Microbial infections affect humans worldwide. Many quaternary ammonium compounds have been synthesized that are not only antibacterial, but also possess antifungal, antiviral and anti-matrix ...metalloproteinase capabilities. Incorporation of quaternary ammonium moieties into polymers represents one of the most promising strategies for preparation of antimicrobial biomaterials. Various polymerization techniques have been employed to prepare antimicrobial surfaces with quaternary ammonium functionalities; in particular, syntheses involving controlled radical polymerization techniques enable precise control over macromolecular structure, order and functionality. Although recent publications report exciting advances in the biomedical field, some of these technological developments have also been accompanied by potential toxicological and antimicrobial resistance challenges. Recent evidenced-based data on the biomedical applications of antimicrobial quaternary ammonium-containing biomaterials that are based on randomized human clinical trials, the golden standard in contemporary medicinal science, are included in the present review. This should help increase visibility, stimulate debates and spur conversations within a wider scientific community on the implications and plausibility for future developments of quaternary ammonium-based antimicrobial biomaterials.
The control of microbial infections is a very important issue in modern society. In general there are two ways to stop microbes from infecting humans or deteriorating materials—disinfection and ...antimicrobial surfaces. The first is usually realized by disinfectants, which are a considerable environmental pollution problem and also support the development of resistant microbial strains. Antimicrobial surfaces are usually designed by impregnation of materials with biocides that are released into the surroundings whereupon microbes are killed. Antimicrobial polymers are the up and coming new class of disinfectants, which can be used even as an alternative to antibiotics in some cases. Interestingly, antimicrobial polymers can be tethered to surfaces without losing their biological activity, which enables the design of surfaces that kill microbes without releasing biocides. The present review considers the working mechanisms of antimicrobial polymers and of contact-active antimicrobial surfaces based on examples of recent research as well as on multifunctional antimicrobial materials.
Antimicrobial surfaces and coatings are rapidly emerging as primary components in functional modification of materials and play an important role in addressing the problems associated with biofouling ...and microbial infection. Polyurethane (PU) consisting of alternating soft and hard segments has been one of the most important coating materials that have been widely applied in many fields due to its versatile properties. This review attempts to provide insight into the recent advances in antimicrobial polyurethane coatings or surfaces. According to different classes of antimicrobial components along with their antimicrobial mechanism, the synthesis pathways are presented systematically herein to afford polyurethane with antimicrobial properties. Also, the challenges and opportunities of antimicrobial PU coatings and surfaces are also discussed. This review will be beneficial to the exploitation and the further studies of antimicrobial polyurethane materials for a variety of applications.
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•First comprehensive review of antimicrobial polyurethane (PU) surfaces and coatings.•Antimicrobial PU surfaces are based on bactericidal and anti-biofouling mechanisms.•Synthesis routes toward antimicrobial PU are critical for long-lasting function.•Dual-functional antimicrobial PU surfaces exhibit more desirable properties.
Infections can lead to severe health issues, even death. Surfaces, such as those of biomedical devices, implants, textiles, tables and doorknobs, play a crucial role as carriers for pathogens to ...migrate, attach and proliferate. Implementing surfaces with antimicrobial properties offers a reliable and long-lasting approach to combat surface transmission of germs, minimize microbial colonization, and reduce infections. In this review, we present recent advancements in antimicrobial surfaces, categorized into four groups based on their action mechanisms: antifouling, bactericidal, antifouling and bactericidal, and dynamic or stimuli-responsive surfaces. The work highlights the fabrication processes and properties of each category, along with discussing their structure-performance relationships. Special attention is given to various anchoring strategies involving tunable molecular interactions. The review also introduces relevant biomedical applications.
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•The recent advances in antimicrobial surfaces are systematically reviewed.•The diverse and tunable molecular interactions involved are discussed.•Antifouling, bactericidal, antifouling and bactericidal, and dynamic surfaces are presented.•Relevant biomedical applications are highlighted.
Graphene oxide (GO) is a promising material for the development of antimicrobial surfaces due to its contact-based antimicrobial activity. However, the relationship between GO physicochemical ...properties and its antimicrobial activity has yet to be elucidated. In this study, we investigated the size-dependency of GO antimicrobial activity using the Gram-negative bacteria Escherichia coli. GO suspensions of average sheet area ranging from 0.01 to 0.65 μm2 were produced and their antimicrobial activity evaluated in cell suspensions or as a model GO surface coating. The antimicrobial activity of GO surface coatings increased 4-fold when GO sheet area decreased from 0.65 to 0.01 μm2. The higher antimicrobial effect of smaller GO sheets is attributed to oxidative mechanisms associated with the higher defect density of smaller sheets. In contrast, in suspension assays, GO interacted with bacteria in a cell entrapment mechanism; in this case, the antimicrobial effect of GO increased with increasing sheet area, with apparent complete inactivation observed for the 0.65 μm2 sheets after a 3 h exposure. However, cell inactivation by GO entrapment was reversible and all initially viable cells could be recovered when separated from GO sheets by sonication. These findings provide useful guidelines for future development of graphene-based antimicrobial surface coatings, where smaller sheet sizes can increase the antimicrobial activity of the material. Our study further emphasizes the importance of an accurate assessment of the antimicrobial effect of nanomaterials when used for antimicrobial surface design.
The increasing number of multidrug-resistant bacteria is a growing threat to global public health. Contaminated surfaces pose a major problem in the spreading of these superbugs and are a source of ...bacterial infections that are difficult to treat. Surfaces that repel bacteria or impede biofilms where bacteria are inaccessible to conventional drugs are in great demand for medical and technological applications. Immense multi-disciplinary efforts are being made to develop biocompatible, long-lasting, scalable, and cost-effective antimicrobial surfaces. Here, we highlight emerging strategies that involve harnessing natural and synthetic polymeric nanoassemblies that are antimicrobial either by themselves or through association with antimicrobial compounds to engineer antimicrobial surfaces. Our aim is to move underexplored nanoassemblies into the limelight. Based on their chemical versatility, structural tenability, and orthogonal activity of associated molecules and structures, the nanoassemblies discussed overcome cytotoxicity, non-biodegradability, and short-term antibacterial activity to offer novel surfaces with improved antibacterial and antibiofilm prospects.
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The scientific and industrial interest in antimicrobial surfaces has significantly increased in recent times. This interest is largely in response to the persistent microbial ...contamination of industrial and, importantly, medical implant surfaces. Bacterial contamination of implant surfaces often leads to infection at the implant-tissue interface, and with the prevalence of increasing levels of antimicrobial resistance, the treatment of these infections is becoming far more challenging. Recently, many naturally occurring, high-aspect-ratio surface topographies have been discovered that exhibit high levels of biocidal efficacy. These include epicuticular lipid nano-architectures that are formed on the surfaces of insect wings, such as cicadae and dragonflies. The antimicrobial activity of such surfaces has been found to be a consequence of the physical interactions between the nanoscale topography of the substrate and the attaching pathogenic cells, meaning that the activity is independent of biochemical surface functionality. Importantly, these desirable surface properties can be translated to synthetic biomimetic surfaces, which, when mimicked, lead to a substantial increase in the antimicrobial properties of such surfaces. This paper reviews the recent advances in understanding the basis of these mechanical antimicrobial mechanisms, and discusses the progress being made towards the fabrication of optimised, biocompatible, synthetic analogues.
•Electrosprayed photoactive coatings of sol-gel ZnO nanoparticles.•Dual action self-cleaning antimicrobial functionalized surfaces.•Excellent photocatalytic and photodisinfection ...properties.•Antimicrobial activity due to bioavailable zinc and photogenerated oxidative species.•Surfaces free from bacterial colonization and biofilm formation.
Photoactive coatings of sol-gel ZnO suspensions were electrosprayed on glass substrates to produce self-cleaning antimicrobial functionalized surfaces. ZnO-functionalized materials exhibited a uniform external surface consisting of a pattern of microspheres with diameters in the 100–300 nm range. Electrospray allowed surface densities up to 0.30 mg cm−2 that displayed considerable hydrophilicity. Water contact angle decreased with UV irradiation to values below 10°. Two different UV doses were tested by adjusting the irradiation time to simulate Summer-Spring and Winter-Fall conditions. The functionalized coatings showed excellent photocatalytic properties towards the photodegradation of Methylene blue. The electrosprayed surfaces also displayed antibacterial activity against Staphylococcus aureus, with >99.5% reduction in the number of culturable cells. The biocidal activity is attributed to the photogenerated reactive oxygen species on the surface of ZnO coatings and the bioavailable zinc ions produced from ZnO dissolution. The photoactive coatings kept surfaces free from bacterial colonization and biofilm formation.
This study aims to assess the effect of two different colloidal silver amount on the durability and biocidal activity of a water-borne wood paint. The influence of this multifunctional pigment on the ...aesthetical features of the coatings was evaluated by colorimetric measurements and optical microscopy observations. The durability of the samples was investigated by means of different accelerated degradation tests, such as the exposure in a climatic chamber and to UV-B radiations. Scanning electron microscope observations, infrared spectroscopy analysis and colorimetric inspections were carried out to highlight the residual influence of silver in altering the protective behavior of the paint. Moreover, the Ag-containing samples exhibited excellent antibacterial activity against Staphylococcus aureus and Escherichia coli, while colloidal silver did not introduce effective fungicidal performances against Coniophora puteana and Trametes versicolor fungi. Ultimately, this work demonstrates how colloidal silver can be used as a functional pigment in wood paint, capable of modifying the appearance of the coating, improving its antibacterial performance, without negatively affecting its protective performance.
•Colloidal silver as functional pigment for water-borne wood paints•Silver does not negatively affect the protective performance of the paint.•Silver introduces aesthetic decay in the paint when exposed to UV-B radiation.•Remarkable antibacterial activity of the Ag-polyurethane paint•No fungicidal activity, due to the low concentration of silver in the paint
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