Recent Advances in Metal-Based Antimicrobial Coatings for High-Touch Surfaces

Abstract

International interest in metal-based antimicrobial coatings to control the spread of bacteria, fungi, and viruses via high contact human touch surfaces are growing at an exponential rate. This interest recently reached an all-time high with the outbreak of the deadly COVID-19 disease, which has already claimed the lives of more than 5 million people worldwide. This global pandemic has highlighted the major role that antimicrobial coatings can play in controlling the spread of deadly viruses such as SARS-CoV-2 and scientists and engineers are now working harder than ever to develop the next generation of antimicrobial materials. This article begins with a review of three discrete microorganism-killing phenomena of contact-killing surfaces, nanoprotrusions, and superhydrophobic surfaces. The antimicrobial properties of metals such as copper (Cu), silver (Ag), and zinc (Zn) are reviewed along with the effects of combining them with titanium dioxide (TiO2) to create a binary or ternary contact-killing surface coatings. The self-cleaning and bacterial resistance of purely structural superhydrophobic surfaces and the potential of physical surface nanoprotrusions to damage microbial cells are then considered. The article then gives a detailed discussion on recent advances in attempting to combine these individual phenomena to create super-antimicrobial metal-based coatings with binary or ternary killing potential against a broad range of microorganisms, including SARS-CoV-2, for high-touch surface applications such as hand rails, door plates, and water fittings on public transport and in healthcare, care home and leisure settings as well as personal protective equipment commonly used in hospitals and in the current COVID-19 pandemic.

Interrogating the Effect of Assay Media on the Rate of Virus Inactivation of High‐Touch Copper Surfaces: A Materials Science Approach

“…[4] High-touch surfaces, such as doorhandles and hand-rails, are prone to continuous recontamination. [5,6] As such, design of materials for high-touch surfaces that can inactivate viruses over short time-scales, is a high priority for materials scientists. [7][8][9][10][11] Copper and copper alloys have been demonstrated to possess excellent antiviral properties, via the release of soluble copper cations (such as Cu 1+ ) into the local environment, through an electrochemical corrosion process.…”

Metal Homeostasis in Pathogenic Streptococci

“…Metals and the mechanisms that are necessary to acquire them may also yield new drug or vaccine targets, or yield new therapies to fight infection and disease. Some examples that have been proposed or developed thus far include targeting the SBPs of transport machinery and exploiting the toxicity of metals such as silver and copper in the form of nanoparticles and metal coatings [ 156 , 157 , 158 , 159 ]. Though recent strides have been made in characterizing Streptococcal metal homeostasis, several important questions remain, including understanding (1) how metal availability differs across biological niches during colonization and infection; (2) what and how host factors impact Streptococcal metal homeostasis; (3) why some species rely on multiple SBPs or seemingly redundant transport systems to maintain homeostasis, while others do not; (4) how downstream Streptococcal physiology is impacted by metal starvation and/or toxicity.…”

Rapid Method to Quantify the Antiviral Potential of Porous and Nonporous Material Using the Enveloped Bacteriophage Phi6

“…The concept of surface heterogeneity is common to materials science and ecology, providing a common perspective that can advance the development of self-sterilizing material. There are a wide array of methods available that are used to create antibacterial environments from mechanochemical processes that create contact-killing surfaces to the nanofabrication of biomimetic superhydrophobic surfaces that repel bacteria . Testing the antiviral potential on known antibacterial surfaces is a high priority.…”