News Column

Researchers Submit Patent Application, "Nanoparticle Implantation in Medical Devices", for Approval

June 5, 2014



By a News Reporter-Staff News Editor at Politics & Government Week -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventors Larsen, Steven R. (Lino Lakes, MN); Petersen, Eric (Maple Grove, MN); Schewe, Scott R. (Eden Prairie, MN), filed on November 12, 2013, was made available online on May 22, 2014.

The patent's assignee is Boston Scientific Scimed, Inc.

News editors obtained the following quote from the background information supplied by the inventors: "Dilatation catheters are devices that have an inflatable balloon at the distal end and are utilized in medical procedures such as angioplasty to eliminate stenoses or blockages. The balloons are inserted into vessels in the body to open stenoses or blockages in the vascular system, usually by means of a catheter having a balloon at its distal end. To this end, the catheters may be inserted into a blood vessel, advanced through the blood vessel to a target site (i.e. the location of the stenosis or blockage) and the balloon is then inflated by supplying a liquid such as a radiopaque substance for angiography, through an inflation lumen. The inflation of the balloon causes stretching and expansion of the target site, i.e. a blood vessel, in order to eliminate the stenosis or blockage, thereby reestablishing acceptable blood flow. There are various types of catheters having single or multiple lumens, some of which are over-the-wire and some of which are not.

"Dilatation balloons are typically made of polymeric materials including nylon, polyether-polyester block copolymers, poly(amide-ether-ester) block copolymers, polyethylene terephthalate, polytetrafluoroethylene, polyvinyl chloride, polyurethanes, polyetherurethanes, polyesterurethanes, polyurethane ureas, polyurethane siloxane block copolymers, polyethylene, polypropylene or other similar extrudable thermoplastic, polymeric materials, or composites thereof. Polymeric films, however, can be damaged by abrasion and can puncture during use, especially when in the presence of calcified lesions. Polymeric balloon catheters can also be compromised during manufacturing. For example, pinholes can be formed during stent crimping.

"Some balloon catheters are designed to supply a moderate amount of heat to a target site. Thermal energy is capable of denaturing the tissue and modulating the collagenous molecules in such a way that treated tissue becomes more resilient. Thermal energy can be supplied to a target site using a radiofrequency ablation catheter. Radiofrequency energy, when coupled with a temperature control mechanism, can be supplied precisely to the electrode-to-tissue contact site to obtain the desired temperature for treating a tissue. Radiofrequency ablation catheters, however, require a permeable membrane to conduct electrons from the coil in the center of the balloon through the thickness of the membrane and into the tissue. The holes in the membrane need to be small enough to ensure that the balloon does not burst, but still large enough to conduct. Some designs use layered structures having an inner permeable layer and an outer dielectric coating, leaving windows to act as electrodes.

"Other medical devices include medical implants. In some cases, certain medical implants can be made of polymers or other materials having certain desired bulk material properties. Certain implant materials, however, can be prone to an inflammatory response and/or bacterial growth, which can cause clotting or other undesirable clinical outcomes. For example, medical implants can include heart valves, occlusions (e.g., left atrial appendage occlusions), vaginal meshes, stents, and stent grafts."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "This document describes nanoparticle implantation techniques for forming medical devices. In general, the methods provided herein include accelerating nanoparticles and embedding the particles into the surface of a medical device or a precursor thereof. The nanoparticles can be embedded until the nanoparticles accumulate in sufficient number to accumulate and adhere together at the surface. A coating formed on a surface can have a thickness such that the bulk properties of the underlying material do not significantly change. In some case, the nanoparticles can include metal and can be used to metallize a surface.

"The plurality of nanoparticles, in some cases, can be accelerated to supersonic speeds. The plurality of nanoparticles can have enough momentum to embed in the material of the surface of the medical device. In some cases, the plurality of nanoparticles are accelerated to a speed of between 100 m/s and 1,000 m/s. A resulting coating can have a significantly higher adhesion that other coating methods For example, a coating can have a thickness of less than 1000 nm. In some cases, the nanoparticles are not positively or negatively charged during implantation. In some case, the nanoparticles have a temperature of less than 100.degree. C. during implantation.

"The surface of the medical device can include a polymer. In some cases, the polymer can include nylon, Selar.RTM., polyether-polyester block copolymers (e.g. Hytrel.RTM. or Amitel.RTM.), poly(amide-ether-ester) block copolymers such as Pebax.RTM., polyethylene terephthalate (PET), polytetrafluoroethylene, polyvinyl chloride, polyurethanes, polyetherurethanes, polyesterurethanes, polyurethane ureas, polyurethane siloxane block copolymers, polyethylene, polypropylene or other similar extrudable thermoplastic, polymeric materials, or composites thereof.

"The nanoparticles can have diameters of 1000 nm or less. In some cases, the nanoparticles have diameters of between 10 nm and 500 nm.

"The nanoparticles can include a variety of different materials. In some cases, the nanoparticles include a metal. The metal nanoparticles can be used to metallize a surface (e.g., a polymer surface). Suitable metals include platinum, iridium, titanium, tungsten, chromium, gold, silver, iron, magnesium, and alloys or other combinations thereof.

"In some cases, the nanoparticles comprise a metal oxide, a metal nitride, a nitrate, an iodide, carbon nanotubes, or a combination thereof.

"The medical device can be a device that is introduced into the body. In some cases, the medical device includes a dilatation balloon. In some cases, the dilatation balloon is a radiofrequency ablation balloon. For example, the methods provided herein can include forming one or more holes in a dilatation balloon and embedding the plurality of nanoparticles into one or more surfaces of the one or more holes in order to form a conductive pathway through the dilatation balloon and allow the dilatation balloon to be used as a radiofrequency ablation balloon. In some cases, the holes are filled thereafter.

"In some cases, the medical device is a medical implant. For example, the medical implant can be a heart valve, a left atrial appendage occlusion device, a vaginal mesh, a stent, a graft, or a stent graft.

"In some cases, the methods provided herein may provide a robust adhesion between a polymer and a metallized surface. For example, the embedded nanoparticles can accumulate in the material under the surface of a polymer medical device until the nanoparticles begin to impact other embedded nanoparticles with such momentum that the nanoparticles start to merge at the surface and form a metal layer. A mixture of polymer and metal under the surface metal layer are intermixed to form a strong connection. In some cases, the metal surface is flexible such that it does not alter the bulk mechanical properties of the polymer. The metal surface can provide an abrasion and/or puncture resistant layer, a pro-healing surface, and/or an anti-bacterial surface.

"In some aspects, a method provided herein includes preparing a dilatation balloon by accelerating a plurality of nanoparticles to a speed of between 100 m/s and 1,000 m/s and embedding the accelerated nanoparticles into a polymer balloon wall to form a network of fused nanoparticles. The network of fused nanoparticles can form a conductive pathway between an inside surface of the polymer balloon wall and an outside surface of the polymer balloon wall. The method can include forming one or more holes in the polymer balloon wall and embedding the plurality of nanoparticles into at least one or more surfaces of the one or more holes to form the conductive pathway between the inside surface of the polymer balloon wall and the outside surface of the polymer balloon wall. In some cases, the method provided herein can include forming one or more holes in the polymer balloon wall and embedding the plurality of nanoparticles into at least one or more surfaces of the one or more holes and filling the hole with a material. The network of fused nanoparticles or the material filling the hole can form a conductive pathway through the thickness of the dilatation balloon. The nanoparticles can include a metal. The network of fused nanoparticles can form a continuous coating of fused nanoparticles over an outer surface of the polymer balloon wall.

"In some aspects, a method provided herein includes forming a coating on a polymer surface by accelerating a plurality of nanoparticles to a speed of between 100 m/s and 1,000 m/s and embedding the accelerated nanoparticles into a polymer surface of a heart valve, a left atrial appendage occlusion device, a vaginal mesh, or a precursor thereof. The nanoparticles can be embedded until the embedded nanoparticles fuse together and a continuous coating of fused nanoparticles is formed over the polymer surface of the medical implant. The network of fused nanoparticles can form a conductive pathway on the polymer surface.

"In some aspects, a method provided herein includes accelerating a plurality of nanoparticles including an anti-bacterial agent to a speed of between 100 m/s and 1,000 m/s and embedding the accelerated nanoparticles into a polymer surface of a heart valve, a left atrial appendage occlusion device, a vaginal mesh, or a precursor thereof. The anti-bacterial agent can include silver or a silver salt.

"The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

"FIG. 1A-1B is a schematic illustrating a supersonic cluster beam deposition process.

"FIG. 2A-2D illustrates structures that can result from a supersonic cluster beam deposition.

"FIG. 3 is a schematic view of a of a dilatation balloon catheter.

"FIG. 4 is an illustration of how nanoparticles can become embedded in a surface using methods provided herein.

"FIG. 5 is an illustration of how a conductive path can be formed though the thickness of a dilatation balloon using a method provided herein.

"FIG. 6 is a perspective view of a left atrial appendage occlusion device.

"FIG. 7 is a perspective view of a heart valve.

"FIG. 8 is a perspective view of a vaginal mesh.

"Like reference symbols in the various drawings indicate like elements."

For additional information on this patent application, see: Larsen, Steven R.; Petersen, Eric; Schewe, Scott R. Nanoparticle Implantation in Medical Devices. Filed November 12, 2013 and posted May 22, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=2982&p=60&f=G&l=50&d=PG01&S1=20140515.PD.&OS=PD/20140515&RS=PD/20140515

Keywords for this news article include: Alkenes, Polyenes, Hydrocarbons, Nanoparticle, Polyethylenes, Nanotechnology, Organic Chemicals, Emerging Technologies, Boston Scientific Scimed Inc..

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Source: Politics & Government Week


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