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Previous studies have proved that the characteristic galloyl moiety in polyphenols is crucial for their biological activities. However, whether the presence of the galloyl moiety in the structure of polyphenols has a great contribution to their inhibition of adipogenic differentiation is not clear. Therefore, in this study, seven polyphenols with different galloylation degrees were chosen for exploring the contribution of the galloyl group to the lipid-lowering property of polyphenols and its molecular mechanism. Our results showed that the existence of the galloyl moiety in the structure of polyphenols was necessary for their inhibition of adipogenic differentiation, which could help to delay cells from entering the G2/M phase as well as to hinder the MCE process in the early stage of differentiation and the downstream PPARγ and C/EBPα related MAPK signaling pathway, probably

Polyphenols have attracted a lot of global attention due to their diverse biological actions against cancer, obesity, and cardiovascular diseases. Although extensive research has been carried out to elucidate the mechanisms of pleiotropic actions of polyphenols, this remains unclear. Lipid rafts are distinct nanodomains enriched in cholesterol and sphingolipids, present in the inner and outer leaflets of cell membranes, forming functional platforms for the regulation of cellular processes and diseases. Recent studies focusing on the interaction between polyphenols and cellular lipid rafts shed new light on the pleiotropic actions of polyphenols. Polyphenols are postulated to interact with lipid rafts in two ways: first, they interfere with the structural integrity of lipid rafts, by disrupting their structure and clustering of the ordered domains; second, they modulate the downstream signaling pathways mediated by lipid rafts, by binding to receptor proteins associated with lipid rafts, such as the 67 kDa laminin receptor (67LR), epidermal growth factor receptor (EGFR), and others. This study aims to elaborate the mechanism of interaction between polyphenols and lipid rafts, and describe pleiotropic preventive effects of polyphenols.

The cell membrane fluidity was very important in adipogenesis and galloyl groups on polyphenolic structures could enhance their antiadipogenic activity. However, the effect of polyphenols on membrane fluidity and the role of galloyl groups in fluidity changes remain unclear. Therefore, the present study chose structurally different polyphenols to compare their effects on the membrane morphology and fluidity of 3T3-L1 preadipocytes, and then the reasons behind the changes of membrane fluidity induced by galloylated polyphenols were explored from structural and molecular insights using liposome model and molecular dynamic simulation technology. Our results indicated that galloylated polyphenols could significantly change 3T3-L1 cell membrane morphology and decrease membrane fluidity, while non-galloylated ones could not. The membrane interference effect of polyphenols was enhanced as the number of galloyl groups increased. Morever, the decrease in membrane fluidity induced by galloylated polyphenols was due to the disturbance of polyphenols on lipid alkyl chains in the cell membrane. Galloylated polyphenols could not only locate in the polar head, but also insert into hydrophobic center of lipid bilayer to interfere with the lipid alkyl chains arrangement, thus decreasing the membrane fluidity and showing strong affinity for the membrane. In addition, differences in position of galloyl groups in polyphenols induced distinct effect on cell membranes interactions, thus affecting the binding manner and bioactivity. The results expanded the understanding on the strong antiadipogenic activity of galloylated polyphenols through the aspect of their effects on cell membrane by both experimental and theoretically simulated ways.

A-type epigallocatechin-3-gallate (EGCG) and epicatechin-3-O-gallate (ECG) dimers have multiply biological activities. In this study, the pharmacokinetics of them were investigated in mice after a single dose intravenous administration, and the metabolites in mice plasma and urine were investigated by ultra-performance liquid chromatography-Quadrupole-time of flight mass spectrometer (UPLC-QTOF-MS). Our results showed that the half-life (

In this study, the physicochemical stability, and the digestive enzymes inhibitory potential of anthocyanins in black peanuts skins (BPS) were evaluated. Cyanidin-3-O-sophoroside (C3So) and cyanidin-3-O-sambubioside (C3Sa) were identified as the main anthocyanins in BPS. The anthocyanins extract showed a certain level of heat resistance. During the storage period (37 °C for 4 weeks), anthocyanins were stable and with a projected half-life of 66.59 days when the pH was 2.5. These results indicated that the anthocyanin from BPS presented higher thermal stability. Moreover, Anthocyanin-rich extracts could inhibit the main digestive enzymes, with the IC50 values were 185.1 μg/ml (pancreatic lipase), 123.4 μg/ml (α-amylase), and 82.75 μg/ml (α-glucosidase), respectively. The in vitro cell study also indicated anthocyanins from back peanut skin showed a strong antiadipogenesis potential in 3T3-L1 cells by inhibiting the expression of the key adipogenic transcription factors and related genes. This research highlights the opportunity that black peanut skin could be considered as a promising resource of anthocyanins as a natural food colorant with multifunction properties.

Shepherd’s purse (Capsella bursa-pastoris (L.) Medik.), a wild herb as a traditional herbal medicine, has been proved with multiple healthy benefits. In this study, the chemical constituents of shepherd’s purse were identified by UPLC-QTOF-MS/MS. The antioxidative and anti-inflammatory potential of shepherd’s purse extract (SPE) were also investigated applying lipopolysaccharide- (LPS-) induced inflammation in RAW 264.7 macrophages and a carrageenan-induced mice paw edema model. Twenty-four chemical compounds were identified mainly including phenolic acids and flavonoids. The data also indicated SPE inhibited the productions of NO, PGE2, TNF-α, and IL-6 stimulated with LPS. In addition, SPE inhibited the increase of reactive oxygen species (ROS) and upregulated the expression of heme oxygenase-1 (HO-1). We further found that SPE inhibited the phosphorylation of P38 MAPK and activation of NF-κB. In vivo mice model also indicated that SPE showed strong antioxidative and anti-inflammatory activity.

Excessive Ultraviolet (UV) irradiation induces skin damage. In the present study, the potential protective activity of anthocyanins (cyanidin-3-O-sophoroside and cyanidin-3-O-sambubioside) from black peanut against skin damage induced by UV-B was evaluated in vitro and in vivo. Treatment with anthocyanins significantly reversed UV-B induced oxidative damage and following apoptotic death in human HaCaT cells. Nuclear-factor-E2-related factor 2 (Nrf 2) was activated by anthocyanins through Nrf 2 protein stabilization and nuclear translocation, along with the expressions of antioxidant responsive element (ARE)- related genes (HO1, GCLC and NOQ1). Nrf 2 knockdown in HaCaT cells by targeted-shRNA plasmid markedly abolished the protective activity of anthocyanins against UV-B irradiation. Additionally, topical application of anthocyanins (5 mg cm-2) inhibited UV-B induced oxidative stress and cell apoptosis in BALB/c mouse skin tissues. The protective effect of anthocyanins can be explained by the regulation of oxidative-stress and the suppression of cell apoptosis through the activation of Nrf-2 by interaction with the MAPK and NF-κB signaling pathways. Our results suggested that anthocyanins from black peanut skin might be used as a potential photochemo-protective agent against UV-B induced skin damage.

Pancreatic lipase (PL) is a critical enzyme associated with hyperlipidemia and obesity. A previous study of ours suggested that persimmon tannin (PT) was the main component accounting for the antihyperlipidemic effects of persimmon fruits, but the underlying mechanisms were unclear. In this present study, the inhibitory effect of PT on PL was studied and the possible mechanisms were evaluated by fluorescence spectroscopy, circular dichroism (CD) spectra, isothermal titration calorimetry (ITC), and molecular docking. PT had a high affinity to PL and inhibited the activity of PL with the half maximal inhibitory concertation (IC50) value of 0.44 mg/mL in a noncompetitive way. Furthermore, molecular docking revealed that the hydrogen bonding and π–π stacking was mainly responsible for the interaction. The strong inhibition of PT on PL in the gastrointestinal tract might be one mechanism for its lipid-lowering effect.

An efficient method was established by high-speed counter-current chromatography (HSCCC) for preparation of four phenolic compounds from the depolymerization products of persimmon tannin. Using the two solvent systems of n-hexane/ethyl acetate/water (3:17:20, v/v/v) and ethyl acetate/methanol/water (50:1:50, v/v/v), the preparative isolation was successfully performed by a two-step separation. The yields of one run (150mg crude sample) for gallic acid, methyl gallate, and epigallocatechin-3-gallate-(4β→8, 2β→O→7)-epigallocatechin-3-gallate dimer (A-type EGCG dimer) were 4.7, 44.2 and 5.9mg, respectively. In addition, 4.6mg epicatechin-3-gallate-(4β→8, 2β→O→7)-epicatechin-3-gallate dimer (A-type ECG dimer) was obtained by further preparative high-performance liquid chromatography (prep-HPLC). The purities of these compounds were all above 95.0% and their structures were identified by HPLC/ESI-MS. We found that HSCCC had definite advantages for the preparation of dimeric procyanidins compared with previous methods. Furthermore, it was shown that the four phenolic compounds possessed greater antioxidant activities than Trolox.

In the present study, the disruptive effects of epigallocatechin-3-gallate (EGCG) and A-type dimeric epigallocatechin-3-gallate (A-type EGCG dimer) on the preformed bovine insulin amyloid fibrils were studied by several biophysical methods including thioflavin-T (ThT) fluorescence assay, 1-anilinonaphthalene-8-sulfonic (ANS) fluorescence assay, Congo red (CR) binding assay, dynamic light scattering (DLS), transmission electron microscopy (TEM), Gel electrophoresis (SDS-PAGE) and Bradford assay. Our results demonstrated that A-type EGCG dimer showed significantly more potential disaggregative effects on the bovine insulin amyloid fibrils than EGCG. A-type EGCG dimer could not only dramatically promote the disaggregation of the preformed bovine insulin amyloid fibrils, but also restructure the amyloid fibrils into amorphous aggregates. While, EGCG could only shorten and thin the fibrils, but induce no small amorphous aggregates. Our present results provided additional evidence for the more potent disaggregation effects of dimeric polyphenols than monomeric polyphenols and suggested that A-type EGCG dimer seems to have potential application as an excellent anti-amyloidogenic agent.

The present study aimed to explore the underlying mechanisms of epicatechin-3-gallate-(4β→8, 2β→O→7)-epicatechin-3-gallate (A-type ECG dimer) and epigallocatechin-3-gallate-(4β→8, 2β→O→7)-epigallocatechin-3-gallate (A-type EGCG dimer) involved in their strong inhibitory effects on 3T3-L1 preadipocytes differentiation. In the synthetic "lipid raft-like" liposome, A-type ECG and EGCG dimers incorporated into the liposome with high affinity and decreased the fluidity of the liposome. In 3T3-L1 preadipocytes, A-type ECG and EGCG dimers possibly bonded to lipid rafts cholesterol and disrupted the integrity of lipid rafts, thus exerting their notable inhibitory effects on 3T3-L1 preadipocytes differentiation by suppressing mitotic clonal expansion process and mRNA levels of PPARγ, C/EBPα and SREBP1C. A highly positive correlation between the cholesterol binding capacity of the two dimers and their inhibitory effect on 3T3-L1 preadipocytes differentiation (R2=0.9328) was observed. Molecular dynamics simulation further verified that A-type ECG and EGCG dimers could bond to cholesterol via hydrogen bonding. The results of this study suggested that the disruption of A-type ECG and EGCG dimers on membrane lipid rafts by targeting cholesterol in the lipid rafts was involved in the underlying mechanisms of their strong inhibitory effects on 3T3-L1 preadipocytes differentiation. This broadens the understanding of the molecular mechanisms of polyphenols on modulating and controlling of metabolic dysregulation, particularly adipocyte differentiation, which is a significant risk factor associated with the development of cardiovascular disease.

Persimmon tannin (PT) has been shown to inhibit snake venom activities and toxicities both in vitro and in vivo. To clarify the detoxifying mechanism of PT on snake venom, the interaction of characteristic structural elements of PT (EGCG, ECG, EGCG dimer and ECG dimer) and Chinese cobra phospholipase A2 (PLA2) was studied. The results revealed that except non-covalent bonds like hydrogen bonds, hydrophobic bonds and iron bonds were formed between PT and PLA2, covalent interaction was also occurred. PT could bind with the key active residues of PLA2, such as lysine, histidine, tryptophan and tyrosine, restraining their activity and disturbing the structure of PLA2, thus showing detoxifying effects on snake venom.

Penta-O-galloyl-β-d-glucose (PGG) was purified and identified from Radix Paeoniae Alba by HSCCC and HPLC/ESI-MS, and its inhibitory effects on adipogenesis and TNF-α-induced inflammation were assessed in 3T3-L1 cell line. The results showed that PGG dose-dependently reduced intracellular lipids accumulation, and this involved decrease the expression levels of major adipogenic markers, PPARγ, C/EBP α, through MAPKs inhibition. This was accompanied by a reduction of lipogenic genes, ACC, FAS, and SCD-1, involved in fatty acid synthesis. Furthermore, PGG also inhibited TNF-α-induced expression of inflammatory cytokines including IL-6 and MCP-1 in the matured 3T3-L1 adipocytes. The inhibitions were likely mediated by blocking the MAPKs and NF-κB activation. These findings highlighted that PGG could serve as a potent therapeutic agent for controlling obesity and obesity-related chronic inflammation.

Proanthocyanidins (PAs) have been widely recognized for their broad spectrum of beneficial health effects, which are highly structure-dependent. It was found that PA dimers epicatechin-3-gallate-(4β→8,2β→O→7)-epicatechin-3-gallate (A-type ECG dimer) and epigallocatechin-3-gallate-(4β→,2β→O→7)-epigallocatechin-3-gallate (A-type EGCG dimer) inhibit the differentiation of 3T3-L1 cells significantly, whereas epicatechin-(4β→8,2β→O→7)-epicatechin (A-type EC dimer) and epicatechin-(4β→8)-epicatechin (B-type EC dimer) showed little effect in previous work. However, the underlying mechanisms are unclear. To test whether bilayer perturbation may underlie this diversity of actions, we examined the bilayer-modifying effects of the four dimers in both 3T3-L1 cell and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine liposome models by using scanning electron microscopy, fluorescent spectroscopy, differential scanning calorimetry, and molecular dynamics methods. Our results revealed that A-type ECG and EGCG dimers had a high affinity for the lipid bilayer and could form simultaneous hydrogen bonds (H-bond) with both the surface oxygen acceptors and the deeper inside lipid oxygen atoms. However, A-type and B-type EC dimers contacted only the surface oxygen atoms with limited and significantly fewer H-bonds. A-type ECG and EGCG dimers notably distorted the membrane morphology of 3T3-L1 cells. In the present study, we found there was a high positive correlation between the membrane-disturbing abilities of the four dimers and their 3T3-L1 cell differentiation inhibitory effects as previously reported. This indicated that the strong 3T3-L1 cell differentiation inhibitory effect of A-type ECG and EGCG dimers might be due to their strong bilayer-perturbing potency.

Persimmon tannin (proanthocyanidins) has been proven to exert significant hypocholesterolaemic effects in a variety of models. However, the regulatory mechanisms of persimmon tannin on cholesterol metabolism have yet to be fully understood. The present study investigated the regulation of persimmon tannin on the expression of genes critical for cholesterol absorption and cholesterol efflux. Our results indicated that persimmon tannin reduced the uptake of 22-NBD-cholesterol and inhibited the accumulation of cholesterol significantly in HepG2 and Caco-2 cell lines. The mRNA and proteins were quantified using real time PCR and western blot, respectively. The expression of SREBP-2 gene, critical for cholesterol synthesis, and NPC1L1 involved in cholesterol absorption were significantly inhibited by persimmon tannin. Moreover, persimmon tannin showed potential in promoting cholesterol efflux through up-regulating mRNA and/or protein levels of ABCA1, ABCG1, SR-BI, CYP7A1 and ABCG5/G8. However, the regulation effects of persimmon tannin on cholesterol homeostasis in both cell lines were LXRα independent.

In this study, a green approach to prepare both porous and dense antifouling membranes was developed through solvent-free bulk polymerization of the casting solution containing 2-hydroxyethyl methacrylate (HEMA) and pre-dispersed silica nanoparticles in two glass sheets under pressure. Porous polyHEMA membranes were prepared via removing the silica nanoparticles embedded in the polymer matrix. Dense poly(HEMA/MAA)/SiO2 membranes were fabricated by adding methacrylic acid (MAA) as co-monomer without removing the silica nanoparticles. Membrane thickness could be conveniently controlled by varying the distance between the two slide glasses. Field emission scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and water contact angle measurement were employed to characterize the morphology and surface chemical composition of the resultant membranes. The porous polyHEMA membranes exhibited high efficiency in purification of bovine serum albumin (BSA) from BSA/yeast solution while the dense poly(HEMA/MAA)/SiO2 membranes exhibited high rejection of orange GII. Both porous membranes and dense membranes exhibited strong hydrophilicity as a result of hydrophilic monomer HEMA, leading to good antifouling properties.

It is well known that the biological activity of gallated proanthocyanidins (PAs) is highly structure-dependent. Polymerization degree (DP) and linkage types affect their biological activity greatly. Positions and orientations of gallated PAs in lipid bilayer reveal their structure-function activity at the molecular level. The present work aimed at determining the locations and orientations of epigallocatechin-3-gallate (EGCG) and its derivatives: A-type and B-type EGCG dimers and trimers in 1-palmitoyl-2-oleoyl phosphatidylcholine (POPC) and 1-palmitoyl-2-oleoyl phosphatidylethanolamine (POPE) lipid bilayer via molecular dynamic (MD) simulations. The results showed that EGCG and its derivatives localized in the lipid bilayer or on the bilayer/water interface. Their penetration depths and orientations depended on both DP and linkage types. The penetration depths decreased with the increase of DP, sequencing to be EGCG > EGCG dimers > EGCG trimers. Spatially stretched A-type PAs could form more hydrogen bonds (H-bonds) with deep oxygen atoms of lipid bilayer and have higher affinity to the lipid bilayer than B-type PAs. Our results will provide an explicit evidence for PAs’ distinct biological activities.

In the present study, an in situ approach to pH and temperature responsive membranes is developed. The membrane matrix is formed through bulk polymerization and crosslinking of liquid monomer 2-hydroxyethyl methacrylate (HEMA) while the membrane pores are formed by the templating of inorganic particles. The functional monomers methacrylic acid (MAA) and N-isopropylacrylamide (NIPAAm) are incorporated into membrane casting solution in order to confer membranes with pH and temperature responsive properties. The poly(HEMA/MAA) membranes exhibit a reversible pH-dependent water flux, while the poly(HEMA/NIPAAm) membranes exhibit a reversible temperature-dependent water flux. The flux of the poly(HEMA/MAA) membrane increased by 70% when pH was decreased from 10.0 to 2.0, while the flux poly(HEMA/NIPAAm) membrane increased by 150% when temperature was increased from 20 to 45 °C. The protein adsorption and antifouling performance of the poly(HEMA/MAA) and poly(HEMA/NIPAAm) membranes also exhibit pH and temperature responsive properties.

Experimental studies have proved the beneficial effects of proanthocyanidins (Pas) relating to interaction with the cell membrane. But the detailed mechanisms and structure-function relationship was unclear. In present study, molecular dynamics (MD) simulations were used to study the interactions of four PA dimers with a lipid bilayer composed of 1:1 mixed 1-palmitoyl-2-oleoyl phosphatidylcholine (POPC) and 1-palmitoyl-2-oleoyl phosphatidylethanolamine (POPE). The results showed that the gallated PA dimers had much higher affinities to the bilayer with lower binding free energies compared with nongallated PA dimers. The gallated PA dimers penetrated deeper into the bilayer and formed more hydrogen bonds (H-bonds) with bilayer oxygen atoms, especially the deeper oxygen atoms of the lipids simultaneously, thus inducing stronger lateral expansion of the membrane and lipid tails disorder. The present results provided molecular insights into the interactions between PA dimers and bio-membranes and agreed with our experimental results well. These molecular interactions helped to elucidate the structure-function relationship of the PA dimers and provided a foundation for a better understanding of the underlying mechanisms of the bioactivities of PA oligomers.

Scope Excessive fat accumulation in adipose tissue leads to obesity and related chronic inflammation. This study aims to examine the effects of gallocatechin -(4→8)-gallocatechin-3-O-gallate (GC-(4→8)-GCG), a main proanthocyanidin dimer from Camellia ptilophylla (Cocoa tea), on adipocyte- and adipose-related inflammation in vivo and in vitro. Methods and results C57BL/6 mice are fed a high-fat diet (HFD) and GC-(4→8)-GCG (40 or 80 mg kg-1 d-1 ) for 8 weeks. The metabolic profiles, adipose tissue hypertrophy, macrophage infiltration, and inflammatory cytokine production are investigated. Additionally, 3T3-L1 preadipocytes are utilized to investigate the effect of GC-(4→8)-GCG on preadipocyte differentiation and the tumor necrosis factor (TNF)-α-stimulated inflammatory response in vitro. GC-(4→8)-GCG supplementation decreases HFD-induced epididymal white adipose tissue (eWAT) hypertrophy, suppresses proinflammatory cytokine production and macrophage infiltration in eWAT, and improves insulin sensitivity in HFD-induced obese mice. In vitro, GC-(4→8)-GCG shows a strong anti-adipogenic potential in 3T3-L1 preadipocyte by inhibiting the expression of key adipogenic transcription factors and decreasing the production of proinflammatory cytokines by inhibiting the activation of the nuclear factor (NF)-κB, Janus tyrosine kinase/signal transducer and activator of transcription (JAK/STAT3) and mitogen-activated protein kinase (MAPK) signaling pathways. Conclusion GC-(4→8)-GCG can modulate obesity and improve obesity-related insulin resistance by inhibiting preadipocyte differentiation and the related proinflammatory responses.

In this study, a solvent-free approach to antifouling membranes is tentatively presented. The membrane bulk matrix is formed through bulk polymerization of liquid monomer 2-hydroxyethyl methacrylate (HEMA) in the absence of an organic solvent. The membrane pores are formed via removal of silica particles generated from the sol–gel process of tetraethyl orthosilicate. The membranes have a homogeneous structure and acquire water flux around 1020 L m–2 h–1 at 0.1 MPa. The rates of rejection of the yeast and oil droplet for all the polyHEMA membranes are above 97.0 and 99.0%, respectively. The polyHEMA membranes exhibit strong hydrophilic and excellent fouling resistance properties as a result of hydrophilic HEMA. The flux recovery ratio is as high as 91.0% using protein as a foulant. After the fluorine-containing additive dodecafluoroheptyl methacrylate (DFHM) had been blended in a casting solution, the poly(HEMA/DFHM) membranes possess an amphiphilic surface and exhibit excellent fouling resistance as well ...

In nature, surfaces simultaneously possessing antifouling and self-cleaning properties allow living systems to sustain diverse functions. Integrating these features into synthetic surfaces will open a novel avenue to advanced surface-based or surface-governed technologies for medical, industrial, ocean, and environmental applications. In this study, we report in situ engineered porous membrane surfaces with hierarchical structure: the external membrane surfaces are covered with zwitterionic (hydrophilic) and low surface energy brushes, endowing the membranes with superior antifouling and self-cleaning abilities. The surface composition, hydrophilicity and surface energy are assessed for the valuation of the antifouling and self-cleaning potential of the membranes. When utilized for model wastewater treatment, the membrane fouling is exquisitely suppressed: permeation flux-decline is decreased to an ultralow level (less than 1%) and permeation flux recovery after simple hydraulic washing is retained at nearly 100%. The present method can be extended to the construction and modification of a broad range surfaces.

Composite nanofiltration membranes comprising polyamide active layer and polyacrylonitrile (PAN) support were prepared by 1-ethyl-(3-3-dimethylaminopropyl) carbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS) mediated interfacial polymerization. PAN support was first hydrolyzed to create carboxyl groups on surface, which were then activated by EDC/NHS to enhance reactivity with amine groups. Afterwards, activated PAN support was impregnated in aqueous phase containing piperazine (PIP). Finally, PIP impregnated PAN support was immersed in organic phase containing trimesoyl chloride (TMC), where the polyamide active layer was formed on the hydrolyzed PAN support. Fourier Transform Infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis verified the formation of amide bonds between PIP molecules and carboxyl groups on the hydrolyzed PAN support. Variation energy positron annihilation spectroscopy (VEPAS) measurement manifested that the active layer and interfacial zone of composite membrane became denser owing to EDC/NHS activation. The water flux slightly decreased but the rejection of Orange GII remarkably increased with an increase in EDC concentration. The composite membrane prepared at EDC concentration 100 mM and PIP concentration 0.20 wt% exhibited a flux of MgSO4 solution as high as 511 L/(m(2) h MPa) while the rejection reached 98.5%. The structural stability of the composite membranes after EDC/NHS treatment was greatly enhanced as tested by alcohol treatment. (C) 2012 Elsevier B.V. All rights reserved.

In this study, a novel kind of fluorinated polyacrylonitrile (PAN) membrane is prepared by grafting perfluoroalkyl groups onto aminated PAN membrane surface through the acylation reaction. The surface composition of the fluorinated PAN membranes is confirmed by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The changes of membrane surface hydrophilicity, chemical heterogeneity and surface free energy after fluorination treatment are evaluated by contact angle measurement. When utilized for the ultrafiltration separation of oil/water emulsion, protein aqueous solution and polysaccharide aqueous solution, the fluorinated PAN membranes exhibit superior fouling release properties, that is, high flux recovery ratio (∼99%) and low total flux decline ratio (the minimal value is ∼13%). These results demonstrate the feasibility of grafting perfluoroalkyl groups onto the membrane surfaces to manipulate the physicochemical features and improve antifouling property. Moreover, the fluorinated PAN membranes acquire distinct reversible multi-responsive properties under ionic strength and pH stimuli.

Because fibrillary protein aggregates is regarded to be closely associated with many diseases such as Alzheimer's disease, diabetes, and Parkinson's disease, growing interest and researches have been focused on finding potential fibrillation inhibitors. In the present study, the inhibitory effects of epigallocatechin-3-gallate (EGCG) and A-type dimeric epigallocatechin-3-gallate (A-type EGCG dimer) on the formation of insulin fibrillation were compared by multi-dimensional approaches including thioflavin-T (ThT) fluorescence assay, 1-anilinonaphthalene-8-sulfonic (ANS) fluorescence assay, dynamic light scattering (DLS), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and circular dichroism (CD) spectroscopy. Our results confirmed that A-type EGCG dimer is a more potent inhibitor against the formation of bovine insulin amyloid fibril than EGCG. In addition, A-type EGCG dimer could not only inhibit insulin amyloid fibril formation, but also change the aggregation pathway and induce bovine insulin into amorphous aggregates. The results of the present study may provide a new guide on finding novel anti-amyloidogenic agents.

Polyvinyl chloride (PVC) and chlorinated polyvinyl chloride (CPVC) were used as membrane materials to fabricate blend ultrafiltration membranes. Polyethylene glycol (PEG2000) and polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer (Pluronic F127) were used as both pore forming agent and surface modifier to improve the permeability. The advantage of amphiphilic Pluronic F127 is that it enables higher −CH2–CH2–O– segment coverage on the membrane surfaces. The increase of CPVC proportion in membrane materials could improve the water fluxes of PVC/CPVC blend membranes with the slight change of protein rejection ratios. All the PVC/CPVC blend membranes with an additive of Pluronic F127 have excellent antifouling property. The blend method is an appropriate way to prepare new antifouling PVC/CPVC ultrafiltration membranes which have lower cost and better performance.

A novel kind of block-like copolymer poly(butyl methacrylate)-b-poly(methacrylic acid)-b-poly(hexafluorobutyl methacrylate) (PBMA-b-PMAA-b-PHFBM) with hydrophobic segments, hydrophilic segments and fluorine-containing segments was prepared by free radical polymerization method. The copolymers were incorporated into PES ultrafiltration membranes through a wet phase inversion method. The surface enrichment of hydrophilic segments and fluorine-containing segments of the copolymer due to the spontaneous and forced surface segregation during non-solvent induced phase separation process was confirmed by X-ray photoelectron spectroscopy (XPS). The modified membranes displayed distinct pH-responsive permeability. The water flux of PES/PBMA 5 -b-PMAA 4.6 -b-PHFBM 1.1 membrane could significantly decrease from 150 L/(m 2 h) to 75 L/(m 2 h) in the pH region of 4.8–6.2. Meanwhile, the modified membranes exhibited desirable fouling release property mainly derived from fluorine-containing segments. The highest cleaning efficiency of the modified membranes could reach 57.4% compared with that less than 5% of the blank membranes.

A novel approach was developed in the present work that antifouling composite nanofiltration membranes were directly and efficiently fabricated with antifouling ultrafiltration membranes. Pluronic F127/polyethersulfone (PES) ultrafiltration membranes with enriched poly(ethylene oxide) (PEO) segments on the surfaces were selected as supporting layers and piperaine (PIP) and trimesoyl chloride (TMC) were used as monomers to fabricate the composite polyamide nanofiltration membranes. X-ray photoelectron spectroscopy (XPS) measurement showed that there were higher 0 contents on the surfaces of nanofiltration membranes, the high solution O1s core-level XPS spectra gave important information that the appearance of PEO segments in the polyamide layer. The water permeability and rejection property of the composite nanofiltration membrane with Pluronic F127 in substrate were better than that without Pluronic F127. Three different pollution systems were chosen to prove the excellent antifouling property of the composite nanofiltration membranes, whose water fluxes were completely recovered by simple water washing. (C) 2011 Elsevier B.V. All rights reserved.

In this study, orange G dye was efficiently removed from aqueous solution by ultrafiltration (UF) membrane separation enhanced with activated carbon adsorption. The powdered activated carbon (PAC) was deposited onto the UF membrane surface, forming an intact filter cake. The enhanced UF process simultaneously exploited the high water permeation flux of porous membrane and the high adsorption ability of PAC toward dye molecules. The influencing factors on the dye removal were investigated. The results indicated that with sufficient PAC incorporation, the formation of intact PAC filtration cake led to nearly complete rejection for dye solution under optimized dye concentration and operation pressure, without large sacrificing the permeation flux of the filtration process. Typically, the dye rejection ratio increased from 43.6% for single UF without adsorption to nearly 100% for the enhanced UF process, achieving long time continuous treatment with water permeation flux of 47 L·m −2 ·h −1 . The present study demonstrated that adsorption enhanced UF may be a feasible method for the dye wastewater treatment.

In the present study, a facile in situ approach for constructing tunable amphiphilic or hydrophilic antifouling membrane surfaces was demonstrated by exquisitely manipulating the microphase separation and surface segregation behavior of the tailor-made ternary amphiphilic block copolymers during the commonly utilized wet phase inversion membrane-formation process. Under dead-end filtration for oily wastewater treatment, the membrane with amphiphilic surface exhibited over 99.5% retention ratio of chemical oxygen demand (COD) without appreciable membrane fouling: the water permeation flux was slightly decreased during operation (total flux decline was 6.8%) and almost completely recovered to the initial value (flux recovery ratio was more than 99.0%) after simple hydraulic washing. While for the proteins-containing wastewater treatment, the membrane with hydrophilic surface exhibited about 52.6% COD retention ratio and superior antifouling performance: only 17.0% total flux decline and also more than 99.0% flux recovery ratio. Hopefully, the present approach can be developed as a competitive platform technology for the preparation of robust and versatile antifouling membrane, leading to the high process efficiency of wastewater treatments.

Pluronic F127/polyethersulfone (PES) blend nanofiltration membranes were fabricated by varying polymer weight ratios of WF127/WPES in casting solutions from 0.0 to 100.0 wt %. The initial wet membranes prepared via the phase inversion method were post-treated by drying at room temperature and then immersion into water for rewetting to obtain Pluronic F127/PES nanofiltration membranes. Membrane shrinkage and swelling, cross section and surface morphologies, water uptake, surface hydrophilicity, X-ray diffraction pattern, water flux, and rejection of dyes for Pluronic F127/PES nanofiltration membranes were investigated. The introduction of Pluronic F127 into PES membranes can substantially alleviate the membrane shrinkage during drying treatment. All of the prepared Pluronic F127/PES nanofiltration membranes can completely reject Alcian blue with a molecular weight of 1299. The water permeance of Pluronic F127/PES nanofiltration membrane at WF127/WPES of 80% is as high as 176.2 L/(m2 h MPa). After long-term...

Critical care doctors are frequently faced with clinical problems that have important ethical and moral dimensions. While Western attitudes and practice are well documented, little is known of the attitudes or practice of Chinese critical care doctors. An anonymous, written, structured questionnaire survey was translated from previously reported ethical surveys used in Europe and Hong Kong. A snowball method was used to identify 534 potential participants from 21 regions in China. A total of 315 (59%) valid responses were analysed. Most respondents (66%) reported that admission to an intensive care unit (ICU) was commonly limited by bed availability, but most (63%) would admit patients with a poor prognosis to ICU. Only 19% of respondents gave complete information to patients and family, with most providing individually adjusted information, based on prognosis and the recipient’s educational level. Only 28% disclosed all details of an iatrogenic incident, despite 62% stating that they should. The use of do not resuscitate orders or limitation of life-sustaining therapy in terminally ill patients reported as uncommon and according to comparable reports, both are more common practice in Hong Kong or Europe. In contrast to European practices, doctors were more acquiescent to families in decision-making at the end of life. A number of differences in ethical attitudes and related behaviour between Chinese, Hong Kong and European ICU doctors were documented. A likely explanation is differing cultural background, and doctors should be aware of likely expectations when treating patients from a different culture.

The suppression of nonspecific protein adsorption to synthetic surfaces, especially membrane surfaces, represents a severe challenge in biotechnological, biomedical and biosensor community. In this work, we utilize short-chain molecules rather than long-chain polymers as modifiers for antibiofouling membrane surface construction. Three types of natural amino acids, including lysine, glycine, and serine, were chemically grafted onto membranes via carbodiimide chemistry to render highly hydrophilic surfaces, which displayed the intrinsic advantages in high surface coverage, three-dimensional modification, and unsacrificed permeability. Although hydrophilicity of membranes modified with these three types of amino acids was quite close, only lysine modified membrane surface showed superior protein fouling resistance under both static exposure and dynamic filtration conditions. Molecular dynamics simulation study was performed to tentatively interpret the underlying differences.

Unlike biofoulants/pollutants, oil foulants/pollutants are prone to coalesce, spread and migrate to form continuous fouling layer covering on the surfaces. Therefore, such kind of fouling can not be simply alleviated by hydrophilic modification with currently extensively used antifouling materials such as poly(ethylene glycol) (PEG)-based or zwitterionic polymers etc. In the present study, an amphiphilic porous membrane surface, comprising hydrophilic fouling resistant domains and hydrophobic fouling release microdomains, is explored via a "forced surface segregation" approach. The resultant membranes exhibit both superior oil-fouling and bio-fouling resistant property: membrane fouling is exquisitely suppressed and the permeation flux-decline is decreased to an ultralow level. It can be envisaged that the present study may open a novel avenue to the design and construction of robust, versatile antifouling surfaces.

Poly(ether sulfone) (PES) ultrafiltration membranes are fabricated via nonsolvent-induced phase separation by blending with hydrophilic homopolymer additive poly(ethylene glycol) (PEG) or amphiphilic block copolymer Pluronic F127. The effects of coagulation bath temperature (CBT) on membrane structure, separation performance, and antifouling property are investigated in detail. All the membranes display an asymmetric morphology. PES/PEG membranes possess only fingerlike pores of support layer, while there is a spongelike sublayer between skin layer and the fingerlike pores for PES/Pluronic F127 membranes. The thickness of the spongelike sublayer for PES/Pluronic F127 membranes is remarkablely decreased with the increase of CBT. For all the membranes, pure water flux increases substantially with the increase of CBT. The rejection of PES/PEG membrane for bovine serum albumin (BSA) is above 95%. However, the rejection of PES/Pluronic F127 membrane for BSA molecules is decreased sharply form 95.3% to 10.2% wi...

Facile graft polymerization of methacrylic acid (MAA) onto polyethersulfone (PES) using benzoyl peroxide (BPO) as chemical initiator had been developed. The polymerization was carried out in a heterogeneous polymer–monomer reaction system using water as reaction medium. The crucial parameters affecting the graft yield, such as monomer concentration, reaction time and temperature, were studied. The amount of grafted PMAA on PES was increased with increasing monomer concentration and reaction time. The optimum temperature for the grafting was around 75 °C. The graft polymers produced herein were cast into ultrafiltration membranes via phase inversion process. The cross-sectional morphology and surface composition of the membranes were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. Remarkable surface enrichment of the hydrophilic MAA segment in the membrane was revealed by XPS analysis. Due to the pH-induced conformational transition of the PMAA chains, the permeability of the membranes cast from the grafted polymers displayed pronounced pH dependence, which was large under low pH values and small under high pH values.

Due to its rigid and tunable structure, inorganic pore-forming agent may exhibit the great potential in fabricating membranes with high flux. In this study, in situ generation of silica (SiO2) nanoparticles was coupled with polymer phase separation process for preparing cellulose acetate (CA) membranes with enhanced permeation property. The pH values of coagulation bath were adjusted with acid and basic solutions to perform the hydrolysis and polycondensation reaction of tetraethyl orthosilicate (TEOS) precursor at moderate rate. The pore-forming mechanism of the generated SiO2 nanoparticles was tentatively proposed. Majority of SiO2 nanoparticles were instantly extracted into the coagulation bath during the phase inversion process and the spaces they once occupied turned into the pores of membranes, ensuring the great improved permeability of the CA membranes. The remained nanoparticles were mostly enriched and homogenously distributed on the membrane surface without lowering the hydrophilicity of CA membranes. Ultrafiltration experiments showed that the as-fabricated CA membranes exhibited higher permeability and kept superior antifouling properties compared with the control CA membrane in oil/water emulsion separation.

Polyethersulfone (PES) membranes modified by the amphiphilic copolymer Pluronic F127 were applied to the separation of oil/water emulsion. Due to the enhanced surface hydrophilicity, all the PES/Pluronic F127 membranes exhibited higher permeate flux and better antifouling property compared with the control membrane. When the weight ratio of Pluronic F127 to PES (WF127/WPES) in the membrane casting solution was increased from 0 to 20%, the flux of oily feed solution was increased from 42.77 to 82.98 L/m2h with 100% oil rejection. There was no flux recovery for all used membranes when being washed with pure water. However, the flux recovery ratio could be increased to 93.33% when washing with sodium dodecylsulfate (SDS) solution. It was proposed that the presence of surfactant prevented the deposited oil droplets from coalescing with each other and spreading on membrane surface (including membrane pore surface).

A mild and facile grafting of poly(ether glycol) methyl ether methacrylate (PEGMA) monomers onto polyethersulfone (PES) was carried out. Then, the PES-g-PEGMA membranes with integrally anisotropic morphology were fabricated through the coupling of non-solvent induced phase inversion and surface segregation. Compared with PES control membrane, the surface hydrophilicity of PES-g-PEGMA membranes was remarkably enhanced due to the drastic enrichment of poly(ethylene glycol) (PEG) segments on the membrane surface; protein adsorption was significantly inhibited due to the hydrogen bonding interactions between hydrophilic groups and water molecules. Ultrafiltration experiments were used to assess the permeability and protein fouling resistance of the PES-g-PEGMA membranes. It was found that the PES-g-PEGMA membranes with higher surface coverage of PEG segments displayed stronger antibiofouling property. Moreover, the stable antibiofouling property for PES-g-PEGMA membranes was acquired due to covalent bonding interactions between hydrophilic PEGMA side chains and PES main chains.

Constructing anti-fouling and self-cleaning membrane surfaces based on covalent attachment of trypsin on poly(methacrylic acid)-graft-polyethersulfone (PMAA-g-PES) membrane was reported. The carboxylic acid groups enriched on asymmetric PMAA-g-PES membrane surface were activated with 1-ethyl-(3-3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS) and employed as chemical anchors for the conjugation with amino groups of trypsin. Activity assays showed that such chemically immobilized trypsin was much more active and stable than that of the physically adsorbed counterpart. Trypsin covalently attached on membrane surface could substantially resist protein fouling in dynamic flow process. The considerable enhancement of protein solution permeation flux was observed as a consequence of rapid enzymatic degradation of protein deposited onto membrane surface. The permeation flux of the membrane could be recovered upon simple hydraulic flush after protein filtration, suggesting superior self-cleaning property. After multi-cycle BSA filtration over 15-day period, the active self-cleaning membrane maintained more than 95.0% of its initial flux.