Single and Competitive Adsorption of Naphthalene, Phenanthrene, and Pyrene on Polystyrene Nanofibers.

In this investigation, polystyrene (PS) nanofibers were prepared by electrospinning for the adsorption of naphthalene (Nap), phenanthrene (Phe), and pyrene (Pyr) from an aqueous solution. Surface morphology and physicochemical characteristics of PS nanofibers were analyzed using Fourier transform infrared spectroscopy (FT-IR) and point-of-zero-charge calorimetry (pHpzc). The effects of pH, ion concentration, and temperature on the adsorption were also investigated. The adsorption mechanism of target pollutants on PS nanofibers was investigated by a batch adsorption method. The adsorption kinetic studies showed that the adsorption of the three polycyclic aromatic hydrocarbons (PAHs) on PS nanofibers conformed to the pseudo-second-order kinetic model in both single and ternary systems. Meanwhile, in a single system, the three PAHs adsorbed on nanofibers were controlled by both intraparticle diffusion and liquid film diffusion, whereas the adsorption of Nap in a ternary system was controlled mainly by intraparticle diffusion, and the adsorption of Phe and Pyr was controlled mainly by liquid film diffusion. The isotherm data indicated that the Freundlich model performed better than the Langmuir model for the adsorptions of Nap, Phe, and Pyr on PS nanofibers in both the single system and the ternary system. Due to competitive adsorption, the adsorption capacities of Nap and Pyr on PS nanofibers decreased from 105.816 and 19.098 mg g-1 in the single system to 23.626 and 12.126 mg g-1 in the ternary system, but the adsorption of Phe was not affected. π-π interactions and pore filling may be jointly involved in the adsorption of PAHs on PS nanofibers.

Preoperative serum cortisone levels are associated with cognition in preschool-aged children with tetralogy of Fallot after corrective surgery: new evidence from human populations and mice.

BACKGROUND: Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease. Children with TOF would be confronted with neurological impairment across their lifetime. Our study aimed to identify the risk factors for cerebral morphology changes and cognition in postoperative preschool-aged children with TOF. METHODS: We used mass spectrometry (MS) technology to assess the levels of serum metabolites, Wechsler preschool and primary scale of intelligence-Fourth edition (WPPSI-IV) index scores to evaluate neurodevelopmental levels and multimodal magnetic resonance imaging (MRI) to detect cortical morphological changes. RESULTS: Multiple linear regression showed that preoperative levels of serum cortisone were positively correlated with the gyrification index of the left inferior parietal gyrus in children with TOF and negatively related to their lower visual spaces index and nonverbal index. Meanwhile, preoperative SpO2 was negatively correlated with levels of serum cortisone after adjusting for all covariates. Furthermore, after intervening levels of cortisone in chronic hypoxic model mice, total brain volumes were reduced at both postnatal (P) 11.5 and P30 days. CONCLUSIONS: Our results suggest that preoperative serum cortisone levels could be used as a biomarker of neurodevelopmental impairment in children with TOF. Our study findings emphasized that preoperative levels of cortisone could influence cerebral development and cognition abilities in children with TOF.

Common alterations in plasma free amino acid profiles and gut microbiota-derived tryptophan metabolites of five types of cancer patients.

Amino acids not only play a vital role in the synthesis of biological molecules such as proteins in cancer malignant cells, they are also essential metabolites for immune cell activation and antitumor effects in the tumor microenvironment. The abnormal changes in amino acid metabolism are closely related to the occurrence and development of tumors and immunity. Intestinal microorganisms play an essential role in amino acid metabolism, and tryptophan and its intestinal microbial metabolites are typical representatives. However, it is known that the cyclic amino acid profile is affected by specific cancer types, so relevant studies mainly focus on one type of cancer and rarely study different cancer forms at the same time. The objective of this study was to examine the PFAA profile of five cancer patients and the characteristics of tryptophan intestinal microbial metabolites to determine whether there are general amino acid changes across tumors. Plasma samples were collected from esophageal (n = 53), lung (n = 73), colorectal (n = 94), gastric (n = 55), breast cancer (n = 25), and healthy control (HC) (n = 139) subjects. PFAA profile and tryptophan metabolites were measured, and their perioperative changes were examined using high-performance liquid chromatography. Univariate analysis revealed significant differences between cancer patients and HC. Furthermore, multivariate analysis discriminated cancer patients from HC. Regression diagnosis models were established for each cancer group using differential amino acids from univariate analysis. Receiver-operating characteristic analysis was applied to evaluate these diagnosis models. Finally, GABA, arginine, tryptophan, taurine, glutamic acid, and melatonin showed common alterations across all types of cancer patients. Metabolic pathway analysis shows that the most significant enrichment pathways were tryptophan, arginine, and proline metabolism. This study provides evidence that common alterations of the metabolites mentioned above suggest their role in the pathogenesis of each cancer patient. It was suggested that multivariate models based on PFAA profiles and tryptophan metabolites might be applicable in the screening of cancer patients.

Determination of aflatoxin B1 by novel nanofiber-packed solid-phase extraction coupled with a high performance liquid chromatography-fluorescence detector.

A novel analytical proposal based on nanofiber-packed solid-phase extraction coupled with high performance liquid chromatography-fluorescence detector (HPLC-FLD) has been successfully developed for determining aflatoxin B1 (AFB1) in foods. Four types of nanofibers, including polystyrene (PS) nanofibers, polypyrrole (PPY) nanofibers, polystyrene-acrylic resin (PS-AR) nanofibers, and polystyrene-polyvinyl pyrrolidone (PS-PVP) nanofibers, were fabricated by electrospinning and utilized to prepare a home-made extraction device. In this study, the factors of different fibers, namely, fiber dosage, pH of extraction solution, type of salt ion, concentration of salt ion, and volume of the eluent were optimized. Under optimized conditions, the method showed good linearity in the range of 0.1-40 ng mL-1 with a correlation coefficient greater than 0.999 and good inter-day accuracy (90.8-112.7% recovery) and precision (1.8-3.6% intra-day RSDs, 2.6% inter-day RSD), and the limit of detection (LOD) was 0.05 ng mL-1. Due to its cost-effective, time-saving, environmentally friendly, and simple performance, it has the potential to be utilized to determine aflatoxins in complicated matrices.

Determination of polyamines in urine via electrospun nanofibers-based solid-phase extraction coupled with GC-MS and application to gastric cancer patients.

The simultaneous determination of polyamines and their metabolites in urine samples was achieved by gas chromatography-mass spectrometry in the selected ion monitoring mode. After conjugating with the ion-pair reagent bis-2-ethylhexylphosphate in the aqueous phase, the polyamines in the samples were extracted with polystyrene nanofiber-based packed-fiber solid-phase extraction followed by a derivatization step using pentafluoropropionyl anhydride. With optimal conditions, all analytes were separated well. For analytes of putrescine, cadaverine, N-acetylputrescine, and N-acetylcadaverine, the linearity was good in the range of 0.05-500 µmol/L (R2  ≥ 0.993). While for spermidine, spermine, acetylspermidine, N8 -acetylspermidine, and N-acetylspermine, the linearity was good in the range of 0.5-500 µmol/L (R2  ≥ 0.990). The recoveries of three spiked concentrations (0.5, 5, 300 µmol/L) were 85.6%-108.4%, and relative standard deviations for intra- and interday were in the range of 2.9%-13.4% and 4.5%-15.1%, respectively. The method was successfully applied to the analysis of urine samples of gastric cancer patients. The results showed that the levels of most polyamines and N-acetylated polyamines from the patient group were significantly higher than those from the control group. The altered concentrations of the above-mentioned metabolites suggest their role in the pathogenesis of gastric cancer, and they should be further evaluated as potential markers of gastric cancer.

Associations of air PM2.5 level with gut microbiota in Chinese Han preschoolers and effect modification by oxytocin receptor gene polymorphism.

Variations in the single nucleotide polymorphisms (SNPs) of the oxytocin receptors (OXTR) indicate individual differences in stress response, social behavior, and psychopathology, but very few paper mentioned OXTR as part of the mechanism linking exposure to air pollution and poor social interactions. The authors investigated the moderating role of Oxytocin receptor (OXTR) rs53576 polymorphism in the relationship between PM2.5 level and gut microbiota in children, in an attempt to provide some reference for the evidence linking biological and environmental factors to children brain development. The study included 86 healthy Chinese preschoolers (50 males, 36 females) from two campuses of a kindergarten with different air PM2.5 levels. Atmospheric PM2.5 values released by air quality monitoring stations where the two campuses are located were collected for 30 days. The genotypes of OXTR rs53576 were determined by PCR and restriction fragment length polymorphism. The gut microbiota situation was evaluated by determining urinary concentrations of short-chain fatty acids. Urinary levels of cortisone and cortisol were determined to assess the impact of air pollution on the HPA axis. Urinary 2'-Deoxy-7,8-dihydro-8-oxoguanosine and 8-oxo-7,8-dihydroguanosine were measured to evaluate the oxidative stress state. The genotype distribution frequency of rs53576 polymorphism was consistent with Hardy-Weinberg equilibrium. The average urinary concentrations of cortisone, cortisol and 8-OHdG in high pollution campus preschoolers were significantly higher than those in low pollution campus preschoolers, while situations were opposite for acetic acid, propionic acid, isobutyric acid, butyric acid and valeric acid. The interaction between OXTR rs53576 and air pollution had a significant effect on urinary acetic acid. Allele G of rs53576 may be a risk factor for gut microbiota disorder caused by air pollution, and children with GA/GG genotype may be more susceptible than those with AA genotype.

Packed-Fiber Solid Phase-Extraction Coupled with HPLC-MS/MS for Rapid Determination of Lipid Oxidative Damage Biomarker 8-Iso-Prostaglandin F2α in Urine.

The 8-iso-prostaglandin F2α (8-iso-PGF2α) biomarker is used as the gold standard for tracing lipid oxidative stress in vivo. The analysis of urinary 8-iso-PGF2α is challenging when dealing with trace amounts of 8-iso-PGF2α and the complexity of urine matrixes. A packed-fiber solid-phase extraction (PFSPE)−coupled with HPLC-MS/MS−method, based on polystyrene (PS)-electrospun nanofibers, was developed for the specific determination of 8-iso-PGF2α in urine and compared with other newly developed LC-MS/MS methods. The method, which simultaneously processed 12 samples within 5 min on a self-made semi-automatic array solid-phase extraction processor, was the first to introduce PS-electrospun nanofibers as an adsorbent for the extraction of 8-iso-PGF2α and was successfully applied to real urine samples. After optimizing the PFSPE conditions, good linearity in the range of 0.05−5 ng/mL with R2 > 0.9996 and a satisfactory limit of detection of 0.015 ng/mL were obtained, with good intraday and interday precision (RSD < 10%) and recoveries of 95.3−103.8%. This feasible method is expected to be used for the batch quantitative analysis of urinary 8-iso-PGF2α.

Nanofibers comprising polystyrene and zinc acetate for extraction of salivary histidine prior to its determination by HPLC-DAD.

A novel nanofiber-based solid phase extraction (NFSPE) coupled with HPLC-DAD was developed for the determination of salivary histidine, a new potential index of physiological events. The treatment of the sample was based on a coupling reaction of histidine with the diazotization products of sulfanilic acid and sodium nitrite in a slightly alkaline medium, followed by NFSPE. Nanofibers comprising polystyrene and zinc acetate were used as a novel solid-phase sorbent to extract derived histidine via the chelation of Zn2+ with the imidazole group in the analyte. The eluted target compound was analyzed by HPLC-DAD. Good linearity was achieved with the concentrations of histidine ranging from 0.645 to 64.5 µM; the detection limit was 0.193 µM. The intra-day and inter-day coefficients of variation were less than 8.0%. The method was successfully applied to the determination of salivary histidine in the subjects exposed to a public speaking stress.

Fiber Nanoarchitectonics for Pre-Treatments in Facile Detection of Short-Chain Fatty Acids in Waste Water and Faecal Samples.

Short-chain fatty acids (SCFAs) are among the active metabolites in biological process both in the intestinal tract and the bioconversion of organic wastes, which has resulted in various human diseases and environmental problems. In order to accurately detect SCFAs, we introduced a novel extraction sorbent. Electrospun polyacrylonitrile (PAN) nanofiber membrane was synthesized, then poly (3, 4-Ethylenedioxythiophene) (PEDOT) was deposited onto the surface of electrospun PAN nanofibers by in situ polymerization. The morphology of the composite PAN/PEDOT nanofiber was characterized by scanning electronic microscopy (SEM) and FTIR spectrum. PAN/PEDOT was used to isolate and concentrate the SCFAs in waste water and fecal samples before gas chromatography mass spectrometry (GC-MS) analysis. The analytical method was evaluated systematically, and low limits of detection (LODs) of 0.34-0.87 µg/L and good linearity (R2 ≥ 0.9953) were obtained. The method was applied successfully for the determination of SCFAs in waste water and fecal samples, with good recovery (87.5-104.6%) and satisfactory reproducibility (relative standard deviation: 6.5-14.1%). The results indicated that the proposed method can be used as a potential approach for the determination of SCFAs with high sensitivity in waste water and biological samples.

Rapid determination of seven synthetic dyes in casual snacks based on packed-fibers solid-phase extraction coupled with HPLC-DAD.

Based on packed-fiber solid-phase extraction and HPLC-DAD, a simple analytical method for the determination of seven synthetic dyes has been successfully developed. Polystyrene/polypyrrole (PS/PPy) fibers were obtained via electro-spinning of polystyrene skeletal nanofibers, followed by the oxidation with FeCl3 to trigger the polymerization of pyrrole and the deposition of polypyrrole coatings on PS fibrous skeleton fibers. The relationship between the extraction performance of the fibers and the electrospinning process at different humidities was investigated based on morphologic study and BET surface area. In the extraction process, purification, concentration, and desorption could be accomplished in one step. The established method exhibited good sensitivity, selectivity, reproducibility, and good efficiency for synthetic dyes in casual snacks (preserved fruit, flavored yogurt, and fruity hard candy) samples. With optimal conditions, the LODs (S/N = 3) were 2.4 to 21.09 ng mL-1, and linearities were acceptable in liquid matrix and solid matrices. The recoveries were 93.9-103.9%.

A novel biosensor based on Blu-ray disc coating film for determination of total amino acid content in tea leaves.

Biosensor substrate materials are a key research focus in the field of sensors. Blu-ray discs (BDs) as universal sensor substrates are advantageous in comparison with other substrates (conventional paper and polycarbonate) in terms of easier activity treatment and higher density of reactive groups on the film surface. In this study, a novel and simple microfluidic biosensor based on BD coating film was developed by treating with sodium hydroxide solution and a piece of filter paper at slightly elevated temperatures. There are no significant physical damages to the substrate morphology, and the aging effect is minimal. The unique wetting, optical, and self-cleaning properties of the modified surfaces can be demonstrated in the paper. We have tested this new type of biosensor substrates for assay applications (the determination of total amino acids in tea leaves), which showed excellent performance in terms of sensitivity and reproducibility. The novel biosensor substrate material based on a simple BD coating film displayed preferable merits with easy making, low cost, easy using, and extensive application prospect.

Simultaneous analysis of two urinary biomarkers of oxidative damage to DNA and RNA based on packed-fiber solid phase extraction coupled with high-performance liquid chromatography.

The determination of the concentrations of urinary biomarkers of oxidative damage to DNA and RNA is difficult due to the low content of targets and the complex matrix of urine. A method using polystyrene/polypyrrole (PS/PPY) electronspun nanofibers as the adsorbent was introduced to the routine urinary treatment and determination of 8-OHdG and 8-oxoG for the first time. And 2-aminoethyl diphenylborate (DPBA) solution was creatively used in the loading and rinsing steps in order to promote the retention of the analytes as well as remove impurities. Under optimal conditions, 8-OHdG, 8-oxoG and IS were separated very well and exhibited a good linearity in the range of 0.5-50 ng mL-1, with correlation coefficients of R2 > 0.996. Limits of detection (LOD) were 0.058 ng mL-1 and 0.093 ng mL-1, and limits of quantification (LOQ) were 0.195 ng mL-1 and 0.309 ng mL-1, respectively. The recoveries were 88.8-104.9%. The proposed method was so simple and economical that it had the potential to be applied to batch quantitative analysis of 8-OHdG and 8-oxoG in urine. And it was successfully applied to real urine samples of cancer patients.

Performance Evaluation of an Electrospun Nanofiber Mat as Samplers for the Trap of Trace Heavy Metals in Atmospheric Particles and Its Application.

Traditional methods for the analysis of trace heavy metals in the atmosphere require collecting atmospheric particles on filter substrates, such as cellulose, quartz fiber member, etc. In this paper, we report on a different filter to capture trace heavy metals in atmospheric particulates. Four kinds of electrospun nanofiber filters, polystyrene (PS), polystyrene-dithizone (PS-DZ), acrylic acid (AR), and acrylic acid-dithizone (AR-DZ) were produced by electrospinning, and used as filters to trap heavy metals in atmospheric particles. Based on these nanofiber filters, the digestion method and eluent were optimized. Under the optimal conditions (oscillation extraction with acetic acid-potassium acetate (HAC-KAC) buffer solution (0.1 mol L-1, pH = 4.5)), the developed method was successfully applied to determine the four particulate metal elements (As, Cd, Hg, and Pb) in air in two urban areas of Suzhou, China. Furthermore, a correlation between heavy metals in air and breast milk was observed. The results confirmed that an electrospun nanofiber mat could be a potential candidate for the sampling of heavy metals in atmospheric particles with higher efficiency.

Blu-Ray Discs as Universal Biochip Substrates: Lithography-Free Surface Activation and Assay Patterning.

Blu-ray discs (BDs) are advantageous in comparison with other optical discs (compact discs and digital versatile discs) in terms of not only their storage capacity but also the high-quality materials fabricated from. We have recently discovered that the "Hard Coat" film of Verbatim BDs is in fact a unique type of polymeric substrates that can be readily activated and adapted for biochip fabrications. Particularly, the Hard Coat film peeled from BDs is optically transparent without any fluorescence background, which can be activated by treating with a common base (1.0 M NaOH) at a slightly elevated temperature (55 °C). The surface density of reactive carboxylic acid groups generated, 6.6 ± 0.7 × 10-9 mol/cm2, is much higher than that on polycarbonate upon UV/ozone irradiation (4.8 ± 0.2 × 10-10 mol/cm2). There are no significant physical damages to the substrate morphology, and the aging effect is minimal. More importantly, the BD substrate can be patterned using either cut-out filter paper masks or microfluidic channel plates; both are lithography-free, bench-top methods that facilitate the device fabrication in a common laboratory setting. With classical biotin-streptavidin binding and DNA hybridization arrays as trial systems, we have also demonstrated this new type of biochip substrates for quantitative assay applications.

Baicalin improves intestinal microecology and abnormal metabolism induced by high-fat diet.

Short-chain fatty acids (SCFAs) are produced by the fermentation of dietary fiber by the gut microbiota and are beneficial to the health of the body. Insufficient SCFAs productions are associated with type 2 diabetes (T2D). We used a long-term high-fat diet to simulate the pathogenesis of T2D and studied the effects of baicalin on gut microbiota and metabolites in mice as well as its mechanism, providing a theoretical basis for the treatment of T2D. Baicalin groups were given 200 mg/kg/day, and control groups were given an equal volume of 0.5% sodium carboxymethyl cellulose solution for 15 weeks. 16S rRNA amplicon pyrosequences was performed to evaluate the gut microbiota composition, and gas chromatography was used to detect SCFAs in stool samples in the different experimental groups. The abundance of gut microbiota in the high-fat model group was altered, and was associated with a decreased production of SCFAs. The microbiota abundance of the baicalin group was closer to that of the control group, increasing the population of SCFA-producing bacteria spp and improving metabolic syndrome, including abnormal glucose and lipid metabolism caused by a high-fat diet. Baicalin may improve abnormalities in glycolipid metabolism by affecting the production of SCFAs.

Solid phase extraction with Polypyrrole nanofibers for simultaneously determination of three water-soluble vitamins in urine.

This paper put forward a prospective pre-cleanup method of packed-fiber solid phase extraction by using Polypyrrole (Ppy) electrospun nanofibers as the sorbent to simultaneously extract three water-soluble vitamins (i.e., folic acid, cyanocobalamin and riboflavin) in human urine. Primary extraction of target analytes was carried out by loading samples onto the column along with diphenylboronic acid 2-aminoethylester (DPBA) reagent, and then the column should be rinsed with DPBA solution for three times before eluting. The DPBA was innovatively applied as complexing reagent to retain as much of three analytes as possible on the column based on the multi interaction between three vitamins and the boronate affinity reagent, thus improving hydrophobicity of targets and adsorption efficiency through loading and rinsing steps. Under optimized conditions, sample concentration factor was five times with small amount of organic solvent consumed and recoveries between 84.9% to 125.4%, and the lowest detection limit (LOD) between 0.020 to 0.041 µg/mL were achieved. Finally, the urine samples from a group of healthy children were processed with the optimized method. It proved that the proposed method is applicable in the determination of urinary B-vitamins in big samples of people.

Simultaneous determination of five phthalate esters and bisphenol A in milk by packed-nanofiber solid-phase extraction coupled with gas chromatography and mass spectrometry.

A novel polystyrene/pyridine composite nanofiber was synthesized and utilized as the sorbent material for the solid-phase extraction of bisphenol A and five common phthalate esters in milk. The method of extraction integrated extraction and preconcentration of target analytes into a single step. Bisphenol A and five common phthalate esters were selected as target compounds for the development and evaluation of the method. The effects of operating parameters for nanofiber-based solid-phase extraction, such as selection and amount of sorbent, the volume fraction of perchlorate (precipitate protein), desorption solvent, volume of desorption solvent, and effect of salt addition were optimized. Under optimal conditions, higher extraction recoveries (89.6-118.0%) of the six compounds in milk spiked at three levels were obtained, and the satisfied relative standard deviation were ranged from 0.6 to 10.9%. The detection limits and quantification limits of the method ranged from 0.01 to 0.06 µg/L and 0.05 to 0.53 µg/L, respectively. Matrix effects were also verified and well controlled in the range of 91.3-109.3%. The new method gave better performance metrics than Chinese standard method and other published methods. Thus, the proposed method may be applied to the analysis of the phthalate esters and bisphenol A in complex matrixes.

Solid-Phase Extraction with Packed-Fiber is a Biological Sample Preparation Tool for Neuro-Active Molecule Detection.

Neurotransmitters play a major role in shaping everyday life and functions. Accurate analytical methods are needed for detection of neurotransmitters. Packed-fiber solid-phase extraction (PFSPE) has been developed and seems to be an efficient method. This novel method is based on use of an electrospun polymer device, based on nanofibers. This strategy will be helpful for the development of real-time methods and techniques with high sensitivity to detect target neurotransmitters with high efficiency. Here we provide a brief overview of PFSPE and its applications for the determination of neuro-active molecules.

Polystyrene nanofibers capped with copper nanoparticles for selective extraction of glutathione prior to its determination by HPLC.

Polystyrene nanofibers were coated with copper nanoparticles (CuNPs) by a combination of electrospinning and in-situ reduction of Cu(II) using sodium borohydride as the reductant. The CuNPs on the nanofibers were characterized by energy dispersive spectrometry, scanning electron microscopy and transmission electron microscopy. A cartridge was packed with the nanofibers which then were activated with methanol and water. Glutathione (GSH) is found to quantitatively adsorbed by the packed cartridge at pH 3.0, and then can be desorbed with aqueous 2-mercaptoethanol and detected, after derivatization with ortho-phthalaldehyde, via high performance liquid chromatography with fluorometric detection. Under optimized conditions, the method has a 1.1 ng·mL-1 detection limit and a response that is linear in the 10-1000 ng·mL-1 GSH concentration range. The recoveries of GSH from artificial urine spiked at three levels (80, 400 and 800 ng·mL-1) are in the range of 94.6-98.6% with relative standard deviations (RSD) of <4.5% (n = 5). The method was applied to assessing the differences in urinary GSH between high-risk infants and healthy infants. The results show that the levels of GSH of normal infants are significantly higher than those of high-risk infants (P < 0.05). Graphical abstract Schematic of the preparation of CuNP-assembled nanofibers and the mechanism of extracting glutathione (GSH). GSH can be extracted by this material based on a strong interaction between the sorbent and GSH. This is attributed to the formation of Cu-S bonds between Cu and -SH.