorescence quenching. The probe displays excellent selectivity for HSO
3
−
(limit of detection = 0.1 µM). Significantly, it can be simply deposited onto filter paper to fabricate easy‐to‐use test strips. Under a 365 nm UV lamp, the test strips exhibit a visible color change from red to blue with increasing HSO
3
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concentration, allowing naked‑eye detection. Coupled with a smartphone color‑reading application, a linear relationship between the blue‐to‐red intensity ratio (B/R) and HSO
3
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concentration enables rapid on‑site quantitative analysis. The test strips were successfully applied to detect residual HSO
3
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in various dried fruit samples. This work provides a simple, low‑cost, and practical method for detecting sulfite levels in food and environmental samples.
Kanli Wang, Chenle Liao, Qian Cao et al.· ChemistrySelect· 0 citations
This study introduces the first reported stepwise fluorimetric strategy for the sensitive and rapid determination of the ultra-short-acting β₁-blocker, landiolol hydrochloride. Initially, an environmentally benign method was developed by exploiting the drug’s native fluorescence in water (λex/λem = 217/298 nm). While this cost-effective approach successfully utilized water as a green solvent, it demonstrated limited LOD of 32.57 ng/mL. To enhance fluorescence performance, various organic solvents were investigated, with acetonitrile providing the highest signal at λex/λem = 222/300 nm and improving the LOD to 16.31 ng/mL. To enable ultra-trace clinical monitoring, a third “turn-on” method was developed using silver nanoparticles (AgNPs). By measuring fluorescence enhancement at λex/λem = 260/524.6 nm upon interaction with landiolol, this platform amplifies the signal, achieving an outstanding LOD of 3.10 ng/mL. AgNPs were prepared using a green synthesis approach employing Aloe vera extract as a natural reducing and stabilizing agent in an aqueous medium avoiding using hazardous chemicals. Water was used throughout both nanoparticle preparation and the AgNP-enhanced determination, reinforcing the eco-friendly profile of the method. Unlike native fluorescence, the AgNP-assisted method enhances sensitivity through nanoparticle-mediated surface passivation, with a possible auxiliary contribution from resonance energy transfer (RET)-like processes. Selectivity is improved through preferential adsorption of landiolol on the AgNP surface and a large Stokes shift that minimizes interference from UV-absorbing matrix components. The resulting enhanced sensitivity and reduced matrix interference make this method a powerful tool for ultra-trace, selective, and sustainable determination of landiolol in pharmaceutical formulations and human plasma, demonstrating its suitability for routine quality control and bioanalytical applications.
Marwa Khaled, Hend Z. Yamani, N. Fares et al.· Scientific Reports· 0 citations
Bisulfite (HSO3-), which exists in equilibrium with sulfite and sulfur dioxide derivatives, plays significant roles in food preservation and biological systems. However, elevated levels of bisulfite are associated with various physiological disorders. Therefore, the development of reliable methods for monitoring bisulfite is of considerable importance. Herein, we report a flavonol-based fluorescent probe, 4-(3-hydroxy-4-oxo-4H-chromen-2-yl) benzaldehyde (BSP), synthesized via a simple two-step reaction using 1-(2-hydroxyphenyl)ethan-1-one and 4-(diethoxy methyl)benzaldehyde. BSP exhibits excellent water solubility and a strong turn-on fluorescence response toward HSO3- in PBS buffer (pH 5.0), with green emission at 515 nm and a large Stokes shift of 155 nm. The probe shows high selectivity and sensitivity with a detection limit of 0.19 µM. The sensing mechanism is attributed to nucleophilic addition of HSO3- to the aldehyde group, suppressing the n → π* transition and enhancing intramolecular charge transfer (ICT), resulting in significant fluorescence enhancement. BSP was successfully applied for bisulfite detection in onion epidermal cells and environmental water samples.
U. Samanta, Anindita Roy, Subhajit Ghosh et al.· Analytical Methods· 0 citations