Anti-adhesion Ability Research Articles

Anti-Fouling Performance of Hydrophobic Hydrogels with Unique Surface Hydrophobicity and Nanoarchitectonics.

Hydrogel is a kind of soft and wet matter, which demonstrates favorable fouling resistance owing to the hydration anti-adhesive surfaces. Different from conventional hydrogels constructed by hydrophilic or amphiphilic polymers, the recently invented “hydrophobic hydrogels” composed of hydrophobic polymers exhibit many unique properties, e.g., surface hydrophobicity and high water content, suggesting promising applications in anti-fouling. In this paper, a series of hydrophobic hydrogels were prepared with different chemical structures and water content for anti-fouling investigations. The hydrophobic hydrogels showed high static water contact angles (WCAs > 90°), indicating remarkable surface hydrophobicity, which is abnormal for conventional hydrogels. Compared with the conventional hydrogels, all the hydrophobic hydrogels exhibited less than 4% E. coli biofilm coverage, showing a contrary trend of anti-fouling ability to the water content inside the polymer. Typically, the poly(2-(2-ethoxyethoxy)ethyl acrylate) (PCBA) and poly(tetrahydrofurfuryl acrylate) (PTHFA) hydrogels with relatively high surface hydrophobicity showed as low as 5.1% and 2.4% E. coli biofilm coverage even after incubation for 7 days in bacteria suspension, which are about 0.32 and 0.15 times of that on the hydrophilic poly(N,N-dimethylacrylamide) (PDMA) hydrogels, respectively. Moreover, the hydrophobic hydrogels exhibited a similar anti-adhesion ability and trend to algae S. platensis. Based on the results, the surface hydrophobicity mainly contributes to the excellent anti-fouling ability of hydrophobic hydrogels. In the meantime, the too-high water content may be somehow detrimental to anti-fouling performance.

Glycosylation increases the anti-QS as well as anti-biofilm and anti-adhesion ability of the cyclo (L-Trp-L-Ser) against Pseudomonas aeruginosa

Pseudomonas aeruginosa infections pose a huge threat to cystic fibrosis patients, as well as those suffering from immunodeficiency. Antimicrobial resistance, especially multi-drug resistance, due to its ability to aggregate the compact biofilm, makes it more inefficient to treat this pathogen with traditional antibiotics. Biofilm and quorum sensing (QS) have become the alternative targets for treating P. aeruginosa infections. Previously, a cyclic dipeptide cyclo(L-Trp-L-Ser) has been identified as a QS inhibitor of P. aeruginosa. On the other hand, some monosaccharides have been proved lectin-targeting behavior and to mediate biofilm formation and adhesion of P. aeruginosa. We constructed novel cyclic dipeptide-carbohydrate conjugates as a low molecular weight dual-functional QS inhibitor, which can not only enhance its anti-QS activity but also enable good anti-biofilm and anti-adhesion ability. The IC50 of galactosylated c(WS) on biofilm formation and glass adhesion was 1/6 and 1/4 of that of the unmodified cyclic dipeptide, respectively. And the ability to eliminate the preformed biofilm was increased 10-fold. Furthermore, the carbohydrate conjugates can increase the germicidal efficiency of clinical antibiotic azithromycin when used synergistically. Our results provide a novel scaffold for developing anti-virulence adjuvants when taken with clinical antibiotics.

Ibuprofen-Loaded Electrospun PCL/PEG Nanofibrous Membranes for Preventing Postoperative Abdominal Adhesion

Electrospun nanofibrous membranes are a widely used physical barrier for reducing postoperative adhesion. However, these physical barriers could not prevent adhesion formation completely. Because a high-intensity inflammation occurs in the surgical area, the presence of relevant drugs to control such an inflammation is desperately needed. In this study, we fabricated an electrospun composite ibuprofen-loaded poly(ethylene glycol) (PEG)/polycaprolactone (PCL) nanofibrous membrane (NFM) to prevent abdominal adhesions. This membrane aimed to act as a barrier between the abdominal wall and surrounding tissues, without interrupting mass transfer and normal wound healing. Among various fabricated composite NFMs, PCL/25PEG-6% NFMs showed the lowest fiber diameter (448.8 ± 124.4 nm), the smallest pore size (<2 μm), and moderate ultimate stress and strain. The PCL/25PEG-6% NFMs had the lowest water contact angle (≈75°) and the highest drug profile release (≈80%) within 14 days. Furthermore, in vitro toxicity examination of PCL/25PEG-6% toward fibroblast cells demonstrated a cell viability of ≈82% after 3 days, proving its prolonged antiadhesion ability. In addition, the low number of adherent cells with a rounded shape and low cell proliferation on these NFMs indicated their special antiadhesive effects. Collectively, these results indicated that the PCL/25PEG-6% membrane might be a suitable barrier to prevent abdominal adhesion.

Inserting Menthoxytriazine into Poly(ethylene terephthalate) for Inhibiting Microbial Adhesion

Antimicrobial modification of poly(ethylene terephthalate) (PET) is effective in preventing the adhesion and growth of microorganisms on its surface. However, few methods are available to modify PET directly at its backbone to impart the antimicrobial effect. Herein, menthoxytriazine-modified PET (PMETM) based on the stereochemical antimicrobial strategy was reported. This novel PET was prepared by inserting menthoxytriazine into the PET backbone. The antibacterial adhesion test and the antifungal landing test were employed to confirm the antiadhesion ability of PMETM. PMETM could effectively inhibit the adhesion of bacteria, with inhibition ratios of 99.9 and 99.7% against Escherichia coli (Gram-negative) and Bacillus subtilis (Gram-positive), respectively. In addition, PMETM exhibited excellent resistance to Aspergillus niger (fungal) contamination for more than 30 days. Cytotoxicity assays indicated that PMETM was a noncytotoxic material. These results suggested that the insertion of menthoxytriazine in the PET backbone was a promising strategy to confer antimicrobial properties to PET.

Functional and Structural Characterization of Pediococcus pentosaceus-Derived Biosurfactant and Its Biomedical Potential against Bacterial Adhesion, Quorum Sensing, and Biofilm Formation.

Biosurfactants are surface-active molecules of microbial origin and alternatives to synthetic surfactants with various applications. Due to their environmental-friendliness, biocompatibility, biodegradability, effectiveness to work under various environmental conditions, and non-toxic nature, they have been recently recognized as potential agents with therapeutic and commercial importance. The biosurfactant produced by various probiotic lactic acid bacteria (LAB) has enormous applications in different fields. Thus, in vitro assessment of biofilm development prevention or disruption by natural biosurfactants derived from probiotic LAB is a plausible approach that can lead to the discovery of novel antimicrobials. Primarily, this study aims to isolate, screen, and characterize the functional and biomedical potential of biosurfactant synthesized by probiotic LAB Pediococcus pentosaceus (P. pentosaceus). Characterization consists of the assessment of critical micelle concentration (CMC), reduction in surface tension, and emulsification index (% EI24). Evaluation of antibacterial, antibiofilm, anti-QS, and anti-adhesive activities of cell-bound biosurfactants were carried out against different human pathogenic bacteria (B. subtilis, P. aeruginosa, S. aureus, and E. coli). Moreover, bacterial cell damage, viability of cells within the biofilm, and exopolysaccharide (EPS) production were also evaluated. As a result, P. pentosaceus was found to produce 4.75 ± 0.17 g/L biosurfactant, which displayed a CMC of 2.4 ± 0.68 g/L and reduced the surface tension from 71.11 ± 1.12 mN/m to 38.18 ± 0.58 mN/m. P. pentosaceus cells bound to the crude biosurfactant were found to be effective against all tested bacterial pathogens. It exhibited an anti-adhesion ability and impeded the architecture of the biofilm matrix by affecting the viability and integrity of bacterial cells within biofilms and reducing the total EPS content. Furthermore, the crude biosurfactant derived from P. pentosaceus was structurally characterized as a lipoprotein by GC-MS analysis, which confirms the presence of lipids and proteins. Thus, our findings represent the potent anti-adhesion and antibiofilm potential of P. pentosaceus crude biosurfactant for the first time, which may be explored further as an alternative to antibiotics or chemically synthesized toxic antibiofilm agents.

Heteropolysaccharides from S. cerevisiae show anti-adhesive properties against E. coli associated with Crohn's disease

The Saccharomyces cerevisiae CNCM I-3856 was previously reported to strongly inhibit adherent-invasive Escherichia coli (AIEC) adhesion to intestinal epithelial cells in vitro and to favor AIEC elimination from the gut in a murine model of Crohn's disease in vivo. In order to identify which cell wall components of yeast are responsible for AIEC elimination, constituent polysaccharides of yeast were isolated and their anti-adhesive ability against AIEC adhesion in vitro was screened. A fraction containing mannan, β-glucan and α-glucan extracted from yeast cell-walls was shown to inhibit 95% of AIEC adhesion in vitro and was thus identified as the strongest anti-adhesive yeast cell wall component. Furthermore, this mannan-glucan-containing fraction was shown to accelerate AIEC decolonization from gut in vivo. This fraction could be proposed as a treatment to eliminate AIEC bacteria in patients with Crohn's disease, a microbial trigger of intestinal inflammation.

Improving bioactive properties of peach juice using Lactobacillus strains fermentation: Antagonistic and anti-adhesion effects, anti-inflammatory and antioxidant properties, and Maillard reaction inhibition

The purpose of the current study was to evaluate the antimicrobial activity of Lactobacillus acidophilus PTCC 1643 and Lactobacillus fermentum PTCC 1744 against Shigella flexneri PTCC 1865 in fermented peach juice, as well as the anti-adhesion ability on epithelial Caco-2 cells. Moreover, the biological activities of peach juice were examined. We found that the studied Lactobacillus strains effectively inhibited the growth of S. flexneri during the peach juice fermentation. In addition, L. acidophilus revealed more anti-adhesion ability than L. fermentum. The inhibition of the Maillard reaction increased from 4.10% to 36.70% and 33.00% in L. acidophilus and L. fermentum treatments, respectively. Additionally, the ferrous reducing power, superoxide anion antiradical and anti-inflammatory activities of the beverage augmented during the fermentation period. These findings may be helpful for inhibition of foodborne pathogens by Lactobacillus strains and production of fruit-based fermented beverages with high functional and nutritional value.

Graphene Oxide Functionalized Double-Layered Patch with Anti-Adhesion Ability for Abdominal Wall Defects.

BackgroundEffective repair of full-thickness abdominal wall defects requires a patch with sufficient mechanical strength and anti-adhesion characteristics to avoid the formation of hernias and intra-abdominal complications such as intestinal obstruction and fistula. However, patches made from polymers or bio-derived materials may not meet these requirements and lack the bionic characteristics of the abdominal wall.Materials and MethodsIn this study, we report a consecutive electrospun method for preparing a double-layer structured nanofiber membrane (GO-PCL/CS-PCL) using polycaprolactone (PCL), graphene oxide (GO) and chitosan (CS). To expand the bio-functions (angiogenesis/reducing reactive oxygen species) of the patch (GO-PCL/NAC-CS-PCL), N-acetylcysteine (NAC) was loaded for the repair of full-thickness abdominal wall defects (2×1.5cm) in rat model.ResultsThe double-layered patch (GO-PCL/NAC-CS-PCL) showed excellent mechanical strength and biocompatibility. After 2 months, rats treated with the patch exhibited the desired repair effect with no hernia formation, less adhesion (adhesion score: 1.50±0.50, P<0.001) and more collagen deposition (percentage of collagen deposition: 34.94%±3.31%, P<0.001).ConclusionThe double-layered nanomembranes presented in this study have good anti-hernia and anti-adhesion effects, as well as improve the microenvironment in vivo. It, therefore, holds good prospects for the repair of abdominal wall defects and provides a promising key as a postoperative anti-adhesion agent.

Extractable surface proteins of indigenous probiotic strains confer anti-adhesion knack and protect against methicillin-resistant Staphylococcus aureus induced epithelial hyperpermeability in HT-29 cell line

Probiotic intervention has been long believed to have beneficial effects on human health by curbing the intestinal colonization of pathogens. However, the application of live probiotics therapy may not be an ideal approach to circumvent the infections of superbug origin due to the risk of horizontal antibiotic resistance genes transfer. In this study, the anti-adhesion ability of extractable cell surface proteins from two indigenous potential probiotic strains (Lactiplantibacillus plantarum A5 and Limosilactobacillus fermentum Lf1) and two standard reference strains (Lactobacillus acidophilus NCFM and Lacticaseibacillus rhamnosus LGG) was evaluated against clinical isolates of Methicillin-Resistant Staphylococcus aureus (MRSA) on porcine gastric mucin and HT-29 cells. The surface proteins from the probiotic strains were extracted by treatment with 5 M lithium chloride. The surface protein quantification and SDS-PAGE profiling indicated that the yield and protein patterns were strain-specific. Surface proteins significantly hampered the mucoadhesion of MRSA isolates via protective, competitive, and displacement. Similarly, the treatment with surface proteins probiotic strains displayed anti-adhesion against MRSA isolates on HT-29 cells without affecting the viability of the cell line. Surface proteins treatment to the confluent monolayer of HT-29 cells maintained the epithelial integrity; however, MRSA isolates (109 cells/mL) showed considerable alteration in the epithelial integrity by exacerbating the FITC-dextran transflux. Contrarily, the co-treatment with surface proteins with MRSA isolates significantly lowered the FITC-dextran transflux across the differentiated HT-29 monolayer. Overall, the findings of this study suggest that probiotic-derived surface proteins could be the novel biotherapeutics to combat the MRSA colonization and their concomitant intestinal infections.

An oxidative stress-responsive electrospun polyester membrane capable of releasing anti-bacterial and anti-inflammatory agents for postoperative anti-adhesion

Peritendinous adhesion, secondary to the repair surgery of tendon rupture or injury, is one of the most common causes of reoperation, owing to the proliferation of fibrous tissue and excessive collagen synthesis caused by the residing inflammatory cells. In this study, a smart oxidative stress-responsive electrospun polyester membrane (EPM) was fabricated as both physical barrier and reservoir of curcumin/celecoxib (CUR/CEL) to prevent peritendinous adhesion. The multicomponent EPM was designed to release the encapsulated drugs in response to oxidative stress of the local microenvironment induced by inflammation. Specifically, sulfides in the EPM were able to react with reactive oxygen species (ROS) and become hydrophilic sulfoxide or sulfone to accelerate the release rate of drugs and regulate oxidative stress level in the inflammatory site intelligently. The oxidation-sensitive multicomponent EPM loaded with CUR and CEL was tested for anti-adhesion capacity in vitro and in vivo. An excellent ROS-sensitive degradation behavior and good cytocompatibility with cell viability of above 85% were presented with the fabricated EPM. The CUR- or CEL-loaded EPM possessed a better anti-adhesion ability compared with EPM without the drugs. Nevertheless, they were inferior to the EPM simultaneously loaded with both drugs, where the adhesion rate and fibrous adhesion number in the EPM+CUR/CEL group were close to extremely low values of about zero, demonstrating that CUR and CEL could synergistically prevent peritendinous adhesion. More interestingly, the multicomponent EPM was able to react with the local oxidative stress, leading to a smart and sustained behavior of releasing approximately 80% of the drug within 20days. Overall, the smart multicomponent EPM offers a promising barrier strategy to prevent peritendinous adhesion.

Charge balanced anti-adhesive polyacrylamidoxime hydrogel membrane for enhancing uranium extraction from seawater

• A charge balanced adsorbent is fabricated for uranium extraction from seawater. • The adsorbent can resistant both biofouling and abiotic fouling. • The uranium extraction capacity is highly enhanced. • The uranium adsorption ability and anti-adhesive ability are highly reusable. The extraction of uranium from seawater is vital to meet the increase demands of uranium resource for the nuclear energy industry, while it is severe hazarded by the marine fouling, including both the biofouling and abiotic fouling. Previous reports only focused on the control of biofouling and rare attention is paid to the abiotic fouling. However, the abiotic fouling is the fundamental of the biofouling. Herein, a charged balanced hydrogel adsorbent is fabricated by introducing the charge-positive tetraethylenepentamine (TEPA) into the charge-negative polyacrylamidoxime (PAO). The fabricated PAO-CB hydrogel membrane shows high anti-adhesive ability to the marine fouling, including both the biofouling and abiotic fouling, which is due to the decrease of the charge attraction between the adsorbent and the charged contaminants. Benefitting from the reduce of marine fouling, the PAO-CB hydrogel membrane shows a high uranium extraction capacity of 8.59 mg g −1 , which is higher than that of PAO hydrogel membrane by 44.59%. The finding of this study indicates that the construction of charge balanced adsorbent would be an effective strategy to control the complicated marine fouling during uranium extraction from seawater.

Preparation of AAEK-functionalized cellulose film with antibacterial and anti-adhesion activities

Bacterial adhesion infection caused by medical materials in clinical application has become a serious threat, and it urgently needs new strategies to deal with these clinical challenges. The purpose of this study is to explore the effectiveness of surface-decorated aryl (β-amino) ethyl ketones (AAEK), a promising sorting enzyme A (SrtA) inhibitor of Staphylococcus aureus, to improve the anti-adhesion ability of biomaterials. AAEK was covalently grafted onto cellulose films (CF) via copper-catalyzed azide-alkyne 1, 3-dipolar cycloaddition click reaction. The data of contact angle measurements, ATR-FTIR and XPS proved the successful covalent attachment of AAEK-CF, and the antimicrobial efficacy of AAEK coating was assessed by CFUs, crystal violet staining, scanning electron microscopy and Living/Dead bacteria staining assay. The results illustrated that AAEK-CF exhibited excellent anti-adhesion ability to Staphylococcus aureus, and significantly reduced the number of bacteria adhering to the film. More importantly, AAEK-CF could hinder the formation of bacterial biofilm. Furthermore, AAEK-CF indicated no cytotoxicity to mammalian cells, and the cells could grow normally on the modified surface. Hence, our present work demonstrated that the grafting of the SrtA inhibitor-AAEK onto cellulose films enabled to combat bacterial biofilm formation in biomedical applications.

Engineered Janus amphipathic polymeric fiber films with unidirectional drainage and anti-adhesion abilities to accelerate wound healing

• Wound dressing with Janus superhydrophilic/superhydrophobic feature is designed. • Superhydrophilic PCL-Gelatin fibers act as a pump-like suction layer. • Suprehydrophobic side shows excellent anti-adhesion effect. Rational design of new wound dressing materials aims to accelerate wound healing. Traditional hydrophilic wound dressings, however, tend to cause retention of wound exudate retention, which increases the risk of bacterial infection, resulting in slower wound healing. Herein, a multifunctional amphiphilic wound dressing nanofibrous materials with Janus superhydrophilic/ superhydrophobic feature is designed to accelerate wound healing. In this design, the top superhydrophilic polycaprolactone (PCL)-Gelatin (PCL-Gelatin, WCA ~ 0°) fibers function as a pump-like suction layer that can effectively isolate wound exudate from the wound site, thereby providing drier condition which lowers the risk of wound infection. More importantly, the superhydrophobic PCL-poly(perfluorodecyl methacrylate)- block -poly(dimethylsiloxane)- block -poly(perfluorodecyl methacrylate) (PFMA- b -PDMS- b -PFMA) (PCL-PFMA, WCA ~ 140°) in contact with the wound site showed excellent anti-adhesion effect to bacterial, cells and tissues, thereby further lowering the risk of bacterial infection and preventing the secondary injuries caused by dressing changes. Sprague-Dawley (SD) rat skin lesion model demonstrated significant improvement in wound healing of the Janus amphipathic PCL-Gelatin / PCL-PFMA fiber films compared with the conventional hydrophilic- and hydrophobic-only wound dressing materials. After 14 days of treatment, the wound healing area in this group was close to 100%. To the best our acknowledge, this is a pioneer exploration of Janus amphipathic wound dressing with unidirectional drainage function and anti-adhesive ability, which may have great potential for real life usage on clinical patients.

Cellulose membrane modified with LED209 as an antibacterial and anti-adhesion material

Bacterial adhesion infection caused by medical materials in clinical application has become a serious threat, and it urgently needs new strategies to deal with these clinical challenges. In this work, LED209, a highly selective histidine sensor kinase inhibitor of Gram-negative bacteria, was covalently attached on cellulose membrane (CM) via click reaction. The data of contact angle measurements, ATR-FTIR and X-ray photoelectron spectroscopy confirmed the successful synthesis of LED-CM. In addition, the results of antibacterial activity of the membranes shown that LED-CM exhibited excellent anti-adhesion ability to Enterohemorrhagic Escherichia coli (EHEC), and significantly reduced the formation of bacterial biofilm. Importantly, LED-CM was able to repress the expression of virulence genes in EHEC. Furthermore, LED209-functionalized cellulose membrane indicated no cytotoxicity to mammalian cells. Hence, our present work demonstrated that CM modified with LED209 possessed markedly anti-adhesion activity against EHEC, which offered a potent antimicrobial material for combating bacterial infections.

Layer-by-Layer-Assembled antifouling films with surface microtopography inspired by Laminaria japonica

Marine biofouling is an important obstacle to the development of marine resources. Problems such as huge economic losses caused by biofouling and environmental damage caused by toxic antifouling agents have not been resolved. Therefore, it is of great significance to develop a novel, environmentally friendly antifouling (AF) materials. However, in the marine environment, Laminaria japonica still has excellent antifouling ability in a relatively static state compared to those parade creatures. Inspired by this, this study reports a synergistic effect between surface topography and chemical modification to inhibit marine biofouling. Firstly, the surface of the Laminaria japonica was analyzed and its morphology was reproduced using a simple moulding process. Additionally, the polyelectrolyte layer composed of sodium alginate and (guanidine-hexamethylenediamine-PEI) (poly(GHPEI)) was chemically modified on the isotropic microstructure surface of PDMS replicas by layer-by-layer assembly method. The anti-adhesion ability of the biomimetic material was tested with Nitzschia closterium (N. closterium) (9 ± 5 diatoms mm−2 of N. closterium adhered). Meanwhile, the antifouling performance of the modified films were evaluated by Escherichia coli (E. coli), and its antibacterial ability were as high as 96.2 ± 1.3%. The combination of microtopography and (GHPEI/ALG) * n films endow the coating with excellent antifouling ability.

Evaluation of Polycaprolactone/Gelatin/Chitosan Electrospun Membrane for Peritoneal Adhesion Reduction.

In this study, a novel antiadhesion membrane made of polycaprolactone, gelatin, and chitosan was fabricated using the electrospinning technique. A series of polycaprolactone/gelatin/chitosan (PGC) electrospun membranes with different amounts of chitosan (0%, 0.5%, 1%, and 2% in weight percentage) was synthesized. The physicochemical properties and biocompatibility of the fabricated membranes were examined and compared with the aim to select an effective antiadhesion membrane. Scanning electron microscopy showed that these 4 electrospun membranes had similar fiber diameter and pore area, with no statistical differences between them. Furthermore, the contact angle decreased with increased chitosan content, indicating that chitosan may contribute to increased hydrophilic properties. The in vitro degradation test revealed that the higher chitosan content corresponded to a lower degradation rate in PGC membranes within 7 days. All PGC membranes exhibited similar cell proliferation; however, cell proliferation was lower than tissue culture polystyrene (P < 0.05). To compare antiadhesion ability, the adhesion between the cecum and abdominal wall was created in a rat model. Assessment after implantation of electrospun membranes revealed that PGCs with higher chitosan content (PGC2) had better antiadhesion effects, as evaluated by an adhesion score at day 14 postsurgery. Thus, PGC2 was effective in reducing the formation of tissue adhesion. Therefore, PGC electrospun membrane may provide a potential peritoneal antiadhesion barrier for clinical use.

Hydration-Enhanced Lubricating Electrospun Nanofibrous Membranes Prevent Tissue Adhesion.

Lubrication is the key to efficient function of human tissues and has significant impact on the comfort level. However, the construction of a lubricating nanofibrous membrane has not been reported as yet, especially using a one-step surface modification method. Here, bioinspired by the superlubrication mechanism of articular cartilage, we successfully construct hydration-enhanced lubricating nanofibers via one-step in situ grafting of a copolymer synthesized by dopamine methacrylamide (DMA) and 2-methacryloyloxyethyl phosphorylcholine (MPC) onto electrospun polycaprolactone (PCL) nanofibers. The zwitterionic MPC structure provides the nanofiber surface with hydration lubrication behavior. The coefficient of friction (COF) of the lubricating nanofibrous membrane decreases significantly and is approximately 65% less than that of pure PCL nanofibers, which are easily worn out under friction regardless of hydration. The lubricating nanofibers, however, show favorable wear-resistance performance. Besides, they possess a strong antiadhesion ability of fibroblasts compared with pure PCL nanofibers. The cell density decreases approximately 9-fold, and the cell area decreases approximately 12 times on day 7. Furthermore, the in vivo antitendon adhesion data reveals that the lubricating nanofiber group has a significantly lower adhesion score and a better antitissue adhesion. Altogether, our developed hydration-enhanced lubricating nanofibers show promising applications in the biomedical field such as antiadhesive membranes.

Mussel-inspired anti-biofouling and robust hybrid nanocomposite hydrogel for uranium extraction from seawater

A major challenge of uranium extraction from seawater (UES) is to effectively block the biofouling without destroying the ecological balance, especially prevent the attachment of macroalgae on the surface of the adsorbent. Herein, a robust montmorillonite-polydopamine/polyacrylamide nanocomposite hydrogel is reported by a two-step method, including PDA intercalation MMT and further free radical polymerization with AM monomers. The interpenetrating structure of hydrogel lead to high water permeability with the swelling ratio of 51, which could fully facilitate the internal accessible sites exposure and increase the uranium diffusion. As a result, a high adsorption capacity of 44 mg g−1 was achieved in lab-scale dynamic adsorption. Most importantly, the prepared anti-biofouling hydrogel adsorbents display excellent anti-adhesion ability towards Nitzschia after 8 days contact. The adsorption capacity of uranium can reach 2130 μg g−1 in algae-contained simulated seawater. This hydrogel also exhibited a long service life of acceptable mechanical strength and adsorption capacity after at least 6 adsorption-desorption cycles. This new anti-biofouling nanocomposite hydrogel shows great potential as a new generation adsorbent for UES.

Electric field endowing the conductive polyvinylidene fluoride (PVDF)-graphene oxide (GO)‑nickel (Ni) membrane with high-efficient performance for dye wastewater treatment

Due to potential toxicity of the dyes and their visibility even at the very low concentration, treatment of dye wastewater has been a matter of considerable interest. Membrane technology is an emerging technology that offers a promising way to remove dyes from wastewater. However, the membrane fouling and trade-off effect severely hinder the removal efficiency. In view of this, the conductive polyvinylidene fluoride (PVDF)-graphene oxide (GO)‑nickel (Ni) composite membrane was firstly developed and implanted into the dead-end filtration cell as the cathode in the sandwich-like electrode. Under the assistance of electric field, the conductive PVDF-GO-Ni membrane displayed 98.02% Congo red (CR) rejection with the flux of 38.39 L·m−2·h−1·bar−1, which was an encouraging result comparing to most previous reports. Moreover, PVDF-GO-Ni membrane possessed certain antibacterial ability and super anti-adhesion ability to CR molecules. The underlying mechanism of super anti-adhesion of CR molecules was investigated by quantitatively calculating the interfacial interaction energy according to the extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) theory. XDLVO theory indicated that the repulsive acid-based (AB) interaction energy between CR molecules and membrane surface predominantly facilitated the super anti-adhesion ability of the hydrophilic PVDF-GO-Ni membrane. The present study not only supplied a novel PVDF-GO-Ni membrane for high-efficient treatment of dye waste water, but also built an approach to quantitatively calculate interfacial interaction energy which should have a wide applications in forecasting and directing the modifications of separation membranes.

Hydrogel hybrid porcine pericardium for the fabrication of a pre-mounted TAVI valve with improved biocompatibility.

Transcatheter aortic valve implantation (TAVI) has been developed years ago for patients who cannot undergo a surgical aortic valve replacement (SAVR). Although TAVI possesses the advantages of lower trauma and simpler manipulation compared to SAVR, the need for storage in glutaraldehyde (GLU) and a tedious intraoperative assembly process have caused great inconvenience for its further application. A pre-mounted TAVI valve assembled by mounting a dry valve frame to a delivery system is expected to address these problems. However, the currently used GLU treated leaflet cannot unfold normally after being crimped for a long-term and loses its function when the BHV is assembled to the catheter. Besides, its cytotoxicity and immune response after implantation are still problems to be solved. In the present study, a hydrogel hybrid porcine pericardium (HHPP) approach was developed to endow the BHVs with a favorable unfolding property and good biocompatibility. Three monomers with different charge characteristics (sodium acrylate, 2-methacryloyloxyethyl phosphorylcholine, and acryloyloxyethyltrimethyl ammonium chloride) were complexed with GLU treated PP (GLU-PP) to form three kinds of HHPPs (SAAH-PP, MPCH-PP, and DACH-PP). The results of the crimping simulation experiment showed that all HHPPs could quickly recover in PBS after being folded for 10 days, while the traditional BHVs (GLU-PP) could not recover under the same conditions. Bovine serum albumin adsorption and platelet adhesion test showed that SAAH-PP and MPCH-PP had good anti-adhesion abilities. A cell culture study indicated that all the three HHPPs promoted HUVEC growth and proliferation. In vivo biocompatibility studies showed that the immune response induced by MPCH-PP was reduced compared to that by GLU-PP. These studies demonstrated that the strategy of MPC hydrogel hybridization may be an effective approach to prepare a pre-mounted TAVI valve with improved biocompatibility.