Controlled Thermal Release of L-Menthol with Cellulose-Acetate-Fiber-Shelled Metal-Organic Framework.

Fragrances have been widely used in many customer products to improve the sensory quality and cover flavor defects. The key to the successful application of fragrance is to realize controlled fragrance release, which relies on the use of an appropriate carrier for fragrance. An ideal fragrance carrier helps to achieve the stable storage and controlled release of fragrance. In this work, a novel composite fragrance carrier with MIL-101 (Cr) as the fragrance host and cellulose acetate fiber (CAF) as the protective shell was developed. The encapsulation effect of MIL-101 (Cr) and the protective function of the CAF shell significantly improved the storage stability of L-menthol (LM). Only 5 wt % of LM was lost after 40 days of storage at room temperature. Encapsulated LM could also be effectively released upon heating due to the thermal responsiveness of CAF. In addition, the composite carrier was highly stable with neglectable Cr leaching under different conditions. The results of this work showed that the developed composite carrier could be a promising carrier for the thermally triggered release of fragrance.

Direct three-dimensional imaging of polymer-water interfaces by nanoscale hard X-ray phase tomography.

We report three-dimensional (3D) direct imaging of complex surface-liquid interfaces by hard X-ray phase contrast tomography as a non-destructive approach for the morphological characterization of surfaces at the micro- and nanoscale in contact with water. Specifically, we apply this method to study the solid-air-water interface in hydrophobic macroporous polymethacrylate surfaces, and the solid-oil-water interface in slippery liquid-infused porous surfaces (SLIPS). Varying the isotropic spatial resolution allows the 3D quantitative characterization of individual polymer globules, globular clusters (porosity) as well as the infused lubricant layer on SLIPS. Surface defects were resolved at the globular level. We show the first application of X-ray nanotomography to hydrated surface characterizations and we anticipate that X-ray nanoscale imaging will open new ways for various surface/interface studies.

Nanostructure-based proton exchange membrane for fuel cell applications at high temperature.

As a clean and highly efficient energy source, the proton exchange membrane fuel cell (PEMFC) has been considered an ideal alternative to traditional fossil energy sources. Great efforts have been devoted to realizing the commercialization of the PEMFC in the past decade. To eliminate some technical problems that are associated with the low-temperature operation (such as catalyst poisoning and poor water management), PEMFCs are usually operated at elevated temperatures (e.g., > 100 degrees C). However, traditional proton exchange membrane (PEM) shows poor performance at elevated temperature. To achieve a high-performance PEM for high temperature fuel cell applications, novel PEMs, which are based on nanostructures, have been developed recently. In this review, we discuss and summarize the methods for fabricating the nanostructure-based PEMs for PEMFC operated at elevated temperatures and the high temperature performance of these PEMs. We also give an outlook on the rational design and development of the nanostructure-based PEMs.

Efficient removal of ethidium bromide from aqueous solutions using chromatin-loaded chitosan polyvinyl alcohol composites.

In this work, a novel chromatin-loaded chitosan polyvinyl alcohol composite was developed as a simple, efficient and environmentally friendly adsorbent for the efficient removal of ethidium bromide (EtBr). SEM images showed that the composites were characterized by dense porous and uniformly distributed morphology. The BET analysis showed the presence of mesopores and macropores in the composites. FTIR and XRD results showed that the chromatin was uniformly dispersed in the chitosan-polyvinyl alcohol carrier through hydrogen bonding. The fluorescence microscopy images showed the change of fluorescence effect before and after the adsorption of the material, which indicated that the chromatin was uniformly distributed in the composites and had a good adsorption effect. The optimal experimental conditions were T = 30℃, t = 120 min, pH = 7.4, m = 0.2 g when the composite with only 5% chromatin content had the ability to adsorb EtBr efficiently (minimum concentration 2 mg·L-1: adsorption rate 99%; maximum concentration 20 mg·L-1: adsorption rate 90%).The adsorption kinetics and thermodynamics showed that the EtBr adsorption kinetics of the composite conformed to the pseudo-second-order kinetic model (0.995 < R2 < 0.999) and the Freundlich isothermal model, and was a spontaneous process (ΔH < 0). This study on the immobilization of chromatin will provide a new way and reference for the application of chromatin in the treatment of EtBr pollutants.

Injectable Double Crosslinked Hydrogel-Polypropylene Composite Mesh for Repairing Full-Thickness Abdominal Wall Defects.

Abdominal wall defects are common clinical diseases, and mesh repair is the standard treatment method. The most commonly used polypropylene (PP) mesh in clinical practice has the advantages of good mechanical properties, stable performance, and effective tissue integration effect. However, direct contact between abdominal viscera and PP mesh can lead to severe abdominal adhesions. To prevent this, the development of a hydrogel-PP composite mesh with anti-adhesive properties may be an effective measure. Herein, biofunctional hydrogel loaded with rosmarinic acid is developed by modifying chitosan and Pluronic F127, which possesses suitable physical and chemical properties and commendable in vitro biocompatibility. In the repair of full-thickness abdominal wall defects in rats, hydrogels are injected onto the surface of PP mesh and applied to intraperitoneal repair. The results indicate that the use of hydrogel-PP composite mesh can alleviate abdominal adhesions resulting from traditional PP mesh implantation by decreasing local inflammatory response, reducing oxidative stress, and regulating the fibrinolytic system. Combined with the tissue integration ability of PP mesh, hydrogel-PP composite mesh has great potential for repairing full-thickness abdominal wall defects.

Formation of a polymer surface with a gradient of pore size using a microfluidic chip.

Here we demonstrate the generation of polymer monolithic surfaces possessing a gradient of pore and polymer globule sizes from ~0.1 to ~0.5 µm defined by the composition of two polymerization mixtures injected into a microfluidic chip. To generate the gradient, we used a PDMS microfluidic chip with a cascade micromixer with a subsequent reaction chamber for the formation of a continuous gradient film. The micromixer has zigzag channels of 400 × 680 µm(2) cross section and six cascades. The chip was used with a reversible bonding connection, realized by curing agent coating. After polymerization in the microfluidic chip the reversible bond was opened, resulting in a 450 µm thick polymer film possessing the pore size gradient. The gradient formation in the microfluidic reaction chamber was studied using microscopic laser-induced fluorescence (µLIF) and different model fluids. Formation of linear gradients was shown using the fluids of the same density by both diffusive mixing at flow rates of 0.001 mL/min and in a convective mixing regime at flow rates of 20 mL/min. By using different density fluids, formation of a two-dimensional wedge-like gradient controlled by the density difference and orientation of the microfluidic chip was observed.

Graphene composite paper synergized with micro/nanocellulose-fiber and silk fibroin for flexible strain sensor.

The fabrication of uniform and strong graphene-based conductive paper is challenging due to easy aggregation and poor film formability of graphene. Herein, on the basis of good dispersing effect of nanocellulose, high content graphene (50 wt%) composite paper with micro/nanocellulose fibers and silk fibroin (SF) was manufactured via simple casting method. The synergistic effects of cellulose microfibers (CMFs), cellulose nanofibers (CNFs) and SF result in the paper with ideal combination of flexibility, electrical conductivity and mechanical strength, where CNFs, CMFs and SF act as dispersing and film forming for GNPs, dimensional stability, and interfacial binding agents, respectively. Extraordinarily, by adding SF, graphene nanosheets are tightly coated on the surface of CMFs. The composite paper shows a tensile strength of 49.29 MPa, surface resistance of 39.0-42.1 Ω and good joints bend sensing performance. Additionally, it is found that CMFs can hinder the micro-cracks from propagating during the cyclic elbow bending test. The graphene-based conductive paper is helpful for the development of smart clothing wearable biosensing devices.

Printable superhydrophilic-superhydrophobic micropatterns based on supported lipid layers.

A new and simple method for creating superhydrophilic micropatterns on a superhydrophobic surface is demonstrated. The method is based on printing an "ink", an ethanol solution of a phospholipid, onto a porous superhydrophobic surface and, thus, is compatible with a variety of commonly available printing techniques.

The salvage of mesh infection after hernia repair with the use of negative pressure wound therapy (NPWT), a systematic review.

BACKGROUND: Mesh infection is the most feared postoperative complication after abdominal wall hernia repair, often needs mesh removal. Negative pressure wound therapy (NPWT) has been used in these situations with diverse results. The aim of this study was to investigate the efficacy of the NPWT in the treatment of mesh infection, the primary outcome was the mesh salvage rates of different type of meshes and mesh positions. METHODS: Major databases were searched using the keywords negative pressure wound therapy, VSD, vacuum assisted, hernia, mesh infection, including various combinations of the terms. All relevant articles and reference lists in these original studies were also obtained from the above databases. RESULTS: Ten articles containing 265 patients on the treatment of mesh infection after hernia repair with the use of NPWT method were included. The general infected mesh salvage rate with NPWT was 76.2%. The highest mesh salvage rate was achieved in polypropylene mesh (93.5%), followed by Proceed mesh (83.3%), and the mesh salvage rate was lower in polyester mesh (PCO) (0%) and the ePTFE mesh (14/3%). The salvage rate was higher when mesh placed in the onlay position (82.6%) or retromuscular/sublay position (98.5%), but lower in the IPOM position (55.6%). CONCLUSION: The treatment of mesh infection after hernia repair should be individualized according to the mesh type, mesh position and the severity of infection. Infected mesh with favourable mesh materials (large pore and monofilament polypropylene) and favourable positions (onlay or sublay/retromuscular) can be salvaged with the use of NPWT based conservative method.

Reduction of Abdominal Adhesions with Elecrospun Fiber Membranes in Rat Models.

PURPOSE: The aim of this study was to assess the effects three electrospun fiber membranes on postoperative adhesion formation in rat surgical models. MATERIALS AND METHODS: The PEG-PHBV (polyethylene glycol and poly-ß-hydroxybutyrate valerate), PLA(Polylactic acid) and CS-PEG(chitosan and polyethylene glycol) were used for submicrometric membranes fabrication by electrospinning. A total of 64 SD male rats were randomly divided into 4 groups, one control group and 3 treatment groups, each consisting of 16 rats. The rats were underwent median laparotomy and standardized abrasion of the cecum. The indicated membranes were applied intraperitoneally at the end of the surgical procedure in the treatment groups, while the controls left without treatment. Two and four weeks after surgery respectively, a relaparotomy was made for adhesion grading and histopathological examination, Hydroxyproline (Hyp) levels at the adhesion sites in each group were measured. RESULTS: The electrospun submicrometric membranes significantly reduced not only the incidence of adhesion but also the adhesion grading scales (p < 0.05 compared to the control group) at both two weeks and four weeks after the initial operation. Furthermore, the fibrosis grades were also higher in control groups as compared with the submicrometric membrane groups. Hyp levels in the control group was significant higher than the three experiment groups at both 2 and 4 weeks time points (p < 0.05). There were no statistical differences between the different treatment groups at either time points. CONCLUSIONS: Three electrospun submicrometric membranes were soft, flexible, easy to handle, and effectively reduced adhesion formation in rat modes.

Surgical repair of abdominal wall defect with biomimetic nano/microfibrous hybrid scaffold.

It is universal to repair abdominal wall defects with prosthetic materials in abdominal surgery worldwide, which are associated with high complications and organ damage. At present, the composite nanofibers composed of natural and synthetic polymers as the new type of nano structure scaffold have attracted considerable attention in the field of tissue engineering. In this study we examined the feasibility of using electrospun silk fibroin (SF)/poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) hybrid scaffolds for repairing of abdominal wall defects. Both in vivo and in vitro characterization were evaluated to access efficacy of the nanofiber for tissue regeneration. Our results showed that the electrospun SF/PHBV nanofiber scaffolds could stimulate the expression of TGF-ß1 and Collagen I in fibroblasts in vitro and then promote granulation and connective tissue depositions, but not result in a strong foreign body reaction in vivo. Moreover, we conjectured the potential molecular biological mechanism of SF/PHBV hybrid scaffolds in the process of tissue regeneration. Thus, the SF/PHBV hybrid nanofiber scaffolds have high efficiency and biocompatibility to repair abdominal wall defects.

Targeted delivery of etoposide to cancer cells by folate-modified nanostructured lipid drug delivery system.

CONTEXT: Cardiotoxicity and myelosuppression of etoposide (ETP) limited its clinical application. Targeted drug delivery system could deliver anticancer agents to the target cancerous cells, thus reducing their toxicity. OBJECTIVE: In this study, folate (FA) was applied for the construction of nanostructured lipid carriers (NLCs), and used for targeted delivery of ETP to tumors overexpresses the FA receptors. METHODS: FA-poly (ethylene glycol)-distearoylphosphatidylethanolamine was synthesized. FA decorated and ETP-loaded NLCs (FA-ETP-NLCs) were prepared and the formulation was optimized by Box-Behnken design. Their particle size (PS), zeta potential and drug encapsulation efficiency (EE) was evaluated. In vitro cytotoxicity studies of FA-ETP-NLCs were tested in CT26, SGC7901, NCI-H209 cell lines. In vivo antitumor efficacies of the carriers were evaluated on mice bearing CT26 cells xenografts. RESULTS: The optimum FA-ETP-NLCs formulations had a PS of 120.86 nm. The growth of CT26, SGC790 or NCI-H209 cells in vitro was obviously inhibited. FA-ETP-NLCs also displayed the best antitumor activity than other formulations in vivo. CONCLUSION: The results demonstrated that FA-ETP-NLCs were efficient in selective delivery to CT26, SGC790 or NCI-H209 cells overexpressing the FA receptors. Also, FA-ETP-NLCs can sufficiently transfer ETP to the cancer cells, enhance the antitumor capacity. Thus, FA-ETP-NLCs could prove to be a superior nanomedicine to achieve tumor therapeutic efficacy.

Staple Fixation Against Adhesive Fixation in Laparoscopic Inguinal Hernia Repair: A Meta-Analysis of Randomized Controlled Trials.

PURPOSE: The aim of this article was to compare the outcomes of tissue adhesive fixation and the staple fixation of meshes in laparoscopic inguinal hernia repair. MATERIALS AND METHODS: A systematic literature review was undertaken to identify studies that compare adhesive fixation and staple fixation of meshes in laparoscopic inguinal hernia repair. RESULTS: The present meta-analysis pooled the effects of outcomes of a total of 1228 patients enrolled into 8 randomized controlled trials. Tissue adhesive fixation of the mesh was associated with less chronic postoperative pain after laparoscopic inguinal hernia repair compared with staple fixation (risk difference=-0.06; 95% confidence interval, -0.08, -0.04). However, statistically, there was no significant difference in the incidence of acute postoperative pain, recurrence, hematoma/seroma, and wound infection. CONCLUSION: The use of the tissue adhesive fixation method reduces the incidence of chronic postoperative pain after laparoscopic inguinal hernia repair, and without any changes in the other outcomes.

Theranostic Polymeric Micelles for the Diagnosis and Treatment of Hepatocellular Carcinoma.

Theranostics, which combine molecular imaging (diagnostics) and drug delivery (therapeutics) in a single platform, have recently shown great potential in cancer therapy. In this article, a polymeric micelle was designed and prepared for simultaneous magnetic resonance imaging (MRI) and treatment of hepatocellular carcinoma (HCC). Theranostic micelles were assembled using Poly(lactic acid)-poly(ethylene glycol)-poly(L-lysine)-diethylenetriamine pentaacetic acid (PLA-PEG-PLL-DTPA) and PLA-PEG-PLL-Biotin. The HCC therapeutic paclitaxel (PTX) was encapsulated in the cores and Gd ions for imaging were chelated to the DTPA moieties. Biotinylated alpha-fetoprotein (AFP) antibodies were linked to the micelle surface by a biotin-avidin reaction to form targeted Gd/PTX-loaded micelles (TGPM). TGPM were of spherical or ellipsoidal shape with uniform particle size distribution (147.50 ± 4.71 nm), positive zeta potential (24.45 ± 1.04 mV), and high encapsulation efficiency (88.76 ± 1.64%) and drug loading (1.59 ± 0.06%). The cytotoxicity of TGPM in HepG2 cells was superior to that of Taxol or Gd/PTX-loaded micelles (GPM). In MRI tests in vitro, the T1 relaxivity of TGPM was 21.589 mM(-1) s(-1), 4.4 times higher than Magnevist (r1 = 4.8 mM(-1) s(-1)). In H22 tumor-bearing mice, TGPM significantly increased tumor imaging intensity (more than 3 times) and prolonged imaging time (from 1 to 6 h) compared to Magnevist. In vivo, TGPM exhibited higher anti-tumor efficiency than Taxol and GPM. These results indicate that TGPM has great potential in HCC theranostics.

Preparation of poly(L-lactic acid)-modified polypropylene mesh and its antiadhesion in experimental abdominal wall defect repair.

A new type of polypropylene (PP) hernia mesh, modified with poly(L-lactic acid) (PLLA), was developed and used to repair rat abdominal wall defect. The PP mesh was first treated with oxygen plasma and then grafted with PLLA in phosphorus pentachloride (PCl5 ) solution in dichloride methane. The water contact angle changed during the procedure, and the coverage percentage of PLLA on the PP was about 80%. ATR-FTIR spectroscopy measurements showed the existence of carbonyl group absorption peak (1756.9 cm(-1) ), and atomic force microscope and scanning electron microscope morphological observation indicated that the surface of the PP mesh was covered with PLLA graft. X-ray photoelectron spectroscopy spectra was used to probe chemical group changes and confirmed that the PLLA was grafted onto the PP. A total of 36 Sprague-Dawley rats were randomly divided into six groups, and they received either modified meshes (experimental groups) or PP meshes (control groups) to repair abdominal wall defects. All animals survived until the end of the experiment. Rats in each group were dissected after the operation (after 1 week, 2 weeks, and 1 month, respectively), and the adhesion effects were evaluated. Sections of the mesh parietal peritoneum overlap were examined histologically and graded for inflammation reaction. Compared with the control groups, the experimental groups showed a better ability to resist peritoneal cavity adhesions (P < 0.05), and there was no increase in inflammation formation (P > 0.05). This new type of PLLA-modified PP mesh displayed an additional property of antiadhesion in animal abdominal wall defect repair.

UV-triggered dopamine polymerization: control of polymerization, surface coating, and photopatterning.

UV irradiation is demonstrated to initiate dopamine polymerization and deposition on different surfaces under both acidic and basic pH. The observed acceleration of the dopamine polymerization is explained by the UV-induced formation of reactive oxygen species that trigger dopamine polymerization. The UV-induced dopamine polymerization leads to a better control over polydopamine deposition and formation of functional polydopamine micropatterns.

Hydrophobic liquid-infused porous polymer surfaces for antibacterial applications.

Biofilms represent a fundamental problem in environmental biology, water technology, food hygiene as well as in medical and technical systems. Recently introduced slippery liquid-infused porous surface (SLIPS) showed great promise for preventing biofilm formation owing to the low surface energy of such surface in combination with its self-cleaning properties. In this study we demonstrated a novel hydrophobic liquid-infused porous poly(butyl methacrylate-co-ethylene dimethacrylate) surface (slippery BMA-EDMA) with bacteria-resistance in BM2 mineral medium and long-term stability in aqueous environments. We showed that the slippery BMA-EDMA surface prevents biofilm formation of different strains of opportunistic pathogen Pseudomonas aeruginosa for at least up to 7 days in low nutrient medium. Only ∼1.8% of the slippery surface was covered by the environmental P. aeruginosa PA49 strain under investigation. In uncoated glass controls the coverage of surfaces reached ∼55% under the same conditions. However, in high nutrient medium, more relevant to physiological conditions, the biofilm formation on the slippery surface turned out to be highly dependent on the bacterial strain. Although the slippery surface could prevent biofilm formation of most of the P. aeruginosa strains tested (∼1% surface coverage), the multiresistant P. aeruginosa strain isolated from wastewater was able to cover up to 12% of the surface during 7 days of incubation. RAPD-PCR analysis of the used P. aeruginosa strains demonstrated their high genome variability, which might be responsible for their difference in biofilm formation on the slippery BMA-EDMA surface. The results show that although the slippery BMA-EDMA surface has a great potential against biofilm formation, the generality of its bacteria resistant properties is still to be improved.

Slippery liquid-infused porous surfaces showing marine antibiofouling properties.

Marine biofouling is a longstanding problem because of the constant challenges placed by various fouling species and increasingly restricted environmental regulations for antifouling coatings. Novel nonbiocidal strategies to control biofouling will necessitate a multifunctional approach to coating design. Here we show that slippery liquid-infused porous surfaces (SLIPSs) provide another possible strategy to obtaining promising antifouling coatings. Microporous butyl methacrylate-ethylene dimethacrylate (BMA-EDMA) surfaces are prepared via UV-initiated free-radical polymerization. Subsequent infusion of fluorocarbon lubricants (Krytox103, Krytox100, and Fluorinert FC-70) into the porous microtexture results in liquid-repellent slippery surfaces. To study the interaction with marine fouling organisms, settlement of zoospores of the alga Ulva linza and cypris larvae of the barnacle Balanus amphitrite is tested in laboratory assays. BMA-EDMA surfaces infused with Krytox103 and Krytox100 exhibit remarkable inhibition of settlement (attachment) of both spores and cyprids to a level comparable to that of a poly(ethylene glycol) (PEG)-terminated self-assembled monolayer. In addition, the adhesion strength of sporelings (young plants) of U. linza is reduced for BMA-EDMA surfaces infused with Krytox103 and Krytox100 compared to pristine (noninfused) BMA-EDMA and BMA-EDMA infused with Fluorinert FC-70. Immersion tests suggest a correlation between the stability of slippery coatings in artificial seawater and fouling resistance efficacy. The results indicate great potential for the application of this concept in fouling-resistant marine coatings.