Antimicrobial and anticorrosive efficacy of inorganic nanoporous surfaces

• Published in: Clean technologies and environmental policy Vol. 19; no. 3; pp. 845 - 857
• Main Authors: Connelly, M. C., Reddy, G. S., Nadagouda, Mallikarjuna N., Sekhar, J. A.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-04-2017; Springer Nature B.V
• Subjects: Antiinfectives and antibacterials; Antimicrobial agents; Bacteria; Biofilms; Chemicals; Corrosion; Corrosion prevention; Disease control; Droplets; Durability; Earth and Environmental Science; Effectiveness; Engineering; Environment; Environmental Economics; Environmental Engineering/Biotechnology; Environmental policy; Industrial and Production Engineering; Industrial Chemistry/Chemical Engineering; Materials engineering; Materials science; Microbial contamination; Microorganisms; Nanoparticles; Nanostructure; Nanotechnology; Prevention; Stainless steel; Surface chemistry; Sustainable Development; Zirconium; Antimicrobial; Top-soil bacteria; Surface scratch tests; Plasma processing methods; Engineered nanostructured nanoporous surfaces; Antibacterial surface
• ISSN: 1618-954X; 1618-9558
• DOI: 10.1007/s10098-016-1272-2

The relationship between microbe populations that are active on engineered-product surfaces and their relationship to surface corrosion or human health is increasingly being recognized by the materials engineering community as a critically important study-direction. Microbial contamination from biofilms and germ colonies leads to costs that are reported to be extremely high every year in infection control, epidemics, corrosion loss and energy/infrastructure materials loss throughout the world. Nanostructured surfaces, particularly those that are hard-surface nanoporous (pore radii between 2 and 1000 nm), are an emerging class of surfaces that have recently been recognized as important for the prevention of microbial colony growth and biofilm formation. Such nanostructured/nanoporous surfaces, whether made with deposited nanoparticles (welded nanoparticles), or formed by ion-assisted growth on a surface have been found to display biocidal activity with varying efficacy that depends on both the microbe and the nanosurface features. The rate of mortality from common pathogens that are resident in ubiquitous bio-films when attached to common engineering surfaces made of steels, titanium and zirconium appears to be increasing. In this short review, we look at methods of manufacture of durable (i.e., highly scratch resistant) nanostructuring on commonly used engineering surfaces. The microstructures, energy dispersive X-ray analysis, X-ray photo-electron spectroscopy and other types of characterization of a few such surfaces are presented. Simple tests are required by the surface engineering community for understanding the efficacy of a surface for antimicrobial action. These are reviewed. The surface drying rate and the dynamics of the droplet spread have been proposed in the literature as quick methods that correlate well with the residual antimicrobial activity efficacy even after some surface abrasion of the nanostructured surface. A categorization of a surface against short-term antimicrobial action and long-term action is proposed in this review article. Test periods that span time-frames greater than 5 years have demonstrated a high efficacy of the nanoporous nanostructures for preventing bio-film formation. New comparative results for diamond- and graphite-containing surfaces are presented. A brief discussion on a recently developed plasma application technique for creating durable nanoporous surfaces is presented. Although considerable information is now available regarding tunable surface nanofeatures for antimicroabial efficacy, there is a need for more research activity, particularly directed toward the low cost manufacture and rapid characterization of durable (wear and chemical resistant) surfaces that display permanent antimicrobial behavior.