Ratiometric luminescent simultaneous sensing of aristolochic acids (I-IV) by a novel metal-organic framework and its nanowire.

Aristolochic acids (AAs), which are a group of nitrophenanthrene carboxylic acids formed by Aristolochia plant, have become an increasing serious threat to humans due to their nephrotoxicity and carcinogenicity. Fast and accurate approaches capable of simultaneous sensing of aristolochic acids (I-IV) are vital to avoid intake of such compounds. In this research, the novel ratiometric fluorescence zinc metal-organic framework and its nanowire have been prepared. The two different coordination modes (tetrahedral configuration and twisted triangular bipyramidal configuration) within zinc metal-organic framework lead to the significant double emissions. The ratiometric fluorescence approach based on nanowire provides a broader concentration range (3.00 × 10-7~1.00 × 10-4 M) and lower limit of detection (3.70 × 10-8 M) than that based on zinc metal-organic framework (1.00 × 10-6~1.00 × 10-4 M, 5.91 × 10-7 M). The RSDs of the results are in the range 1.4-3.5% (nanowire). The density functional theory calculations and UV-Vis absorption verify that the sensing mechanism is due to charge transfer and energy transfer. Excellent spiked recoveries for AAs(I-IV) in soil and water support that nanowire is competent to simultaneously detect these targets in real samples, and the proposed approach has potential as a fluorescence sensing platform for the simultaneous detection of AAs (I-IV) in complex systems.

Bipyridine-linked three-dimensional covalent organic frameworks for fluorescence sensing of cobalt(II) at nanomole level.

A novel fluorometric method based on bipyridine-linked three-dimensional covalent organic frameworks (COFs) was developed for the determination of Co2+. The COFs were synthesized by the polyreaction of tetrakis(4-aminophenyl)methane (TAPM), 2,2'-bipyridine-5,5'-diamine (Bpy), and 4,4'-biphenyldicarboxaldehyde (BPDA) under solvothermal conditions. The fluorescence of the COFs, with excitation/emission peaks at 324/406 nm, is quenched by Co2+. Under the optimal conditions, the fluorescence quenching degrees (F0-F) of the resulted COFs linearly enhance as the concentrations of Co2+ increase in the range 0.01 to 0.25 µM, and a limit of detection of 2.63 nM is achieved. The fluorescence response mechanism was discussed in detail. This proposed approach has also been successfully employed to determine Co2+ in complex samples (shrimp and tap water), and satisfactory recoveries (88.1 ~ 109.7%) was obtained. The relative standard deviations are below 4.9%.

Genetic Variations at rs3129891 and rs77005575 are Associated With Reduced Expression of Enteric α-defensins in IBD Patients.

BACKGROUND AND AIMS: Human enteric antimicrobial peptides composed predominantly of human enteric α-defensins (HD5 and HD6) are important in the mucosal antimicrobial barrier. Previous studies have identified that genetic variations at rs2066844, rs2066845, rs2066847 are associated with diminished enteric α-defensins in ileal Crohn's disease (CD). However, genetic variations associated with enteric antimicrobial peptides in colonic inflammatory bowel disease (IBD) remain unclear. To investigate it, we compared the colonic expression of antimicrobial peptides with respect to genotypes at 22 IBD-associated single-nucleotide polymorphisms (SNPs). MATERIALS AND METHODS: In total, 16 controls and 102 colonic IBD patients including 42 ulcerative colitis (UC) and 60 CD were studies. Mutation assay was performed to determine their genotypes at 22 IBD-associated SNPs. Real-time PCR was performed to determine the colonic mRNA expression of HD5, HD6, lysozyme, and secretory phospholipase A2. RESULTS: Mutant genotypes at rs2066844, rs2066845, rs2066847 were not found, and only SNPs rs3129891 and rs77005575 were associated with enteric α-defensin expression in colonic IBD. In both inflamed and noninflamed tissues, colonic expression of HD5 and HD6 was significantly decreased in UC and CD patients carrying rs3129891 homozygous mutant genotype. And their colonic expression was significantly decreased in inflamed but not noninflamed tissues from UC patients carrying rs77005575 homozygous mutant genotype. However, both lysozyme and secretory phospholipase A2 in UC and CD were unaffected by rs3129891 and rs77005575 genotypes. CONCLUSIONS: As enteric α-defensins play critical roles in the mucosal antimicrobial barrier, their reduced expression may partly explain the microbial-induced mucosal inflammation in colonic IBD patients, especially in patients carrying rs3129891 and rs77005575 mutant genotypes.

Surface chemistry modified upconversion nanoparticles as fluorescent sensor array for discrimination of foodborne pathogenic bacteria.

BACKGROUND: The identification of foodborne pathogenic bacteria types plays a crucial role in food safety and public health. In consideration of long culturing times, tedious operations and the desired specific recognition elements in conventional methods, the alternative fluorescent sensor arrays can offer a high-effective approach in bacterial identification by using multiple cross-reactive receptors. Herein, we achieve this goal by constructing an upconversion fluorescent sensor array based on anti-stokes luminogens featuring a series of functional lanthanide-doped upconversion nanoparticles (UCNPs) with phenylboronic acid, phosphate groups, or imidazole ionic liquid. The prevalent spotlight effect of microorganism and the electrostatic interaction between UCNPs and bacteria endow such sensor array an excellent discrimination property. RESULTS: Seven common foodborne pathogenic bacteria including two Gram-positive bacteria (Staphylococcus aureus and Listeria monocytogenes) and five Gram-negative bacteria (Escherichia coli, Salmonella, Cronobacter sakazakii, Shigella flexneri and Vibrio parahaemolyticus) are precisely identified with 100% accuracy via linear discriminant analysis (LDA). Furthermore, blends of bacteria have been identified accurately. Bacteria in real samples (tap water, milk and beef) have been effectively discriminated with 92.1% accuracy. CONCLUSIONS: Current fluorescence sensor array is a powerful tool for high-throughput bacteria identification, which overcomes the time-consuming bacteria culture and heavy dependence of specific recognition elements. The high efficiency of whole bacterial cell detection and the discrimination capability of life and death bacteria can brighten the application of fluorescence sensor array.

Fluorometric determination of tyramine by molecularly imprinted upconversion fluorescence test strip.

A fluorometric method based on molecularly imprinted upconversion fluorescence test strip was developed for the determination of tyramine. It exploited the green fluorescence of upconversion nanoparticles (UCNPs) and the specific recognition property of molecularly imprinted polymers (MIPs). UCNPs were attached to filter paper with glue, and MIPs were prepared via in situ polymerization on the surface of UCNPs by using tyramine as template, methacrylic acid as functional monomer, and ethylene glycol dimethacrylate as cross-linker. The green fluorescence of the test strip, with excitation/emission wavelength 980/550 nm, was enhanced by tyramine. The test strip was suitable for the determination of tyramine in the linear range 1.0-100.0 mg L-1, and a relatively low limit of detection (0.2 mg L-1) was achieved. The test strip also worked well for the quantitation of tyramine in spiked red wine and mature vinegar. Recoveries are ranged from 84.9 to 99.9%. The relative standard deviations are below 5.6%. Graphical abstract.

Fluorometric determination of fipronil by integrating the advantages of molecularly imprinted silica and carbon quantum dots.

A fluorometric method is described for the determination of fipronil, a frequently-used insecticide. It exploits the blue fluorescence of carbon quantum dots (CQDs) and the selectivity of molecularly imprinted silica (MIS). The MIS was prepared via the sol-gel method by using fipronil as the template, 3-aminopropyltriethoxysilane as functional monomer, and tetraethoxysilane as cross-linker in the presence of CQDs. The blue fluorescence of the CQD@MIS, with excitation/emission peaks at 340/422 nm, is quenched by fipronil. The assay works in the 0. 70 pM to 47 µM fipronil concentration range, and the limit of detection is 19 pM. The method was successfully applied to the quantitation of fipronil in spiked eggs, milk, and tap water. Recoveries between 83.8 and 114.0% were achieved. The corresponding relative standard deviations (RSD) are less than 6.67%. Graphical abstractSchematic representation of a high sensitivite and selectivite fluorescence nanoprobe constructed by combining the excellent fluorescence property of carbon quantum dots and the predicted selectivity of molecularly imprinted silica. It was applied to analyze fipronil in egg, milk and tap water, respectively.

MiR-218 regulates epithelial-mesenchymal transition and angiogenesis in colorectal cancer via targeting CTGF.

BACKGROUND: Endothelial-to-mesenchymal transition (EMT) and angiogenesis play important roles in colorectal cancer (CRC) development. Connective tissue growth factor (CTGF) has been reported to promote several kinds of cancer progression and miR-218 has been identified as a tumor suppressor miRNA. However, little is known about the function of miR-218 in CRC. Here we investigated the effects of miR-218 on EMT and angiogenesis process in CRC cells. As well, the relation between miR-218 and CTGF was identified. The mechanism of miR-218's function was illustrated. METHODS: CRC cell lines were transfected with miR-218 mimics. Proliferation, migration and angiogenesis were identified by MTT assay, Transwell assay, colony formation assay and tube formation assay. Protein and mRNA expression levels of associated genes were measured by Western blotting and RT-PCR. Dual luciferase assay was used to determine the relation of miR-218 and CTGF. RESULTS: miR-218 was down-regulated in CRC cell lines and over expression of miR-218 could significantly inhibit EMT and angiogenesis. CTGF was a direct target of miR-218. Up regulation of CTGF level after miR-218 transfection could sufficiently rescue the suppression effects on EMT and angiogenesis. CONCLUSION: miR-218 directly targets CTGF and inhibits its expression, leading to suppression on EMT and angiogenesis of CRC cells. miR-218 might be used as potential therapeutic strategy for CRC treatment.

Capillary electrochromatography immunoassay for alpha-fetoprotein based on poly(guanidinium ionic liquid) monolithic material.

Alpha-fetoprotein (AFP) is widely used as a tumor marker for the serum diagnosis of primary hepatoma. Sensitive detection of AFP level plays an important role in the early diagnosis of disease and highly reliable prediction. In this study, a novel non-competitive immunoassay (IA) based on poly(guanidinium ionic liquid) monolithic material was developed for detecting ultra trace levels of AFP in capillary electrochromatography (CEC) mode. The AFP was mixed with an excess amount of fluorescently labeled antibody. After incubation, the immunocomplex was separated from the free labeled antibody and detected by CEC coupled with laser-induced fluorescence detector. Under the optimized conditions, the developed CEC-IA performed a low detection limit of 0.05 µg L-1 (S/N = 3) and a wide linearity ranging from 0.1 to 1000 µg L-1 for AFP, which can be largely attributed to the high separation and enrichment efficiency of poly(guanidinium ionic liquid) monolithic material for the targets. The application of this method was demonstrated by determining AFP in human serum.

Facile preparation of organic-inorganic hybrid polymeric ionic liquid monolithic column with a one-pot process for protein separation in capillary electrochromatography.

An organic-inorganic hybrid monolithic column based on 1-vinyl-3-dodecylimidazolium bromide (VC12Im(+)Br(-)) has been prepared in a single step by combining radical copolymerization with a non-hydrolytic sol-gel (NHSG) process. The NHSG process was significantly shortened to 6 h by using formic acid as catalyst. For comparison, we also prepared polymeric ionic liquid (PIL) monolithic columns by hydrolytic sol-gel and organic polymeric process, respectively. The resulting monolithic columns were characterized by Fourier transform infrared spectra, scanning electron microscopy, and Brunauer-Emmett-Teller. Under the capillary electrochromatography mode, these columns were applied to separate alkylbenzenes, anilines, and proteins, respectively. The results indicated that the NHSG-based hybrid PIL monolithic column exhibited the highest column efficiency among the three types of columns; organic solvent, commonly required by the traditional columns to achieve satisfactory separation efficiency for proteins, was absent in the NHSG-based hybrid PIL monolithic column because of the biocompatibility of the VC12Im(+)Br(-), which was beneficial to analysis of protein containing samples. In order to demonstrate its application potential, the developed NHSG-based hybrid PIL monolithic column was also employed to separate egg white sample.

Polyphenols functionalized MOF encapsulated BPQDs for synergistic photothermal/photodynamic antibacterial properties and multifunctional food preservation.

Active antibacterial materials play an important role in solving food safety problems caused by pathogen contamination. In this study, a composite active antibacterial material with the synergistic antibacterial effectiveness of photothermal, photodynamic and the surface charge of polyphenols was developed, where the multi-porous polyphenol functionalized metal-organic frameworks (ZIF-8-TA) were used as the framework carrier, and black phosphorus quantum dots (BPQDs) were used as the photosensitive source. The resulted ZIF-8-TA/PBQDs possesses excellent photothermal conversion efficiency (27.92%), photodynamic performance and surface charge, and these factors ensure the outstanding broad-spectrum antibacterial performance (100%). Multifunctional characteristics and excellent biocompatibility endow the materials with vast potential for foodstuff packaging. The results showed that the composite antibacterial film produced by doping ZIF-8-TA/PBQDs into chitosan could effectively prolong the shelf life of foodstuff compared with commercial membrane. The successful implementation of this research provides a new idea for controlling microbial contamination and developing multifunctional antibacterial materials.

Fluorescence sensing of water in various organic solvents based on a novel cyclic polymer.

A sensor capable of sensing of water in various organic solvents ranging from water-soluble to water-miscible solvents is still a challenging task. In this research, a cyclic polymer fluorescence chemosensor (CPFC) has been developed for sensing of water by turn-on model in 9 organic solvents and turn-off model in DMA, where the broadest concentration range and the lowest detection limit was obtained for water in DMA (10 %-90 %) and dioxane (0.011 %), respectively. The sensing mechanism is explored by theory calculation and experimental investigation. The amphiphilic nature endows the polymer probe with great potential for measuring various contaminants from aqueous and nonaqueous mediums. Furthermore, the present search highlights the potential applications of cyclic polymer as fluorescence probes in the field of sensing.

Bibliometric analysis and evaluation of publications on non-Helicobacter pylori helicobacters from 1993 to 2023.

Aim: A bibliometric analysis and evaluation of research on non-Helicobacter pylori Helicobacter species (NHPHs) is essential to determining future research directions. Materials & methods: A comprehensive search was carried out using predetermined search terms within the Web of Science Core Collection (WoSCC) to gather publications spanning from 1993 to 2023. VOSviewer and Citespace were employed for data analysis and visualization. Results: 308 publications on NHPHs were included. Among these, gastric NHPHs received more publications and attention compared with enterohepatic NHPHs. Key findings included the identification of most productive countries, institutions, journals, authors, keywords, research trends and notable perspectives in the field. Conclusion: The article guides further research and clinical applications on NHPHs.

Highly selective fluorescent sensing of proteins based on a fluorescent molecularly imprinted nanosensor.

A fluorescent molecularly imprinted nanosensor was obtained by grafting imprinted polymer onto the surface of multi-wall carbon nanotubes and post-imprinting treatment with fluorescein isothiocyanate (FITC). The fluorescence of lysozyme-imprinted polymer (Lys-MIP) was quenched more strongly by Lys than that of nonimprinted polymer (NIP), which indicated that the Lys-MIP could recognize Lys. The resulted imprinted material has the ability to selectively sense a target protein, and an imprinting factor of 3.34 was achieved. The Lys-MIP also showed selective detection for Lys among other proteins such as cytochrome C (Cyt C), hemoglobin (HB) and bovine serum albumin (BSA) due to the imprinted sites in the Lys-MIP. This approach combines the high selectivity of surface molecular imprinting technology and fluorescence, and converts binding events into detectable signals by monitoring fluorescence spectra. Therefore, it will have further applications for Lys sensing.

Determination of metolcarb in food by capillary electrophoresis immunoassay with a laser-induced fluorescence detector.

A capillary electrophoresis immunoassay (CEIA) was developed for the determination of trace metolcarb (MTMC) in food. The method was based on the competitive reactions between fluorescently labeled MTMC tracer and free MTMC with a limited amount of anti-MTMC antibody and the separation and determination by CE with LIF detector. A fluorescent reagent, FITC was labeled on MTMC to construct an immunofluorescent probe. CEIA experimental parameters such as the pH value and concentration of the running buffer and separation voltage as well as incubation time were systematically investigated. Under the optimized conditions, fluorescently labeled antigen and antibody bound could be well separated within 3 min using Na2B4O7/NaH2PO4 buffer (20:10 mmol/L, pH 9.0) for background electrolyte, 20 kV for the separation voltage, and 20°C for the column temperature. The linear range of the method was 0.25-50.0 µg/L with LOD 0.07 µg/L. The RSD for relative migration time and relative fluorescence intensity ratio were 2.90% (intraday) and 4.73% (intraday), respectively. The proposed method has been applied to determine the residue of MTMC in food samples with the satisfactory recovery.

PAK1-dependent MAPK pathway activation is required for colorectal cancer cell proliferation.

P21-activated protein kinase1 (PAK1), a main downstream effector of small Rho GTPases, Rac1, and Cdc42, plays an important role in the regulation of cell morphogenesis, motility, mitosis, and angiogenesis. Despite its importance, the molecular mechanisms of PAK1 that contributed to colorectal carcinogenesis remain unclear. Our immunohistochemistry showed that PAK1 expression was increased with colorectal cancer (CRC) progression through the adenoma to carcinoma sequence. Furthermore, our results suggested a relationship between PAK1 nuclear localization and the Dukes staging. In the present study, we showed that PAK1 knockdown decreased proliferation and delayed the G1/S cell-cycle transition, and increased apoptosis in vivo and in vitro. In addition, PAK1 knock-down downregulated c-Jun amino terminal kinases (JNK) activity and the levels of cyclinD1, CDK4/6. Inhibition of the JNK activity by chemical inhibitor (SP600125) significantly reduced the effects of PAK1 on CRC proliferation via accumulation of phosphatase and tensin homolog deleted on chromosome 10 (PTEN). In conclusion, our results demonstrate that knockdown of PAK1 could enhance the chemosensitivity of CRCs to 5-fluorouracil through G1 arrest. The mechanism by which PAK1 induced cancer growth might involve activation of JNK as well as downregulation of PTEN. Targeting PAK1 may represent a novel treatment strategy for developing novel chemotherapeutic agents.

Highly selective capture of phosphopeptides using a nano titanium dioxide-multiwalled carbon nanotube nanocomposite.

In this study, a titanium dioxide-multiwalled carbon nanotube (TiO2-MWNT) nanocomposite was first used to enrich phosphopeptides as a binding agent. The TiO2-MWNT nanocomposite was synthesized by the hydrothermal reaction process and characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR), and X-ray powder diffraction (XRD). The results demonstrated that the anatase phase TiO2 nanoparticles had been successfully linked by MWNTs. The TiO2-MWNT nanocomposite was applied as a sorbent to enrich phosphopeptides, and the results showed that the performance of the TiO2-MWNT nanocomposite was better than 5 µm TiO2, as confirmed by the analysis of phosphopeptides from a tryptic digest of a standard protein (ß-casein and bovine serum albumin) using high-performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS). The use of lactic acid in the loading buffer significantly enhances the selectivity of the TiO2-MWNT nanocomposite. This nanocomposite material was further applied to enrich the phosphopeptides in a protein digest obtained from nonfat milk successfully.

Fluorescence sensor based on molecularly imprinted polymers and core-shell upconversion nanoparticles@metal-organic frameworks for detection of bovine serum albumin.

A novel strategy for sensing protein was proposed through combining the high selectivity of molecular imprinting technology with the excellent upconversion fluorescence of upconversion nanoparticles (UCNPs) and high specific surface area of metal-organic frameworks (MOFs). Herein, the UCNPs acted as signal reporter and MOFs were introduced to increase the rate of mass transfer. The UCNPs@MIL-100 as support material was prepared via a step-by-step method. The imprinted material-coated UCNPs@MIL-100 (UCNPs@MIL-100@MIPs) were obtained by sol-gel technique. The results showed that as the increase of the template protein concentration, the fluorescence intensity of UCNPs@MIL-100@MIPs quenched gradually, and the imprinting factor was 2.90. The linear in the range of 1.00 to 8.00 µM, and the detection limit was 0.59 µM. Therefore, the novel optosensing material is very promising for future applications.

Enhancement of inhibition rate of antibiotic against bacteria by molecularly imprinted nanoparticles targeting alarmone nucleotides as antibiotic adjuvants.

Antibiotic tolerance and resistance in bacteria have caused a great threat to humankind. Bacteria can rapidly accumulate alarmone nucleotides (guanosine tetra- and pentaphosphate, usually denoted as (p)ppGpp) to repair damaged DNA under adverse conditions. The inhibition synthetase enzyme activity of (p)ppGpp, indirectly preventing synthesis, or promoting degradation, has been reported; however, transferring these strategies to practical applications is still a challenging task due to the lack of highly effective molecules for these purposes. Here, an approach based on molecularly imprinted polymer nanoparticles (MIP-NPs) as antibiotic adjuvants was proposed, where MIP-NPs with specific recognition sites were used to capture alarmone nucleotides released by bacteria during stringent response activation. Enhanced inhibition rates of 40-80% were achieved in the presence of the MIP-NPs. The dose of antibiotic could be greatly reduced by utilizing the MIP-NPs as adjuvants for a similar deactivation effectiveness. Good biocompatibility (no obvious hemolysis or cytotoxic effects) and apparent antimicrobial efficiency for resisting wound infection in vivo support the fact that well-designed MIP-NPs have a bright future in dealing with the growing threat of antibiotic tolerance and resistance.

Synthesis of Magnetic Ferrocene-Containing Polymer with Photothermal Effects for Rapid Degradation of Methylene Blue.

Photothermal materials are attracting more and more attention. In this research, we synthesized a ferrocene-containing polymer with magnetism and photothermal properties. The resulting polymer was characterized by Fourier-transform infrared (FT-IR), vibrating sample magnetometer (VSM), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Its photo-thermocatalytic activity was investigated by choosing methylene blue (MB) as a model compound. The degradation percent of MB under an irradiated 808 nm laser reaches 99.5% within 15 min, and the degradation rate is 0.5517 min-1, which is 145 times more than that of room temperature degradation. Under irradiation with simulated sunlight, the degradation rate is 0.0092 min-1, which is approximately 2.5 times more than that of room temperature degradation. The present study may open up a feasible route to degrade organic pollutants.

Black Phosphorus Nanosheet Encapsulated by Zeolitic Imidazole Framework-8 for Tumor Multimodal Treatments.

Black phosphorus (BP) nanosheet is easily oxidized by oxygen and water under ambient environment, thus, reliable BP passivation techniques for biomedical applications is urgently needed. A simple and applicable passivation strategy for biomedical applications was established by encapsulating BP nanosheet into zeolitic imidazole framework-8 (ZIF-8). The resulted BP nanosheet in ZIF-8 (BP@ZIF-8) shows not only satisfied chemical stability in both water and phosphate buffered saline (PBS), but also excellent biocompatibility. Notably, BP nanosheet endows the prepared BP@ZIF-8 with prominent photothermal conversion efficiency (31.90%). Besides passivation BP, ZIF-8 provides the BP@ZIF-8 with high drug loading amount (1353.3 mg g-1). Moreover, the loaded drug can be controlled release by pH stimuli. Both in vitro and in vivo researches verified the resulted BP@ZIF-8 an ideal candidate for tumor multimodal treatments.