Patent Description:
The present disclosure relates to methods for making implantable or insertable medical devices having a reduced friction. More specifically, the disclosure relates to silicone devices having a lubricous coating and methods of forming the same.

Silicone is commonly used in implantable or insertable medical devices because of silicone's desirable mechanical and biological properties. Silicone is flexible, durable, and biostable. However, silicone can have a tacky surface. When implanted in a patient, a medical device with a tacky silicone surface can contact body tissue and may result in tissue inflammation or abrasion of the silicone itself. Similarly, when inserted into a patient, a tacky silicone surface of a medical device can require a higher insertion force to overcome the tack, causing tissue inflammation or other damage.

For example, a medical electrical lead may include an outer insulating body for electrically insulating the conductor and allowing only the electrodes to make electrical contact with the body tissue. The outer lead body may be formed from silicone. The lead may be implanted by feeding the lead through a catheter system. It is desirable that the lead is lubricous enough to slide through the catheter system without sticking. Other implantable or insertable medical devices may include a silicone substrate that would benefit from a lubricous surface. <CIT> discloses an implantable cardiac lead comprising an elongate sheath of insulative material including an insulative first layer and a protective second layer, wherein the insulative first layer has at least one adhesive enhancing activated surface.

While multiple embodiments are disclosed, still other embodiments will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments.

While the invention is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the invention to the particular embodiments described.

An implantable or insertable medical device may include a silicone substrate. As described herein, a coating may be formed on at least a portion of the silicone substrate to provide a surface with lubricous coating to reduce both static and dynamic friction. In some embodiments, the coating may completely cover or surround the silicone substrate. The coating may be formed by treating the silicone substrate with an atmospheric plasma formed from a noble gas, and then applying a thermoplastic polyurethane solution directly to the treated silicone substrate. The coated silicone substrate may be baked or allowed to air dry to form a lubricous coating on the silicone substrate.

A plasma is a gas in which a significant percentage of the atoms or molecules are ionized. Generally, plasmas are formed within vacuum chambers under sub-atmospheric conditions because the lower pressures permit the plasmas to be generated using a variety of gases, such as oxygen or nitrogen, which may be difficult to ionize at higher pressures. An atmospheric plasma may be created as a flow, or jet, of noble gas is ionized at about atmospheric pressure without the use of a vacuum chamber. As used herein, about atmospheric pressure means normal atmospheric pressure plus any increase in local pressure due to the flow of the noble gas which must be somewhat above atmospheric pressure in order to flow.

An atmospheric plasma may be more efficient compared to a sub-atmospheric plasma because there is no need to pump down a vacuum chamber before use, and then vent the vacuum chamber after use, saving time and energy. An atmospheric plasma also does not require the capital investment or maintenance associated with a vacuum chamber and its attendant vacuum pumps, filters, traps, and vacuum instrumentation.

It has been found that a thermoplastic polyurethane coating formed on a silicone substrate treated with an atmospheric plasma formed from a noble gas according to this disclosure is not only lubricous, but is also durable, bonding tenaciously to the silicone substrate. The lubricous coating is bonded directly to the silicone substrate without the need for an intervening tie layer or the need for complex chemistry to create functional groups on the silicone substrate. It has also been found that a thermoplastic polyurethane coating formed on a silicone substrate without the atmospheric plasma formed from a noble gas according to this disclosure does not adhere well to the silicone substrate and easily rubs off. Without wishing to be bound by any theory, it is believed that the atmospheric plasma removes low-molecular weight materials from the surface of the silicone substrate and creates a thin, cross-linked silica-like surface layer, rendering the surface receptive to bonding with the thermoplastic polyurethane.

The lubricous coatings as described herein are not hydrogels. Thus, they may provide lubricity under dry conditions. Hydrogels also swell when exposed to water, requiring a lead or medical device coated with a hydrogel to be smaller in diameter to use a given delivery mechanism. The lubricous coatings as described herein are believed to be more durable than hydrogels.

Implantable or insertable medical devices suitable for use with the lubricious coatings disclosed herein can include devices such as catheters, shunts, heart pumps, male incontinence devices, erectile restoration devices, ostomy ports, gastric balloons, bladder devices, breast implants, intubation tubes, guide wires, medical electrical leads, and medical electrical devices for use with medical electrical leads, for example.

Medical electrical devices can include implantable electrical stimulation systems including neurostimulation systems such as spinal cord stimulation (SCS) systems, deep brain stimulation (DBS) systems, peripheral nerve stimulation (PNS) systems, gastric nerve stimulation systems, cochlear implant systems, and retinal implant systems, among others, and cardiac systems including implantable cardiac rhythm management (CRM) systems, implantable cardioverter-defibrillators (ICD's), cardiac resynchronization and defibrillation (CRDT) devices, and subcutaneous implantable cardioverter-defibrillators (SICD's), for example.

<FIG> is a schematic illustration of a medical electrical device <NUM> for delivering and/or receiving electrical pulses or signals to stimulate, shock, and/or sense a heart <NUM>. The device <NUM> may include pulse generator <NUM> and an electrical lead <NUM>. The pulse generator <NUM> may include a source of power as well as an electronic circuitry portion (not shown). Optionally, the electronic circuitry can include one or more microprocessors that provide processing and/or evaluation functions, and that can determine and deliver electrical shocks or pulses of different energy levels and timing. The pulse generator <NUM> can be employed as part of a variety of useful therapies, including for neurostimulation, ventricular defibrillation and/or cardioversion. In the case of ventricular defibrillation and/or cardioversions, it can also be used to pace the heart in response to one or more sensed cardiac arrhythmia including fibrillation, cardiac resynchronization, tachycardia, or bradycardia. The pulse generator <NUM> can be powered by one or more batteries, though any other internal or external power source may be used for the given application. The pulse generator <NUM> may sense intrinsic signals of the heart <NUM> and generate a series of timed electrical discharges or pulses.

The pulse generator <NUM> may be generally implanted into a subcutaneous pocket made in the wall of the chest. Alternatively, the pulse generator <NUM> may be placed in a subcutaneous pocket made in the abdomen, or in another location. It should be noted that while the electrical lead <NUM> is illustrated for use with a heart, the electrical lead <NUM> is suitable for other forms of electrical stimulation/sensing as well.

As shown in <FIG>, the electrical lead <NUM> can extend from a proximal end <NUM>, where it is coupled with the pulse generator <NUM> to a distal end <NUM>, where it coupled with a portion of the heart <NUM>, when implanted or otherwise coupled therewith. Also disposed along at least a portion of the electrical lead <NUM>, for example near the distal end <NUM>, is at least one electrode <NUM>. The electrode <NUM> electrically couples the electrical lead <NUM> with the heart <NUM> and allows for electrical signals to be delivered from the pulse generator <NUM> to the target tissue or location. At least one electrical conductor (not shown) is disposed within electrical lead <NUM> and extends generally from the proximal end <NUM> to the distal end <NUM> of the electrical lead <NUM>. The at least one electrical conductor electrically couples the electrode <NUM> with the proximal end <NUM> of the electrical lead <NUM>. The electrical conductor carries electrical current and pulses between the pulse generator <NUM> and the electrode <NUM>, and to and from the heart <NUM>. In one option, the at least one electrical conductor is a coiled conductor. In another option, the at least one electrical conductor includes one or more cables.

During implantation, the electrical lead <NUM> may be inserted through tissue and body lumens until the distal end <NUM> and electrode <NUM> are suitably disposed for effective therapy. Once implanted, the electrical lead <NUM> may be in continuous or intermittent contact with body tissues. During implantation and once implanted, it is beneficial for at least the distal end <NUM> of the electrical lead <NUM> to have a lubricous surface as described below to reduce any inflammation of, or damage to, body tissues.

<FIG> is schematic cross-sectional view of a distal end <NUM> of the electrical lead <NUM> of <FIG>, according to some embodiments of this disclosure. As shown in <FIG>, the electrical lead <NUM> may include a lead body <NUM>, a lubricous coating <NUM>, and a lumen <NUM>. The lead body <NUM> may include an inner surface <NUM> and an outer surface <NUM>. The inner surface <NUM> forms the lumen <NUM>. The lead body <NUM> may extend the length of the electrical lead <NUM> from the proximal end <NUM> to the distal end <NUM>. The lumen <NUM> is a channel extending axially through the lead body <NUM>. Although only one lumen <NUM> is shown, it is understood that the lead body <NUM> may include more than one lumen <NUM> extending axially thorough the lead body.

The lead body <NUM> can be flexible, but is generally non-compressible along its length. The lead body <NUM> can have a substantially circular cross-section, as shown in <FIG>. The at least one electrical conductor (not shown) may extend through the lumen <NUM> such that the lead body <NUM> can isolate the electrical conductor from the surrounding tissue or environment.

The lead body <NUM> can be formed, at least in part, of silicone. The lead body <NUM> at the distal end <NUM> may be formed entirely of silicone, as shown in <FIG>. The lead body <NUM> may be formed entirely of silicone from the proximal end <NUM> to the distal end <NUM>. The composition of the lead body <NUM> may be substantially uniform along its length, or it may vary in composition along it length, along its width, or along its length and width. The outer surface <NUM> may be a silicone substrate upon which the lubricous coating <NUM> is formed.

The lubricous coating <NUM> may be disposed on at least a portion of the outer surface <NUM>. The lubricous coating <NUM> may extend along a portion of the length of the lead body <NUM>, or along the length of the entire lead body <NUM> from the proximal end <NUM> to the distal end <NUM>. The lubricous coating <NUM> may radially surround the lead body <NUM>, as shown in <FIG>. The lubricous coating <NUM> is disposed directly on the outer surface <NUM> of the lead body <NUM>. That is, there is no intervening layer, such as a tie layer between the lubricous coating <NUM> and the lead body <NUM>.

The lubricous coating <NUM> may be a conformal coating on the outer surface <NUM> of the lead body <NUM>. That is, the lubricous coating <NUM> may conform to the topography of the outer surface <NUM>. The lubricous coating <NUM> may have a radially and/or axially uniform composition and/or thickness.

The lubricious coating <NUM> may have a thickness as small as <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, or as large as <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, or be within any range defined between any two of the foregoing values, such as <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, or <NUM> to <NUM>, for example.

The lubricous coating <NUM> may include a thermoplastic polyurethane. The thermoplastic polyurethane may include at least one selected from the group of polycarbonate polyurethane, silicone polycarbonate polyurethane, a polyether polyurethane, and a silicone polyether urethane. The thermoplastic polyurethane may be selected from the group consisting of polycarbonate polyurethane, silicone polycarbonate polyurethane, a polyether polyurethane, and a silicone polyether urethane, or combinations thereof.

Examples of polycarbonate polyurethanes include Carbothane™ from Lubrizol, Wickliffe, Ohio, Bionate® from DSM Biomedical, Exton, Pennsylvania, and ChronoFlex C® and ChronoFlex AL® from AdvanSource Biomaterials Corp. , Wilmington, Massachusetts. Examples of silicone polycarbonate polyurethanes include CarboSil® <NUM> from DSM Biomedical, Exton, Pennsylvania and ChronoSil AL® from AdvanSource Biomaterials Corp. , Wilmington, Massachusetts. An example of a silicone polyether polyurethane is PurSil® from DSM Biomedical, Exton, Pennsylvania.

As describe further herein, the lubricous coating <NUM> may reduce the frictional force experienced when the electrical lead <NUM> is moved within a patient, or upon insertion through a medical system, such as a catheter system. Friction forces include dynamic friction and static friction. Dynamic (or kinetic) friction occurs between two objects that are moving relative to one another, and static friction occurs between two objects that are not moving relative to one another. The lubricous coating <NUM> may reduce the dynamic friction force and the static friction force of the electrical lead <NUM>, compared to the uncoated silicone lead body <NUM>.

<FIG> is schematic cross-sectional view of the distal end <NUM> of an electrical lead 110b. The electrical lead 110b is identical to the electrical lead <NUM> of <FIG>, except that instead of a lubricous coating <NUM> disposed on the outer surface <NUM>, the electrical lead 110b includes a lubricous coating 122b disposed on the inner surface <NUM>. The lubricous coating 122b may be as described above for the lubricous coating <NUM> in reference to <FIG>.

So disposed, the lubricous coating 122b may improve the lubricity (i.e. reduce the static and dynamic frictional forces) of the inner surface <NUM> compared to the uncoated inner surface <NUM>. The improved lubricity may reduce the force required to install the electrical conductor into and through the lumen <NUM>. The improved lubricity may also reduce the abrasion of the inner surface <NUM> from the movement of the electrical conductor within the lumen <NUM> as the electrical lead flexes from the movement of body tissues during use.

Thus, the silicone substrate upon which the lubricous coating <NUM> or the lubricous coating 122b is disposed may be the outer surface <NUM> of the lead body <NUM>, as shown in <FIG> or an inner surface <NUM> of the lead body <NUM>, as shown in <FIG>, respectively. Alternatively, the lubricous coating <NUM> may be disposed on the outer surface <NUM> and the lubricous coating 122b may be disposed on the inner surface <NUM> of the same lead body <NUM>.

A method for making an insertable or implantable medical device including a lubricous coating on a silicone substrate includes treating the silicone substrate with an atmospheric plasma, as described above. The atmospheric plasma is formed exclusively from a noble gas.

The medical device can be treated by moving and/or rotating the medical device through the flow, or jet, of the atmospheric plasma. One example of a device for creating the atmospheric plasma suitable for treating the silicone substrate of the medical device according to this disclosure is a PT-2000P Duradyne Plasma Treatment System from Tri-Star Technologies, El Segundo, California.

Once the silicone substrate is treated, a solution including a thermoplastic polyurethane is applied directly to the treated silicone substrate. The thermoplastic polyurethane may be any of those described above in reference to <FIG>. The solution may include at least one solvent selected from the group of dimethylformamide, dimethylacetamide tetrahydrofuran, trichloroethane, methylene chloride, cyclohexanone, cyclopentanone, dioxane, chloroform, tetrahydrofurfuryl alcohol, benzyl alcohol, n-butanol, t-butanol, phenoxyethanol, benzyl benzoate, butyl benzoate, butyl diglycol acetate, caprolactone (epsilon), dimethyl isosorbide, ethylene carbonate, ethylene glycol <NUM>-ethylhexyl ether, fatty acid methyl ester, glycerol carbonate, glycerol diacetate, glycerol triacetate, hexylene glycol, methyl oleate, propylene carbonate, propylene glycol, propylene glycol phenyl ether, sulfolane, texanol, and tributyl phosphate. The solution may consist of the thermoplastic polyurethane in solution with a solvent selected from the group consisting of dimethylformamide, dimethylacetamide tetrahydrofuran, trichloroethane, methylene chloride, cyclohexanone, cyclopentanone, dioxane, chloroform, tetrahydrofurfuryl alcohol, benzyl alcohol, n-butanol, t-butanol, phenoxyethanol, benzyl benzoate, butyl benzoate, butyl diglycol acetate, caprolactone (epsilon), dimethyl isosorbide, ethylene carbonate, ethylene glycol <NUM>-ethylhexyl ether, fatty acid methyl ester, glycerol carbonate, glycerol diacetate, glycerol triacetate, hexylene glycol, methyl oleate, propylene carbonate, propylene glycol, propylene glycol phenyl ether, sulfolane, texanol, and tributyl phosphate and combinations thereof.

The solution may be applied by spraying the solution onto the silicone substrate. The solution may be applied by sponging the solution onto the silicone substrate. The solution may be applied by spinning the solution onto the silicone substrate. The solution may be applied by dipping the silicone surface into the solution.

The solution may be applied at room temperature, or at an elevated temperature to enhance processing for more viscous solutions having higher concentrations of thermoplastic polyurethane and/or thermoplastic polyurethanes of high molecular weight. The elevated temperature may be as low as <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, or as high as <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, or be within any range defined between any two of the foregoing values, such as <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, or <NUM> to <NUM>, for example.

It has been found that a time delay between the plasma treatment of the silicone substrate and the subsequent application of the solution to the silicone substrate does not result in a significant reduction in the adhesion of the lubricious coating to the silicone substrate for delays as great as <NUM> hours.

Once the solution has been applied to the silicone surface, the silicone substrate with the applied solution may be exposed to air at room temperature to allow the one or more solvents to evaporate, thus forming the lubricious coating. However, it has been found that while exposure to room-temperature air evaporates the one or more solvents, it may result in an inconsistent coating should the solution pool and settle along the silicone substrate. Alternatively, or additionally, the silicone substrate with the applied solution may be heated to drive off the one or more solvents more quickly, forming a more consistent lubricious coating. The heating can be by baking in an oven, heating with a heat gun, and/or by exposure to infrared radiation. Heating in an oven can include by natural convection and/or forced convection. The heating may be in air or an inert atmosphere.

The silicone substrate with the applied solution may be heated to a temperature as low as <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, or to a temperature as high as about <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, or to a temperature within any range defined between any two of the foregoing values, such as <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM> or <NUM> to <NUM>, for example.

Although the method described above provides the lubricious coating from a single application of the solution to the silicone substrate, it is understood that the process steps of applying the solution and heating the solution may be repeated to obtain a thicker lubricous coating.

As used herein, the phrase "within any range defined between any two of the foregoing values" literally means that any range may be selected from any two of the values listed prior to such phrase regardless of whether the values are in the lower part of the listing or in the higher part of the listing. For example, a pair of values may be selected from two lower values, two higher values, or a lower value and a higher value.

In this Example, the manufacture of a lubricous silicone polycarbonate polyurethane coating on a silicone substrate as described above is demonstrated. A silicone polycarbonate polyurethane, CarboSil® 55D, was dissolved in dimethylformamide at <NUM> to form a solution having a concentration of <NUM> grams of silicone polycarbonate polyurethane per milliliter of dimethylformamide. The solution was cooled to room temperature. A silicone substrate was treated for <NUM> seconds with an atmospheric plasma formed from argon gas at <NUM> watts. The plasma treatment system was a PT-2000P Duradyne Plasma Treatment System. Within about <NUM> seconds, the solution was applied the treated silicone substrate by dipping the silicone substrate into the solution and then removing the silicone substrate from the solution. The silicone substrate with the applied solution was baked in an oven at <NUM> for <NUM> minutes in ambient air to form the lubricous silicone polycarbonate polyurethane coating on the silicone substrate.

In this Example, the manufacture of another lubricous silicone polycarbonate polyurethane coating on a silicone substrate as described above is demonstrated. A silicone polycarbonate polyurethane, CarboSil® 55D, was dissolved in dimethylformamide at <NUM> to form a solution having a concentration of <NUM> grams of silicone polycarbonate polyurethane per milliliter of dimethylformamide. The solution was cooled to room temperature. A silicone substrate was treated for <NUM> seconds with an atmospheric plasma formed from argon gas at <NUM> watts. The plasma treatment system was a PT-2000P Duradyne Plasma Treatment System. Within about <NUM> seconds, the solution was applied the treated silicone substrate by dipping the silicone substrate into the solution and then removing the silicone substrate from the solution. The solution was at room temperature. The silicone substrate with the applied solution was baked in an oven at <NUM> for <NUM> minutes in ambient air to form the lubricous silicone polycarbonate polyurethane coating on the silicone substrate.

In this Example, the manufacture of a lubricous silicone polycarbonate polyurethane coating on a silicone substrate as described above is demonstrated. Another silicone polycarbonate polyurethane, ChronoSil AL® 5D, was dissolved in dimethylformamide at room temperature to form a solution having a concentration of <NUM> grams of silicone polycarbonate polyurethane per milliliter of dimethylformamide. A silicone substrate was treated for <NUM> seconds with an atmospheric plasma formed from argon gas at <NUM> watts. The plasma treatment system was a PT-2000P Duradyne Plasma Treatment System. Within about <NUM> seconds, the solution was applied the treated silicone substrate by dipping the silicone substrate into the solution and then removing the silicone substrate from the solution. The solution was at room temperature. The silicone substrate with the applied solution was baked in an oven at <NUM> for <NUM> minutes in ambient air to form the lubricous silicone polycarbonate polyurethane coating on the silicone substrate.

In this Example, the manufacture of a lubricous silicone polycarbonate polyurethane coating on a silicone substrate as described above is demonstrated. A silicone substrate was treated for <NUM> seconds with an atmospheric plasma formed from argon gas at <NUM> watts. The plasma treatment system was a PT-2000P Duradyne Plasma Treatment System. Within about <NUM> seconds, the solution of Example <NUM> was applied the treated silicone substrate by dipping the silicone substrate into the solution and then removing the silicone substrate from the solution. The solution was at room temperature. The silicone substrate with the applied solution was baked in an oven at <NUM> for <NUM> minutes in ambient air. Following the bake, the coated silicone substrate was again dipped into the room temperature solution and then removed from the solution. The silicone substrate was again baked in an oven at <NUM> for <NUM> minutes in ambient air to form the lubricous silicone polycarbonate polyurethane coating on the silicone substrate.

In this Example, the manufacture of a lubricous polycarbonate polyurethane coating on a silicone substrate as described above is demonstrated. A polycarbonate polyurethane, ChronoFlex® C 55D, was dissolved in dimethylacetamide at room temperature to form a solution having a concentration of <NUM> grams of silicone polycarbonate polyurethane per milliliter of dimethylacetamide. A silicone substrate was treated for <NUM> seconds with an atmospheric plasma formed from argon gas at <NUM> watts. The plasma treatment system was a PT-2000P Duradyne Plasma Treatment System. Within about <NUM> seconds, the solution was applied the treated silicone substrate by dipping the silicone substrate into the solution and then removing the silicone substrate from the solution. The solution was at room temperature. The silicone substrate with the applied solution was baked in an oven at <NUM> for <NUM> minutes in ambient air to form the lubricous polycarbonate polyurethane coating on the silicone substrate.

In this Example, the manufacture of a lubricous polycarbonate polyurethane coating on a silicone substrate as described above is demonstrated. A silicone substrate was treated for <NUM> seconds with an atmospheric plasma formed from argon gas at <NUM> watts. The plasma treatment system was a PT-2000P Duradyne Plasma Treatment System. Within about <NUM> seconds, the solution of Example <NUM> was applied the treated silicone substrate by dipping the silicone substrate into the solution and then removing the silicone substrate from the solution. The solution was at room temperature. The silicone substrate with the applied solution was baked in an oven at <NUM> for <NUM> minutes in ambient air. Following the bake, the coated silicone substrate was again dipped into the solution at room temperature and then removed from the solution. The silicone substrate was again baked in an oven at <NUM> for <NUM> minutes in ambient air to form the lubricous polycarbonate polyurethane coating on the silicone substrate.

In this Example, the manufacture of a lubricous polycarbonate polyurethane coating on a silicone substrate as described above is demonstrated. A silicone substrate was treated for <NUM> seconds with an atmospheric plasma formed from argon gas at <NUM> watts. The plasma treatment system was a PT-2000P Duradyne Plasma Treatment System. Within about <NUM> seconds, the solution was applied the treated silicone substrate by dipping the silicone substrate into the solution of Example <NUM> and then removing the silicone substrate from the solution. The solution was at <NUM>. The silicone substrate with the applied solution was baked in an oven at <NUM> for <NUM> minutes in ambient air to form the lubricous polycarbonate polyurethane coating on the silicone substrate.

Substrates from each of the Examples described above were evaluated on a sled style friction tester to compare reductions in dynamic and static friction relative to an uncoated silicone substrate. The tester was a Hanatek Advanced Friction Tester. <FIG> illustrates the relative static and dynamic friction force of the substrates when pulled over a polytetrafluoroethylene (PTFE) surface. <FIG> illustrates the relative static and dynamic friction force of the substrates when pulled over a stainless-steel surface. As shown in <FIG>, the silicone substrates with lubricous coatings according to this disclosure had an <NUM>% to <NUM>% reduction in the dynamic friction force and a <NUM>% to <NUM>% reduction in the static friction force when pulled over the PTFE surface compared to the uncoated silicone substrate (control). Similarly, as shown in <FIG>, the silicone substrates with lubricous coatings according to this disclosure had a <NUM>% to <NUM>% reduction in the dynamic friction force and a <NUM>% to <NUM>% reduction in the static friction force when pulled over the stainless-steel surface compared to the uncoated silicone substrate (control).

Claim 1:
A method for making an insertable or implantable medical device including a lubricous coating on a silicone substrate, the method comprising:
treating the silicone substrate with an atmospheric plasma at about atmospheric pressure, wherein the atmospheric plasma is formed exclusively from a noble gas;
applying a solution directly to the treated silicone substrate, the solution including a thermoplastic polyurethane; and
heating the silicone substrate and the applied solution to form the lubricous coating on the silicone substrate.