Biocompatible coatings

In a different way, metallic-core nanoparticles [346-349] (prepared cf. Section 3.10) equipped with biocompatible coats such as L-cysteine or dextrane may be exploited for highly efficient and cell-specific cancer cell targeting, i.e., for improving diagnosis and therapy of human cancer. In a recent proof-of-principle experiment an unexpectedly low toxicity of the L-cysteine-covered cobalt nanoparticles was demonstrated [433] For diagnostic purposes, it is expected to use the advantageous magnetic properties of the metallic-core nanoparticles to obtain a contrast medium for MRI with considerably increased sensitivity, capable to detect micro-metastases in the environment of healthy tissues [434 37]. 

Brynda E, Houska M (2000) Ordered multilayer assemblies albumin/heparin for biocompatible coating and monoclonal antibodies for optical immunosensors. In Lvov Y, Mohwald H (ed) Protein architecture interfacial molecular assembly and immobilization biotechnology. Dekker, New York... 

Muller [2] prepared hydrogels that were used in contact lenses with difunctional sUiconecontaining crosslinkers, (11), with amphiphilic block prepolymers. Tetrafunctional crosslinkers, (111), prepared by Lewis [3] were used as biocompatible coating applications. 

Current research and development efforts have focused on the use of more biocompatible coatings to reduce the biological response of both intravascular and subcutaneous devices. These efforts are based on the expectation that such developments wfllbe critical to the ultimate success in developing implanted sensors that yield continuous analytical results that match closely with conventional in vitro test methods. One new approach in this direction employs novel nitric oxide (NO) release polymers to coat the surface of intravascular sensors.The potent antiplatelet activity of NO has been shown to greatly reduce the formation of thrombus on the surface of implantable electrochemical oxygen sensing catheters, and yield much more accurate continuous PO2 values in animal experiments. 

A variant of CVD, termed plasma polymerization, has been used to produce polymer coatings. So far, it has been used in a limited number of applications most notably to produce biocompatible coatings for electronic sensors that are implanted in humans. This process is also being investigated for polymer coating applications. As the name implies, an RF generator is used to induce a plasma environment into which the monomer components are introduced. The electrons from the plasma induce the polymerization reaction at the surface of the substrate. The power input to the plasma must be kept low to prevent secondary reactions from destroying the polymer structure. 

Polyethylene glycol (PEG) and the very similar polyethylene oxide (PEO) are used as biocompatible coating agents and hydrogel forming materials, often as block or graft copolymers with other materials (Eig. IF). They are often bound to polyurethanes to form hydrophilic foams such as Biopol (Metabolix Inc.). 

Polyacrylamides are also suitable for a variety of biomedical uses the structure of polyacrylamide is shown in Fig. IG, although the use of acrylamides in copolymers is much more common. Polyvinylpyrrolidinone has also found use as a biocompatible coating material (Fig. IH). Polyacrylonitrile, though not suitable in itself, can be hydrolyzed to form some hydrophilic polymers such as the Hypan (Hymedix Inc.) series of hydrogels. 

Polymer-based heart valves are widely used as replacements for diseased or damaged human heart valves. Most mechanical heart valves are made from metals, silicone, or polyesters, although some work has gone into incorporating biocompatible coatings such as PEO into these systems. 

Planar supported lipid membranes were first prepared and studied as simplified structural models of cell membranes [4,6, 32], and more recently as biocompatible coatings for sensor transducers and other synthetic materials [33-37], A major advantage of the planar geometry relative to vesicles, and a major contributor to the expansion of this field, is the availability of powerful surface-sensitive analyti-cal/physical techniques. Confining a lipid membrane to the near-surface region of a solid substrate makes it possible to study its structural and functional properties in detail using a variety of techniques such as surface plasmon resonance, AFM, TIRF, attenuated total reflection, and sum frequency vibrational spectroscopy [38 -2]. 

Lu H, Qu Z, Zhou YC (1998) Preparation and mechanical properties of dense polycrystalline hydroxylapatite through freeze-drying. J Mater Sci Mater in Med 9 583-587 Lugscheider E, Weber Th, Knepper M (1991a) Production of biocompatible coatings by atmospheric plasma spraying. Mater Sci Eng 139A 45-48... 

IPECs are of considerable interest because of their numerous promising (potential) applications in agriculture, water treatment, biotechnology, and medicine. Some examples include effective and available binders for dispersed systems and flocculants of colloidal dispersions [2], biocompatible coatings [3, 4], components of membranes [5-11], carriers of biologically active compounds (including enzymes and DNA) [12-16], matrices for metal ions and metal nanoparticles [17-22], and the formation of multilayered PE films and capsules using layer-by-layer techniques [23-32]. 

Uses Dispersant, emulsifier for latex polymerization, wastewater treatment foamable hydrophilic prepolymer for wound dressings, biocompatible coatings, drug delivery vehicles absorbent foam, carrier food-contact PU, rubber articles ManufJDistrib. Air Prods. Bayer CasChem Conap Hampshire Huntsman Polyurethanes Monomer-Polymer Dajac Labs NeoResins Noveon Polyurethane Corp. of Am. Polyurethane Spec. Soluol Uniroyal... 

As a biocompatible coating [16], parylene C has recently been explored as a stmctural and packaging material for miniaturized biomedical devices. Parylene protects the sensors and serves as electrical isolation. In order to... 

Bychkova, A. V Sorokina, O. N. Rosenfeld, M. A. Kovarski, A. L. Multifunctional biocompatible coatings on magnetic nanoparticles. Uspekhi Khimii (Russian Journal), in press (2012). 

Mullett WM and Pawlisyzn J (2003) The development of selective and biocompatible coating for solid-phase microextraction. Journal of Separation Science 26 251-260. 

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