Ultraviolet activated antimicrobial surfaces
The invention is directed to an ion plasma deposition (IPD) method adapted to coat polymer surfaces with highly adherent antimicrobial films. A controlled ion plasma deposition (IPD) process is used to coat a metal or polymer with a selected metal/metal oxide. Exposing the coated surface to ultraviolet light significantly improves the antimicrobial properties of the deposited coatings.
1. A method for producing an adherent, antimicrobial coating, comprising: depositing a first layer of ion plasma produced metal and metal oxide nanoparticulates on a substrate in a vacuum chamber, said first layer consisting of metal and metal oxide nanoparticulates substantially free of macroparticulates; depositing a second layer of ion plasma from an ion plasma source to produce metal and metal oxide macroparticulates over the first layer, said second layer consisting of mixed sizes of metal and metal oxide medium size macroparticulates ranging from 100 nm up to about 1 micron; irradiating the nanoparticulates and macroparticulates during ion plasma deposition with ultraviolet light (UV) from a separate source located in the vacuum chamber to activate ground state oxygen in the metal oxide plasma to a reactive oxygen species thereby providing an antimicrobially active coating on the substrate that is enhanced compared with the coating deposited without UV irradiation from the separate source during ion plasma deposition.
2. The method of claim 1 wherein the deposited metal and metal oxide first or second layer is selected from the group consisting of silver, gold, platinum, copper, tantalum, titanium, zirconium, hafnium, and zinc.
3. The method of claim 1 wherein the deposited metal and metal oxide first or second layer deposition is controlled by adjusting distance of the substrate holder from a cathodic arc target from which the ion plasma is generated.
4. The method of claim 3 wherein the metal and metal oxide first or second layer deposition is controlled by varying speed of the arc on the target surface.
5. The method of claim 1 wherein the metal and metal oxide first or second layer is selected from silver, copper and titanium.
6. The method of claim 1 wherein the ultraviolet light frequencies for irradiating are in the range of 200-400 nm.
7. The method of claim 1 wherein the substrate is a polymer selected from the group consisting of polypropylene, polyurethane, PTFE, polyimide, polyester, PEEK, UHMWPE, and nylon.
8. The method of claim 1 wherein the substrate is a metal selected from the group consisting of tantalum, titanium, zirconium, hafnium, silicon, iron, cobalt, chromium, zinc, alloys, and combinations thereof.
9. The method of claim 1 wherein the substrate is glass.
10. The method of claim 1 further comprising introducing ozone into the ionic plasma deposition chamber during deposition of the metal and metal oxide first and second layers.
11. The method of claim 1 wherein the first layer thickness is between about 100 nm and 1 micron.
12. The method of claim 1 wherein the metal and metal oxide first or second layer comprises Ti, TiO and TiO 2 .
13. The method of claim 1 wherein metal and metal oxide first or second layer comprises Cu, CuO and Cu 2 O.
14. The method of claim 1 wherein the metal and metal oxide first or second layer comprises Ag, AgO and Ag 2 O.
15. The method of claim 1 wherein the metal and metal oxide first and second layers are independently selected from Ti/TiO/TiO 2 , Cu/CuO/Cu 2 O, and Ag/AgO/Ag 2 O.
16. The method of claim 1 wherein the substrate is a medical device.
17. The method of claim 16 wherein the medical device is a stent, catheter, valve or implant.