Organophosphorus pesticides (OPPs) in foods pose a serious threat to human health, motivating the development of novel analytical methods for their rapid detection and quantification. A magnetic covalent organic framework (M-COF) adsorbent for the magnetic solid-phase extraction (MSPE) of OPPs from foods was reported. M-COF was synthesized by the Schiff base condensation reaction of 1,3,5-tris (4-aminophenyl)benzene and 4,4-biphenyldicarboxaldehyde on the surface of amino-functionalized magnetic nanoparticles. Density–functional theory (DFT) calculations showed that adsorption of OPPs onto the surface of M-COF involved hydrophobic effects, Van der Waals interactions, π–π interactions, halogen-N bonding, and hydrogen bonding. Combined with gas chromatography–mass spectrometry (GC–MS) technology, the MSPE method features low limits of detection for OPPs (0.002–0.015 µg/L), good reproducibility (1.45%–6.14%), wide linear detection range (0.01–1 µg/L, R≥ 0.9935), and satisfactory recoveries (87.3%–110.4%). The method was successfully applied for the trace analysis of OPPs in spiked fruit juices.

Herein, a novel interference-free surface-enhanced Raman spectroscopy (SERS) strategy based on magnetic nanoparticles (MNPs) and aptamer-driven assemblies was proposed for the ultrasensitive detection of histamine. A core-satellite SERS aptasensor was constructed by combining aptamer-decorated Fe₃O₄@Au MNPs (as the recognize probe for histamine) and complementary DNA-modified silver nanoparticles carrying 4-mercaptobenzonitrile (4-MBN) (Ag@4-MBN@Ag-c-DNA) as the SERS signal probe for the indirect detection of histamine. Under an applied magnetic field in the absence of histamine, the assembly gave an intense Raman signal at “Raman biological-silent” region due to 4-MBN. In the presence of histamine, the Ag@4-MBN@Ag-c-DNA SERS-tag was released from the Fe₃O₄@Au MNPs, thus decreasing the SERS signal. Under optimal conditions, an ultra-low limit of detection of 0.65 × 10^-3 ng/mL and a linear range 10^-2–10⁵ ng/mL on the SERS aptasensor were obtained. The histamine content in four food samples were analyzed using the SERS aptasensor, with the results consistent with those determined by high performance liquid chromatography. The present work highlights the merits of indirect strategies for the ultrasensitive and highly selective SERS detection of small biological molecules in complex matrices.

This novel study identifies the effective anti-inflammatory phenolic compounds in dandelion and provides mechanistic insights into their interactions with receptor proteins (toll-like receptor 4, TLR4; co-receptor myeloid differentiation protein-2, MD-2) using UHPLC-ESI-MS/MS, lipopolysaccharide (LPS)-stimulated THP-1 cell line, fluorescence quenching and anisotropy, molecular docking (single ligand and multi-ligand docking) and molecular dynamics simulation. A 50% aqueous methanol extract had a greater anti-inflammatory effect and higher chicoric acid content, compared with the 100% water and 100% methanol extracts. Chicoric acid, chlorogenic acid, methylophiopogonone A, caffeic acid, gallic acid monohydrate and 4'-O-demethylbroussonin A had relatively high binding energies and contents in all extracts. Chicoric acid competed with chlorogenic acid, 4'-O-demethylbroussonin A and quercetin for MD-2. Among dandelion’s phenolics, chicoric acid most effectively hindered TLR4-MD-2 complex formation, with a quenching constant of 0.62 × 10⁶ L/mol for MD-2 or TLR4 at 320 K, and binding energies of -6.87 and -5.97 kcal/mol, respectively, for MD-2 and TLR4.

Two immunomodulatory polysaccharides (Vp2a-Ⅱ and Vp3) were isolated and identified from Apocynum venetum L. flowers, and their innate immune-stimulating functions and working mechanisms were evaluated in RAW264.7 cells. Both the level of released nitric oxide (NO) and expression of inducible nitric oxide synthase (iNOS) mRNA were significantly enhanced in the RAW264.7 macrophages cells treated by Vp2a-Ⅱ and Vp3. Vp2a-Ⅱ (100–800 µg/mL) and Vp3 (400 µg/mL) could significantly increase the phagocytic activity of RAW264.7 cells and the secretion and mRNA expression of TNF-α and IL-6 in a concentration-dependent manner through affecting mitogen-activated protein kinase (MAPK) activity and nuclear factor κB (NF-κB) nuclear translocation. Vp2a-Ⅱ might activate the MAPK signaling pathways and induce the nuclear translocation of NF-κB p65, whilst Vp3 likely activated the NF-κB and MAPK signaling pathways without influencing the p38 MAPK route.