Medical device applications of nanostructured surfaces

Abstract

This invention provides novel nanofiber enhanced surface area substrates and structures comprising such substrates for use in various medical devices, as well as methods and uses for such substrates and medical devices. In one particular embodiment, methods for enhancing cellular functions on a surface of a medical device implant are disclosed which generally comprise providing a medical device implant comprising a plurality of nanofibers (e.g., nanowires) thereon and exposing the medical device implant to cells such as osteoblasts.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation-in-part application of U.S. patent Application Ser. No. 10 / 902,700 filed Jul. 29, 2004, which claims priority to U.S. Provisional Patent Application Ser. No. 60 / 549,711, filed Mar. 2, 2004. This application also claims priority as a continuation-in-part application of U.S. patent application Ser. No. 10 / 828,100, filed Apr. 19, 2004, which is a continuation-in-part of U.S. patent application Ser. No. 10 / 661,381, filed Sep. 12, 2003, which claims priority to U.S. Provisional Patent Application No. 60 / 463,766, filed Apr. 17, 2003; and as a continuation-in-part of U.S. patent application Ser. No. 10 / 833,944, filed Apr. 27, 2004, which claims priority to U.S. Provisional Application Ser. No. 60 / 466,229, filed Apr. 28, 2003; and as a continuation-in-part application of U.S. patent application Ser. No. 10 / 840,794 filed May 5, 2004, which is a continuation-in-part of U.S. patent application Ser. No. 10 / 792,402...

AI Technical Summary

Benefits of technology

[0006] The embodiments of the current invention comprise various medical devices, such as clamps, valves, intracorporeal or extracorporeal devices (e.g., catheters), temporary or permanent implants, stents, vascular grafts, anastomotic devices, aneurysm repair devices, embolic devices, and implantable devices (e.g., orthopedic implants) and the like which comprise nanofiber enhanced surfaces. Such enhanced surfaces provide many enhanced attributes to the medical devices in, on, or within which they are used including, e.g., to prevent / reduce bio-fouling, increase fluid flow due to hydrophobicity, increase adhesion, biointegration, etc.

[0007] In a first aspect of the invention, a medical device is disclosed comprising a body structure having one or more surfaces having a plurality of nanostructured components associated therewith. The medical device may comprise an intracorporeal or extracorporeal device, a temporary or permanent implant, a stent, a vascular graft, an anastomotic device, an aneurysm repair device, an embolic device, an implantable device, a catheter, valve or other device which would benefit from a nanostructured surface according to the teachings of the present invention. The plurality of nanostructured components may comprise, for example, a plurality of nanofibers or nanowires. The plurality of nanostructured components enhance one or more of adhesion, non-adhesion, friction, patency or biointegration of the device with one or more tissue surfaces of a body of a patient depending on the particular application of the device. The nanofibers (or other nanostructured components) on the surfaces of the medical device can optionally be embedded in a slowly-soluble biocompatible polymer (or other) matrix to make the nanofiber surfaces more robust. The polymer matrix can protect most of the length of each nanofiber, leaving only the ends susceptible to damage. The generation of water soluble polymers can be accomplished in a number of different ways. For example, polymer chains can be formed in situ in a dilute aqueous solution primarily consisting of a monomer and an oxidizing agent. In this case, the polymer is actually created in the solution and subsequently spontaneously adsorbed onto the nanofiber surfaces as a uniform, ultra-thin film of between approximately 10 to greater than 250 angstroms in thickness, more preferably between 10 and 100 angstroms.

[0014] In another embodiment of the invention, a bioengineered scaffold device for providing a scaffold for nerve regeneration is disclosed which comprises a base membrane or matrix having a plurality of nanostructured components associated therewith. The membrane or matrix may be made from one or more of the following materials: natural or synthetic polymers, electrically conducting polymers, metals, alloys, ceramics, glass fabrics, or silicone. The plurality of nanostructured components may comprise, for example, a plurality of nanofibers or nanowires. The nanostructured surface of the membrane or matrix may be impregnated or bound with one or more drugs, cells, fibroblasts, nerve growth factors (NGF), cell seeding compounds, neurotrophic growth factors or genetically engineered cells producing such factors, VEGF, laminin or other drugs or substances to encourage axonal elongation and functional nerve performance.

[0019] Methods of use are also disclosed for treating patients with any one or more of the medical devices disclosed herein, which include, for example, a method of therapeutically treating a patient comprising contacting the patient with a medical device comprising a surface and plurality of nanofibers associated with the surface. Methods are disclosed for administering a drug compound to a body of a patient which comprises, for example, providing a drug-eluting device comprising at least one surface, a plurality of nanofibers associated with the surface, and a drug compound associated with the plurality of nanofibers; introducing the drug-eluting device into a body of a patient; and delivering the drug compound into the body of the patient. The drug-eluting device in one embodiment comprises a coronary stent, although any device which would benefit from local drug delivery at the site of disease (e.g., lesion) could be used in the methods of the invention. Where a coronary stent is used as the drug-eluting device, the drug compound may comprise paclitaxel or sirolimus, for example, or a variety of other medications including without limitation one or more of the following: anti-inflammatory immunomodulators such as Dexamethasone, M-prednisolone, Interferon, Leflunomide, Tacrolimus, Mizoribine, statins, Cyclosporine, Tranilast, and Biorest; antiproliferative compounds such as Taxol, Methotrexate, Actinomycin, Angiopeptin, Vincristine, Mitomycin, RestenASE, and PCNA ribozyme; migration inhibitors such as Batimastat, Prolyl hydroxylase inhibitors, Halofuginone, C-proteinase inhibitors, and Probucol; and compounds which promote healing and re-endothelialization such as VEGF, Estradiols, antibodies, NO donors, and BCP671. The drug compound may be adsorbed directly to the nanofiber surface of the drug-eluting device or otherwise associated with it via the use of one or more silane groups, linker molecules or other covalent, ionic, van der waals etc. attachment means. The nanofiber surface may be configured such that the drug compound elutes slowly over time. The plurality of nanofibers optionally are embedded in a biocompatible, non-thrombogenic polymer coating to provide enhanced durability to the nanofibers.

Problems solved by technology

The polymer matrix can protect most of the length of each nanofiber, leaving only the ends susceptible to damage.

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