Latest ArticlesNanomaterials provide an ideal platform for biomolecular display due to their dimensions approach the molecular scale, facilitating binding behavior akin to that observed in solution-based processes. DNA nanoprobes hold great promise as miniature detectives capable of detecting miRNAs within cells. However, current nanoprobes face a challenge in achieving the required precision for accurate miRNA detection, particularly within the intricate confines of the cellular microenvironment, due to interference with biological autofluorescence, off-target effects, and a lack of spatiotemporal control. Here, we have designed a dual-stimuli responsive DNA tracker, synergistically utilizing specific intracellular cues and external triggers, which enables spatiotemporal-controlled and precise detection and imaging of miRNAs "on demand". The tracker, which combines zeolitic imidazolate framework-67 (ZIF-67) and unique hairpin DNA structures, effectively anchored onto the ZIF-67 through electrostatic interactions, remains in a dormant state until activated by abundant cellular ATP, resulting in the release of the hairpin structures that include a PC linker incorporated into the loop region. Subsequent irradiation triggers specific recognition of the target miRNA. The newly developed HP-PC-BT@ZIF-67 tracker demonstrates precise spatiotemporal miRNA detection and exhibits excellent biocompatibility, enabling specific miRNA recognition "on demand" within cancer cells. This research presents a reliable miRNA imaging platform in the intricate cellular environment, opening up the possibilities for precise biomedical analysis and disease diagnosis.
Piperidine is a crucial pharmacophore and a special scaffold in the realm of drug discovery. Its flexibility increases the molecule's capability to bind to the receptor. The piperidine-containing compounds are distinguished by their remarkable activity, and are increasingly becoming a vital category of pesticides. In this review, the research progress of piperidines in the discovery of pesticides was updated according to their active characteristics. The structure-activity relationships (SARs), and mechanisms of action of piperidine-containing compounds were also discussed. This article is meant to enable readers to quickly understand piperidines, while providing ideas for creating piperidines with novel structures and unique mechanisms of action.
Early diagnosis and accurate boundary delineation are the key steps of tumor precision medicine. Circulating tumor cells (CTCs) detection of liquid biopsy can provide abundant information for early diagnosis of cancer. High detection specificity and good enrichment features are two key factors for CTCs accurate identification in peripheral blood sample. For this purpose, iron oxide (IO)-based surface-enhanced Raman scattering (SERS) bioprobes with good biocompatibility, high detection sensitivity, remarkable detection specificity, and good enrichment efficiency, were developed for detecting different types of CTCs. Magnetic SERS bioprobes combined with programmed death ligand-1 (PD-L1) antibody are regarded as an effective way to boost the targeting ability and detection specificity, benefiting for accurately capturing and identifying rare CTCs. Four types of CTCs with different PD-L1 expression were accurately distinguished among white blood cells via high-resolution SERS mapping images and stable Raman signals. Subsequently, CTCs blood samples obtained from the triple negative breast cancer patients were also successfully recognized compared to that of health people, indicating IO@AR@PDA-aPD-L1 SERS bioprobe possessed great potential for CTCs detection in liquid biopsy. Additionally, IO-based bioprobe exhibited excellent dual-modal imaging abilities of high-resolution SERS imaging mode and microimaging magnetic resonance imaging mode. These two highly complementary imaging modes endowed IO-based bioprobes unrivalled capacity in tumor boundary differentiation, supporting tumor accurate resection and precise surgery. To our best knowledge, this is the first time that biocompatible IO-based SERS bioprobes without noble metal element were reported not only for CTCs accurate detection, but also for precise tumor boundary delineation, showing great advantages in tumor diagnosis and treatment.
Poly(butylene adipate-terephthalate) (PBAT), as one of the most common and promising biodegradable plastics, has been widely used in agriculture, packaging, and other industries due to its strong biodegradability properties. It is well known that PBAT suffers a series of natural weathering, mechanical wear, hydrolysis, photochemical transformation, and other abiotic degradation processes before being biodegraded. Therefore, it is particularly important to understand the role of abiotic degradation in the life cycle of PBAT. Since the abiotic degradation of PBAT has not been systematically summarized, this review aims to summarize the mechanisms and main factors of the three major abiotic degradation pathways (hydrolysis, photochemical transformation, and thermochemical degradation) of PBAT. It was found that all of them preferentially destroy the chemical bonds with higher energy (especially C-O and C=O) of PBAT, which eventually leads to the shortening of the polymer chain and then leads to reduction in molecular weight. The main factors affecting these abiotic degradations are closely related to the energy or PBAT structure. These findings provide important theoretical and practical guidance for identifying effective methods for PBAT waste management and proposing advanced schemes to regulate the degradation rate of PBAT.
The contamination of water resources by phenolic compounds (PCs) presents a significant environmental hazard, necessitating the development of novel materials and methodologies for effective mitigation. In this study, a metallic copper-doped zeolitic imidazolate framework was pyrolyzed and designated as Cu-NC-20 for the activation of peroxymonosulfate (PMS) to degrade phenol (PE). Cu-NC-20 could effectively address the issue of metal agglomeration while simultaneously diminishing copper dissolution during the activation of PMS reactions. The Cu-NC-20 catalyst exhibited a rapid degradation rate for PE across a broad pH range (3–9) and demonstrated high tolerance towards coexisting ions. According to scavenger experiments and electron paramagnetic resonance analysis, singlet oxygen (1O2) and high-valent copper-oxo (Cu(Ⅲ)) were the predominant reactive oxygen species, indicating that the system was nonradical-dominated during the degradation process. The quantitative structure-activity relationship (QSAR) between the oxidation rate constants of various substituted phenols and Hammett constants was established. It indicated that the Cu-NC-20/PMS system had the optimal oxidation rate constant with σ− correlation and exhibited a typical electrophilic reaction pattern. This study provides a comprehensive understanding of the heterogeneous activation process for the selective removal of phenolic compounds.
Membrane distillation (MD) has gained extensive attention for treating highly saline wastewater. However, membrane scaling during the MD process has hindered the rapid development of this technology. Current approaches to mitigate scaling in membrane distillation focus primarily on achieving enhanced hydrophobicity and even superhydrophobicity via utilizing fluorinated fibrous membrane or introducing perfluorosilane modification. Considering the environmental hazards posed by fluorinated compounds, it is highly desirable to develop non-fluorinated membranes with enhanced anti-scaling properties for effective membrane distillation. In this study, we present a non-fluorinated liquid-like MD membrane with exceptional anti-scaling performance. This membrane was facilely fabricated by grafting linear polydimethylsiloxane (LPDMS) onto a hydrophilic polyether sulfone (PES) membrane pre-coated with the intermediate layers of polydopamine and silica (denoted as LPDMS-PES). Remarkably, LPDMS-PES manifested a drastically improved scaling resistance in continuous MD tests than its perfluorinated counterpart, i.e., 1H,1H,2H,2H-perfluorooctyltrichlorosilane-modified PES membrane (PFOS-PES), in both heterogeneous nucleation-dominated and crystal deposition-dominated scaling processes, despite the latter having a smaller surface energy. LPDMS-PES demonstrated a reduction of crystal accumulation of approximately 85% for NaCl and 73% for CaSO4 in the heterogeneous nucleation-dominated scaling process compared to PFOS-PES. Additionally, in the crystal deposition-dominated scaling process LPDMS-PES exhibited a reduction of about 70% in scale accumulation. These results explicitly evidenced the great potential of the liquid-like membrane to minimize scaling in membrane distillation by inhibiting both scale nucleation and adhesion onto the membrane. We believe the findings of this study have important implications for the design of high-performance MD membranes, particularly in the quest for environmentally sustainable alternatives to perfluorinated materials.
Deep learning neural network incorporating surface enhancement Raman scattering technique (SERS) is becoming as a powerful tool for the precise classifications and diagnosis of bacterial infections. However, the large amount of sample requirement and time-consuming sample collection severely hinder its applications. We herein propose a spectral concatenation strategy for residual neural network using non-specific and specific SERS spectra for the training data augmentation, which is accessible to acquiring larger training dataset with same number of SERS spectra or same size of training dataset with fewer SERS spectra, compared with pure non-specific SERS spectra. With this strategy, the training loss exhibit rapid convergence, and an average accuracy up to 100% in bacteria classifications was achieved with 50 SERS spectra for each kind of bacterium; even reduced to 20 SERS spectra per kind of bacterium, classification accuracy is still > 95%, demonstrating marked advantage over the results without spectra concatenation. This method can markedly improve the classification accuracy under fewer samples and reduce the data collection workload, and can evidently enhance the performance when used in different machine learning models with high generalization ability. Therefore, this strategy is beneficial for rapid and accurate bacteria classifications with residual neural network.
Inactivation of carbon-based transition metal catalysts, which was caused by electron loss, limited their application in advanced oxidation processes. Therefore, Co and TiO2 double-loaded carbon nanofiber material (Co@CNFs-TiO2) was synthesized in this study. Photocatalytic and chemical catalytic systems were synergized efficiently. Tetracycline was eliminated within 15 min. The degradation rate remained above 90% after five cycles, and the 50% promotion proved the high stability of Co@CNFs-TiO2. The main reactive oxygen species in this system were sulfate radicals, whereas Co and TiO2 represented the active sites of the catalytic reaction. Electrons generated from TiO2 during the photocatalytic process were transferred to Co, which promoted the Co(Ⅲ)/Co(Ⅱ) cycle and maintained Co in a low-valence state, thereby stimulating the generation of sulfate radicals. In this study, the effective regulation of reactive oxygen species in the reaction system was realized. The results provided a guidance for in situ electron replenishment and regeneration of carbon-based transition metal catalysts, which will expand the practical application of advanced oxidation processes.
An ionic liquid assisted hydrogel modified silica was synthesized using a one-pot polymerization and physical coating technique and subsequently applied to mixed-mode liquid chromatography. Analytical techniques, including Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and elemental analysis, etc., confirmed the successful prepared of this innovative stationary phase. The unique combination of amide, long alkyl chain, and imidazole ring in the hydrogel coating enables the stationary phase to function effectively in hydrophilic/reversed-phase/ion exchange liquid chromatography. Notably, the stationary phase exhibited superior separation performance owing to the synergistic effect of the ionic liquid and hydrogel. This was particularly evident when analyzing various analytes such as organic acids, nucleosides/bases, polycyclic aromatic hydrocarbons (PAHs) and anions. Furthermore, under our operating conditions, an excellent column efficiency of 53, 642.9 plates/m was achieved for theobromine. In summary, we have proposed a straightforward strategy to enhance the separation performance of hydrogel coatings in liquid chromatography, thereby broadening the potential applications of hydrogels in the field of separation.
Selenium is one of the important trace elements in the human body. Its deficiency will directly affect human health. With people's attention to health, the content of selenium in food has gradually attracted attention. However, detecting selenium compounds in complex samples remains a challenge. In this work, we built an online heating-reaction device. This device combines the electrospray extraction ionization mass spectrometry (EESI-MS) with the heating reaction device, which can simultaneously detect various selenium compounds in complex liquid samples. Under acidic conditions, the sample was heated and catalyzed by a heating reaction device, so that the SeO32− and O-phenylenediamine (OPD) could generate 1,3-dihydro-2,1,3-benzoselenadiazole. Based on the above reactions, we can detect organic selenium, inorganic selenium and other compounds in liquid samples by organic mass spectrometry. In this experiment, we determined the content of three forms of selenium: selenomethionine (SeMet), l-selenocystine (SeCys(2)), and sodium selenite. The calibration curves for SeMet, SeCys(2), and sodium selenite showed strong linearity within a range of 0.50–50.00 µg/L. The limits of detection (LOD) for the three compounds were 0.22, 0.27, and 0.41 µg/L, respectively. The limits of quantification (LOQ) were 0.68, 0.81, and 1.23 µg/L, respectively. Spiked recoveries at three levels ranged from 98.8% to 106.1%. In addition, this method can simultaneously detect three selenium compounds and three other specific chemical components in tea infusion samples, providing a rapid and efficient method for identifying tea quality.
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