Search

A non-solvent induced phase separation (NIPS) process was used to fabricate a series of sulfonated polyethersulfone (SPES) membranes blending with different concentrations of SBA-15-g-PSPA with the applications in the ultrafiltration (UF) process. SBA-15 was modified with 3-methacrylate-propyltrimethoxysilane (MPS) to form SBA-15-g-MPS. It was further modified with the charge tailorable polymer chains by reacting with 3-sulfopropyl methacrylate potassium salt. The nanoparticles were uniformly dispersed and finger-like channels were developed within the membrane. The adding of surface modified SBA-15-g-PSPA nanoparticles has significantly improved membrane water permeability, hydrophilicity, and antifouling properties. The pure water fluxes of the composite SPES membranes were significantly higher than the pristine SPES membrane. For the membrane containing 5% (mass) of SBA-15-g-PSPA (MSSPA5), the pure water flux was increased dramatically to 402.15 L∙m–2∙h–1, which is ∼ 1.5 times that of MSSPA0 (268.0 L∙m–2∙h–1). The high flux rate was achieved with 3% (mass) of SBA-15 nanoparticles with retained high rejection ratio 98% for natural organic matter. The results indicate that the fashioned composite membrane comprising SBA-15-g-PSPA nanoparticles have a promising future in ultrafiltration applications.

Bacterial cellulose (BC) is one of the most versatile natural biopolymers with unique physical, chemical, and biological features. However, the lack of intrinsic antibacterial property of native BC limits its broad biomedical applications where such property is highly required to prevent contamination or infection caused by attached bacteria. In this work, we developed a simple and facile method to fabricate a dual-functional BC membrane by physical incorporation of gold nanorods (GNRs) followed by deposition of a phase-transitioned bovine serum albumin (PTB) film. Due to the broad-spectrum antifouling property of the PTB film, the resulting membrane could prevent the adhesion and accumulation of bacteria. A few bacteria that broke through the protection of the PTB film could be eradicated under short-term irradiation of a near-infrared laser due to the excellent photothermal property of incorporated GNRs. The whole fabrication was conducted in a simple and environmentally friendly manner, avoiding complicated processes and toxic organic solvents. Moreover, because all the components were biocompatible, the resulting membrane showed negligible cytotoxicity in vitro and good histocompatibility in vivo. This work thus provided a reliable way to endow BC with antibacterial property, being beneficial for diverse biomedical applications.

PVDF membrane has strong hydrophobicity and low anti-pollution performance, greatly limiting its practical application. These drawbacks have been successfully overcome by designing and then preparing a membrane with a semi-interpenetrating polymer (semi-IPN) of PVDF/poly(acrylic acid) (PAA) as the membrane matrix, TiO2 nanoparticles as functional components and F127 as pore-forming agent. The semi-IPN was prepared by copolymerizing acrylic acid with N,N methyl acrylamide in the presence of PVDF, and the TiO2 gel nanoparticles were in situ formed in the membrane-forming process. The properties of the composite membrane were significantly affected by the semi-IPN, F127 and TiO2. By adjusting the membrane structure with the semi-IPN, F127 and TiO2 nanoparticles, we prepared a composite membrane with a water contact angle of 40o, a BSA rejection ratio of 87.5% and a water flux of 802.5 L/m2/h/bar. After a simple UV irradiation, the water flux of this composite membrane rose to 1030 L/m2/h/bar, without any rejection decline. The membrane contaminated by humic acid could recover the water flux up to above 95.3% of its original value by a single UV irradiation, showing a very good antifouling performance. In addition, the composite membrane also exhibited a very strong pollution resistance and separation performance for bovine serum albumin and oil-water emulsion. All in all, based on the synergy of the semi-IPN and the evenly dispersed TiO2 nanoparticles, the prepared composite membrane exhibited excellent comprehensive properties and demonstrated a great potential for various separation applications.

Addressing thrombosis and biofouling of indwelling medical devices within healthcare institutions is an ongoing problem. In this work, two types of ultra-low fouling surfaces (i.e., superhydrophobic and lubricant-infused slippery surfaces) were fabricated to enhance the biocompatibility of commercial medical grade silicone rubber (SR) tubes that are widely used in clinical care. The superhydrophobic (SH) coatings on the tubing substrates were successfully created by dip-coating in superhydrophobic paints consisting of polydimethylsiloxane (PDMS), perfluorosilane-coated hydrophobic zinc oxide (ZnO) and copper (Cu) nanoparticles (NPs) in tetrahydrofuran (THF). The SH surfaces were converted to lubricant-infused slippery (LIS) surfaces through the infusion of silicone oil. The anti-biofouling properties of the coatings were investigated by adsorption of platelets, whole blood coagulation, and biofilm formation in vitro. The results revealed that the LIS tubes possess superior resistance to clot formation and platelet adhesion than uncoated and SH tubes. In addition, bacterial adhesion was investigated over 7 days in a drip-flow bioreactor, where the SH-ZnO-Cu tube and its slippery counterpart significantly reduced bacterial adhesion and biofilm formation of Escherichia coli relative to control tubes (>5 log10 and >3 log10 reduction, respectively). The coatings also demonstrated good compatibility with fibroblast cells. Therefore, the proposed coatings may find potential applications in high-efficiency on-demand prevention of biofilm and thrombosis formation on medical devices to improve their biocompatibility and reduce the risk of complications from medical devices.

Enormous demands on the separation of oil/water (O/W) emulsions in various industries, such as petrochemical, food and pharmaceutical industries, are looking for high performance and energy-efficient separation methods. Ceramic membranes have been used to deal with O/W emulsions, for its outstanding characteristics of easy-operation, high-flux, and long-term stability. However, membrane fouling is still a challenge in the industrial application of ceramic membranes. Herein, antifouling ceramic membranes were fabricated by grafting zwitterions on the membrane surface via an environment-friendly two-step grafting method, which improves the antifouling property and permeability. Successful grafting of such zwitterion on the ceramic surface was assessed by the combination of FTIR and XPS characterization. More importantly, the hydration can be formed by electrostatic interactions layer on the modified membrane, which was confirmed by TGA characterization. The antifouling performance of prepared zwitterionic ceramic membranes in the separation of O/W emulsions was systematically tested. The results suggested that zwitterion can significantly improve the flux of ceramic ultrafiltration membrane, and can also improve antifouling property dramatically by reducing the irreversible fouling in the separation of O/W emulsions. Therefore, zwitterionic ceramic membranes hold promising potentials as an antifouling, highly efficient and green method in the practical purification of the O/W emulsions.

Developing multifunctional, efficient and durable membrane for long-term usage for treating complex oily wastewater is highly desirable but still a challenge due to the severe membrane fouling. Herein, a hierarchical structured superhydrophilic/underwater superoleophobic nanofibrous with antifouling and visible-light-induced self-cleaning performance was manufactured by a facile combination of electrospun silver/β-cyclodextrin/polyacrylonitrile (Ag/β-CD/PAN) nanofibers and then the in-situ growth of a zinc oxide (ZnO) layer. The formed micro/nano sized hierarchical structure greatly increased the roughness and improved the underwater superoleophobic ability of the membrane. Therefore, the resultant ZnO/Ag/β-CD/PAN membrane displays splendid separation performance for oil/dye/water complex emulsions and high flux recovery (>90%). Meanwhile, the permeation flux of a variety of oil/water emulsions was higher than 619 L m−2h−1 with a separation efficiency above 99.7% under the action of gravity. Furthermore, the as-fabricated membrane exhibits excellent stability towards different harsh conditions (e. g. corrosive solution, high temperature, UV irradiation and ultrasound washing). The robust mechanical and chemical stability, outstanding separation capabilities as well as excellent flux recovery capabilities makes the self-cleaning membrane a good candidate for the remediation of complex oily wastewater.

The simultaneous introduction of two new functionalities into the same polymeric substrate under mild reaction conditions is an interesting and important topic. Herein, dual-functional polydimethylsiloxane (PDMS) surfaces with antibacterial and antifouling properties were conveniently developed

Two novel superhydrophobic nanocomposite series of polydimethylsiloxane (PDMS) enriched with reduced graphene oxide (RGO) and graphene oxide/boehmite nanorods (GO-γ-AlOOH) nanofillers were synthesized as maritime fouling-release (FR) surfaces. Controlling the nanofillers' structures and distribution in the silicone matrix influenced the self-cleaning and antifouling properties. γ-AlOOH nanorods had a single crystallinity with an average diameter of 10-20 nm and 200 nm length. A hydrothermal method was used to prepare RGO, while the chemical deposition method was used to synthesis GO-γ-AlOOH nanocomposites for use as fouling-release coating materials. For studying the synergetic effects of graphene-based materials on the surface, mechanical, and FR features, these nanofillers were dispersed in the silicone matrix using the solution casting method. The hydrophobicity and antifouling properties of the surface were studied using water contact angle (WCA), scanning electron, and atomic force microscopes (SEM and AFM). Coatings' roughness, superhydrophobicity, and surface mechanical properties all improved for the homogeneity of the dispersion of the nanocomposite. Laboratory assessments were carried out for 30 days using selected microorganisms to determine the antifouling effects of the coating systems. PDMS/GO-γ-AlOOH nanorod composite had better antibacterial activity than PDMS/RGO nanocomposite against different bacterial strains. This is caused by the high surface area and stabilizing effects of the GO-γ-AlOOH hybrid nanofillers. The PDMS/GO-γ-AlOOH nanorod composite (3 wt%) had the lowest biodegradability percentage (1.6%) and the microbial endurability percentages for gram-positive, gram-negative, and fungi were 86.42%, 97.94%, and 85.97%, respectively. A field trial in natural seawater was conducted to confirm the coatings' FR performance based on the screening process and image analysis for 45 days in a tropical area. The most profound superhydrophobic antifouling nanostructured coating was the homogeneity of the GO-γ-AlOOH (3 wt%) dispersion, which had a WCA of 151° and a rough surface.

Photocatalytic membrane reactors (PMRs) are a promising treatment technology for degradation of organic compounds discharged from wastewater treatment facilities. This review presents information about TiO2 nanoparticles, which are the widely used photocatalyst semiconductor in PMRs, and how doping can be used to make TiO2 able to absorb part of the visible spectrum. Then, many examples are presented showing PMR applications for various feedwater types ranging from dyes, oils, pharmaceuticals, and antibiotic resistant bacteria, either in simulated wastewater or water from real matrices. Although the results are dependent on the feed, photocatalyst, and type of reactor, the PMR technology can achieve removal efficiency higher than 95% for some situations. PMRs have also shown antimicrobial properties in removing 99.9% of antibiotic-resistant bacteria in one study presented. Additionally, PMRs have demonstrated antifouling properties due to their surface modification – resulting in their reuse and extended lifespan. Although photocatalytic membrane reactors can achieve quantitative removal in some feed water types, more development is needed before employing them for more widespread wastewater treatment. In this sense, the article ends with a perspective section where some possible advances in the photocatalyst and reactor design are suggested which can expand the range of PMR applications.

Background Unlimited energy demand and rapid urbane development are major deriving forces to generate bioelectricity through microbial fuel cells (MFCs) and have been a hot area for 2-decades. Various advancements have been employed to improve the MFC's efficiency through electrode and membrane materials. Methods Here, we discussed the recent innovations and developments to fabricate the electrode and membrane materials, which play a key role in bio-energy production and performance. Specifically, the morphological aspects, including pure/doped carbon-based electrodes and their large surface area, directly enhanced the oxygen reduction efficiency of MFCs. Findings The impact of organic and inorganic hybrid composite bio-polymer membranes and separators to improve the electron transfer ability and remedies for associated biofouling problems are also highlighted. Numerous enhancements to the material's physical, mechanical, and chemical properties are explored in detail to prevent biofouling issues. In addition, it highlights how the well-ordered mesopores, large surface area, and biocompatibility of MFCs directly affect their stability and performance. Finally, this review article introduces current issues with smart, feasible solutions, stability improvements, and future perspectives of MFCs and critically evaluated recent progress and developments in MFCs technology which can be useful for academic and industrial researchers.

A submerged membrane system was used in this work to investigate the effect of the polyaluminum chloride (PAC) coagulant on the antifouling performance of the polyvinyl chloride/alumina (PVC/Al2O3) nanocomposite membrane. The prepared nanocomposite membranes were characterized with field emission scanning electron microscopy (FE-SEM), atomic force microscopy, contact angle, porosity measurement, and pure water flux. The results revealed that the membrane containing Al2O3 nanoparticles (the mass ratio of PVC to Al2O3 was 98.5/1.5) had a higher hydrophilicity, porosity, and pure water flux than other membranes. The FE-SEM images showed that when Al2O3 nanoparticles were present in the PVC membrane, large pores and macrovoids formed on the surface and cross-section of the membrane. The fouling behavior of membranes was investigated through the filtration of humic acid (HA) solution with and without the PAC coagulant. Without PAC addition, the PVC/Al2O3 membrane significantly decreased the irreversible fouling ratio from 60.7% to 19.4% and showed a high HA removal efficiency of approximately 90.5%. The Hermia model confirmed that the cake formation mechanism best described the experimental data for the neat PVC and nanocomposite membranes with the presence and absence of the PAC coagulant. This confirms that the PAC coagulant can significantly mitigate fouling and improve HA removal in the submerged membrane system.

Thrombosis is an important factor that causes the failure of artificial biological valves in addition to calcification and immune rejection. A hydrophobic antifouling surface can improve blood compatibility by reducing the absorption of protein. In this study, porcine pericardium was cross-linked with glycidyl methacrylate, and carbon-carbon double bonds were introduced. Then, fluoride monomer was added so that the pericardial surface would become hydrophobic and antifouling. Fluoride modification changed the hydrophilicity of the pericardium surface, and the surface water contact angle increased from 84° to 143°. Compared with unmodified pericardium, the adsorption of bovine serum albumin and fibrinogen decreased by 93.1% and 85%, respectively, and the anti-thrombogenicity was greatly enhanced.

Silver-functionalized textiles, as the most common protective medical materials, have attracted considerable attention. However, poor antibacterial durability and relatively tedious preparation process limit their applications. In this study, a kind of multifunctional cotton fabric was prepared through simultaneous dip-coating of silver-silica hybrid nanoparticles (Ag-MSNs) and fluorinated MSNs (F-MSNs), providing excellent antifouling ability due to superhydrophobicity and long-term antibacterial properties from the sustained release of Ag ions (Ag+). Detailed studies were performed to evaluate their structure and protective performance, especially the long-term antibacterial properties of the obtained fabrics were tested by the inhibition zone experiment for 25 d. The as-prepared fabrics showed good non-wetting properties and sustained antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Further washing and abrasion experimentations demonstrated that the as-prepared fabrics had stable hydrophobicity and antibacterial properties, much more reliable than commercial antibacterial gauze. Considering the inexpensive and simple preparation process as well as long-term and efficient effect for sterilization, the strategy paves a new and facile way for the fabrication of multifunctional fabrics with robust hydrophobic and antibacterial activity.

Two-dimensional (2D) membranes as a new type of water filtration membrane have shown great potential in water separation and purification. However, their long-term stability under cross-flow conditions and their antifouling property are two main concerns for practical separation and purification processes. In this work, a strategy of nanoparticle bridges based on amorphous TiO2 is developed to link adjacent WS2 nanosheets on a WS2 membrane surface, leading to a strong membrane surface with excellent stability during 204 h of continuous cross-flow filtration. Moreover, the amorphous TiO2 bridges also form a TiO2/WS2 heterojunction on the WS2 membrane surface, exhibiting an impressive photocatalysis-driving self-cleaning property by pollutant photodegradation. And the flux recovery ratio (FRR) exceeds 95% after three cycles of separation experiments. The excellent long-term stability and photocatalysis-driving self-cleaning property of the WS2/TiO2 membrane provide a new approach to construct robust 2D membranes.

The protein corona on nanoparticles (NPs) is a critical problem that often screens the targeting molecules and becomes one of the key reasons for the lack of practical application in nanotherapy. It is critical to fully understand the mechanism of the nanoparticle-biological interactions to design the nanoparticle-based therapeutic agents. Some types of proteins can be precoated on the nanoparticles to avoid unwanted protein attachment; however, the ultralow level of protein corona is hard to achieve, and the relationship of the antifouling property of the precoated protein nanoparticles with protein conformation and protein-nanoparticle interaction energy has never been investigated. In this work, we provided the quantitative protein corona composition analysis on different precoated protein nanoparticles, and on the basis of the molecular simulation process, we found their antifouling property strongly depended on the interaction energy of the precoated protein-serum protein pair and the number of hydrogen bonds formed between them. Furthermore, it also depended on the nanoparticle-serum protein pair interaction energy and the protein conformation on the nanoparticle. The casein coated nanoparticle with the antifouling property was determined, and after aptamer conjugation and drug loading, they exhibited superior targeting and internalization behavior for photodynamic and photothermal therapy in vitro and in vivo. Our work adds to the understanding of the protein corona behavior of precoated protein nanoparticles, and the determined antifouling NP can potentially be used as a highly efficient nanodrug carrier.

This review provides a comprehensive overview on applications, preparation methods, and most notably the performance efficiency of polyvinyl alcohol (PVA)-based membranes for filtration of aqueous environments. Incorporation of PVA into the membrane matrix significantly enhances such characteristics as antifouling and antibacterial properties as well as hydrophilicity and permeability in the water and wastewater filtrations. Contribution of different PVA-based modular membranes for water purification targets via a comparative review on previous researches is the main theme in this work. Alongside with the focused topic, some basic theories and principals of blend and composite polymer films as well as polymer fibers are debated before the main discussions. This review will ultimately facilitate further development of PVA membranes for the future investigations.

The electrochemical behavior of titanium (Ti) was investigated before and after anodic polarization at different potentials in simulated seawater solutions. The results showed that the Ti anodically polarized at 3.2 V was much more stable than those at 0.5 V and the open-circuit potential (OCP), and the passive film formed at the low potentials could be transformed to a more protective film after polarization at the high potential. The polarization at the high anodic potential could effectively enhance the long-term durability of Ti under natural immersion conditions. Nitzschia closterium f. minutissima could only slightly influence the electrochemical behavior of Ti. The film formed at the 3.2 V on Ti appeared to have very limitedly better antifouling performance than those formed at the 0.5 V and OCP.

Effective dye separation and desalination are critical for the treatment of highly saline textile wastewater with dye mixtures. In this study, a graphene oxide (GO) membrane with a tunable interlayer distance (d) was fabricated to generate clean water via two-stage filtration, namely, the dye/salt separation and desalination stages. In the first stage, under low pressure (e.g., 0.3 MPa), the membrane with a d value of ca. 7.60 A was suitable for removing the dye from the saline wastewater. The dye and salt (i.e., Na2SO4) rejection rates of >99% and

Modified graphene oxide with 5,10,15,20-tetrakis-(4-hexyloxyphenyl)-porphyrin and palladium (II) (signified by GO-CPTMS@Pd-TKHPP) prepared as a novel antifouling polyether sulfone (PES) blended nanofiller membrane. The membrane efficiency has been analyzed such as pure water flux (PWF), hydrophilicity, and antifouling features. By increasing of modified graphene oxide percentage from 0 to 0.1 wt.% in the polymer matrix, the PWF was incremented from 14.35 to 37.33 kg/m2·h at 4 bar. The membrane flux recovery ratio (FRR) has been investigated by applying powdered milk solution; the FRR results indicated that the 0.1 wt.%-modified graphene oxide membrane showed a positive effect on fouling behavior with Rir and FRR value 8.24% and 91.76%, respectively. The nanofiltration membrane performance was assessed applying the Direct Red 16 dye rejection. It was demonstrated that the optimal membranes (0.1 wt.%-modified graphene oxide) had notable dye removal (99.58% rejection). The results are also verified by measuring the scanning electron microscopy (SEM), water contact angle (WCA), and atomic microscopy analysis (AFM).

In this research, the application of mesoporous carbon CMK-3 and modified CMK-3 (M-CMK-3) to improve antifouling and rejection rate of polyethersulfone nanofiltration (NF) membrane was assessed. CMK-3 was modified with H-acid to increase hydrophilic characteristics of CMK-3. The synthesized CMK-3 and M-CMK-3 membranes revealed high values of pure water flux and flux recovery ratio (up to 95%) compared to bare NF membrane. Also, the performances of the membranes with optimum additive loading (0.1 wt%) of CMK-3 and M-CMK-3 in terms of rejecting different salts and dyes were compared. From the obtained results, the membrane embedded with M-CMK-3 showed higher rejection rate rather than bare NF membrane (up to 95% for Na2SO4 and 64% for CaCl2). As a result, the flux permeability was increased from 6.44 kg/m2 h for bare NF membrane to 20.11 kg/m2 h for the membrane embedded with M-CMK-3 with optimum additive loading. A higher rejection data for different dyes under different pH conditions (up to 90%) were reported for the synthesized membrane embedded with M-CMK-3. After all, from the obtained data, M-CMK-3 with higher negative surface charge presented a higher performance to remove salts and dyes rather than CMK-3. Therefore, M-CMK-3 could be a proper proposed additive to develop cost-effective NF membranes with high antifouling properties and super high filtration capacity for removing dyes and salts from wastewaters.

Zwitterionic peptides are facile low-fouling compounds for environmental applications as they are biocompatible and fully biodegradable as their degradation products are just amino acids. Here, a set of histidine (H) and glutamic acid (E), as well as lysine (K) and glutamic acid (E) based peptide sequences with zwitterionic properties were synthesized. Both oligopeptides (KE)4K and (HE)4H were synthesized in d and l configurations to test their ability to resist the nonspecific adsorption of the proteins lysozyme and fibrinogen. The coatings were additionally tested against the attachment of the marine organisms Navicula perminuta and Cobetia marina as well as the freshwater bacterium Pseudomonas fluorescens on the developed coatings. While the peptides containing lysine performed better in protein resistance assays and against freshwater bacteria, the sequences containing histidine were generally more resistant against marine organisms. The contribution of amino acid-intrinsic properties such as side chain pKa values and hydrophobicity, as well as external parameters such as pH and salinity of fresh water and seawater on the resistance of the coatings is discussed. In this way, a detailed picture emerges as to which zwitterionic sequences show advantages in future generations of biocompatible, sustainable, and nontoxic fouling release coatings.

Membrane biofouling has long been a major obstacle to highly efficient water treatment. The modification of the membrane surface with hydrophilic materials can effectively enhance biofouling resistance. However, the water flux of the membranes is often compromised for the improvement of antifouling properties. In this work, a composite membrane composed of a zwitterionic hydrogel and electrospinning fibers was prepared by a spin-coating and UV cross-linking process. At the optimum conditions, the composite membrane could effectively resist the biofouling contaminations, as well as purify polluted water containing bacteria or diatoms with a high flux (1349.2 ± 85.5 L m-2 h-1 for 106 CFU mL-1 of an Escherichia coli solution). Moreover, compared with the commercial poly(ether sulfone) (PES) membrane, the membrane displayed an outstanding long-term filtration performance with a lower water flux decline. Therefore, findings in this work provide an effective antifouling modification strategy for microfiltration membranes and hold great potential for developing antifouling membranes for water treatment.

Biofilms formed from the pathogenic bacteria that attach to the surfaces of biomedical devices and implantable materials result in various persistent and chronic bacterial infections, posing serious threats to human health. Compared to the elimination of matured biofilms, prevention of the formation of biofilms is expected to be a more effective way for the treatment of biofilm-associated infections. Herein, we develop a facile method for endowing diverse substrates with long-term antibiofilm property by deposition of a hybrid film composed of tannic acid/Cu ion (TA/Cu) complex and poly(ethylene glycol) (PEG). In this system, the TA/Cu complex acts as a multifunctional building block with three different roles: (i) as a versatile "glue" with universal adherent property for substrate modification, (ii) as a photothermal biocidal agent for bacterial elimination under irradiation of near-infrared (NIR) laser, and (iii) as a potent linker for immobilization of PEG with inherent antifouling property to inhibit adhesion and accumulation of bacteria. The resulted hybrid film shows negligible cytotoxicity and good histocompatibility and could prevent biofilm formation for at least 15 days in vitro and suppress bacterial infection in vivo, showing great potential for practical applications to solve the biofilm-associated problems of biomedical materials and devices.

Highly hydrophobic surface property is important for many applications, such as anticorrosion, antifogging, and antifouling. With regard to some practical applications, both mechanical endurance and thermal stability are essential. Here, we report a new method for making highly hydrophobic surfaces with simultaneously enhanced mechanical endurance and thermal stability. Such high-performance hydrophobic surfaces were prepared by coating electrospraying derived fluorinated SiO2 particles on various substrates, including glass slide, ceramic wafer, metal foil, and polymer sheet, with methyl silicone resin as the binder. Fluorinate silane was homogenously doped in the matrix of SiO2 particles, which can provide excellent protection effect. Meanwhile, the thermally stable methyl silicone resin can afford strong binding force between SiO2 particles and the substrates. Therefore, the hydrophobic surfaces created here possess both high mechanical endurance and excellent thermal stability.

Hydrophilic modification is a promising method to inhibit fouling formation on ultrafiltration membrane. In this work, different mass concentrations (1%–16%) of hydrophilic polyvinylpyrrolidone were incorporated into polyethersulfone (PES) membranes fabricated by none-solvent induced phase separation. Then, polydopamine (PDA) coating on the surface of prepared membrane was carried out at pH 8.5. The morphology and structure, surface hydrophilicity, permeation flux, BSA rejection, antifouling and stability performances of PES and PDA/PES modified membranes were investigated in detail. The results indicated that PDA was successfully attached onto the membranes. Membrane hydrophilicity was evaluated by water contact angle measurement. The contact angles of modified membranes reduced remarkably, suggesting that the membrane hydrophilicities were significantly increased. The results of filtration tests, which were done by dead-end filtration of bovine serum albumin solution, showed that the properties of permeability and fouling resistance were obviously improved by PDA modification. When polyvinylpyrrolidone mass content reached 10%, flux recovery ratio of modified membrane was up to 91.23%, and its BSA rejection were over 70%. The results of stability tests showed that the modified membranes had good mechanical stability and chemical stability. This facile fabrication procedure and outstanding performances suggested that the modified membranes had a potential in treating fouling.

Photocatalytic materials can be used as self-cleaning functional materials to alleviate the irreversible fouling of ultrafiltration membranes. In this work, the small size g-C3N4/Bi2MoO6 (SCB) blended polysulfone (PSF) ultrafiltration membranes was fabricated by hydrothermal and phase inversion methods. As a functional filler of ultrafiltration membranes, the small size g-C3N4 nanosheet decorated on the surface of Bi2MoO6 can enhance the photocatalytic performance for bovine serum albumin (BSA) degradation, and remove irreversible fouling under visible light irradiation. In addition, the introduction of SCB microspheres into PSF matrix obviously increased the porosity of ultrafiltration membranes. Therefore, the SCB-PSF ultrafiltration membranes displayed excellent antifouling performance (flux recovery ratio is 82.53%) and BSA rejection rates (94.77%). SCB-PSF also had high photocatalytic self-cleaning activity, indicating excellent application prospects in organic wastewater treatment.

In vivo electrochemistry is a vital tool of neuroscience that allows for the detection, identification, and quantification of neurotransmitters, their metabolites, and other important analytes. One important goal of in vivo electrochemistry is a better understanding of progressive neurological disorders (e.g., Parkinson's disease). A complete understanding of such disorders can only be achieved through a combination of acute (i.e., minutes to hours) and chronic (i.e., days or longer) experimentation. Chronic studies are more challenging because they require prolonged implantation of electrodes, which elicits an immune response, leading to glial encapsulation of the electrodes and altered electrode performance (i.e., biofouling). Biofouling leads to increased electrode impedance and reference electrode polarization, both of which diminish the selectivity and sensitivity of in vivo electrochemical measurements. The increased impedance factor has been successfully mitigated previously with the use of a counter electrode, but the challenge of reference electrode polarization remains. The commonly used Ag/AgCl reference electrode lacks the long-term potential stability in vivo required for chronic measurements. In addition, the cytotoxicity of Ag/AgCl adversely affects animal experimentation and prohibits implantation in humans, hindering translational research progress. Thus, a move toward biocompatible reference electrodes with superior chronic potential stability is necessary. Two qualifying materials, iridium oxide and boron-doped diamond, are introduced and discussed in terms of their electrochemical properties, biocompatibilities, fabrication methods, and applications. In vivo electrochemistry continues to advance toward more chronic experimentation in both animal models and humans, necessitating the utilization of biocompatible reference electrodes that should provide superior potential stability and allow for unprecedented chronic signal fidelity when used with a counter electrode for impedance mitigation.

Considerable toxic tellurium-containing wastewater has been discharged into water environment and constantly accumulates, due to the widespread applications but low utilization of tellurium, causing irreversible harm to the environment and human health, thus it is crucial to find an efficient strategy for tellurium separation. Herein, hierarchical porous magnesium oxide modified cellulose acetate membranes (MgO@CAM) were prepared via a facile physical blending and phase inversion method for tellurium separation. Diverse characterization methods and batch separation experiments were conducted to investigate the morphological structure of MgO@CAM, tellurium separation mechanism, and the separation behavior under different influencing factors. The results exhibit that MgO@CAM has a hierarchical porous structure and a hydroxyl-rich surface, which facilitates the separation of tellurium. Besides, MgO@CAM reveals eligible regeneration performance, good stability and thermal stability due to the hydrogen bonding and skeletal structure of cellulose acetate. The study on the effect of pH suggests that an acidic environment is more conducive to the separation of tellurium by MgO@CAM, and the prepared membranes show outstanding separation efficiency of tellurium, with a maximum of 97.6%. Furthermore, the membranes also achieve satisfactory separation efficiency of tellurium in the presence of multiple coexisting ions. Thomas dynamics indicate the practical application of MgO@CAM in tellurium separation. More importantly, prominent hydrophilic enables MgO@CAM to demonstrate excellent antifouling performance. Therefore, the preparation of hierarchical porous MgO@CAM provides an efficient and economic strategy for tellurium separation in wastewater and has promising applications in water treatment.

Pathogenic biofilms formed on the surfaces of implantable medical devices and materials pose an urgent global healthcare problem. Although conventional antibacterial surfaces based on bacteria-repelling or bacteria-killing strategies can delay biofilm formation to some extent, they usually fail in long-term applications, and it remains challenging to eradicate recalcitrant biofilms once they are established and mature. From the viewpoint of microbiology, a promising strategy may be to target the middle stage of biofilm formation including the main biological processes involved in biofilm development. In this work, a dual-functional antibiofilm surface is developed based on copolymer brushes of 2-hydroxyethyl methacrylate (HEMA) and 3-(acrylamido)phenylboronic acid (APBA), with quercetin (Qe, a natural antibiofilm molecule) incorporated via acid-responsive boronate ester bonds. Due to the antifouling properties of the hydrophilic poly(HEMA) component, the resulting surface is able to suppress bacterial adhesion and aggregation in the early stages of contact. A few bacteria are eventually able to break through the protection of the anti-adhesion layer leading to bacterial colonization. In response to the resulting decrease in the pH of the microenvironment, the surface could then release Qe to interfere with the microbiological processes related to biofilm formation. Compared to bactericidal and anti-adhesive surfaces, this dual-functional surface showed significantly improved antibiofilm performance to prevent biofilm formation involving both Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus for up to 3 days. In addition, both the copolymer and Qe are negligibly cytotoxic, thereby avoiding possible harmful effects on adjacent normal cells and the risk of bacterial resistance. This dual-functional design approach addresses the different stages of biofilm formation, and (in accordance with the growth process of the biofilm) allows sequential activation of the functions without compromising the viability of adjacent normal cells. A simple and reliable solution may thus be provided to the problems associated with biofilms on surfaces in various biomedical applications.

Antifouling coatings are critical in preventing the surface of sea vessels being heavily fouled by bio-organisms. In this work, we attached biocidal moieties (Isobornyl methacrylate, IBOMA) to the side chains of the polyacrylic polymer to form the antifouling polymer (AFP). Then, the hydrophilic polysiloxane (HP) was prepared through the polyaddition of polyethylene glycol (PEG) and alkoxysilane onto the main chain of the hydrogen silicone oil. Finally, the hydrophilic fouling release coatings (FRCs) were formed by the reaction or winding of antifouling polymer and HP polymer with an interpenetrating polymer network (IPN) method (IPN-FRCs). The effects of the content of AFP and HP on the adhesion, surface roughness, and antifouling performance of the applied coatings on substrate are thoroughly studied and revealed in details through different analytic techniques. The IPN-FRCs exhibit high adhesion strength to the substrate, and the surface roughness is greatly reduced when submerged in seawater. Furthermore, the IPN-FRCs have high performance against seawater bio-organisms, such as barnacles, during both in-lab and marine field tests when right polymer ratios were chosen. Thus, the novel FRCs may have great potential to be applied for marine vessels in line with their low-cost in raw materials and high performance of the final products. The silicone-based antifouling polymer coatings show high resistance to the foulants of marine bio-organisms.

The ability to perform multiplexed detection of various biomarkers within complex biological fluids in a robust, rapid, sensitive, and cost-effective manner could transform clinical diagnostics and enable personalized healthcare. Electrochemical (EC) sensor technology has been explored as a way to address this challenge because it does not require optical instrumentation and it is readily compatible with both integrated circuit and microfluidic technologies; yet this approach has had little impact as a viable commercial bioanalytical tool to date. The most critical limitation hindering their clinical application is the fact that EC sensors undergo rapid biofouling when exposed to complex biological samples (e.g., blood, plasma, saliva, urine), leading to the loss of sensitivity and selectivity. Thus, to break through this barrier, we must solve this biofouling problem.In response to this challenge, our group has developed a rapid, robust, and low-cost nanocomposite-based antifouling coating for multiplexed EC sensors that enables unprecedented performance in terms of biomarker signal detection compared to reported literature. The bioinspired antifouling coating that we developed is a nanoporous composite that contains various conductive nanomaterials, including gold nanowires (AuNWs), carbon nanotubes (CNTs), or reduced graphene oxide nanoflakes (rGOx). Each study has progressively evolved this technology to provide increasing performance while simplifying process flow, reducing time, and decreasing cost. For example, after successfully developing a semipermeable nanocomposite coating containing AuNWs cross-linked to bovine serum albumin (BSA) using glutaraldehyde, we replaced the nanomaterials with reduced graphene oxide, reducing the cost by 100-fold while maintaining similar signal transduction and antifouling properties. We, subsequently, developed a localized heat-induced coating method that significantly improved the efficiency of the drop-casting coating process and occurs within the unprecedented time of

Using natural product-based antifouling coatings has proven to be an effective strategy to combat biofouling. However, their antifouling mechanisms are still unclear. In this study, the antifouling mechanism of natural product-based coatings consisting of bio-sourced poly(lactic acid)-based polyurethane and eco-friendly antifoulant (butenolide) derived from marine bacteria was revealed by observing 3D bacterial motions utilizing a 3D tracking technique-digital holographic microscopy (DHM). As butenolide content increases, the density of planktonic marine bacteria (Pseudomonas sp.) near the surface decreases and thus leads to a reduced adhesion, indicating that butenolide elicits the adaptive response of Pseudomonas sp. to escape from the surface. Meanwhile, among these remained cells, an increased percentage is found to undergo subdiffusive motions compared with the case of smaller dose of butenolide. Further experiments show that butenolide can accelerate their swimming velocity and reduce flick frequency. Antibacterial assay confirms that butenolide-based coating shows high efficacy of antifouling performance against Pseudomonas sp. but without killing them like 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT).

Background Marine biofouling has done great economic damage to people every year, and it seriously affects the development of national economy. Methods In this paper, three types of antifouling films were prepared, including pristine silicon rubber (PSR), graphene added silicon rubber (GSR), and GSR filled with quaternary ammonium salt of different concentrations (QGSR). These antifouling films have strong salt resistance ability, and their surface free energy is in the range of 19.3078 mJ/m2–21.4384 mJ/m2, which is calculated by contact angle. Based on Baier curve, the surface free energy in this zone is benefit to fouling-release. Then, the antifouling ability were explored under both laboratory conditions and real marine environments. Significant Findings Results showed that the bactericidal film of QGSR have antiadhesion effect under laboratory conditions, but the antiadhesion effect is not durable, and it lose antifouling effects completely in real marine conditions. However, the non-bactericidal film of GSR exhibited stronger antifouling ability than QGSR after immersed in marine environment for 9 months. Therefore, the physical interaction to expel bacteria is more conducive to long-term antifouling in the complex marine environment.

Marine biofouling is a ubiquitous and longstanding challenge that causes both economic and environmental problems. To address this, several antifouling strategies have been proposed, such as the release of biocidal compounds or surface chemical/physical design. Here we report a coating with surface structures (chemical heterogeneity) triggered by phase segregation, which endues the good antifouling properties, alongside robust mechanical properties, low underwater oil adhesion, and excellent optical transparency. This is achieved by arranging the hydrophobic and hydrophilic components to control the assembly and phase separation under the cross-linking and localized swelling process. The structure designs are based on the poly(ethylene glycols) (PEG), zwitterions, and hydrophobic components, which may lower the entropic and enthalpic driving forces for the adsorption of the marine organisms. Our approach could provide an effective way of manufacturing novel coating with amphiphilic micro/nanodomains structure, particularly for the marine industry. And we also showed that the coatings were stable under different temperatures and shear environments. To illustrate the applicability of such a robust coating in marine biofouling, we demonstrated significantly reduced algal adhesion and barnacle attachment in the sea (p

Hydrogels with good antifouling and mechanical properties as well as biocompatibility have great application potential in the field of biomedicine. In this paper, a newly double network (DN) hydrogel was prepared based on zwitterionic material sulfobetaine methacrylate (SBMA) and natural polysaccharide, sodium alginate (SA). The PSBMA network is covalently crosslinked while the SA network is ionically crosslinked by Ca2+. The hybrid crosslinked double network structure endows the DN hydrogel with excellent mechanical properties (E = 0.19 ± 0.01 MPa, σ = 0.73 ± 0.03 MPa), fast self-recovery ability as well as excellent fatigue resistance. Moreover, the results show that the PSBMA/SA-Ca2+ DN hydrogel is biocompatible and resists the absorption of non-specific proteins and adhesion of microorganisms, such as cells and algae, exhibiting outstanding antifouling properties. These unique characteristics of PSBMA/SA-Ca2+ DN hydrogel make it a promising candidate for biomedical application, such as artificial connective tissues, implantable devices, and underwater equipment.

Bacterial infections associated with biomedical devices and implants have posed a great challenge to global healthcare systems. These infections are mainly caused by bacterial biofilm formed on the surface of biomaterials, protecting the encapsulated bacteria from conventional antibiotic treatment and attack of the immune system. As the bacterial biofilm is difficult to eradicate, bactericidal and antifouling coatings have emerged as promising strategies to prevent biofilm formation and subsequent infections. Hydrogels with three-dimensional crosslinked hydrophilic networks, tunable mechanical property and large drug-loading capacity are desirable coating materials, which can kill bacteria and/or prevent bacterial adhesion on the surface, inhibiting biofilm formation. Herein, we review recent developments of hydrogels as anti-infective coatings. Particularly, we highlight two chemical approaches (graft-from and graft-to), which have been used to immobilize hydrogels on surfaces, and present advances in the development of bactericidal (contact-killing and antimicrobial-releasing), antifouling (hydrophilic polymer network) and bifunctional hydrogel coatings with both bactericidal and antifouling activities. In addition, the challenges of hydrogel coatings for clinical applications are discussed, and future research directions of anti-infective hydrogel coatings are proposed.

The development of antifouling coating for sensor is desirable because the biofilm can shorten sensor’s life and cause inaccurate reading. In this study, a facile one-pot reaction was used to synthesized ZnO–graphene oxide (GO) (ZnO–GO) nanocomposites. Different amount of ZnO–GO was incorporated in the polydimethylsiloxane (PDMS) matrix respectively though a simple solution mixing method, in order to create PDMS/ZnO–GO nanocomposite (PZGO). The coating was obtained directly by spin coating of PZGO/tetrahydrofuran suspension. The hydrophobicity, surface roughness (Ra), surface free-energy (SFE) and nanoscale structure were investigated as antifouling factors. Antifouling tests were performed using two marine microorganisms, the cyanobacterium Synechococcus sp. Strain PCC 7002 and the diatom Phaeodactylum tricornutum. PZGO0.2 (mass ratio of ZnO–GO to PDMS: 0.2 wt%) displayed excellent antifouling property with 8.5% of Synechococcus sp. Strain PCC 7002 biofilm coverage, while PZGO0.1 (mass ratio of ZnO–GO to PDMS: 0.1 wt%) showed 2.4% P. tricornutum biofilm coverage. The antifouling property of the synthesized PZGO nanocomposite can be attributed to its high Ra and hydrophobicity which was caused by the good dispersion of ZnO–GO in PDMS matrix. This study suggests a potential of PZGO nanocomposite for sensor’s antifouling coating, which could contribute to improve sensor’s durability relating to biofouling in future. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

Disinfecting pathogenic contaminated water rapidly and effectively on sites is one of the critical challenges at point-of-use (POU) situations. Currently available technologies are still suffering from irreversible depletion of disinfectants, generation of toxic by-products, and potential biofouling problems. Herein, we developed a chlorine rechargeable biocidal nanofibrous membrane, poly(acrylonitrile-co-5-methyl-5-(4'-vinylphenyl)imidazolidine-2,4-dione) (P(AN-VAPH)), via a combination of a free radical copolymerization reaction and electrospun technology. The copolymer exhibits good electrospinnability and desirable mechanical properties. Also, the 5-methyl-5-(4'-vinylphenyl)imidazolidine-2,4-dione (VAPH) moieties containing unique hydantoin structures are able to be chlorinated and converted to halamine structures, enabling the P(AN-VAPH) nanofibrous membrane with rapid and durable biocidal activity. The chlorinated P(AN-VAPH) nanofibrous membranes showed intriguing features of unique 3D morphological structures with large specific surface area, good mechanical performance, rechargeable chlorination capacity (>5000 ppm), long-term durability, and desirable biocidal activity against both bacteria and viruses (>99.9999% within 2 min of contact). With these attributes, the chlorinated P(AN-VAPH) membranes demonstrated promising disinfecting efficiency against concentrated bacteria-contaminated water during direct filtration applications with superior killing capacity and high flowing flux (5000 L m-2 h-1).

The efficiency of filtration membranes is substantially lowered by bacterial attachments and potential fouling processes, which reduce their durability and lifecycle. The antibacterial and antifouling properties exhibited by the added materials play a substantial role in their application. We tested a material poly(vinylidene fluoride)-co-hexafluoropropylene (PDVF-co-HFP) based on an electrospun copolymer, where an agent was incorporated with a small amount of ester of glycerol consecutively with caprylic, capric, and lauric acids. Each of these three materials differing in the esters (1-monoacylglycerol, 1-MAG) used was prepared with three weighted concentrations of 1-MAG (1, 2, and 3 wt %). The presence of 1-MAG with an amphiphilic structure resulted in the hydrophilic character of the prepared materials that contributed to the filtration performance. The tested materials (membranes) were characterized with rheological, optical (scanning electron microscopy, SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and other methods to evaluate antibacterial and antifouling activities. The pure water flux was 6 times higher than that of the neat PVDF-co-HFP membrane when the added 1-MAG attained only 1 wt %. It was experimentally shown that the PVDF-co-HFP/1-MAG membrane with high wettability improved antibacterial activity and antifouling ability. This membrane is highly promising for water treatment due to the safety of antibacterial 1-MAG additives.

Marine facilities and ships are easily plagued by biofouling. Synergistic surfaces combining surface reactive ion etching and peptide modification were designed and prepared to tackle surface biofouling. Six microstructural surfaces were first designed and machined based on the contact point theory; the synergistic surfaces were then prepared by peptide modification. Laser confocal scanning microscope (LCSM), scanning electron microscopy (SEM), contact angle measurement, and X-ray photoelectron spectroscopy (XPS) were utilized to analyze the surface morphology and surface chemical properties; the results demonstrated that six synergistic surfaces were prepared successfully with 0.8-mu m depth, surface contact angle increased from 75 degrees to 116.99 degrees, and the surface chemical compositions were also changed significantly due to peptide modification. Antibiofilm assays showed that surface modification and surface topology could slightly reduce the formation of biofilm. While the synergistic surfaces possess strong anti-algal performance, and anti-Chlorella pyrenoidosa (C. pyrenoidosa) and anti-Phaeodactylum tricornutum (P. tricornutum) rates reached 78.56% and 87.80%, respectively after 7-day immersion in artificial seawater. Compared with the single surface treatment method, the antifouling performance of the synergetic surfaces were stronger. This strategy demonstrated a realistic paradigm for the further improving surface antifouling performance in a green method.

Antifouling ability and blood compatibility are critically important in the development of medical metallic implants for clinical applications. Here, we report the zwitterionic-phosphonate block polymer as a new type of high-efficiency antifouling coating for metallic substrates. Six block polymers (pSBMA-b-pDEMMP) with different segment lengths (nSBMA: nDEMMP = 10:25, 40:25, 100:25, 75:5, 75:40, 75:100) were prepared and anchored on titanium alloy (TC4) substrates. 1H nuclear magnetic resonance (NMR) results clearly showed the precise preparation of the block polymers. XPS analysis and water contact angle measurement indicated the successful construction of the block polymer on TC4 substrates. The relationship between the antifouling performance of the polymer coating and the length of pDEMMP and pSBMA segments in the block polymer was established. Results showed that the polymer containing the pSBMA segment above 40 repeat units could significantly inhibit protein adsorption, platelet adhesion, bacterial adhesion and cell adhesion, while the pDEMMP segment above 5 repeat units is able to generate stable zwitterionic polymer coating on TC4 substrates. This ease of production and high-efficiency antifouling modification strategy elucidated here may find broad application for biomedical implants and devices in clinical applications.