Heparin-coated poly

To make nanoparticles able to escape complement activation, Passirani et alJ" proposed to coat nanospheres with heparin. This compound, which is a polysaccharide, is a physiological inhibitor of complement activation in vivo. Heparin-coated poly(methylmetha-crylate) nanoparticles were prepared by emulsion polymerization. In the method, the radical polymerization of methylmethacrylate was initiated by heparin according to an original method involving cerium ions and allowing heparin to covalently attach to poly(methyl-methacrylate). 

ChauvierreC,MardenMC, VauthierC (2004). Heparin coated poly (alkylcyanoacrylate) nanoparticles coupled to hemoglobin a new oxygen carrier. Biomaterials. 24 3081-3086. 

Cellulose acetate membrane [69] and cellulose fiber [70] were coated on PPy to remove gold iodide and Cr(VI), respectively. Ionic exchange was ascribe for the gold iodide removal and the reduction of Cr(VI) to Cr(III), followed by adsorption. A covalently immobilized heparin-PPy/ poly(ethylene glycol) methacrylate composite was also fabricated for biological applications to reduce the protein and thrombus formation [71]. 

Thermoresponsive Heparin Coating Heparin Conjugated with Poly(N-Isopropylacrylamide) at One Terminus, 2002,18,4862—4872. 

In practice, some anticoagulation agents such as heparin or antiplatelet agents, e.g. nitric oxide (NO) are delivered to sensor sites in order to reduce the risk of thrombus formation. Nitric oxide (NO), which is a potent inhibitor of platelet adhesion and activation as well as a promoter of wound healing in tissue, has been incorporated in various polymer metrics including PVC (poly(vinyl-chloride)), PDMS (poly-dimethyl-siloxane) and PU (poly-urethanes). Those NO release polymers have been tested in animals as outer protection coatings and have shown promising effects for the analytical response characteristics of the sensor devices [137],... 

Na K, Kim S, Park K, Kim K, Woo DG, Kwon IC, Chung HM, Park KH (2007) Heparin/poly(L-lysine) nanoparticle-coated polymeric microspheres for stem-cell therapy. J Am Chem Soc 129 5788-5789. 

This type of matrix has been evaluated with limited success. The chief drawbacks include poor control of drug release, particularly for drugs that are water-soluble, and poor biocompatibility due to matrix swelling in preclinical animal studies. Hydrogels comprising heparin (37) or poly(EO) (38,39) in the very top layer of DES coating may have local antithrombotic activity. 

PVPyrH Poly-4-vinylpyridine (PVPyr) prepared by conventional persulfate catalyzed polymerization was dissolved in ethyl alcohol or methyl Cellosolve (2 to 3% solution) for application to polyester film substances. These films adsorb heparin from solutions of sodium heparin to produce anticoagulant surfaces (PVPyrH). Films were painted on, or spread by knife coating. 

Several hydrophilic coatings were applied to PUs to increase surface hydrophilicity, including poly(ethylene glycol) (PEG), hyaluronan, dermatan sulfate, and heparin. 

Interest continues in the binding of heparin to polymers in an attempt to produce non-thrombogenic surfaces. This has been the aim in the use of glutaralde-hyde-protein complexes as coatings for latex rubber and polyurethanes. Glutaraldehyde has also been used to bind antibodies to partially hydrolysed polyamide surfaces for enzyme-linked radioassay techniques. One of the few examples of direct polymerization (as opposed to surface modification) in an attempt to produce polymers having improved compatibility involves the use of 2-methacryloyloxyethylphosphoryl choline in the formation of homopolymers and copolymers with methyl methacrylate. An isocyanato-urethane methacrylate has been synthesized from 2-hydroxyethyl methacrylate in connection with dental materials research in which the preparation of poly functional monomers for improvement of interfacial bonding with tooth tissue is a topic of some interest. 

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