A dual-recognition strategy based on pH-responsive molecularly imprinted membrane for highly selective capture of catecholamines: From construction to practical application.

BACKGROUND: Catecholamines (CAs) are involved in a wide range of physiological and pathological processes in the body and are progressively being used as important biomarkers for a variety of diseases. It is of great significance for accurate quantification of CAs to the diagnosis and treatment of diseases. However, the separation of CAs from complex biological matrices is still a great challenge due to the trace levels of CAs and the limited selectivity of existing pretreatment methods. RESULTS: In this work, a dual-recognition imprinted membrane (BA-MIM) was developed to utilize the synergistic action of pH-responsive boron affinity and molecular imprinted cavities for highly selective capture and release of CAs. The prepared BA-MIM possessed remarkable adsorption capacity (maximum capacity, 43.3 mg g-1), desirable surface hydrophilicity (46.2°), superior selectivity (IF = 6.2, α = 14.3), as well as favorable reusability (number of cycles, 6 times). On this basis, an integrated analytical method based on BA-MIM extraction combined with ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was innovatively developed to highly selective separation, enrichment, and detection of CAs in rat brain tissue. Under the optimum conditions, a low quantitation limits (0.05-0.10 ng mL-1), wide linear range (10-1000 ng mL-1), good linearity (r2 > 0.99), and satisfactory recoveries (88.5%-98.5 %) were obtained for CAs. The proven method was further applied to kidney-yang-deficiency-syndrome (KYDS) group rat model, revealed the intrinsic connection between kidney disease and catecholamine metabolism. SIGNIFICANCE: This work provides an excellent reference paradigm for the effective construction of dual-recognition functional membrane material to the high-selective analysis of trace targets in complex matrices. Additionally, this integrated analytical strategy demonstrates its efficiency, sustainability, versatility, and convenience, showing remarkable prospect in a variety of applications for biological sample analysis.

Preparation of deep eutectic solvent modified magnetic graphene oxide/metal organic framework nanocomposites for the extraction of three estrogens in cosmetics.

A novel magnetic dispersive solid phase extraction (MDSPE) procedure based on the deep eutectic solvent (DES) modified magnetic graphene oxide/metal organic frameworks nanocomposites (MGO@ZIF-8@DES) was established and used for the efficient enrichment of estradiol, estrone, and diethylstilbestrol in cosmetics (toner, lotion, and cream) for the first time. Then, the three estrogens were separated and determined by UHPLC-UV analysis method. In order to study the features and morphology of the synthesized adsorbents, various techniques such as FT-IR, SEM, and VSM measurements were executed. The MGO@ZIF-8@DES nanocomposites combine the advantages of high adsorption capacity, adequate stability in aqueous solution, and convenient separation from the sample solution. To achieve high extraction recoveries, the Box-Behnken design and single factor experiment were applied in the experimental design. Under the optimum conditions, the method detection limits for three estrogens were 20-30 ng g-1. This approach showed a good correlation coefficient (r more than 0.9998) and reasonable linearity in the range 70-10000 ng g-1. The relative standard deviations for intra-day and inter-day were beneath 7.5% and 8.9%, respectively. The developed MDSPE-UHPLC-UV method was successfully used to determine  three estrogens in cosmetics, and acceptable recoveries in the intervals of 83.5-95.9% were obtained. Finally, three estrogens were not detected in some cosmetic samples. In addition, the Complex GAPI tool was used to evaluate the greenness of the developed pretreatment method. The developed MDSPE-UHPLC-UV method is sensitive, accurate, rapid, and eco-friendly, which provides a promising strategy for determining hormones in different complex samples.

Integrated untargeted and targeted testicular metabolomics to reveal the regulated mechanism of Gushudan on the hypothalamic-pituitary-gonadal axis of kidney-yang-deficiency-syndrome rats.

Modern studies have shown that neuroendocrine disorders caused by the dysfunction of the hypothalamic-pituitary-gonadal (HPG) axis are one of the important pathogenetic mechanisms of kidney-yang-deficiency-syndrome (KYDS). The preventive effect of Gushudan on KYDS has been reported, but its regulatory mechanisms on the HPG axis have not been elucidated. In this study, we developed an integrated untargeted and targeted metabolomics analysis strategy to investigate the regulatory mechanism of Gushudan on the HPG axis in rats with KYDS. In untargeted metabolomics, we screened 14 potential biomarkers such as glycine, lysine, and glycerol that were significantly associated with the HPG axis. To explore the effect of changes in the levels of potential biomarkers on KYDS, all of them were quantified in targeted metabolomics. With the quantitative results, correlations between potential biomarkers and testosterone, a functional indicator of the HPG axis, were explored. The results showed that oxidative stress, inflammatory response, and energy depletion, induced by metabolic disorders in rats, were responsible for the decrease in testosterone levels. Gushudan improves metabolic disorders and restores testosterone levels, thus restoring HPG axis dysfunction. This finding elucidates the special metabolic characteristics of KYDS and the therapeutic mechanism of Gushudan from a new perspective.

Multi-strain probiotics ameliorate Alzheimer's-like cognitive impairment and pathological changes through the AKT/GSK-3ß pathway in senescence-accelerated mouse prone 8 mice.

BACKGROUND: Alzheimer's disease (AD), the most prevalent type of dementia, still lacks disease-modifying treatment strategies. Recent evidence indicates that maintaining gut microbiota homeostasis plays a crucial role in AD. Targeted regulation of gut microbiota, including probiotics, is anticipated to emerge as a potential approach for AD treatment. However, the efficacy and mechanism of multi-strain probiotics treatment in AD remain unclear. METHODS: In this study, 6-month-old senescence-accelerated-mouse-prone 8 (SAMP8) and senescence-accelerated-mouse-resistant 1 (SAMR1) were utilized. The SAMP8 mice were treated with probiotic-2 (P2, a probiotic mixture of Bifidobacterium lactis and Lactobacillus rhamnosus) and probiotic-3 (P3, a probiotic mixture of Bifidobacterium lactis, Lactobacillus acidophilus, and Lactobacillus rhamnosus) (1 × 109 colony-forming units) once daily for 8 weeks. Morris water maze (MWM) and novel object recognition (NOR) tests were employed to assess the memory ability. 16S sequencing was applied to determine the composition of gut microbiota, along with detecting serum short-chain fatty acids (SCFAs) concentrations. Neural injury, Aß and Tau pathology, and neuroinflammation level were assessed through western blot and immunofluorescence. Finally, potential molecular mechanisms was explored through transcriptomic analysis and western blotting. RESULTS: The MWM and NOR test results indicated a significant improvement in the cognitive level of SAMP8 mice treated with P2 and P3 probiotics compared to the SAMP8 control group. Fecal 16S sequencing revealed an evident difference in the α diversity index between SAMP8 and SAMR1 mice, while the α diversity of SAMP8 mice remained unchanged after P2 and P3 treatment. At the genus level, the relative abundance of ten bacteria differed significantly among the four groups. Multi-strain probiotics treatment could modulate serum SCFAs (valeric acid, isovaleric acid, and hexanoic acid) concentration. Neuropathological results demonstrated a substantial decrease in neural injury, Aß and Tau pathology and neuroinflammation in the brain of SAMP8 mice treated with P3 and P2. Transcriptomic analysis identified the chemokine signaling pathway as the most significantly enriched signaling pathway between SAMP8 and SAMR1 mice. Western blot test indicated a significant change in the phosphorylation level of downstream AKT/GSK-3ß between the SAMP8 and SAMR1 groups, which could be reversed through P2 and P3 treatment. CONCLUSIONS: Multi-strain probiotics treatment can ameliorate cognitive impairment and pathological change in SAMP8 mice, including neural damage, Aß and Tau pathology, and neuroinflammation. This effect is associated with the regulation of the phosphorylation of the AKT/GSK-3ß pathway.

pH-responsive magnetic graphene oxide composite as an adsorbent with high affinity for rapid capture of nucleosides.

A novel pH-responsive magnetic graphene oxide composite (MGO@PEI-BA) is proposed for the first time as an adsorbent for the rapid capture and detection of nucleosides (cytidine, uridine, guanosine, and adenosine). The morphology, structure, and magnetic properties of the composite were evaluated using various characterization techniques. The results indicated that the composite was successfully fabricated. A series of parameters that affect extraction and elution were optimized through one-factor-at-a-time and Box-Behnken design of response surface methodology (BBD-RSM). The unique layered structures and easily accessible active sites of the composite facilitated molecular transport, resulting in instantaneous equilibrium of nucleosides adsorption within 5 min. Based on this study, a magnetic dispersive micro-solid-phase extraction (MD-µ-SPE) method assisted by the MGO@PEI-BA was developed in combination with UHPLC-UV analysis for the determination of nucleosides in rat urine. Under the optimum conditions, a wide linear range (10-2000 ng mL-1), good linearity (r > 0.99), low detection limits (1-3 ng mL-1), low relative standard deviations (RSDs ≤ 3.9%), and satisfactory recoveries (82.7-96.3%) were achieved. These results demonstrate that the MGO@PEI-BA is an excellent adsorbent for extracting nucleosides from biological samples.

Hydrophilic molecularly imprinted membranes based on GO-loading for simultaneously selective recognition and detection of three amphenicols drugs in pork and milk.

It plays an important role to effective detection of amphenicols antibiotic residues in food and an important issue considering of possible impact on human health. In this work, the molecularly imprinted membranes (MIMs) were proposed to simultaneously recognize and detect thiamphenicol (TAP), florfenicol (FF) and chloramphenicol (CAP) in pork and milk samples. The synergistic effect of graphene oxide (GO), double functional monomer (methacrylate and acrylamide) and "click chemistry" strategy prompted the membranes to possess good surface hydrophilicity (48.6°), excellent selectivity and capacity to exclude macromolecules. The theoretical models of selectivity mechanism showed the selective recognition depended mainly on the hydrogen bond interaction and van der Waals interaction between the analytes and monomers. The limit of detection for 3 analytes were 0.04-0.28 µg kg-1, and showed a good correlation (r > 0.9949). Finally, this study established an effective MIMs-UHPLC-MS/MS method with great potential for the monitor of antibiotics residue in complicated matrices.

Dummy molecularly imprinted membranes based on an eco-friendly synthesis approach for recognition and extraction of enrofloxacin and ciprofloxacin in egg samples.

In this work, novel dummy molecularly imprinted membranes (MIMs) were fabricated using the nylon-66 (NY-66) membranes as the subtracts based on an eco-friendly "sandwich" technology with less consumption of organic reagents at mild conditions for recognition and extraction of enrofloxacin (ENR) and ciprofloxacin (CIP) in egg samples. The prepared MIMs were characterized by SEM, ATR-FTIR and TGA, showing the successful construction of uniform and porous polymers on the surface of membranes. A series of adsorption affinity tests were investigated, indicating the prepared materials had specific recognition capacity and excellent stability as novel sorbents. Furthermore, Box-Benhnken design (BBD) and single factor investigations were applied to optimize pretreatment procedures, coupling with Ultra High Performance Liquid Chromatograph (UHPLC) detection. The method showed a good correlation (r2>0.9999) within the linear range of 5.0~5000.0 µg kg-1, and limit of detection (LOD) of ENR and CIP were 0.3 and 0.7 µg kg-1, respectively. The mean recovery ranged from 84.5% to 97.0% within relative standard deviations (RSDs) of 10.2%. Finally, ENR and CIP were not detected in 3 batches of egg samples. The current study developed the dummy MIMs as sorbents combined with UHPLC analysis for extraction and detection of target analytes in food matrices.

An optically pumped XeF(C-A) laser with repetitive rate of 10 Hz.

A novel XeF(C-A) laser which can be operated in repetition mode has been developed based on surface discharge optical pumping technique. Its maximum repetitive rate is up to 10 Hz. The influence of repetitive rate and gas flow rate on the stability of output energy is studied and the main factor which influences the stability of output energy is analyzed. The experimental results show that increasing the gas flow rate into laser chamber can improve the stability of the output energy. The ideal output energy results of 20 laser pulses under different repetitive rates and their optimal experimental conditions are presented. Output energies of more than 4 J and better stability can be obtained when the laser device operates at 1, 2, and 5 Hz, respectively. When the gas feed rate is larger than 53 l/s, the stability of output energy is improved obviously at the repetitive rate of 10 Hz, and the average energy of 20 laser pulses is up to 3.2 J.