Liling Hao

Based on dual-template molecular imprinting polymerization technology, a fluorescent molecularly imprinted polymer doped with CdSe/ZnS quantum dots was developed to construct a “Turn-on” fluorescence sensor for the rapid, sensitive, and specific detection of two biogenic amines. The biogenic amines bind to the quantum dots, which eliminates surface defects and enhances the fluorescence emission intensity of the quantum dots. By optimizing both the polymerization and detection processes, the results demonstrate that the sensor can detect biogenic amines within the range of 0.01–10 mmol/L, with a low detection limit of 14.57 μmol/L and a detection time of only ten minutes. Moreover, the sensor is cost-effective and does not require specialized instrument operation, offering a practical approach for the rapid detection of biogenic amines in complex food matrices. This study advances the development of simultaneous recognition and rapid detection technologies for multiple target molecules.

A novel electrochemical biosensor for the detection of lead ions (Pb²⁺) with improved specificity and sensitivity was developed. The sensor design incorporated molecular imprinting technology, where chitosan was polymerized on the electrode surface to form a lead-specific cavity structure, thereby enhancing selectivity in complex sample matrices. Meanwhile, the tetrahedral DNA nanostructure was employed as the recognition probe to mitigate the entanglement issues commonly associated with single-stranded DNA, thus improving the sensitivity of the detection. The developed sensor exhibited a linear dynamic range from 0.050 to 2.000 μg/mL, with a limit of detection (LOD) of 0.0034 μg/mL. The aptasensor’s efficacy was verified through the analysis of aquatic samples, demonstrating a high degree of reliability comparable to that of inductively coupled plasma mass spectrometry (ICP-MS). Graphical Abstract

Lead contamination is a major concern in food safety and, as such, many lead detection methods have been developed, especially aptamer-based biosensors. However, the sensitivity and environmental tolerance of these sensors require improvement. A combination of different types of recognition elements is an effective way to improve the detection sensitivity and environmental tolerance of biosensors. Here, we provide a novel recognition element, an aptamer-peptide conjugate (APC), to achieve enhanced affinity of Pb²⁺. The APC was synthesized from Pb²⁺ aptamers and peptides through clicking chemistry. The binding performance and environmental tolerance of APC with Pb²⁺ was studied through isothermal titration calorimetry (ITC); the binding constant (K_a) was 1.76*10⁶ M⁻¹, indicating that the APC’s affinity was increased by 62.96% and 802.56% compared with the aptamers and peptides, respectively. Besides, APC demonstrated better anti-interference (K⁺) than aptamer and peptide. Through the molecular dynamics (MD) simulation, we found that more binding sites and stronger binding energy between APC with Pb²⁺are the reasons for higher affinity between APC with Pb²⁺. Finally, a carboxyfluorescein (FAM)-labeled APC fluorescent probe was synthesized and a fluorescent detection method for Pb²⁺ was established. The limit of detection of the FAM-APC probe was calculated to be 12.45 nM. This detection method was also applied to the swimming crab and showed great potential in real food matrix detection. Graphical abstract

Four new indolyl diketopiperazines, aspamides A–E (1–4) and two new diketopiperazines, aspamides F–G (5–6), along with 11 known diketopiperazines and intermediates were isolated from the solid culture of Aspergillus versicolor, which is an endophyte with the sea crab (Chiromantes haematocheir). Further chiral high-performance liquid chromatography resolution gave enantiomers (+)- and (−)-4, respectively. The structures and absolute configurations of compounds 1–6 were determined by the comprehensive analyses of nuclear magnetic resonance (NMR), high-resolution mass spectrometry (HR-MS), and electronic circular dichroism (ECD) calculation. All isolated compounds were selected for the virtual screening on the coronavirus 3-chymoretpsin-like protease (Mpro) of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), and the docking scores of compounds 1–2, 5, 6, 8 and 17 were top among all screened molecules, may be helpful in fighting with Corona Virus Disease-19 (COVID-19) after further studies.

Six new depsidones, curdepsidones B–G (1–6), were obtained from the marine-derived fungus Curvularia sp. IFB-Z10. Their planar structures were determined by comprehensive analysis of HRESIMS and 1D/2D-NMR data. The absolute configuration of curdepsidones B–C (1–2) were established by synergistic use of DFT/NMR (density functional theory/nuclear magnetic resonance) and TDDFT/ECD (time-dependent density functional theory/electronic circular dichroism) calculations. Partial isolated compounds were tested for their anti-inflammatory activities in Propionibacterium acnes-induced THP-1 cells. Curdepsidone C (2) displayed significant anti-inflammatory properties with an IC₅₀ value of 7.47 ± 0.35 μM, and reduced the P. acnes-induced phosphorylation levels of JNK and ERK in a dose-dependent mechanism. The possible anti-inflammatory mechanism of 2 was also investigated by molecular docking.