PVD technologies have been proven to be an effective weapon against bacteria and viral infections and will help to fight against pandemics
In this Covid-19 pandemic era, we become obsessed with the world of microorganisms. We are even wary to touch anything in public spaces from door handles to elevator buttons. And we have good reason to be. Researchers in biotechnology field evidently reported that many potentially infectious bacteria and viruses(Pathogens) can thrive on surfaces for ample amounts of time.
Pathogens spread by many ways either through direct contact with infectious person or through sneezes and coughs. Surfaces that are used in common add a new level of difficulty. An infecting pathogen land on a surface and be able to survive on it until you touch it.
Commonly shared public spaces such as, faucets and sinks, arm rest, equipment, countertops, tables, arm rest in public transports are the most common environment sources for pathogens (bacteria and viruses) transmission between person to person.Pathogenic infections originating from touching hospital equipment and objects are also serious threat to public community.
Although antibiotics have been utilized worldwide, increasing antibiotic resistance presents a global threat to public health.
Antibacterial coatings step up as a critical approach to restrict the pathogenic infection rate without any side effects while negating the development of antibiotic resistance.
Nowadays antibacterial coatings are rapidly emerging as the main mitigation strategy against pathogenic bacterial and viral transmissions by preventing bacterial colonization and biofilm formation. Biofilms are a collective of one or more types of bacteria, fungi, and protists that can thrive and multiply on different surfaces such as, wood, steel, cardboard, plastics etc. Surfaces applied with antibacterial coatings restrict the pathogenic infection rate without any side effects while negating the development of antibiotic resistance.
Ag-containing coatings are by far the most prevailing antibacterial nanomaterials, but it is not favorable due to its toxicity side effects. Antibacterial coatings by wet chemistry methods are very less stable and does not stay for years.
(Viability of SARS-CoV-1 and SARS-CoV-2 in Aerosols and on various surfaces, New England Journal of Medicine, April 16,2020)
Bimetal and trimetal nitride and oxide coatings applied on substrates by Physical Vapor Deposition PVD techniques possess excellent antibacterial properties while preserving superior mechanical properties such as good adhesion and less bio-corrosive.
PVD based antibacterial coatings on a surface does not require a wet medium to transfer the deposits, as in electroplating or anodizing. So, any material can be coated with another metal or ceramic material.
Ionized PVD operates on plasma-based deposition processes.The importance of low-energy ion impact during coating processcannot be undermined. Ion bombardment is an important physical tool available to materials scientists in the design of new materials and new structures. Anti-bacterial and antiviral coatings by ionized PVD are very stable with no side effects while providing excellent protection against pathogenic infections.
PVD also facilitates to produce antibacterial coatings on flexible surfaces.
One of the most important criteria to have a long live antibacterial and antiviral coatings are:
biocidal activity (killing pathogens)
removal of killed pathogens (elimination)
Owing to the possibility to combine materials with different and robust properties, coatings by PVD provides very responsive and synergistic antipathogenic coatings, including.
i) self-defensive coatings against pathogen, which can “turn on” biocidal activity, killing pathogens in response to a bacteria- or virus attachment.
ii) smart “kill-and-release” antibacterial coatings, which can switch functionality between bacteria killing and bacteria releasing under a proper stimulus. The design principles and potential applications of these coatings
Smart “kill-and-release” antibacterial coatings
The past decade has witnessed the development of “smart” and “synergistic” antibacterial coatings. Compared with “traditional” antibacterial coatings having a permanent, single killing mechanism, these coatings show several advanced capabilities to activate bactericidal activity in response to bacterial infection microenvironment, to effectively eliminate bacteria using positively interacting multiple mechanisms, and to release dead bacteria from the surfaces under external stimuli. These coatings are suitable for long-term applications and for the elimination of biofilms related to MDR bacteria.
Coatings against pathogens has witnessed a substantial development of “smart” and “synergistic” antibacterial coatings. Compared with early years antibacterial coatings (which just have a permanent, single killing mechanism) PVD made new coatings show several advanced capabilities to activate bactericidal activity in response to bacterial infection microenvironment, to effectively eliminate bacteria using positively interacting multiple mechanisms, and to release dead bacteria from the surfaces under external stimuli.
These coatings are suitable for long-term applications and for the elimination of biofilms on surfaces.
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