Anti-biofouling Activity Research Articles

Polymeric Membrane Marine Sensors with a Regenerable Antibiofouling Coating Based on Surface Modification of a Dual-Functionalized Magnetic Composite.

Environmentally compatible polymeric membrane marine sensors with excellent antiadhesive and antibacterial properties have recently been developed. However, the regeneration abilities of these sensors after fouling have rarely been investigated. Herein, a novel strategy for preparation of a regenerable antibiofouling coating via surface modification of a dual-functionalized magnetic composite is proposed. A zwitterionic polymer (i.e., poly(sulfobetaine methacrylate)) and a quaternary ammonium compound (i.e., 3-trimethoxysilylpropyl octadecyldimethyl ammonium chloride) are coated on the surface of Fe3O4 microspheres for antiadhesion and bacterial inactivation, respectively. The antifouling magnetic composite can readily be modified on the sensor's surface via the magnetically assisted self-assembly technology. Using a polymeric membrane calcium ion-selective electrode as a model sensor, the protection layer-coated electrode shows the markedly improved antibiofouling activities as compared to the unmodified sensor. More importantly, by altering the direction of the external magnetic field, the antifouling coating can easily be removed after fouling along with the removal of the adsorbed bacterial cells from the electrode's surface, which is followed by re-modifying a fresh coating for regeneration of the antifouling electrode. The proposed methodology for fabrication of a regenerable antibiofouling coating is promising to improve the durability of a marine sensor.

Biofouling-Resistant Ultrafiltration Membranes via Codeposition of Dopamine and Cetyltrimethylammonium Bromide with Retained Size Selectivity and Water Flux.

Biofouling is a serious problem in ultrafiltration (UF) membrane applications. Modifying the surface of membranes with low molecular weight, commercially available antibacterial chemistries is an excellent strategy to mitigate biofouling. Herein, we report a new strategy to impart antibacterial and anti-biofouling behavior without changing the support membrane’s size selectivity and pure water permeance (PWP). To this end, a strong antibacterial agent, cetyltrimethylammonium bromide (CTAB), was codeposited with dopamine onto commercial polyethersulfone (PES) UF membranes in the presence of nitrogen (N2) gas backflow. The PWP and pore size of the support membrane did not change with codeposition, confirming the benefit of N2 backflow in mitigating the solution intrusion phenomenon. X-ray photoelectron spectroscopy (XPS), surface ζ potentials, and contact angle measurements confirmed the successful codeposition of polydopamine (PDA) and CTAB onto the membrane. Among three different CTAB concentrations systematically investigated, the membrane functionalized with CTAB at the critical micelle concentration (CMC) provided the best anti-biofouling activity against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria and retained its surface ζ potential after being stored in 1 M NaCl (pH = 6.8) for 3 months. Our results demonstrate the potential of using a facile, one-step approach to modify commercial UF membranes without compromising their pore size or flux, while simultaneously endowing antibacterial activity.

Multipurpose of Zwitterionic Poly(imidazolium)-Based Hydrogel Coating for Oil/Water Separation with Long-Term Antibiofouling Property

Hydrogel coatings have been applied to separate oil/water mixtures with low oil fouling property. However, most contemporary hydrogels have a short lifespan because of their poor antimicrobial and anti-biofouling ability. Zwitterionic polymeric materials have shown their potential to inhibit microbe (e.g., bacteria) adhesion and can deactivate bacteria by cationic moieties in zwitterion. Herein, we developed a zwitterionic poly(imidazolium) (ZPIM)-based hydrogel coated stainless steel mesh (SSM) with superhydrophilicity and underwater superoleophobicity. The 3D hydrogel network was constructed via cross-linking chitosan with the Debus-Radziszewski reaction, which resulted in the formation of poly(imidazolium) chain. Moreover, PVA and diatomite were also introduced to improve the mechanical property of ZPIM hydrogel coating, resulting in outstanding stability and endurance under harsh conditions. Finally, the ZPIM coated SSM demonstrated high water flux and oil separation efficiency (>99.5 %) as well as superb antibacterial and anti-biofouling activity against both Gram-positive and Gram-negative bacteria. Overall, the study of ZPIM hydrogel coating revealed a new technique for fabricating oil/water separation materials for practical application with low in cost, effective in preparation and excellent bio-fouling resistance.

A Membrane with Strong Resistance to Organic and Biological Fouling Using Graphene Oxide and D-Tyrosine as Modifiers.

Membrane fouling markedly influences the service life and performance of the membrane during the using process. Herein, hydrophilic polyvinylidene fluoride (PVDF) nanocomposite (P-GO-DAA) membranes with antifouling and anti-biofouling characteristics were fabricated by employing graphene oxide (GO) and different concentrations of D-Tyrosine. The structural properties of the prepared nanocomposite membranes as well as pure PVDF membranes were characterized using FTIR, XPS, SEM, AFM, and contact angle analysis. It was found that the introduction of GO fillers made an excellent antifouling performance compared to pure PVDF indicated by the pure water flux, flux recovery rate, and rejection rate during ultrafiltration experiments as a result of the formation of the hydrophilic and more porous membrane. In particular, the nanocomposite membranes showed an increased flux of 305.27 L/(m2·h) and the rejection of 93.40% for the mixed pollutants solution (including Bull Serum Albumin, Sodium Alginate, and Humic Acid). Besides, the outstanding anti-biofouling activity was shown by the P-GO-DAA membrane with the properties of D-Tyrosine for inhibiting biofilm formation during the bacterial adhesion experiments. Furthermore, the adhesion ratio of bacteria on the membrane was 26.64% of the P-GO-DAA membrane compared to 84.22% of pure PVDF. These results were confirmed by CLSM.

Single-atom tungsten engineering of MOFs with biomimetic antibiofilm activity toward robust uranium extraction from seawater

Selective uranium extraction from seawater is challenging because of ubiquitous marine biofouling and poor reusability of adsorbents. A reusable atomic-scale tungsten nanozyme integrating uranium capture capacity and intrinsic haloperoxidase-like activity is constructed, resulting in strong antibiofouling ability and superb reusability for uranium extraction after consecutive multiple regeneration cycles in bio-aggressive seawater. • Atomically dispersed tungsten is anchored in metal organic frameworks (W-UiO). • The presence of atomic-scale tungsten endows W-UiO with haloperoxidase-mimicking activity. • W-UiO nanozyme exerts strong antibacterial activity and inhibition effect against marine microbial colonization. • Such nanozyme exhibits excellent reusability for uranium extraction from seawater. Uranium is the essential element for nuclear power industry. Selective uranium extraction from seawater is very attractive, but challenging because ubiquitous marine biofouling seriously impairs the uranium extraction capacity and reusability of absorbents in bio-aggressive seawater. Herein, we construct a reusable nanozyme for uranium recovery from seawater based on atomically dispersed tungsten anchored on metal organic frameworks (W-UiO). We illustrate that W-UiO nanozyme mimics naturally occurring vanadium haloperoxidase that catalytically converting halides to biocidal hypobromous acid, inducing strong antibiofouling activity against marine microbial colonization. As demonstrated, W-UiO nanozyme shows superb reusability in raw seawater simultaneously, preserving a 78.0% of its initial uranium capture capacity (6.8 times higher than its pristine counterpart) after five consecutive adsorption-desorption cycles. This study is anticipated to spur rationally realizing robust absorbents by mimicking the natural enzymes for practical application in uranium recovery from seawater.

Metal-organic framework (MOF)-based slippery liquid-infused porous surface (SLIPS) for purely physical antibacterial applications

Medical device-associated infections, caused by bacterial adhesion and biofilm formation, remain a leading threat to public healthcare due to continuous emergence of drug-resistant pathogens. Slippery liquid-infused porous surface (SLIPS) is deemed as a promising mean to reduce colonization of bacteria by exceptional repellency property. However, such inert and mono-functional surface becomes helpless once bacterial adhesion occurs. Here, we report a zeolitic imidazolate framework-L (ZIF-L)-based SLIPS (ZLS) with both anti-biofouling and bactericidal activity that all performances are derived from purely physical interactions. Assembled on various substrates, the porous ZIF-L layer is not only the foundation for constructing SLIPS, but exhibits the mechanical bactericidal activity. Fabricating on the catheters, the ZLS exhibit good biocompatibility and can be utilized in a mice subcutaneous implanted model of infection in vivo without inducing the inflammatory response. Thus, we anticipate that the ZLS could provide a new insight into multifunctional and bactericide-free antibacterial surface modifications.

Kelp inspired bio-hydrogel with high antibiofouling activity and super-toughness for ultrafast uranium extraction from seawater

Highly efficient extraction of uranium from seawater is vital for meeting the growth demands of uranium resources for the development of nuclear energy industry. However, currently available uranium adsorbents encounter multiple challenges, including the ultralong extraction period, severe marine biofouling, and violent impact of ocean motions. Targeting on these challenges and inspiring by the high tolerance of kelp to marine biofouling and motions, a kelp inspired super-toughness (KIST) bio-hydrogel is fabricated for uranium extraction from seawater. The hydrogel KIST is prepared by compositing the biofriendly and low-cost bacterial cell debris with polyvinyl alcohol, making the KIST hydrogel possesses high environment friendly. Attributing to the fast uranium adsorption rate of the bacterial cell debris, the KIST hydrogel realizes a uranium extraction capacity of 1.18 mg g−1 in biofouling-containing natural seawater with an ultrafast equilibrium adsorption time of 28 h, which is the shortest among all available uranium adsorbents in natural seawater. The antimicrobial activity of the bacterial cell debris empowers KIST hydrogel with as high as 99.21% inhibition rate to the growth of a broad range marine biofouling microorganisms, including the marine bacteria and marine algae. The KIST hydrogel also possesses outstanding tensile ability, flexibility, and rheological property, endowing the hydrogel with high resistance to the ocean current. Taking into consideration these advantages, the KIST hydrogel would be a promising adsorbent for practical uranium extraction.

Porous and biofouling-resistant amidoxime-based hybrid hydrogel with excellent interfacial compatibility for high-performance recovery of uranium from seawater

For a massive uranium recovery from seawater, designing an adsorbent with ultrahigh uranium uptake capacity and good biofouling-resistant activity is crucial, but difficult. Here, a facile and eco-friendly freeze-thawing strategy was explored for the first time to create a physically crosslinked poly(amidoxime) (PAO)-chitosan (CS) hybrid hydrogel (PAO@CHM) with excellent interfacial compatibility, superior uranium uptake capacity and good anti-biofouling activity. The porous 3D network architecture of PAO@CHM, combined with its good hydrophilicity as well as antibacterial property, synergistically constructs numerous hydrophilic and biofouling-resistant ion channels for the rapid diffusion of uranyl ions into the interior of the hydrogel, achieving maximum use of adsorption active sites on PAO@CHM. Consequently, superior uranium uptake capacities (743.87, 865.27, and 1091.53 mg g−1 for PAO fixed on hydrogel) were obtained in 8, 16, and 32 ppm U-spiked water, respectively. Benifiting from the enhanced uranium adsorption activity and good antibacterial property, the uranium extraction capacity of PAO@CHM reached 7.46 mg g−1 after 28 days of exposure in 500 L of natural seawater, which is significantly higher than that of most of adsorbents. The O and N atoms in amidoxime group act as main bonding sites for uranium uptake. The finding of this study provides a facile and eco-friendly strategy to construct hydrophilic and biofouling-resistant amidoxime-based adsorbent for efficient uranium recovery from seawater.

Ion cross-linking assisted synthesis of ZIF-8/chitosan/melamine sponge with anti-biofouling activity for enhanced uranium recovery

A ZIF-8/chitosan/melamine sponge (CMZ8) uranium adsorbent was prepared using chitosan and zinc ions as adjuvants to achieve the integration of anti-fouling, adsorption and separation properties.

Barrettides: A Peptide Family Specifically Produced by the Deep-Sea Sponge Geodia barretti.

Natural product discovery by isolation and structure elucidation is a laborious task often requiring ample quantities of biological starting material and frequently resulting in the rediscovery of previously known compounds. However, peptides are a compound class amenable to an alternative genomic, transcriptomic, and in silico discovery route by similarity searches of known peptide sequences against sequencing data. Based on the sequences of barrettides A and B, we identified five new barrettide sequences (barrettides C–G) predicted from the North Atlantic deep-sea demosponge Geodia barretti (Geodiidae). We synthesized, folded, and investigated one of the newly described barrettides, barrettide C (NVVPCFCVEDETSGAKTCIPDNCDASRGTNP, disulfide connectivity I–IV, II–III). Co-elution experiments of synthetic and sponge-derived barrettide C confirmed its native conformation. NMR spectroscopy and the anti-biofouling activity on larval settlement of the bay barnacle Amphibalanus improvisus (IC50 0.64 μM) show that barrettide C is highly similar to barrettides A and B in both structure and function. Several lines of evidence suggest that barrettides are produced by the sponge itself and not one of its microbial symbionts.

Biodegradable polyurethane based clay composite and their anti-biofouling properties

The colonization of tiny marine organisms on ship's hull which are connected directly from seawater, is a costly issue. Biofouling contributes to enhanced hydrodynamic drag, which leads to higher consumption of fuel and greenhouse gas emissions. Therefore, the environment-friendly solution is very necessary for anti-biofouling activity. For this purpose, we have synthesized biodegradable polyurethane (CL-PU) composed of ε-CL and 4,4′-methylenebis(cyclohexyl isocyanate) (H12MDI) and 1,4 butanediol (1,4 BD). The synthesized CL-PU was further modified with 4, 5-dicholoro-2-octyl-isothiazolone (DCOIT) and clay by mixing of the solution to make composites. Our study showed that CL-PU/DCOIT/clay composite degraded in the artificial seawater (ASW), enzymatic solution and seawater (through laboratory test) due to the contents of clay. Because the existence of clay reduced the size of the spherulite of polycaprolactone (PCL) in the composite, therefore remarkably improved the crystallinity as determined via the polarizing optical microscope (POM) and differential scanning calorimetry (DSC). The composite acted as carrier of antifoulant (DCOIT) and controlled their release rate. The anti-bacterial and anti-diatom experiments exhibited that the composite with DCOIT contents were effective in preventing the accretion of Escherichia coli (E.coli) (region inhibition 14 mm) and marine diatom Navicula incerta (82.5% reduction). The degradable CL-PU/DCOIT/clay composite will have tremendous durability and excellent anti-fouling activity for marine biofouling owning to sustainability and tunability without being toxic to aquatic biota.

RGO-based covalent organic framework hydrogel for synergistically enhance uranium capture capacity through photothermal desalination

Capturing of uranium from the natural seawater is considered to be one of the most promising methods to meet the current demand for nuclear energy. Herein, we prepared a reduced graphene oxide-based (rGO-based) covalent organic framework hydrogel (KTG) with three-dimensional porous structure as a platform for enhancing uranium capture capacity through photothermal desalination. Under light irradiation, the KTG produces a local heat that can be used to generate steam while promoting the rapid diffusion of uranium inside the hydrogel 3D network, thereby increasing the adsorption efficiency and capacity of uranium. KTG can achieve exceptional uranium capture capacity (521.6 mg g−1) under one sun irradiation, which is 42.4% higher than that under dark conditions. In addition, excellent photocatalytic activity and mechanical properties make KTG possess high anti-biofouling activity, good reusability, and achieving continuous uranium capture and solar distillation.

Stimuli-Responsive Lysozyme Nanocapsule Engineered Microfiltration Membranes with a Dual-Function of Anti-Adhesion and Antibacteria for Biofouling Mitigation.

Biofouling remains as a persistent problem impeding the applications of membranes for water and wastewater treatment. Green anti-biofouling of membranes made of natural and environmentally friendly materials and methods is a promising strategy to tackle this problem. Herein, we have developed a functionalized PVDF membrane with stimuli-responsive lysozyme nanocapsules (NCP). These nanocapsules can responsively release lysozyme according to environmental stimuli (pH and redox) induced by bacteria. Results showed that (i) the surface of the functionalized membrane with NCP had enhanced hydrophilicity, reduced roughness, and negative charge, (ii) a remarkable reduction of adsorption of proteins, polysaccharides, and bacteria was achieved by the functionalized membrane, and (iii) the colony forming unit (CFU) of bacteria on a membrane surface was reduced more than 80% within 24 h of contact. In addition, the NCP membrane showed excellent anti-biofouling activity regarding the bacterial viability being 12.5 and 8.3% on the membrane after filtration with 108 CFU mL-1 Escherichia coli and Staphylococcus aureus solution as feed, respectively. The coating layer and assembled nanocapsules endowed the membrane with improved lysozyme stability, anti-adhesion performance, and antibacterial activity. Stimuli-responsive lysozyme nanocapsule engineered microfiltration membranes show great potential for anti-biofouling in future practical application.

Covalent Organic Framework Sponges for Efficient Solar Desalination and Selective Uranium Recovery.

Energy and fresh water are essential for the sustainable development of human society, and both could be obtained from seawater. Herein, we explored the first covalent organic framework (COF) sponge (named BHMS) by in situ loading the benzoxazole-linked COF (DBD-BTTH) onto a porous polymer scaffold (polydimethylsiloxane) as a synergistic platform for efficient solar desalination and selective uranium recovery. In natural seawater, BHMS shows a high evaporation rate (1.39 kg m-2 h-1) and an exceptional uranium recovery capacity (5.14 ± 0.15 mg g-1) under 1 sun, which are due to its desirable inbuilt structural hierarchy and elastic macroporous open cells providing adequate water transport, increased evaporation sites of seawater, and selective binding sites of uranyl. Besides, the excellent photothermal performance and photocatalytic activity endow the BHMS with high solar desalination efficiency and excellent anti-biofouling activity and promote selective coordination of uranyl.

One-pot synthesis of silver nanoparticle deposited cellulose nanocrystals with high colloidal stability for bacterial contaminated water purification

Cellulose nanocrystals (CNCs) have been utilized as a scaffold to immobilize silver nanoparticles (AgNPs) for their potential application as an antibacterial agent and bactericidal filler. However, the present implemented strategies involve synthesis by multi-step and utilize environment non-friendly reducing agents for the deposition of AgNPs on CNCs. Furthermore, the long-time aqueous dispersion stability of prepared AgNPs hybrids is another issue of concern for their efficient utilization as an antibacterial filler. We have developed an environmentally benign one-pot method using a biocompatible polyvinyl+pyrolidone (PVP) as a reducing agent to deposit AgNPs on CNCs. The developed method exhibited the uniform in-situ deposition of AgNPs on CNCs. The formed (CNC-PVP-Ag) nanohybrid displayed excellent long time aqueous colloidal stability (8 months), antibacterial and anti-biofouling activities (12.5 µg/mL and 25 µg/mL for E. coli and S. aureus) which is 4 and 2 times lower than AgNPs (w/o CNCs) prepared by the identical process as of CNC-PVP-Ag. As water-borne microbial contaminations are a global water quality concern, the excellent antibacterial and anti-biofouling activity of CNC-PVP-Ag was applied for water purification. An efficient bacterial filtration performance (100% reduction of Escherichia coli viability) was achieved after two filtration cycles.

Blow spinning of pre–acid-activated polyamidoxime nanofibers for efficient uranium adsorption from seawater

Polyamidoxime (PAO)-based adsorbents have been extensively studied for uranium (U) extraction from seawater for decades. ‘Hot alkali activation’ treatments are found to significantly improve the U adsorption capacity while inevitably decreasing the strength of PAO-based adsorbents, especially nanofiber (NF) adsorbents. Herein, for the first time, we report that, with proper modification, PAO can be dissolved in acid solution with high solubility, and the pre–acid-activated PAO (PA-PAO) exhibits high uranium capture ability (>1800 mg/g). For better use and collection in large-scale application, PA-PAO is mixed with chitosan (CS) and fabricated to PA-PAO/CS NFs via acidic aqueous solution blow spinning and glutaraldehyde vapor cross-linking. The covalently cross-linked PA-PAO/CS NFs are ready to use without postactivation treatment and achieve highly efficient U capturing performance in U-spiked seawater (913.13 mg/g) and natural seawater (4.91 mg/g, in 10 days), as well as enhanced mechanical stability and antibiofouling (antibacterial) activity. This strategy shows great potential for extraction of U from seawater and contaminated water in a cost-effective, industrial-scale manner.

Alkynyl-Based sp 2 Carbon-Conjugated Covalent Organic Frameworks with Enhanced Uranium Extraction from Seawater by Photoinduced Multiple Effects

Biofouling is a major obstacle to the efficient extraction of uranium from seawater due to the numerous marine microorganisms in the ocean. Herein, we report a novel amidoxime (AO) crystalline cova...

Polydimethylsiloxane-graphene oxide nanocomposite coatings with improved anti-corrosion and anti-biofouling properties.

We demonstrate enhanced anti-corrosion and anti-biofouling properties of graphene oxide-silica-polydimethylsiloxane (GSP) coating on carbon steel (CS). Electrochemical analyses of GSP-coated carbon steel exposed to Gram-positive Bacillus sp., Gram-negative Pseudomonas sp., and freshwater bacterial cultures for 72h showed a 3-5 orders of magnitude reduction in icorr values and high impedance values (107Ω) as compared with polished specimens. The corrosion protection efficiency of GSP-coated specimens was 99.9% against Bacillus sp. and freshwater culture and it was 89.6% against Pseudomonas sp. Evaluation of anti-biofouling property of GSP coating using microbiological and epifluorescence microscopic techniques showed three order reductions in total viable cells on GSP-coated specimens exposed to bacterial cultures. Confocal laser scanning microscopic analysis of biofilm architecture confirmed a significant reduction of biomass and biofilm thickness on GSP-coated CS demonstrating an excellent anti-biofouling activity of GSP.

Regenerable Covalent Organic Frameworks for Photo-enhanced Uranium Adsorption from Seawater.

Uranium is a key resource for the development of the nuclear industry, and extracting uranium from the natural seawater is one of the most promising ways to address the shortage of uranium resources. Herein, a semiconducting covalent organic framework (named NDA-TN-AO) with excellent photocatalytic and photoelectric activities was synthesized. The excellent photocatalytic effect endowed NDA-TN-AO with a high anti-biofouling activity by generating biotoxic reactive oxygen species and promoting photoelectrons to reduce the adsorbed UVI to insoluble UIV , thereby increasing the uranium extraction capacity. Owing to the photoinduced effect, the adsorption capacity of NDA-TN-AO to uranium in seawater reaches 6.07 mg g-1 , which is 1.33 times of that in dark. The NDA-TN-AO with enhanced adsorption capacity is a promising material for extracting uranium from the natural seawater.

Garlic-based phenolic nanopowder as antibiofouling agent in mixed-matrix membrane

The mixed matrix membrane has been developed in this work by using cellulose acetate as a membrane matrix and garlic-based phenolic nanopowder as an anti-biofouling filler. The membrane prepared using the phase inversion method, utilizing dimethylformamide (DMF) as a solvent. Three variation of garlic extract (GE) nanopowder concentration of 0.5%, 0.75%, and 1% were used, respectively. The mixed matrix membranes were tested their final thickness, morphology by using SEM, tensile strength, elasticity, clean water flux, and bacterial adhesion. Anti-biofouling activities of the garlic extract nanopowders were confirmed from the Escherichia coli bacterial adhesion, which 32 cells adhered in the pristine membrane surface, whereas nanopowder concentration of 0.5%, 0.75%, and 1% mixed matrix membranes show 9, 12 and 10 cells adhered in the membrane surface, respectively. The phenolic compounds in the mixed matrix membranes were able to inhibit bacterial growth and potentially used for a safe and non-toxic tool for food processing, including juice clarification.