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The attachment of microbial biomass on solid surfaces is a universal phenomenon that occurs in both natural and engineering systems and it is responsible for various types of biofouling. Biological fouling also referred to as biofouling, remains one of the most critical problems towards the durable application of materials. The eradication of this...
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... globally to fabricate materials with similar properties. The lotus flower is referred to as the symbol of purity in Asian religions (Ganesh et al., 2011). According to literature (Solga et al., 2007), Ward was the first to observe that, although the lotus leaf arises from muddy water, it is always clean and remains untouched by dirt and other pollutants (Fig. 8) (Ganesh et al., 2011; Zhang et al., 2008). The invention of the scanning electron microscope (SEM) in the mid-1960s unravelled the mystery behind this observation. Investigations using the SEM showed that even though the surfaces of the lotus leaf appear smooth with the naked eye, they exhibited microscopic roughness on different length scales. These surfaces, along with the presence of (hydrophobic) epicuticular wax crystalloids, make the leaves superhydrophobic (Ganesh et ...
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... 11,12 Chemical disinfectants also react with natural organic matter (NOM) and can produce disinfection byproducts (DBPs), which are toxic and suspected carcinogens. 13,14 Ultraviolet (UV) light inactivates protozoa, viruses, and bacteria by disrupting the genetic material. 15 Conventional UV treatments include the use of mercury-based low-pressure (LP) or medium-pressure (MP) lamps. ...
This study assesses the efficacy of ultraviolet light-emitting diodes (UV LEDs) for deactivating Legionella pneumophila (pure culture) and Pseudomonas fluorescens (pure culture and biofilms) on relevant drinking water distribution system surfaces (cast iron and stainless steel). UV LED treatment at 280 nm demonstrated superior performance compared to that at 365 nm, achieving a 4.8 log reduction value (LRV) for P. fluorescens pure cultures and, for biofilms, 4.02 LRV for stainless steel and 2.96 LRV for cast iron at 280 nm. Conversely, the results were less effective at 365 nm, with suspected photolytic reactions on cast iron. Quantification of L. pneumophila yielded varying results: 4 LRV using standard plate counts, 1.8 LRV with Legiolert, and 1 LRV with quantitative polymerase chain reaction at 280 nm, while the results were less than 1.5 LRV at 365 nm. This study provides insights into managing opportunistic pathogens and biofilms, emphasizing the need for improved quantification tools to better assess treatment efficacy.
... 22 Biological fouling is the accumulation of microorganisms such as bacteria, fungi, and algae on the membrane surface. 23 This type of fouling is the most recalcitrant because: (i) it is not easily reversible, (ii) it is complex due to the growth, multiplication, and subsequent relocation of the foulant microorganisms on the membrane surface, and (iii) pretreatment techniques are rendered inefficient due to strong adhesion of the extracellular polysaccharide layer on the membrane surface. 24 Biofouling is initiated by the adhesion and accumulation of microorganisms, their subsequent growth and multiplication. ...
Membrane biofouling is a major stumbling block in membrane technology and particularly in the water treatment industry. Biofouling, in particular, is a serious concern because it is irreversible and thus cuts the lifespan of the polymeric membranes. This review, therefore, explores the fundamentals of biofouling development and the factors that promote biofilm growth in polymeric membrane systems. In this pursuit, we discuss avenues through which antibiofouling polymeric membranes have been fabricated using inorganic and carbon-based nanomaterials as membrane nanofillers to enhance the hydrophilicity and antibiofilm properties of the resultant composite membranes without significantly compromising the membrane filtering abilities. We further elucidate the chemistry by which the membrane nanofillers mitigate or inhibit the formation and growth of the undesirable biofilms on the surface and pores of the membranes. In achieving this, recent works on polymeric membrane biofouling are reviewed, with a particular focus on the correlation between the membrane performance and the physicochemical properties of the filler nanomaterials. The merits and demerits of inorganic and carbon-based nanomaterials as fillers to confer an antibacterial effect to the membranes are presented and perspectives and opinions on the future direction of biofouling mitigation in membranes are outlined.
... These recent years, bioinspired membranes have attracted increasing interest to improve the performances of the separation processes they are involved in [11]. These membranes reproduce the properties (forms, functions, etc.) of biological systems to solve technological problems, and in this sense, they represent the next generation of filtration membranes for water treatment [11][12][13][14][15]. Among these biological functions, those that control material fouling represent an important target as they could significantly contribute to improving the performance of membranes and of water treatment plants in which they are involved [16]. ...
... For that, some membrane modification strategies considered are those that: (i) mimic biological structures, such as grafting of polymers containing zwitterionic moieties [17], coating of thin film polymer brushes [18,19], and creating Sharklet patterns on the membrane surface [20][21][22] to prevent physical-chemical interactions, and/or (ii) mimic biological functions, such as grafting to or adding in the bulk material of membranes antibacterial or enzymatic molecules to inhibit and/or kill microorganisms [23]. However, while for antibacterial there is a high risk to develop bacterial resistance, enzymes are costly and unstable [14]. The contact-type antibiofouling effects are promising to limit the adhesion of bacteria to the surface but is limited to micro-organisms that come into contact with the surface [24] with a risk for the cell contents to be released into the treated water. ...
... The adherence of microbes on the conditioned film is promoted by sedimentation, water flow, convective and Brownian motion. [18][19][20][21] Finally, after a week of activity, some single-celled algal spores, protists, and marine biological larvae adhere over the biofilm surface to provide nutrition to increase their population to create a vast biological fouling community. 22 The attached organism colonizes onto the ship's hull surface thereafter increasing the ship's drag, reducing the ship's speed, and increasing the hydrodynamic weight of the vessel. ...
Biofouling is a major issue for many industries including shipping, oil, and gas and can lead to accelerated corrosion, particularly for structures and components in and around salt water. Many efforts are undertaken to lessen its impact and financial losses. One of the promising methodologies is application of antibiofouling coatings to minimize biofouling, and the best results were observed with a superhydrophobic coating. Ample literature reviews on superhydrophobic coating have shown biofouling inhibition on the surface due to high wetting angles similar to the phenomenon on a lotus leaf. The hydrophobic coating can be deposited using multiple techniques such as electroless plating, chemical vapor deposition (CVD), sol–gel, and electrodeposition. In this review, an effort has been made to encompass such experimental work under a single domain and compare the effectiveness of each coating. In addition, mechanical properties and surface characteristics such as wetting angle, surface energy, and morphology were also discussed for various types of polymeric coating. Similarly, the application of nanoparticles such as ZnO, SiO2, TiO2, and CeO2 was found to improve the substrate's mechanical properties, the durability of coatings, improvement in wear properties, adhesion, interlaminar cohesion, and increased wetting angle and above all, improve superhydrophobicity. These improvements are compared for various nanoparticle integrated coatings. In addition, other novel approaches to prevent marine biofouling by various polymer-based coatings such as superhydrophobic, foul-release, and foul-resistant coatings are discussed in this paper.
... Essentially, chemical control often includes the use of biocidal to kill microorganisms in cooling water or biocides to lessen their activity. Biocides are classified as oxidizing or non-oxidizing [109]. Chlorine, ozone, bromine, and peracetic acid are examples of oxidizing biocides, whereas acrolein, glutaraldehyde, isothiazolones, biodispersants, and heavy metal compounds are examples of non-oxidizing biocides [110]. ...
Biofouling accumulates living organisms on surfaces in contact with the water and causes significant economic, structural, and microbial problems on ship hulls, piers, oil rigs, power plants, pipework, water treatment facilities as well as medical devices. In order to mitigate problems associated with biofouling, many toxic and non-toxic antifouling methods have been developed. Unfortunately, most of the methods used to control biofouling are either harmful to the environment or, in some cases, considered effective. Thus, antifouling research's main objective is to develop green, sustainable, viable, widely applicable, and environmentally friendly antifouling technology. In this review, chemical, physical, and biological mitigation methods to prevent biofilm formation employed in the past and present have been discussed along with the current literature. Chemical antifouling methods generally contain antifouling (AF) paints with biocides including copper, silver, thiocyanate, Copper powder, Irgarol 1051, Zinc pyrithione, and Tributyltin (TBT). The physical antifouling control methods employ physical force or surface modifications such as low drag, low adhesion, wettability (super hydrophobicity or super hydrophilicity), as well as microtextured structures that minimize microorganism adhesion and/or accumulation on contact surfaces, hindering the formation of biofouling. The use of nature-inspired antibiological and biomimetic surfaces like shark skin, whale skin, dolphin skin, and lotus leaves are promising for the effective control of biofouling and present opportunities for developing non-polluting technologies.
... The emerging marine renewable energy industry (MRE) and the development of mechanical energy converters are especially afflicted by biofouling [9]. To counter these difficulties, different biofouling control strategies have been proposed: chemical, mechanical, biological, electrochemical, and surface modification [10]. The chemical control known as coating is currently the most common antifouling (AF) strategy, is designed to be effective against various taxa and environmental conditions and has comparatively long durability. ...
Biofouling control on human-made structures and seagoing technologies that minimize environmental impacts is a major focus of research in marine industries. However, the most widely used antifouling (AF) method is still copper-based coatings. Some “eco-friendly” approaches are commercially available but have been scarcely tested in natural conditions, especially high-energy environments. We conducted a replicated long-term field experiment in a highly wave-exposed, high productivity coastal environment to test three untreated materials used in maritime industries, two traditional copper-based AF coatings, and two materials offered as “eco-friendly” AF in the market (i.e., a slow-copper release and a self-adhesive, fiber-covered, skin-like coating). We showed that biofouling cover and biomass increased at similar rates over time among all untreated materials, including the skin-like AF. The two traditional copper-based AF coatings and the slow-release AF paint both showed similarly low biofouling biomass and richness, demonstrating their efficacy after 12 months in the field. Although the “eco-friendly” slow-release technologies are not completely innocuous to the environment, we suggest this approach over the more environmentally aggressive traditional copper paints, which are the most widely used in aquaculture and shipping industries today. However, further research is needed to test whether their environmental impact is significantly lower in the long-term than traditional AF paints, and therefore the search for non-toxic coating must continue. The fortuitous settlement and growth of sea urchins in our experiments also suggest that a combination of “eco-friendly” AF and biological control would be possible and should be further investigated. The skin-like coatings must be tested under different environmental conditions, and they are not recommended in wave-exposed coastal habitats.
... The increased resistance of biofilm against antimicrobials and the host immune system imposed the need for new strategies (Rabin et al., 2015). Biological control of biofilms uses certain mechanisms (from living matter, microorganisms, or microbes within the biofilm itself) in order to interfere with their existence (Gule et al., 2016). This is mainly used to target the QS, degrade the extracellular matrix, inhibit microbial adherence, and eliminate persister cells. ...
... Biofouling gives rise to problems in a wide range of industrial processes, such as water treatment, electricity production, and in the health sector. 1 The microbial community structure of biofilms provides bacteria with important advantages because it helps them better endure stressors and harsh conditions. 2 This makes the presence of biofilms on industrially or medically relevant surfaces problematic because it makes the microorganisms more resistant, in turn making them difficult and expensive to remove. 3 The U.S. National Institutes of Health estimate that 65% of all microbial infections are associated with biofilms. ...
Chitosan hydrogels have widespread industrial applications due to their versatility and antimicrobial potential. However, their applicability can be limited by poor mechanical properties or because their fabrication requires the use of toxic compounds which can leach into their environment. Additionally, their poor water solubility under neutral conditions restricts their fabrication and applications to low pHs. Here, we synthesized a modified derivative [N-(2-hydroxy-3-trimethylammonium)propyl] chitosan chloride (HTCC), which is soluble and antimicrobial at neutral pH, and used it to compare the effect of three crosslinking agents on the formation of industrially relevant hydrogels. The crosslinkers sodium tripolyphosphate (TPP), glutaraldehyde (GA), and citric acid (CA) were compared in terms of their impact on the swelling potential, hydrophobicity, and mechanical properties. Swelling degrees ranging from 350 to 2350% for GA and TPP, respectively, were observed. Silver nanoparticles (Ag NPs) were synthesized in situ, leading to improved mechanical properties as evidenced by an increase in the Young modulus from 10.3 MPa for TPP-crosslinked systems to 87.4 MPa for TPP-crosslinked/Ag NP composites. Ag ion release rather than Ag NP leaching was determined to be the dominant strategy for antimicrobial action against Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Acinetobacter baumanii, causing significant increases (p < 0.05) in clearance ratios and biofilm shape factors, pointing to a synergism between the crosslinked HTCC and Ag NPs. The exceptional broad-spectrum antimicrobial/antifouling properties of these materials regardless of the crosslinking method allow for selection of different preparation techniques to tune desired traits for diverse industrial applications.
... The need to search for viable solutions to tackle marine biofouling issues has allowed the development of antifouling and anticorrosion coatings associated with the design of nanocomposite materials based on biocidal agents or acting through the so-called fouling release mechanism [4]. From a general point of view, the development of nanocomposite materials with antimicrobial and antifouling properties represents a well-known topic finding application in many research fields including the fabrication of biomedical devices, water purification systems, and food packaging as well as marine equipment [5][6][7][8]. ...
Silica, titania, and mixed silica–titania powders have been used as supports for loading 5 wt% Cu, 5 wt% Ag, and 2.5 wt% Cu-2.5 wt% Ag with the aim of providing a series of nanomaterials with antifouling properties. All the solids were easily prepared by the wetness-impregnation method from commercially available chemical precursors. The resulting materials were characterized by several techniques such as X-ray diffraction analysis, X-ray photoelectron spectroscopy, N2 physisorption, and temperature-programmed reduction measurements. Four selected Cu and Ag SiO2- and TiO2-supported powders were tested as fillers for the preparation of marine antifouling coatings and complex viscosity measurements. Titania-based coatings showed better adhesion than silica-based coatings and the commercial topcoat. The addition of fillers enhances the resin viscosity, suggesting better workability of titania-based coatings than silica-based ones. The ecotoxicological performance of the powders was evaluated by Microtox luminescence tests, using the marine luminescent bacterium Vibrio fisheri. Further investigations of the microbiological activity of such materials were carried out focusing on the bacterial growth of Pseudoalteromonas sp., Alteromonas sp., and Pseudomonas sp. through measurements of optical density at 600 nm (OD600nm).
... Biofilm formation can cause several infections of living tissues including wound infection, lung epithelium infection (such as cystic fibrosis), dental plaque,and endocarditis as well as infection of external devices such as contact lenses, prosthetic joints, catheters,and pharyngeal tubes (Wolcott and Ehrlich, 2008;Francolini and Donelli, 2010;Veerachamy et al., 2014). Biofilm control is important for industries because their accumulation can cause significant economic losses, including equipment failure through inducing microbiologically influenced corrosion (MIC) and biofouling which are great problems in the gas, oil and water utilities, due to increased maintenance operations and costs (Gule et al., 2016;Zhao et al., 2017). Biofilms are usually of mixed-species, which can pose a greater challenge than single species, because, different microbial species within the biofilm increase its physical and biological complexity and resistance to antimicrobials. ...
Biofilms are complex aggregates of microbes that are tightly protected by an extracellular matrix (ECM) and may attach to a surface or adhere together. A higher persistence of bacteria on biofilms makes them resistant not only to harsh conditions but also to various antibiotics which led to the emergence of problems in different applications. Recently, it has been discovered that many bacteria produce and release various D-amino acids (D-AAs) to inhibit biofilm formation, which made a great deal of interest in research into the control of bacterial biofilms in diverse fields, such as human health, industrial settings, and medical devices. D-AAs have various mechanisms to inhibit bacterial biofilms such as: (i) interfering with protein synthesis (ii) Inhibition of extracellular polymeric materials (EPS) productions (protein, eDNA, and polysaccharide) (iii) Inhibition of quorum sensing (autoinducers), and (iv) interfere with peptidoglycan synthesis, these various modes of action, enables these small molecules to inhibit both Gram-negative and Gram-positive bacterial biofilms. Since most biofilms are multi-species, D-AAs in combination with other antimicrobial agents are good choices to combat a variety of bacterial biofilms without displaying toxicity on human cells. This review article addressed the role of D-AAs in controlling several bacterial biofilms and described the possible or definite mechanisms involved in this process.
