Enhancing Biocidal Capability in Cuprite Coatings.

The SARS-CoV-2 global pandemic has reinvigorated interest in the creation and widespread deployment of durable, cost-effective, and environmentally benign antipathogenic coatings for high-touch public surfaces. While the contact-kill capability and mechanism of metallic copper and its alloys are well established, the biocidal activity of the refractory oxide forms remains poorly understood. In this study, commercial cuprous oxide (Cu2O, cuprite) powder was rapidly nanostructured using high-energy cryomechanical processing. Coatings made from these processed powders demonstrated a passive "contact-kill" response to Escherichia coli (E. coli) bacteria that was 4× (400%) faster than coatings made from unprocessed powder. No viable bacteria (>99.999% (5-log10) reduction) were detected in bioassays performed after two hours of exposure of E. coli to coatings of processed cuprous oxide, while a greater than 99% bacterial reduction was achieved within 30 min of exposure. Further, these coatings were hydrophobic and no external energy input was required to activate their contact-kill capability. The upregulated antibacterial response of the processed powders is positively correlated with extensive induced crystallographic disorder and microstrain in the Cu2O lattice accompanied by color changes that are consistent with an increased semiconducting bandgap energy. It is deduced that cryomilling creates well-crystallized nanoscale regions enmeshed within the highly lattice-defective particle matrix. Increasing the relative proportion of lattice-defective cuprous oxide exposed to the environment at the coating surface is anticipated to further enhance the antipathogenic capability of this abundant, inexpensive, robust, and easily handled material for wider application in contact-kill surfaces.

Development of polyurethane antimicrobial coatings by composition with phenolic-, ionic- and copper-based agents

Microorganisms can be found in almost all environments with high-touch surfaces being an important fomite for microbial growth. Considering the health issues associated to acquired infection from inanimate surfaces, as well as the raising hygienic concerns, the incorporation of antimicrobial compounds in high-touch surfaces emerges as an effective solution for biomedical and common daily applications. In this work we incorporated different antimicrobial agents (phenolic-, ionic- and copper-based compounds) into polyurethane commercial formulations to produce antimicrobial lacquer-films and evaluated not only their physical/chemical properties, but also their antimicrobial activity against bacteria (Staphylococcus aureus, Escherichia coli), fungi (Candida albicans), and virus (SARS-Cov-2). The incorporation of antimicrobial agents did not affect the performance of lacquer-films and the main properties were maintained, specifically the visual aspect, gloss values, optical properties and its chemical stability. Among the different compounds tested copper-based lacquer-films, exhibited the strongest antibacterial and antifungal activity, with a >4log reduction, but not against virus. Importantly, copper-based lacquer-films maintained their cytocompatibility, even at high concentrations. Regarding the ionic lacquer-films, the highest tested concentration also showed a strong antimicrobial action (5log reduction) against fungi and gram-positive bacteria, but not against gram-negative bacteria and virus. However, at this concentration the ionic-containing lacquer-films presented cytotoxic potential. The phenolic-based compounds were not associated with antimicrobial activity, regardless the concentrations tested. Collectively, these results highlight the potential of incorporating antimicrobial agents in plastic surface coatings as a promising strategy to avoid the microbial colonization on inanimate surfaces and ultimately prevent the spreading of potentially harmful pathogens among humans.

Cationic Conjugated Microporous Polymers Coating for Dual-Modal Antimicrobial Inactivation with Self-Sterilization and Reusability Functions

COVID-19 pandemic outbreak poses a great threat to human health. Face masks have been considered as important personal protective equipment to prevent the COVID-19 transmission. However, pathogens can survive up to several days on the fabrics of commercial masks, which increases the risk of direct/indirect microbial transmission. Herein, new cationic conjugated microporous polymers (CCMPs)-based coating is developed, which possesses extended π-conjugated skeletons and massive quaternary ammonium salt (QAS) groups, exhibiting dual-modal antimicrobial inactivation, including sunlight-driven photodynamic sterilization through the generation of reactive oxygen species and contact sterilization through QAS groups. As a result, the CCMPs coatings can rapidly and efficiently eradicate 99% of model microbes, such as Escherichia coli and Staphylococcus aureus under solar illumination, and also ensure the great antimicrobial effect in the absence of light. More importantly, the CCMPs coatings exhibit excellent durability, reusability as well as antimicrobial stability in humid environment. Contributing to the outstanding processability and formability, CCMPs can be in situ synthesized and coated over fibers through a simple spray procedure. Taken together, the design provides a promising strategy for developing reusable and self-sterilizing antimicrobial fabrics, particularly for the application of face masks to tackle infectious pathogen and viruses in daily protection and medical applications. © 2023 Wiley-VCH GmbH.

Antimicrobial Performance of Innovative Functionalized Surfaces Based on Enamel Coatings: The Effect of Silver-Based Additives on the Antibacterial and Antifungal Activity.

Frequently touched surfaces (FTS) that are contaminated with pathogens are one of the main sources of nosocomial infections, which commonly include hospital-acquired and healthcare-associated infections (HAIs). HAIs are considered the most common adverse event that has a significant burden on the public's health worldwide currently. The persistence of pathogens on contaminated surfaces and the transmission of multi-drug resistant (MDR) pathogens by way of healthcare surfaces, which are frequently touched by healthcare workers, visitors, and patients increase the risk of acquiring infectious agents in hospital environments. Moreover, not only in hospitals but also in high-traffic public places, FTS play a major role in the spreading of pathogens. Consequently, attention has been devoted to developing novel and alternative methods to tackle this problem. This study planned to produce and characterize innovative functionalized enameled coated surfaces supplemented with 1% AgNO3 and 2% AgNO3. Thus, the antimicrobial properties of the enamels against relevant nosocomial pathogens including the Gram-positive Staphylococcus aureus and the Gram-negative Escherichia coli and the yeast Candida albicans were assessed using the ISO:22196:2011 norm.

Antiviral Peptides in Antimicrobial Surface Coatings-From Current Techniques to Potential Applications.

The transmission of pathogens through contact with contaminated surfaces is an important route for the spread of infections. The recent outbreak of COVID-19 highlights the necessity to attenuate surface-mediated transmission. Currently, the disinfection and sanitization of surfaces are commonly performed in this regard. However, there are some disadvantages associated with these practices, including the development of antibiotic resistance, viral mutation, etc.; hence, a better strategy is necessary. In recent years, peptides have been studied to be utilized as a potential alternative. They are part of the host immune defense and have many potential in vivo applications in drug delivery, diagnostics, immunomodulation, etc. Additionally, the ability of peptides to interact with different molecules and membrane surfaces of microorganisms has made it possible to exploit them in ex vivo applications such as antimicrobial (antibacterial and antiviral) coatings. Although antibacterial peptide coatings have been studied extensively and proven to be effective, antiviral coatings are a more recent development. Therefore, this study aims to highlight antiviral coating strategies and the current practices and application of antiviral coating materials in personal protective equipment, healthcare devices, and textiles and surfaces in public settings. Here, we have presented a review on potential techniques to incorporate peptides in current surface coating strategies that will serve as a guide for developing cost-effective, sustainable and coherent antiviral surface coatings. We further our discussion to highlight some challenges of using peptides as a surface coating material and to examine future perspectives.

Inorganic Coatings and Films for Antibacterial and Antivirus Functionality

The global pandemic of COVID-19 has caused serious harm to people's healthy life and the normal operation of society. People have paid more attention to the prevention and control of microbial contamination such as bacteria and viruses. Blocking the spread of disease-causing microorganisms through indirect contact with humans through contaminated surfaces, or avoiding direct contact with them, is the primary way to protect us from harm. Current solutions include designing antibacterial and antiviral surface coatings and developing personal protective equipment made from self-cleaning films or fabrics. In this paper, the work of several widely studied metals, metal oxides, metal organic framework materials, etc. with antibacterial and antiviral functionality is reviewed, their microbial inactivation mechanisms as well as performance are summarized and discussed. In the end, the future perspectives on emerging research directions and challenges in the development of antibacterial and antiviral coatings and films are presented.

Antimicrobial peptides and their potential application in antiviral coating agents.

Coronavirus pandemic has evidenced the importance of creating bioactive materials to mitigate viral infections, especially in healthcare settings and public places. Advances in antiviral coatings have led to materials with impressive antiviral performance; however, their application may face health and environmental challenges. Bio-inspired antimicrobial peptides (AMPs) are suitable building blocks for antimicrobial coatings due to their versatile design, scalability, and environmentally friendly features. This review presents the advances and opportunities on the AMPs to create virucidal coatings. The review first describes the fundamental characteristics of peptide structure and synthesis, highlighting the recent findings on AMPs and the role of peptide structure (α-helix, ß-sheet, random, and cyclic peptides) on the virucidal mechanism. The following section presents the advances in AMPs coating on medical devices with a detailed description of the materials coated and the targeted pathogens. The use of peptides in vaccine formulations is also reported, emphasizing the molecular interaction of peptides with different viruses and the current clinical stage of each formulation. The role of several materials (metallic particles, inorganic materials, and synthetic polymers) in the design of antiviral coatings is also presented, discussing the advantages and the drawbacks of each material. The final section offers future directions and opportunities for using AMPs on antiviral coatings to prevent viral outbreaks.

ZnO-based antimicrobial coatings for biomedical applications.

Rapid transmission of infectious microorganisms such as viruses and bacteria through person-to-person contact has contributed significantly to global health issues. The high survivability of these microorganisms on the material surface enumerates their transmissibility to the susceptible patient. The antimicrobial coating has emerged as one of the most interesting technologies to prevent growth and subsequently kill disease-causing microorganisms. It offers an effective solution a non-invasive, low-cost, easy-in-use, side-effect-free, and environmentally friendly method to prevent nosocomial infection. Among antimicrobial coating, zinc oxide (ZnO) stands as one of the excellent materials owing to zero toxicity, high biocompatibility to human organs, good stability, high abundancy, affordability, and high photocatalytic performance to kill various infectious pathogens. Therefore, this review provides the latest research progress on advanced applications of ZnO nanostructure-based antibacterial coatings for medical devices, biomedical applications, and health care facilities. Finally, future challenges and clinical practices of ZnO-based antibacterial coating are addressed.

Applications of green nanomaterials in coatings

Green nanotechnology produces nanomaterials and nanoproducts without impairing the environment and living organisms and also provides a way to deal with environmental problems. Green-synthesized nanomaterials from biological systems are a superior biomimetic engineered methodology for the synthesis of nanostructured materials, and are reflected as secure, cost-effective, realistic, and environmentally friendly methodology without toxic ingredients, and renewable inputs. Currently, green nanotechnology is an incredible and interdisciplinary field that has come out as a safe and rapidly emergent research area of many disciplines of research and development. Various kinds of natural biological sources such as plants, phototrophic eukaryotes, namely, algae, microbes, biopolymers, bacteria, actinomycetes, fungi, yeasts, virus, and many biocompatible agents are capable of reducing metal ions to metal nanoparticles. These are also utilized as efficient and environmentally friendly green nanofactories for the production of different metal and metal oxide nanoparticles.The use of green nanomaterial-based technology in various coating industries is a current interest of many researchers. The integration of nanostructured materials in preferred coatings enhances product qualities in terms of chemical and corrosion resistance, antireflection, wear resistance, permeability with state-of-art electrical, mechanical, and surface properties. The green nanotechnology involves coatings including the use of nanoparticles as resource materials, in situ, of nanostructure coatings comprised of nanostructured thin films.Green nanomaterials for application in various coatings, such as anticorrosion coatings, ultraviolet (UV) protective coatings, coatings for making buildings and homes cleaner and stronger, sensors, self-cleaning coatings, depolluting coatings, antifogging coatings, anti-COVID coating, antifouling coatings, antigraffiti coatings, carbon nanotube (CNT)-based coatings, paint coatings, fabric nanocoatings to thwart certain chemical weapons, textile coatings, antibacterial and antifungal coatings, hydrophobic and hydrophilic coatings, are currently commercially available and an immense interest area of research for materials scientists and technologist.This chapter mainly highlights and reviews the fabrication of green nanomaterials in brief with wide-scale state-of-the-art applications of green nanomaterials in coatings for using in various fields such as medical, buildings, energy storage, sensing, agriculture, textiles and allied industrial segments, etc. © 2022 Elsevier Inc. All rights reserved.

Influence of surface material and reprocessing on the durability of antimicrobial surfaces

The risk of infection from contaminated surfaces has already been shown in several publications. Due to the increased demand for optimized infection control measures during the Corona pandemic, antimicrobial surface technologies have gained more an interest. Apart from many proofs of efficacy, there are only a few studies dealing with the durability of these surface coatings with regard to the material and the reprocessing measures. This work did therefore examine the impact of different materials and surface textures, as well as different detergents and disinfectants, on the durability of antimicrobial surface technologies. Differently structured materials (glass, wood, plastics, metal) and wallpaper bonded to plasterboard were coated with an TiO2Ag based antimicrobial coating (HECOSOL GmbH, Bamberg). These test samples are then used to perform abrasion tests with various cleaning and disinfecting agents and cloth systems (microfiber cloth, cotton cloth, foam cloth). The majority of the test samples in our experimental setup showed at least significant activity. According to our results, both the selection of cleaning and disinfection methods including wiping systems and the surface material have a major impact on the durability of antimicrobial coatings. In order to be able to come to conclusions about the long-term activity of these surface technologies, the effectiveness should be tested not only during the development phase, but also in the finished product and again after several reprocessing cycles in use. © 2021 by Walter de Gruyter Berlin/Boston.

Antimicrobial Copper Cold Spray Coatings and SARS-CoV-2 Surface Inactivation.

This article contextualizes how the antimicrobial properties and antipathogenic contact killing/inactivating performance of copper cold spray surfaces and coatings and can be extended to the COVID-19 pandemic as a preventative measure. Specifically, literature is reviewed in terms of how copper cold spray coatings can be applied to high-touch surfaces in biomedical as well as healthcare settings to prevent fomite transmission of SARS-CoV-2 through rapidly inactivating SARS-CoV-2 virions after contaminating a surface. The relevant literature on copper-based antipathogenic coatings and surfaces are then detailed. Particular attention is then given to the unique microstructurally-mediated pathway of copper ion diffusion associated with copper cold spray coatings that enable fomite inactivation.

Antimicrobial Nanomaterials and Coatings: Current Mechanisms and Future Perspectives to Control the Spread of Viruses Including SARS-CoV-2.

The global COVID-19 pandemic has attracted considerable attention toward innovative methods and technologies for suppressing the spread of viruses. Transmission via contaminated surfaces has been recognized as an important route for spreading SARS-CoV-2. Although significant efforts have been made to develop antibacterial surface coatings, the literature remains scarce for a systematic study on broad-range antiviral coatings. Here, we aim to provide a comprehensive overview of the antiviral materials and coatings that could be implemented for suppressing the spread of SARS-CoV-2 via contaminated surfaces. We discuss the mechanism of operation and effectivity of several types of inorganic and organic materials, in the bulk and nanomaterial form, and assess the possibility of implementing these as antiviral coatings. Toxicity and environmental concerns are also discussed for the presented approaches. Finally, we present future perspectives with regards to emerging antimicrobial technologies such as omniphobic surfaces and assess their potential in suppressing surface-mediated virus transfer. Although some of these emerging technologies have not yet been tested directly as antiviral coatings, they hold great potential for designing the next generation of antiviral surfaces.