Surface modified devices and sterile packaging therefor
A method for sterile packaging of a surface modified implantable device includes irradiating a surface of the device such that the hydrophobicity of the surface is decreased and, optionally, the device is simultaneously sterilized. The surface of the sterile, surface-modified implantable device is then covered in a polar solution to prevent hydrophobic recovery of the surface.
1. A system comprising:
a cochlear implant comprising a sterilized hydrophilic silicone outer surface;
a polar solution, the cochlear implant immersed in the polar solution; and
sterile packaging enclosing the polar solution and cochlear implant.
2. The system of claim 1 , in which molecules in the polar solution bond with polar groups on silicone molecules by physisorbed bonding to prevent backbone rotation of the silicone molecules.
3. A method for sterile packaging the system of claim 1 , the method comprising:
irradiating the silicone outer surface of the cochlear implant such that the surface is simultaneously sterilized and hydrophobicity of the surface is decreased;
covering the surface in the polar solution to suppress hydrophobic recovery of the surface; and
enclosing the polar solution and cochlear implant in the sterile packaging.
4. The method of claim 3 , further comprising sterilizing the polar solution using terminal sterilization to form the sterile polar solution.
5. The method of claim 3 , further comprising:
sealing the sterile packaging, and
transporting the sealed packaging to an operating theater.
6. The method of claim 3 , in which the surface comprises a medical grade silicone.
7. The method of claim 3 , in which the implant comprises components with varying coefficients of thermal expansion.
8. The method of claim 3 , in which the implant comprises active components.
9. The method of claim 3 , in which irradiating the surface comprises:
placing the implant in a plasma chamber;
energizing low pressure process gas to create a plasma; and
exposing the implant to the plasma for a predetermined period of time.
10. The method of claim 3 , in which the polar solution comprises water, sodium chloride, and polyvinyl alcohol.
11. The method of claim 9 , in which plasma irradiating the silicone outer surface comprises using oxygen as a process gas in the plasma chamber, the oxygen creating hydroxyl functionality that decreases the hydrophobic nature of the silicon surface.
12. The method of claim 9 , further comprising depositing a coating on the silicone outer surface prior to plasma treatment, in which molecules in the coating are crosslinked onto the silicone outer surface.
13. The method of claim 9 , in which plasma irradiating the silicone outer surface comprises forming a hard skin on the surface of the silicone outer surface less than 10 μm in depth.
14. The method of claim 3 , further comprising sterilizing the polar solution and packaging using heat treatment in an autoclave.
15. A method for sterile packaging the system of claim 1 , the method comprising:
selecting a treatment time and treatment power of a plasma chamber such that energetic species in a gas plasma impact the silicone outer surface of the implant and create polar groups in silicone molecules near the surface, the hydrophobic nature of the surface being decreased; and
before significant hydrophobic recovery occurs, submerging the silicone outer surface in the polar solution.
16. The method of claim 15 , in which the polar solution comprises water and polyvinyl alcohol.
17. The method of claim 15 , in which the polar solution comprises water and hyaluronic acid.
18. The method of claim 15 , further comprising aseptically packaging the implant and polar solution in an aseptic environment.
19. The method of claim 15 , in which backbone rotation of silicone molecules at the silicone surface is suppressed by physisorbed bonding between the silicone molecules and the polar solution.
20. The method of claim 15 , further comprising sterilizing the polar solution and a package, the polar solution contained in the package, prior to submerging the silicone outer surface in the polar solution.
21. The method of claim 15 , further comprising separately sterilizing a polar solution and a package; in which submerging the silicone outer surface in the polar solution comprises placing the sterilized polar solution in the sterilized package and then placing the implant in the sterilized polar solution.
22. The method of claim 15 , in which submerging the silicone outer surface in the polar solution comprises placing the implant in the sterile packaging and then adding the sterile polar solution to the packaging.
23. The method of claim 15 , further comprising electrically testing the implant while the device is submerged in the sterile polar solution.