Coating processes – Direct application of electrical – magnetic – wave – or... – Polymerization of coating utilizing direct application of...
Reexamination Certificate
2002-11-26
2003-09-09
Pianalto, Bernard (Department: 1762)
Coating processes
Direct application of electrical, magnetic, wave, or...
Polymerization of coating utilizing direct application of...
C427S164000, C427S331000, C427S333000, C427S385500, C427S407100
Reexamination Certificate
active
06616982
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is generally in the area of the fabrication of poly(ethylene oxide) (“PEO”) coatings on surfaces.
PEO is a polymer which has many unique properties. It is soluble in a wide variety of solvents including water, benzene and tetrahydrofuran. In organic solvents, it solvates the monovalent metal ions, Li
+
, K
+
and Na
+
. PEO is unusual in its lack of interaction with biological matter and can provide an inert surface in certain biological applications. • Merrill, E. W.,
J. Biomat. Sci. Polymer Edn
., 5:1-11 (1993). PEO is an important biomaterial because it is non-thrombogenic, i.e., it does not adsorb proteins of the intrinsic clotting system, and platelets do not adhere to it.
PEO star-shaped macromolecules are available which have many PEO chains or “arms” connected to a central body which is called the core. PEO star macromolecules can be synthesized, for example, by a living anionic polymerization using a divinylbenzene (DVB) core. • Gnanou et al.,
Makromol. Chemie
, 189:2885-2892 (1988); and Merrill,
J. Biomater. Sci. Polymer Edn
., 5:1-11 (1993).
There has been recent interest focused on the development of methods for coating surfaces with PEO. A PEO surface coating is very useful in blood-contacting devices, such as tubes and catheters, and products intended for diagnostic use, because such surfaces have the least non-specific binding to proteins and other biopolymers of any known synthetic polymer. Thus, the use of PEO coatings permits blood clotting to be minimized, and diagnostic assays to be improved.
A major problem has been the development of a thin, dense layers of PEO to cover support materials such as hard plastics, such as polyethylene terephthalate (“PETE”) or flexible materials, such as silicone rubber and segmented polyurethane.
U.S. Pat. Nos. 5,171,264 and 5,275,838 to Merrill disclose that a water solution of PEO, either linear or in star form, can be cross-linked by electron irradiation to form a hydrogel layer. The hydrogel has a thickness ranging down to about 0.5 mm, which is not strongly attached to the supporting material and rather easily sheared off. Upon attachment of affinity ligands to the hydrogels, the surfaces can be used for separating and purifying therapeutic proteins.
Alternatively, PEO polymers can be attached to surfaces by hydroxyl group activation followed by chemical coupling. The terminal hydroxyl groups of the PEO molecule can chemically activated, for example, by tresyl chloride, and then attached to a surface which contains appropriate reactive groups, e.g., amino or thiol. U.S. Pat. Nos. 5,171,264 and 5,275,838 to Merrill. There are, however, problems associated with this route. It is difficult to prepare stable surfaces having amino or thiol groups, and some procedures result in degradation of the surface to the extent that it can be readily washed off, thus providing no anchor for the PEO. Additionally, it is very difficult to implant linear PEO molecules on surfaces via this route with sufficient density to prevent the adsorption of biopolymers.
There is a need for methods for improving the hydrophilicity of hydrophobic polymer surfaces, while still maintaining the physical properties of the hydrophobic polymers. There is further a need for the development of methods for forming biocompatible coatings on surfaces. There further is a need for methods for producing hydrophilic coatings on surfaces to improve the biocompatibility of the surfaces, wherein the coatings can be readily derivatized by the attachment of biological molecules to the coating.
It is therefore an object of the invention to provide methods for the production of hydrophilic coatings on hydrophobic polymers. It is a further object of the invention to provide hydrophilic coatings on surfaces, such as PEO coatings, which reduce non-specific binding to the surfaces. It is still another object of the invention to provide methods for fabricating coatings on surfaces which can be readily derivatized by the attachment of biological molecules for use in a variety of biomedical applications.
SUMMARY OF THE INVENTION
Methods are provided for the fabrication of hydrophilic coatings on hydrophobic surfaces. In one embodiment, a poly(ethylene oxide) (“PEO”) coating is fabricated on the surface of a hydrophobic polymeric material by contacting the surface with a monomer comprising an unsaturated group, such as methacrylic acid or acrylic acid. The monomer then is reacted, for example by irradiation with an electron beam, to polymerize and, as a polymer, to be covalently attached to the surface. A coating of PEO molecules then may be attached to the polymer surface by hydrogen bond complexation. The PEO coating optionally may be covalently grafted onto the surface, for example, by irradiation grafting with an electron beam. The covalent polymerization and grafting of a coating of the monomers to the surface greatly improves the wettability of the surface, and also facilitates the covalent or non-covalent attachment of a coating of PEO to the hydrophobic polymer surface. Thus, hydrophilic PEO coatings can be fabricated on hydrophobic polymer surfaces, to improve the biocompatibility and other properties of the polymers, and to provide coated polymers which can be used in a variety of different applications.
REFERENCES:
patent: 4487808 (1984-12-01), Lambert
patent: 5171264 (1992-12-01), Merrill
patent: 5275838 (1994-01-01), Merrill
patent: 5276110 (1994-01-01), Zhou et al.
patent: 5290548 (1994-03-01), Goldberg et al.
patent: 5308428 (1994-05-01), Simpson et al.
patent: 5401327 (1995-03-01), Ellis et al.
patent: 5509899 (1996-04-01), Fan et al.
patent: WO 91/12886 (1991-09-01), None
patent: WO 95/18840 (1995-07-01), None
patent: WO 96/09086 (1996-03-01), None
Bayer & Stadler, “Synthesis and properties of ampiphili ‘dumbell’-shaped grafted block copolymers, 1,”Macromol. Chem. Phys.195: 2709-2722 (1994). (No month avail.).
Encyclopedia of Polymer Science and Engineering,Supp. vol., pp. 647-689. (No date avail.).
Gnanou, et al., “Synthesis of star-shaped poly(ethylene oxide),”Makromol. Chemie.189: 2885-2892 (1988). (No month avail.).
Harris, et al., “Laboratory synthesis of polyethylene glycol derivatives,”J. Macromol. Sci. Rev. Macro. Chem. Phys.C25(3): 325-373 (1985). ( No month avail.).
Merrill, “Poly(ethylene oxide) star molecules: synthesis, characterization, and applications in medicine and biology,”J. Biomat. Sci. Polymer Edn5: 1-11 (1993). (No month avail.).
Merrill, et al., “Transformation of polymer surfaces by covalent grafting of poly(ethylene oxide) star molecules for biomedical applications,”Mit. Chem. Eng.,1-2. (No date avail.).
Streutwiesser & Heathcock,Introduction to Organic Chemistry,2nded., 1981. (No month avail.).
Teyssic & Jerome, “Naphthalene chemistry: II. A novel route for the synthesis of well defined star block copolymers displaying an A(B) architecture from hydrocarbon monomers (A) and ethylene oxide (B),”Polymer Preprints,20(2): 344-348 (1979). (No month avail.).
Zhou & Roovers, “Synthesis of novel carbosilane dendritic macromolecules,”Macromolecules26: 963-968 (1993). (No month avail).
Allgor Susan S.
Leung Gladys C.
Merrill Edward W.
Holland & Knight LLP
Massachusetts Institute of Technology
Pianalto Bernard
LandOfFree
Poly(ethylene oxide) coated surfaces does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Poly(ethylene oxide) coated surfaces, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Poly(ethylene oxide) coated surfaces will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3069449