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A high protein retention polyethersulfone (PES) membrane was prepared by nonsolvent-induced phase separation and surface coating, which exhibited enhanced hemocompatibility and antioxidant stress performance. The cross-linked network was constructed by tannic acid (TA) and alpha-lipoic acid (α-LA) on the surface of the membrane, which controlled the pores to a reasonable size. The enrichment of heparin-like groups on the membrane surface, implemented by "hydrophobic interaction" and "click reaction", confers anticoagulant properties; the presence of a large number of phenolic hydroxyl groups from TA and the introduction of α-LA allows the modified membranes to intervene in oxidative stress. The hemocompatibility characterizations included plasma recalcification time (PRT), activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT) and hemolysis rate (HR). Additionally, the DPPH ABTS radical scavenging capacity was tested to evaluate the antioxidant performance. The results show that the modified membrane presents an outstanding protein retention rate (99.3%) along with permeability. In addition, the PRT is prolonged to 341.7 s, and the DPPH• scavenging ability reaches 0.74 µmol•cm

Transforming biomass waste into cost-effective non-precious-metal catalysts for the oxygen reduction reaction (ORR) provides a great opportunity for the development of microbial fuel cells (MFCs). ...

Mass spectrometers are sensitive tools used to identify and quantify both small and large analytes using the mass-to-charge ratios ( m/ z) of ions generated by electrospray ionization (ESI) or other methods. Ionization typically generates protonated or deprotonated forms of the analytes or adducts with adventitious metal ions derived from the spray solvent. The formation of a variety of ionized forms of the analyte as well as the presence of cluster ions complicates the data and can have deleterious effects on the performance of the mass spectrometer, especially under high salt or buffer conditions. To address this, a method involving a dual-electrode nano-electrospray source has been implemented to rapidly and temporarily desalt the spray solution of interfering cationic and anionic species using electrophoretic transport from the spray tip. Peptides, proteins, and pharmaceutical drugs all showed improved results after the desalting process as measured by the quality of the mass spectra and the limits of detection achieved. Importantly ordinary phosphate buffers could be used to record protein mass spectra by nano-ESI.

It is of practical significance to develop a heparin-free hemodialysis membrane that can be used for clinical applications in a simple way. In this work, a heparin-like coating loaded with SO3− and COOH was formed on a polyethersulfone (PES) ultrafiltration membrane by the hydrophobic interactions and hydrogen bonding of tannic acid (TA) with the PES membrane, the cross-linking of D-asparagine (DAS) with TA, and a Michael addition reaction of sodium 3-mercapto-1-propanesulfonic acid (SMP) with TA. The plasma recalcification time of the modified PES membrane was increased to 256 s, and the BSA rejection rate and urea clearance rate were 97.1% and 92.0%, respectively. The results demonstrated that a heparin-like tannic acid coating was successfully formed on the surface of the PES ultrafiltration membrane. The synergistic effect of the catechol and hydrophilic groups on the coating reduced platelet adhesion and activation, thus significantly improving the hemocompatibility modification of the PES membranes. Modified membranes with both high flux and excellent rejection (clearance) properties were also selected through the control of the coating. This study provides a novel and facile strategy for the direct preparation of a membrane material with excellent anti-hemagglutination properties.

A rapid method is described for quantification of six illegal colorants in beverages, i.e., soft beverages, energy beverages, alcoholic beverages, teas, and fruit juices. Paper spray (PS) ionization combined with tandem mass spectrometry (MS/MS) allowed detection of particular dyes in times of less than 1 min per sample. Samples where diluted in methanol and isotopically-labeled internal standards were utilized to obtain linear responses over ranges of two or three orders of magnitude. The LODs were below 1.5 ng mL−1 and LOQs were below 5 ng mL−1. Quality control experiments gave accuracies that ranged between 80% and 120%. Matrix effects were evaluated for different samples but had little effect given the use of the dilution method.

In this work, an electro-kinetic assisted electrospray ionization (EK-ESI) source is proposed and characterized. In EK-ESI, an additional auxiliary electric field is introduced in the liquid flow of a nano-ESI. While traveling forward in the electrospray flow, charged analytes also experience a reverse electric field, which pushes them backwards. As a result, analytes could be separated preliminarily based on their electrophoretic mobility during the electrospray process. Experiments show that EK-ESI can reduce charge competition effects in the ESI source and increase biomolecule detection sensitivities. It was also found that EK-ESI effectively ionizes proteins in a relatively mild solvent condition, which does not require the addition of acids or salt buffers into the solvent. As a proof-of-concept study, a very rough separation effect was observed in this study, further experiments and theoretical study will be carried out to enhance its performances.