Stock material or miscellaneous articles – Composite – Of silicon containing
Reexamination Certificate
2002-05-16
2004-03-16
Dawson, Robert (Department: 1712)
Stock material or miscellaneous articles
Composite
Of silicon containing
C427S002100, C427S457000, C427S470000, C427S487000, C428S448000, C428S450000, C428S451000, C428S452000, C522S113000, C522S127000, C522S126000, C522S130000, C522S151000, C522S153000, C522S154000
Reexamination Certificate
active
06706408
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The invention provides an inorganic substrate having a first coating layer that includes a silane compound or a reaction product thereof and a second coating layer that includes at least one hydrophilic polymer and at least one photoactivatable cross-linking agent.
BACKGROUND OF THE INVENTION
The properties of the various substrate can be altered through the use of coatings applied to the substrate. For example, medical devices can be covered with one or more coating layers to alter the lubricity of the device, the hydrophobic/hydrophilic nature of the device, the biocompatibility of the device, the attachment of bioactive molecules to the device, and the release of bioactive molecules from the device.
Coating medical devices is particularly challenging. Such devices are often twisted or contorted upon use. The coatings need to adhere sufficiently to the device with minimal cracking or peeling. Further, such coatings typically are thin so that the dimensions and modulus of the device are minimally affected by the presence of the coatings.
SUMMARY OF THE INVENTION
The invention provides an inorganic substrate having at least two coating layers. The first coating layer is attached to the inorganic substrate and contains a silane compound, a hydrolysis reaction product of the silane compound, a polymeric reaction product formed from the hydrolysis reaction product of the silane compound, or a combination thereof. The silane compound has at least two tri(C
1
-C
3
)alkoxysilyl groups and lacks a sulfide group. The second coating layer is attached to the first coating layer and includes at least one hydrophilic polymer and at least one photoactivatable cross-linking agent. The second layer can also include a photopolymer. One or more additional coating layers can be added having a composition that includes at least one hydrophilic polymer, at least one photoactivatable cross-linking agent, and an optional photopolymer.
Another aspect of the invention provides a method of forming two or more coating layers on an inorganic substrate.
Yet another aspect of the invention provides a medical device having multiple coating layers. A first coating layer is attached to the medical device and contains a silane compound, a hydrolysis reaction product of the silane compound, a polymeric reaction product formed from the hydrolysis reaction product of the silane compound, or a combination thereof. The silane compound has at least two tri(C
1
-C
3
)alkoxysilyl groups and lacks a sulfide group. The second coating layer is attached to the first coating layer and has at least one hydrophilic polymer and at least one photoactivatable cross-linking agent. The second layer can also include a photopolymer. The medical device can have a third or subsequent coating layer containing at least one hydrophilic polymer, at least one photoactivatable cross-linking agent, and an optional photopolymer.
DETAILED DESCRIPTION OF THE INVENTION
The invention provides an inorganic substrate having at least two coating layers. Another aspect of the invention provides a method of forming two or more coating layers on an inorganic substrate. In particular, the first coating layer is bound to the surface of the inorganic substrate and includes a silane compound, a hydrolysis reaction product of the silane compound, a polymeric reaction product formed from the hydrolysis reaction product of the silane compound, or a combination thereof. The silane compound has at least two tri(C
1
-C
3
)alkoxysilyl groups. The second coating layer is attached to the first coating layer and includes at least one hydrophilic polymer and at least one photoactivatable cross-linking agent. The second coating layer can also include a photopolymer. The first layer is attached to both the inorganic substrate and the second layer; the first layer is between the inorganic substrate and the second layer.
One or more additional coating layers can be added having a composition that includes at least one hydrophilic polymer, at least one photoactivatable cross-linking agent, and an optional photopolymer. Each subsequent layer is attached to the previous layer. The coating layers are tenacious and not easily removed from the inorganic substrate or from adjacent coating layers by abrasion. The coating layers can cover all or only a portion of the inorganic substrate.
Inorganic Substrate
As used herein, the term “substrate” refers to a support material. The substrate is prepared from an inorganic material. In some embodiments, the inorganic substrate contains a metal. The metal can be, for example, iron, titanium, nickel, chromium, cobalt, tantalum, or alloys thereof. Suitable alloys include stainless steel, nitinol (an alloy of nickel and titanium), and the like. The metal can also be a metal such as, for example, platinum, gold, palladium, iridium, or alloys thereof. In other embodiments, the substrate contains a ceramic material, mineral, or glass. Such substrates can be prepared from silicon carbide, silicon nitride, zirconium, alumina, hydroxyapatite, quartz, silica, and the like.
Some embodiments of the inorganic substrate include medical devices that can be inserted into the body of a mammal. Such medical devices include, but are not limited to, vascular devices such as guidewires, stents, stent grafts, covered stents, catheters, valves, distal protection devices, aneurysm occlusion devices, septal defect closures, and artificial hearts; heart assist devices such as defibrillators, pacemakers, and pacing leads; orthopedic devices such as joint implants and fracture repair devices; dental devices such as dental implants and fracture repair devices; ophthalmic devices and glaucoma drain shunts; urological devices such as penile, sphincter, urethral, ureteral, bladder, and renal devices; and synthetic prostheses such as breast prostheses and artificial organs. The multiple coating layers on the medical device are durable and well suited for applications in which the medical device is subjected to twisting and bending.
Other embodiments of inorganic substrate include non-implanted biomedical devices such as, but are not limited to, diagnostic slides such as gene chips, DNA chip arrays, microarrays, protein chips, and fluorescence in situ hybridization (FISH) slides; arrays including cDNA arrays, and oligonucleotide arrays; chromatographic support materials, cell culture devices, biosensors, and the like.
First Coating Layer
The first coating layer is attached to the inorganic substrate and includes a silane compound, a hydrolysis reaction product of the silane compound, a polymeric reaction product formed from the hydrolysis reaction product of the silane compound, or a combination thereof. The silane compound has at least two tri(C
1
-C
3
)alkoxysilyl groups. Suitable groups include trimethoxysilyl, triethoxysilyl, and tripropoxysilyl, and combinations thereof. In some embodiments, the silane compound has at least two trimethoxysilyl groups. The silane is free of other groups that can bind to the inorganic substrate such as a sulfide group.
The silane compound has at least two tri(C
1
-C
3
)alkoxysilyl groups. Examples of suitable tri(C
1
-C
3
)alkoxysilyl containing silane compounds include, but are not limited to, bis(trimethoxysilyl)hexane, bis(trimethyoxysilyl)ethane, and bis(trimethoxysilylethyl)benzene. A mixture of the tri(C
1
-C
3
)alkoxysilyl silane compounds can be used. In some embodiments, the silane compound is bis(trimethoxysilylethyl)benzene.
The silane compound, a hydrolysis reaction product of the silane compound, a polymeric reaction product formed from the hydrolysis reaction product, or a combination thereof can bind to the surface of the inorganic substrate by reacting with oxide or hydroxide groups on the surface of the inorganic substrate. A covalent bond forms between the inorganic substrate and at least one compound in the first coating layer. The inorganic substrate can be treated to generate hydroxide or oxide groups on the surface. For example, the substrate can be treated with a strong base s
Dawson Robert
Merchant & Gould P.C.
SurModics, Inc.
Zimmer Marc S.
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