Regeneration of antimicrobial coatings containing metal derivatives upon exposure to vapor-phase hydrogen peroxide
Inventors
Toreki, William • Kanga, Rustom Sam • Crampsie, Bernard Christopher • Wynn, Brendan Barry
Assignees
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Publication Number
US-9808548-B2
Publication Date
2017-11-07
Expiration Date
Abstract
A regenerable antimicrobial coating with long-lasting efficacy for use in medical applications including implants, medical instruments or devices, and hospital equipment is disclosed. The regenerable antimicrobial coating is derived from a polymer doped with a metal derivative which has been exposed to vapor-phase hydrogen peroxide, wherein hydrogen peroxide is sequestered in or on the doped polymer.
Core Innovation
The invention provides a method of enhancing and regenerating durable antimicrobial activity of the surface of an article. The method includes providing, on the surface of the article, a polymer doped with a metal derivative and exposing the polymer doped with a metal derivative to a source of vapor-phase hydrogen peroxide for a time sufficient to permit an antimicrobially-enhancing amount of hydrogen peroxide to be sequestered thereon, and then removing the source of vapor-phase hydrogen peroxide.
The metal derivative comprises 1% to 50% (w/w) of the weight of the doped polymer, and is a hydroxide, an oxide, or a peroxide of a metal selected from zinc, magnesium, titanium, and zirconium. The polymer has water absorbency between 0.5% and 20% (w/w). The invention emphasizes persistent antimicrobial activity after vapor-phase hydrogen peroxide removal, including antimicrobial testing performed using ASTM Standard Method E2180-07(2012) at least 24 hours after removal.
By sequestering hydrogen peroxide in or on the polymer using reversible metal-hydrogen peroxide chemistry, the method enhances antimicrobial activity and supports regeneration after subsequent hydrogen peroxide vapor treatments. The resulting treated surfaces provide at least a 3-log reduction of viable Escherichia coli bacteria greater than that of a corresponding surface of the polymer doped with the metal derivative that has not been exposed to vapor phase hydrogen peroxide.
Claims Coverage
The claim set contains one independent claim defining a method for enhancing and regenerating durable antimicrobial surface activity using a polymer doped with metal derivatives and vapor-phase hydrogen peroxide sequestration. The coverage includes three core inventive features, with dependent claims further refining vapor generation conditions, exposure environment, exposure duration, metal loading, polymer water absorbency, and example article categories.
Metal-derivative-doped polymer on an article
Providing, on the surface of an article on which durable antimicrobial activity is desired, a polymer doped with a metal derivative, wherein the metal derivative comprises 1% to 50% (w/w) of the weight of the doped polymer and is a hydroxide, an oxide, or a peroxide of a metal selected from zinc, magnesium, titanium, and zirconium, and wherein the water absorbency of the polymer is between 0.5% and 20% (w/w).
Vapor-phase hydrogen peroxide exposure for sequestration followed by removal
Exposing the polymer doped with a metal derivative to a source of vapor-phase hydrogen peroxide for a time sufficient to permit an antimicrobially-enhancing amount of hydrogen peroxide to be sequestered thereon, and thereafter removing the source of vapor-phase hydrogen peroxide.
Durable antimicrobial enhancement defined by ASTM testing versus an unexposed control
When tested using ASTM Standard Method E2180-07(2012) at least 24 hours after removal of the source of vapor-phase hydrogen peroxide, the antimicrobial activity provides at least a 3-log reduction of viable Escherichia coli bacteria greater than that of a corresponding surface of the polymer doped with the metal derivative that has not been exposed to vapor phase hydrogen peroxide.
The inventive coverage centers on applying a water-absorbing polymer doped with metal hydroxides, oxides, or peroxides of zinc, magnesium, titanium, or zirconium, exposing that doped polymer to vapor-phase hydrogen peroxide to sequester an antimicrobially-enhancing amount, removing the vapor source, and achieving durable antimicrobial performance measured by ASTM E2180-07(2012) at least 24 hours after removal.
Stated Advantages
Provides durable antimicrobial activity after removal of the vapor-phase hydrogen peroxide, as measured by ASTM E2180-07(2012) at least 24 hours after removal.
Provides at least a 3-log reduction of viable Escherichia coli bacteria greater than an unexposed control surface.
Supports regeneration of durable antimicrobial activity through subsequent hydrogen peroxide vapor treatments.
Documented Applications
Medical and hospital surface and equipment contexts, including medical instruments or devices, hospital equipment, bed rails, table tops, bedpans, i.v. stands, lamp handles, blood pressure cuffs, dental equipment, surgical instruments, orthopedic devices, hot/cold packs, wheelchair cushions, doorknobs, and bathroom fixtures.
Home and public-transport settings, including food preparation surfaces, equipment touch-screens, floor waxes, paints, inks, clear coats, varnish, kitchen equipment and tables in restaurants, schools, and other institutions, home appliances, textiles, clothing, upholstery, curtains, seats, armrests, railings, and tray tables for airlines and other public transportation.
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